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  • Building extensions for Expression Blend 4 using MEF

    - by Timmy Kokke
    Introduction Although it was possible to write extensions for Expression Blend and Expression Design, it wasn’t very easy and out of the box only one addin could be used. With Expression Blend 4 it is possible to write extensions using MEF, the Managed Extensibility Framework. Until today there’s no documentation on how to build these extensions, so look thru the code with Reflector is something you’ll have to do very often. Because Blend and Design are build using WPF searching the visual tree with Snoop and Mole belong to the tools you’ll be using a lot exploring the possibilities.  Configuring the extension project Extensions are regular .NET class libraries. To create one, load up Visual Studio 2010 and start a new project. Because Blend is build using WPF, choose a WPF User Control Library from the Windows section and give it a name and location. I named mine DemoExtension1. Because Blend looks for addins named *.extension.dll  you’ll have to tell Visual Studio to use that in the Assembly Name. To change the Assembly Name right click your project and go to Properties. On the Application tab, add .Extension to name already in the Assembly name text field. To be able to debug this extension, I prefer to set the output path on the Build tab to the extensions folder of Expression Blend. This means that everything that used to go into the Debug folder is placed in the extensions folder. Including all referenced assemblies that have the copy local property set to false. One last setting. To be able to debug your extension you could start Blend and attach the debugger by hand. I like it to be able to just hit F5. Go to the Debug tab and add the the full path to Blend.exe in the Start external program text field. Extension Class Add a new class to the project.  This class needs to be inherited from the IPackage interface. The IPackage interface can be found in the Microsoft.Expression.Extensibility namespace. To get access to this namespace add Microsoft.Expression.Extensibility.dll to your references. This file can be found in the same folder as the (Expression Blend 4 Beta) Blend.exe file. Make sure the Copy Local property is set to false in this reference. After implementing the interface the class would look something like: using Microsoft.Expression.Extensibility; namespace DemoExtension1 { public class DemoExtension1:IPackage { public void Load(IServices services) { } public void Unload() { } } } These two methods are called when your addin is loaded and unloaded. The parameter passed to the Load method, IServices services, is your main entry point into Blend. The IServices interface exposes the GetService<T> method. You will be using this method a lot. Almost every part of Blend can be accessed thru a service. For example, you can use to get to the commanding services of Blend by calling GetService<ICommandService>() or to get to the Windowing services by calling GetService<IWindowService>(). To get Blend to load the extension we have to implement MEF. (You can get up to speed on MEF on the community site or read the blog of Mr. MEF, Glenn Block.)  In the case of Blend extensions, all that needs to be done is mark the class with an Export attribute and pass it the type of IPackage. The Export attribute can be found in the System.ComponentModel.Composition namespace which is part of the .NET 4 framework. You need to add this to your references. using System.ComponentModel.Composition; using Microsoft.Expression.Extensibility;   namespace DemoExtension1 { [Export(typeof(IPackage))] public class DemoExtension1:IPackage { Blend is able to find your addin now. Adding UI The addin doesn’t do very much at this point. The WPF User Control Library came with a UserControl so lets use that in this example. I just drop a Button and a TextBlock onto the surface of the control to have something to show in the demo. To get the UserControl to work in Blend it has to be registered with the WindowService.  Call GetService<IWindowService>() on the IServices interface to get access to the windowing services. The UserControl will be used in Blend on a Palette and has to be registered to enable it. This is done by calling the RegisterPalette on the IWindowService interface and passing it an identifier, an instance of the UserControl and a caption for the palette. public void Load(IServices services) { IWindowService windowService = services.GetService<IWindowService>(); UserControl1 uc = new UserControl1(); windowService.RegisterPalette("DemoExtension", uc, "Demo Extension"); } After hitting F5 to start debugging Expression Blend will start. You should be able to find the addin in the Window menu now. Activating this window will show the “Demo Extension” palette with the UserControl, style according to the settings of Blend. Now what? Because little is publicly known about how to access different parts of Blend adding breakpoints in Debug mode and browsing thru objects using the Quick Watch feature of Visual Studio is something you have to do very often. This demo extension can be used for that purpose very easily. Add the click event handler to the button on the UserControl. Change the contructor to take the IServices interface and store this in a field. Set a breakpoint in the Button_Click method. public partial class UserControl1 : UserControl { private readonly IServices _services;   public UserControl1(IServices services) { _services = services; InitializeComponent(); }   private void button1_Click(object sender, RoutedEventArgs e) { } } Change the call to the constructor in the load method and pass it the services property. public void Load(IServices services) { IWindowService service = services.GetService<IWindowService>(); UserControl1 uc = new UserControl1(services); service.RegisterPalette("DemoExtension", uc, "Demo Extension"); } Hit F5 to compile and start Blend. Got to the window menu and start show the addin. Click on  the button to hit the breakpoint. Now place the carrot text _services text in the code window and hit Shift+F9 to show the Quick Watch window. Now start exploring and discovering where to find everything you need.  More Information The are no official resources available yet. Microsoft has released one extension for expression Blend that is very useful as a reference, the Microsoft Expression Blend® Add-in Preview for Windows® Phone. This will install a .extension.dll file in the extension folder of Blend. You can load this file with Reflector and have a peek at how Microsoft is building his addins. Conclusion I hope this gives you something to get started building extensions for Expression Blend. Until Microsoft releases the final version, which hopefully includes more information about building extensions, we’ll have to work on documenting it in the community.

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  • Wrapping ASP.NET Client Callbacks

    - by Ricardo Peres
    Client Callbacks are probably the less known (and I dare say, less loved) of all the AJAX options in ASP.NET, which also include the UpdatePanel, Page Methods and Web Services. The reason for that, I believe, is it’s relative complexity: Get a reference to a JavaScript function; Dynamically register function that calls the above reference; Have a JavaScript handler call the registered function. However, it has some the nice advantage of being self-contained, that is, doesn’t need additional files, such as web services, JavaScript libraries, etc, or static methods declared on a page, or any kind of attributes. So, here’s what I want to do: Have a DOM element which exposes a method that is executed server side, passing it a string and returning a string; Have a server-side event that handles the client-side call; Have two client-side user-supplied callback functions for handling the success and error results. I’m going to develop a custom control without user interface that does the registration of the client JavaScript method as well as a server-side event that can be hooked by some handler on a page. My markup will look like this: 1: <script type="text/javascript"> 1:  2:  3: function onCallbackSuccess(result, context) 4: { 5: } 6:  7: function onCallbackError(error, context) 8: { 9: } 10:  </script> 2: <my:CallbackControl runat="server" ID="callback" SendAllData="true" OnCallback="OnCallback"/> The control itself looks like this: 1: public class CallbackControl : Control, ICallbackEventHandler 2: { 3: #region Public constructor 4: public CallbackControl() 5: { 6: this.SendAllData = false; 7: this.Async = true; 8: } 9: #endregion 10:  11: #region Public properties and events 12: public event EventHandler<CallbackEventArgs> Callback; 13:  14: [DefaultValue(true)] 15: public Boolean Async 16: { 17: get; 18: set; 19: } 20:  21: [DefaultValue(false)] 22: public Boolean SendAllData 23: { 24: get; 25: set; 26: } 27:  28: #endregion 29:  30: #region Protected override methods 31:  32: protected override void Render(HtmlTextWriter writer) 33: { 34: writer.AddAttribute(HtmlTextWriterAttribute.Id, this.ClientID); 35: writer.RenderBeginTag(HtmlTextWriterTag.Span); 36:  37: base.Render(writer); 38:  39: writer.RenderEndTag(); 40: } 41:  42: protected override void OnInit(EventArgs e) 43: { 44: String reference = this.Page.ClientScript.GetCallbackEventReference(this, "arg", "onCallbackSuccess", "context", "onCallbackError", this.Async); 45: String script = String.Concat("\ndocument.getElementById('", this.ClientID, "').callback = function(arg, context, onCallbackSuccess, onCallbackError){", ((this.SendAllData == true) ? "__theFormPostCollection.length = 0; __theFormPostData = ''; WebForm_InitCallback(); " : String.Empty), reference, ";};\n"); 46:  47: this.Page.ClientScript.RegisterStartupScript(this.GetType(), String.Concat("callback", this.ClientID), script, true); 48:  49: base.OnInit(e); 50: } 51:  52: #endregion 53:  54: #region Protected virtual methods 55: protected virtual void OnCallback(CallbackEventArgs args) 56: { 57: EventHandler<CallbackEventArgs> handler = this.Callback; 58:  59: if (handler != null) 60: { 61: handler(this, args); 62: } 63: } 64:  65: #endregion 66:  67: #region ICallbackEventHandler Members 68:  69: String ICallbackEventHandler.GetCallbackResult() 70: { 71: CallbackEventArgs args = new CallbackEventArgs(this.Context.Items["Data"] as String); 72:  73: this.OnCallback(args); 74:  75: return (args.Result); 76: } 77:  78: void ICallbackEventHandler.RaiseCallbackEvent(String eventArgument) 79: { 80: this.Context.Items["Data"] = eventArgument; 81: } 82:  83: #endregion 84: } And the event argument class: 1: [Serializable] 2: public class CallbackEventArgs : EventArgs 3: { 4: public CallbackEventArgs(String argument) 5: { 6: this.Argument = argument; 7: this.Result = String.Empty; 8: } 9:  10: public String Argument 11: { 12: get; 13: private set; 14: } 15:  16: public String Result 17: { 18: get; 19: set; 20: } 21: } You will notice two properties on the CallbackControl: Async: indicates if the call should be made asynchronously or synchronously (the default); SendAllData: indicates if the callback call will include the view and control state of all of the controls on the page, so that, on the server side, they will have their properties set when the Callback event is fired. The CallbackEventArgs class exposes two properties: Argument: the read-only argument passed to the client-side function; Result: the result to return to the client-side callback function, set from the Callback event handler. An example of an handler for the Callback event would be: 1: protected void OnCallback(Object sender, CallbackEventArgs e) 2: { 3: e.Result = String.Join(String.Empty, e.Argument.Reverse()); 4: } Finally, in order to fire the Callback event from the client, you only need this: 1: <input type="text" id="input"/> 2: <input type="button" value="Get Result" onclick="document.getElementById('callback').callback(callback(document.getElementById('input').value, 'context', onCallbackSuccess, onCallbackError))"/> The syntax of the callback function is: arg: some string argument; context: some context that will be passed to the callback functions (success or failure); callbackSuccessFunction: some function that will be called when the callback succeeds; callbackFailureFunction: some function that will be called if the callback fails for some reason. Give it a try and see if it helps!

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  • C#: Optional Parameters - Pros and Pitfalls

    - by James Michael Hare
    When Microsoft rolled out Visual Studio 2010 with C# 4, I was very excited to learn how I could apply all the new features and enhancements to help make me and my team more productive developers. Default parameters have been around forever in C++, and were intentionally omitted in Java in favor of using overloading to satisfy that need as it was though that having too many default parameters could introduce code safety issues.  To some extent I can understand that move, as I’ve been bitten by default parameter pitfalls before, but at the same time I feel like Java threw out the baby with the bathwater in that move and I’m glad to see C# now has them. This post briefly discusses the pros and pitfalls of using default parameters.  I’m avoiding saying cons, because I really don’t believe using default parameters is a negative thing, I just think there are things you must watch for and guard against to avoid abuses that can cause code safety issues. Pro: Default Parameters Can Simplify Code Let’s start out with positives.  Consider how much cleaner it is to reduce all the overloads in methods or constructors that simply exist to give the semblance of optional parameters.  For example, we could have a Message class defined which allows for all possible initializations of a Message: 1: public class Message 2: { 3: // can either cascade these like this or duplicate the defaults (which can introduce risk) 4: public Message() 5: : this(string.Empty) 6: { 7: } 8:  9: public Message(string text) 10: : this(text, null) 11: { 12: } 13:  14: public Message(string text, IDictionary<string, string> properties) 15: : this(text, properties, -1) 16: { 17: } 18:  19: public Message(string text, IDictionary<string, string> properties, long timeToLive) 20: { 21: // ... 22: } 23: }   Now consider the same code with default parameters: 1: public class Message 2: { 3: // can either cascade these like this or duplicate the defaults (which can introduce risk) 4: public Message(string text = "", IDictionary<string, string> properties = null, long timeToLive = -1) 5: { 6: // ... 7: } 8: }   Much more clean and concise and no repetitive coding!  In addition, in the past if you wanted to be able to cleanly supply timeToLive and accept the default on text and properties above, you would need to either create another overload, or pass in the defaults explicitly.  With named parameters, though, we can do this easily: 1: var msg = new Message(timeToLive: 100);   Pro: Named Parameters can Improve Readability I must say one of my favorite things with the default parameters addition in C# is the named parameters.  It lets code be a lot easier to understand visually with no comments.  Think how many times you’ve run across a TimeSpan declaration with 4 arguments and wondered if they were passing in days/hours/minutes/seconds or hours/minutes/seconds/milliseconds.  A novice running through your code may wonder what it is.  Named arguments can help resolve the visual ambiguity: 1: // is this days/hours/minutes/seconds (no) or hours/minutes/seconds/milliseconds (yes) 2: var ts = new TimeSpan(1, 2, 3, 4); 3:  4: // this however is visually very explicit 5: var ts = new TimeSpan(days: 1, hours: 2, minutes: 3, seconds: 4);   Or think of the times you’ve run across something passing a Boolean literal and wondered what it was: 1: // what is false here? 2: var sub = CreateSubscriber(hostname, port, false); 3:  4: // aha! Much more visibly clear 5: var sub = CreateSubscriber(hostname, port, isBuffered: false);   Pitfall: Don't Insert new Default Parameters In Between Existing Defaults Now let’s consider a two potential pitfalls.  The first is really an abuse.  It’s not really a fault of the default parameters themselves, but a fault in the use of them.  Let’s consider that Message constructor again with defaults.  Let’s say you want to add a messagePriority to the message and you think this is more important than a timeToLive value, so you decide to put messagePriority before it in the default, this gives you: 1: public class Message 2: { 3: public Message(string text = "", IDictionary<string, string> properties = null, int priority = 5, long timeToLive = -1) 4: { 5: // ... 6: } 7: }   Oh boy have we set ourselves up for failure!  Why?  Think of all the code out there that could already be using the library that already specified the timeToLive, such as this possible call: 1: var msg = new Message(“An error occurred”, myProperties, 1000);   Before this specified a message with a TTL of 1000, now it specifies a message with a priority of 1000 and a time to live of -1 (infinite).  All of this with NO compiler errors or warnings. So the rule to take away is if you are adding new default parameters to a method that’s currently in use, make sure you add them to the end of the list or create a brand new method or overload. Pitfall: Beware of Default Parameters in Inheritance and Interface Implementation Now, the second potential pitfalls has to do with inheritance and interface implementation.  I’ll illustrate with a puzzle: 1: public interface ITag 2: { 3: void WriteTag(string tagName = "ITag"); 4: } 5:  6: public class BaseTag : ITag 7: { 8: public virtual void WriteTag(string tagName = "BaseTag") { Console.WriteLine(tagName); } 9: } 10:  11: public class SubTag : BaseTag 12: { 13: public override void WriteTag(string tagName = "SubTag") { Console.WriteLine(tagName); } 14: } 15:  16: public static class Program 17: { 18: public static void Main() 19: { 20: SubTag subTag = new SubTag(); 21: BaseTag subByBaseTag = subTag; 22: ITag subByInterfaceTag = subTag; 23:  24: // what happens here? 25: subTag.WriteTag(); 26: subByBaseTag.WriteTag(); 27: subByInterfaceTag.WriteTag(); 28: } 29: }   What happens?  Well, even though the object in each case is SubTag whose tag is “SubTag”, you will get: 1: SubTag 2: BaseTag 3: ITag   Why?  Because default parameter are resolved at compile time, not runtime!  This means that the default does not belong to the object being called, but by the reference type it’s being called through.  Since the SubTag instance is being called through an ITag reference, it will use the default specified in ITag. So the moral of the story here is to be very careful how you specify defaults in interfaces or inheritance hierarchies.  I would suggest avoiding repeating them, and instead concentrating on the layer of classes or interfaces you must likely expect your caller to be calling from. For example, if you have a messaging factory that returns an IMessage which can be either an MsmqMessage or JmsMessage, it only makes since to put the defaults at the IMessage level since chances are your user will be using the interface only. So let’s sum up.  In general, I really love default and named parameters in C# 4.0.  I think they’re a great tool to help make your code easier to read and maintain when used correctly. On the plus side, default parameters: Reduce redundant overloading for the sake of providing optional calling structures. Improve readability by being able to name an ambiguous argument. But remember to make sure you: Do not insert new default parameters in the middle of an existing set of default parameters, this may cause unpredictable behavior that may not necessarily throw a syntax error – add to end of list or create new method. Be extremely careful how you use default parameters in inheritance hierarchies and interfaces – choose the most appropriate level to add the defaults based on expected usage. Technorati Tags: C#,.NET,Software,Default Parameters

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  • jBullet Collision/Physics not working correctly

    - by Kenneth Bray
    Below is the code for one of my objects in the game I am creating (yes although this is a cube, I am not making anything remotely like MineCraft), and my issue is I while the cube will display and is does follow the physics if the cube falls, it does not interact with any other objects in the game. If I was to have multiple cubes in screen at once they all just sit there, or shoot off in all directions never stopping. Anyway, I am new to jBullet, and any help would be appreciated. package Object; import static org.lwjgl.opengl.GL11.GL_QUADS; import static org.lwjgl.opengl.GL11.glBegin; import static org.lwjgl.opengl.GL11.glColor3f; import static org.lwjgl.opengl.GL11.glEnd; import static org.lwjgl.opengl.GL11.glPopMatrix; import static org.lwjgl.opengl.GL11.glPushMatrix; import static org.lwjgl.opengl.GL11.glVertex3f; import javax.vecmath.Matrix4f; import javax.vecmath.Quat4f; import javax.vecmath.Vector3f; import com.bulletphysics.collision.shapes.BoxShape; import com.bulletphysics.collision.shapes.CollisionShape; import com.bulletphysics.dynamics.RigidBody; import com.bulletphysics.dynamics.RigidBodyConstructionInfo; import com.bulletphysics.linearmath.DefaultMotionState; import com.bulletphysics.linearmath.Transform; public class Cube { // Cube size/shape variables private float size; boolean cubeCollidable; boolean cubeDestroyable; // Position variables - currently this defines the center of the cube private float posX; private float posY; private float posZ; // Rotation variables - should be between 0 and 359, might consider letting rotation go higher though I can't think of a purpose currently private float rotX; private float rotY; private float rotZ; //collision shape is a box shape CollisionShape fallShape; // setup the motion state for the ball DefaultMotionState fallMotionState; Vector3f fallInertia = new Vector3f(0, 1, 0); RigidBodyConstructionInfo fallRigidBodyCI; public RigidBody fallRigidBody; int mass = 1; // Constructor public Cube(float pX, float pY, float pZ, float pSize) { posX = pX; posY = pY; posZ = pZ; size = pSize; rotX = 0; rotY = 0; rotZ = 0; // define the physics based on the values passed in fallShape = new BoxShape(new Vector3f(size, size, size)); fallMotionState = new DefaultMotionState(new Transform(new Matrix4f(new Quat4f(0, 0, 0, 1), new Vector3f(0, 50, 0), 1f))); fallRigidBodyCI = new RigidBodyConstructionInfo(mass, fallMotionState, fallShape, fallInertia); fallRigidBody = new RigidBody(fallRigidBodyCI); } public void Update() { Transform trans = new Transform(); fallRigidBody.getMotionState().getWorldTransform(trans); posY = trans.origin.x; posX = trans.origin.y; posZ = trans.origin.z; } public void Draw() { fallShape.calculateLocalInertia(mass, fallInertia); // center point posX, posY, posZ float radius = size / 2; //top glPushMatrix(); glBegin(GL_QUADS); { glColor3f(1.0f,0.0f,0.0f); // red glVertex3f(posX + radius, posY + radius, posZ - radius); glVertex3f(posX - radius, posY + radius, posZ - radius); glVertex3f(posX - radius, posY + radius, posZ + radius); glVertex3f(posX + radius, posY + radius, posZ + radius); } glEnd(); glPopMatrix(); //bottom glPushMatrix(); glBegin(GL_QUADS); { glColor3f(1.0f,1.0f,0.0f); // ?? color glVertex3f(posX + radius, posY - radius, posZ + radius); glVertex3f(posX - radius, posY - radius, posZ + radius); glVertex3f(posX - radius, posY - radius, posZ - radius); glVertex3f(posX + radius, posY - radius, posZ - radius); } glEnd(); glPopMatrix(); //right side glPushMatrix(); glBegin(GL_QUADS); { glColor3f(1.0f,0.0f,1.0f); // ?? color glVertex3f(posX + radius, posY + radius, posZ + radius); glVertex3f(posX + radius, posY - radius, posZ + radius); glVertex3f(posX + radius, posY - radius, posZ - radius); glVertex3f(posX + radius, posY + radius, posZ - radius); } glEnd(); glPopMatrix(); //left side glPushMatrix(); glBegin(GL_QUADS); { glColor3f(0.0f,1.0f,1.0f); // ?? color glVertex3f(posX - radius, posY + radius, posZ - radius); glVertex3f(posX - radius, posY - radius, posZ - radius); glVertex3f(posX - radius, posY - radius, posZ + radius); glVertex3f(posX - radius, posY + radius, posZ + radius); } glEnd(); glPopMatrix(); //front side glPushMatrix(); glBegin(GL_QUADS); { glColor3f(0.0f,0.0f,1.0f); //blue glVertex3f(posX + radius, posY + radius, posZ + radius); glVertex3f(posX - radius, posY + radius, posZ + radius); glVertex3f(posX - radius, posY - radius, posZ + radius); glVertex3f(posX + radius, posY - radius, posZ + radius); } glEnd(); glPopMatrix(); //back side glPushMatrix(); glBegin(GL_QUADS); { glColor3f(0.0f,1.0f,0.0f); // green glVertex3f(posX + radius, posY - radius, posZ - radius); glVertex3f(posX - radius, posY - radius, posZ - radius); glVertex3f(posX - radius, posY + radius, posZ - radius); glVertex3f(posX + radius, posY + radius, posZ - radius); } glEnd(); glPopMatrix(); } }

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  • Using JDialog with Tabbed Pane to draw different pictures [migrated]

    - by Bryam Ulloa
    I am using NetBeans, and I have a class that extends to JDialog, inside that Dialog box I have created a Tabbed Pane. The Tabbed Pane contains 6 different tabs, with 6 different panels of course. What I want to do is when I click on the different tabs, a diagram is supposed to be drawn with the paint method. My question is how can I draw on the different panels with just one paint method in another class being called from the Dialog class? Here is my code for the Dialog class: package GUI; public class NewJDialog extends javax.swing.JDialog{ /** * Creates new form NewJDialog */ public NewJDialog(java.awt.Frame parent, boolean modal) { super(parent, modal); initComponents(); } /** * This method is called from within the constructor to initialize the form. * WARNING: Do NOT modify this code. The content of this method is always * regenerated by the Form Editor. */ @SuppressWarnings("unchecked") // <editor-fold defaultstate="collapsed" desc="Generated Code"> private void initComponents() { jTabbedPane1 = new javax.swing.JTabbedPane(); jPanel1 = new javax.swing.JPanel(); jPanel2 = new javax.swing.JPanel(); jPanel3 = new javax.swing.JPanel(); jPanel4 = new javax.swing.JPanel(); jPanel5 = new javax.swing.JPanel(); jPanel6 = new javax.swing.JPanel(); jPanel7 = new javax.swing.JPanel(); jLabel1 = new javax.swing.JLabel(); jLabel2 = new javax.swing.JLabel(); setDefaultCloseOperation(javax.swing.WindowConstants.DISPOSE_ON_CLOSE); javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1); jPanel1.setLayout(jPanel1Layout); jPanel1Layout.setHorizontalGroup( jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 466, Short.MAX_VALUE) ); jPanel1Layout.setVerticalGroup( jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 242, Short.MAX_VALUE) ); jTabbedPane1.addTab("FCFS", jPanel1); javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2); jPanel2.setLayout(jPanel2Layout); jPanel2Layout.setHorizontalGroup( jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 466, Short.MAX_VALUE) ); jPanel2Layout.setVerticalGroup( jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 242, Short.MAX_VALUE) ); jTabbedPane1.addTab("SSTF", jPanel2); javax.swing.GroupLayout jPanel3Layout = new javax.swing.GroupLayout(jPanel3); jPanel3.setLayout(jPanel3Layout); jPanel3Layout.setHorizontalGroup( jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 466, Short.MAX_VALUE) ); jPanel3Layout.setVerticalGroup( jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 242, Short.MAX_VALUE) ); jTabbedPane1.addTab("LOOK", jPanel3); javax.swing.GroupLayout jPanel4Layout = new javax.swing.GroupLayout(jPanel4); jPanel4.setLayout(jPanel4Layout); jPanel4Layout.setHorizontalGroup( jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 466, Short.MAX_VALUE) ); jPanel4Layout.setVerticalGroup( jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 242, Short.MAX_VALUE) ); jTabbedPane1.addTab("LOOK C", jPanel4); javax.swing.GroupLayout jPanel5Layout = new javax.swing.GroupLayout(jPanel5); jPanel5.setLayout(jPanel5Layout); jPanel5Layout.setHorizontalGroup( jPanel5Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 466, Short.MAX_VALUE) ); jPanel5Layout.setVerticalGroup( jPanel5Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 242, Short.MAX_VALUE) ); jTabbedPane1.addTab("SCAN", jPanel5); javax.swing.GroupLayout jPanel6Layout = new javax.swing.GroupLayout(jPanel6); jPanel6.setLayout(jPanel6Layout); jPanel6Layout.setHorizontalGroup( jPanel6Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 466, Short.MAX_VALUE) ); jPanel6Layout.setVerticalGroup( jPanel6Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 242, Short.MAX_VALUE) ); jTabbedPane1.addTab("SCAN C", jPanel6); getContentPane().add(jTabbedPane1, java.awt.BorderLayout.CENTER); jLabel1.setText("Distancia:"); jLabel2.setText("___________"); javax.swing.GroupLayout jPanel7Layout = new javax.swing.GroupLayout(jPanel7); jPanel7.setLayout(jPanel7Layout); jPanel7Layout.setHorizontalGroup( jPanel7Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(jPanel7Layout.createSequentialGroup() .addGap(21, 21, 21) .addComponent(jLabel1) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addComponent(jLabel2) .addContainerGap(331, Short.MAX_VALUE)) ); jPanel7Layout.setVerticalGroup( jPanel7Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(jPanel7Layout.createSequentialGroup() .addContainerGap() .addGroup(jPanel7Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE) .addComponent(jLabel1) .addComponent(jLabel2)) .addContainerGap(15, Short.MAX_VALUE)) ); getContentPane().add(jPanel7, java.awt.BorderLayout.PAGE_START); pack(); }// </editor-fold> /** * @param args the command line arguments */ public static void main(String args[]) { /* Set the Nimbus look and feel */ //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) "> /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel. * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html */ try { for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) { if ("Nimbus".equals(info.getName())) { javax.swing.UIManager.setLookAndFeel(info.getClassName()); break; } } } catch (ClassNotFoundException ex) { java.util.logging.Logger.getLogger(NewJDialog.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); } catch (InstantiationException ex) { java.util.logging.Logger.getLogger(NewJDialog.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); } catch (IllegalAccessException ex) { java.util.logging.Logger.getLogger(NewJDialog.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); } catch (javax.swing.UnsupportedLookAndFeelException ex) { java.util.logging.Logger.getLogger(NewJDialog.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); } //</editor-fold> /* Create and display the dialog */ java.awt.EventQueue.invokeLater(new Runnable() { public void run() { NewJDialog dialog = new NewJDialog(new javax.swing.JFrame(), true); dialog.addWindowListener(new java.awt.event.WindowAdapter() { @Override public void windowClosing(java.awt.event.WindowEvent e) { System.exit(0); } }); dialog.setVisible(true); } }); } // Variables declaration - do not modify private javax.swing.JLabel jLabel1; private javax.swing.JLabel jLabel2; private javax.swing.JPanel jPanel1; private javax.swing.JPanel jPanel2; private javax.swing.JPanel jPanel3; private javax.swing.JPanel jPanel4; private javax.swing.JPanel jPanel5; private javax.swing.JPanel jPanel6; private javax.swing.JPanel jPanel7; private javax.swing.JTabbedPane jTabbedPane1; // End of variables declaration } This is another class that I have created for the paint method: package GUI; import java.awt.Graphics; import javax.swing.JPanel; /** * * @author TOSHIBA */ public class Lienzo { private int width = 5; private int height = 5; private int y = 5; private int x = 0; private int x1 = 0; public Graphics Draw(Graphics g, int[] pistas) { //Im not sure if this is the correct way to do it //The diagram gets drawn according to values from an array //The array is not always the same thats why I used the different Panels for (int i = 0; i < pistas.length; i++) { x = pistas[i]; x1 = pistas[i + 1]; g.drawOval(x, y, width, height); g.drawString(Integer.toString(x), x, y); g.drawLine(x, y, x1, y); } return g; } } I hope you guys understand what I am trying to do with my program.

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  • C#/.NET Little Wonders: The Timeout static class

    - by James Michael Hare
    Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. When I started the “Little Wonders” series, I really wanted to pay homage to parts of the .NET Framework that are often small but can help in big ways.  The item I have to discuss today really is a very small item in the .NET BCL, but once again I feel it can help make the intention of code much clearer and thus is worthy of note. The Problem - Magic numbers aren’t very readable or maintainable In my first Little Wonders Post (Five Little Wonders That Make Code Better) I mention the TimeSpan factory methods which, I feel, really help the readability of constructed TimeSpan instances. Just to quickly recap that discussion, ask yourself what the TimeSpan specified in each case below is 1: // Five minutes? Five Seconds? 2: var fiveWhat1 = new TimeSpan(0, 0, 5); 3: var fiveWhat2 = new TimeSpan(0, 0, 5, 0); 4: var fiveWhat3 = new TimeSpan(0, 0, 5, 0, 0); You’d think they’d all be the same unit of time, right?  After all, most overloads tend to tack additional arguments on the end.  But this is not the case with TimeSpan, where the constructor forms are:     TimeSpan(int hours, int minutes, int seconds);     TimeSpan(int days, int hours, int minutes, int seconds);     TimeSpan(int days, int hours, int minutes, int seconds, int milliseconds); Notice how in the 4 and 5 parameter version we suddenly have the parameter days slipping in front of hours?  This can make reading constructors like those above much harder.  Fortunately, there are TimeSpan factory methods to help make your intention crystal clear: 1: // Ah! Much clearer! 2: var fiveSeconds = TimeSpan.FromSeconds(5); These are great because they remove all ambiguity from the reader!  So in short, magic numbers in constructors and methods can be ambiguous, and anything we can do to clean up the intention of the developer will make the code much easier to read and maintain. Timeout – Readable identifiers for infinite timeout values In a similar way to TimeSpan, let’s consider specifying timeouts for some of .NET’s (or our own) many methods that allow you to specify timeout periods. For example, in the TPL Task class, there is a family of Wait() methods that can take TimeSpan or int for timeouts.  Typically, if you want to specify an infinite timeout, you’d just call the version that doesn’t take a timeout parameter at all: 1: myTask.Wait(); // infinite wait But there are versions that take the int or TimeSpan for timeout as well: 1: // Wait for 100 ms 2: myTask.Wait(100); 3:  4: // Wait for 5 seconds 5: myTask.Wait(TimeSpan.FromSeconds(5); Now, if we want to specify an infinite timeout to wait on the Task, we could pass –1 (or a TimeSpan set to –1 ms), which what the .NET BCL methods with timeouts use to represent an infinite timeout: 1: // Also infinite timeouts, but harder to read/maintain 2: myTask.Wait(-1); 3: myTask.Wait(TimeSpan.FromMilliseconds(-1)); However, these are not as readable or maintainable.  If you were writing this code, you might make the mistake of thinking 0 or int.MaxValue was an infinite timeout, and you’d be incorrect.  Also, reading the code above it isn’t as clear that –1 is infinite unless you happen to know that is the specified behavior. To make the code like this easier to read and maintain, there is a static class called Timeout in the System.Threading namespace which contains definition for infinite timeouts specified as both int and TimeSpan forms: Timeout.Infinite An integer constant with a value of –1 Timeout.InfiniteTimeSpan A static readonly TimeSpan which represents –1 ms (only available in .NET 4.5+) This makes our calls to Task.Wait() (or any other calls with timeouts) much more clear: 1: // intention to wait indefinitely is quite clear now 2: myTask.Wait(Timeout.Infinite); 3: myTask.Wait(Timeout.InfiniteTimeSpan); But wait, you may say, why would we care at all?  Why not use the version of Wait() that takes no arguments?  Good question!  When you’re directly calling the method with an infinite timeout that’s what you’d most likely do, but what if you are just passing along a timeout specified by a caller from higher up?  Or perhaps storing a timeout value from a configuration file, and want to default it to infinite? For example, perhaps you are designing a communications module and want to be able to shutdown gracefully, but if you can’t gracefully finish in a specified amount of time you want to force the connection closed.  You could create a Shutdown() method in your class, and take a TimeSpan or an int for the amount of time to wait for a clean shutdown – perhaps waiting for client to acknowledge – before terminating the connection.  So, assume we had a pub/sub system with a class to broadcast messages: 1: // Some class to broadcast messages to connected clients 2: public class Broadcaster 3: { 4: // ... 5:  6: // Shutdown connection to clients, wait for ack back from clients 7: // until all acks received or timeout, whichever happens first 8: public void Shutdown(int timeout) 9: { 10: // Kick off a task here to send shutdown request to clients and wait 11: // for the task to finish below for the specified time... 12:  13: if (!shutdownTask.Wait(timeout)) 14: { 15: // If Wait() returns false, we timed out and task 16: // did not join in time. 17: } 18: } 19: } We could even add an overload to allow us to use TimeSpan instead of int, to give our callers the flexibility to specify timeouts either way: 1: // overload to allow them to specify Timeout in TimeSpan, would 2: // just call the int version passing in the TotalMilliseconds... 3: public void Shutdown(TimeSpan timeout) 4: { 5: Shutdown(timeout.TotalMilliseconds); 6: } Notice in case of this class, we don’t assume the caller wants infinite timeouts, we choose to rely on them to tell us how long to wait.  So now, if they choose an infinite timeout, they could use the –1, which is more cryptic, or use Timeout class to make the intention clear: 1: // shutdown the broadcaster, waiting until all clients ack back 2: // without timing out. 3: myBroadcaster.Shutdown(Timeout.Infinite); We could even add a default argument using the int parameter version so that specifying no arguments to Shutdown() assumes an infinite timeout: 1: // Modified original Shutdown() method to add a default of 2: // Timeout.Infinite, works because Timeout.Infinite is a compile 3: // time constant. 4: public void Shutdown(int timeout = Timeout.Infinite) 5: { 6: // same code as before 7: } Note that you can’t default the ShutDown(TimeSpan) overload with Timeout.InfiniteTimeSpan since it is not a compile-time constant.  The only acceptable default for a TimeSpan parameter would be default(TimeSpan) which is zero milliseconds, which specified no wait, not infinite wait. Summary While Timeout.Infinite and Timeout.InfiniteTimeSpan are not earth-shattering classes in terms of functionality, they do give you very handy and readable constant values that you can use in your programs to help increase readability and maintainability when specifying infinite timeouts for various timeouts in the BCL and your own applications. Technorati Tags: C#,CSharp,.NET,Little Wonders,Timeout,Task

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  • SortedDictionary and SortedList

    - by Simon Cooper
    Apart from Dictionary<TKey, TValue>, there's two other dictionaries in the BCL - SortedDictionary<TKey, TValue> and SortedList<TKey, TValue>. On the face of it, these two classes do the same thing - provide an IDictionary<TKey, TValue> interface where the iterator returns the items sorted by the key. So what's the difference between them, and when should you use one rather than the other? (as in my previous post, I'll assume you have some basic algorithm & datastructure knowledge) SortedDictionary We'll first cover SortedDictionary. This is implemented as a special sort of binary tree called a red-black tree. Essentially, it's a binary tree that uses various constraints on how the nodes of the tree can be arranged to ensure the tree is always roughly balanced (for more gory algorithmical details, see the wikipedia link above). What I'm concerned about in this post is how the .NET SortedDictionary is actually implemented. In .NET 4, behind the scenes, the actual implementation of the tree is delegated to a SortedSet<KeyValuePair<TKey, TValue>>. One example tree might look like this: Each node in the above tree is stored as a separate SortedSet<T>.Node object (remember, in a SortedDictionary, T is instantiated to KeyValuePair<TKey, TValue>): class Node { public bool IsRed; public T Item; public SortedSet<T>.Node Left; public SortedSet<T>.Node Right; } The SortedSet only stores a reference to the root node; all the data in the tree is accessed by traversing the Left and Right node references until you reach the node you're looking for. Each individual node can be physically stored anywhere in memory; what's important is the relationship between the nodes. This is also why there is no constructor to SortedDictionary or SortedSet that takes an integer representing the capacity; there are no internal arrays that need to be created and resized. This may seen trivial, but it's an important distinction between SortedDictionary and SortedList that I'll cover later on. And that's pretty much it; it's a standard red-black tree. Plenty of webpages and datastructure books cover the algorithms behind the tree itself far better than I could. What's interesting is the comparions between SortedDictionary and SortedList, which I'll cover at the end. As a side point, SortedDictionary has existed in the BCL ever since .NET 2. That means that, all through .NET 2, 3, and 3.5, there has been a bona-fide sorted set class in the BCL (called TreeSet). However, it was internal, so it couldn't be used outside System.dll. Only in .NET 4 was this class exposed as SortedSet. SortedList Whereas SortedDictionary didn't use any backing arrays, SortedList does. It is implemented just as the name suggests; two arrays, one containing the keys, and one the values (I've just used random letters for the values): The items in the keys array are always guarenteed to be stored in sorted order, and the value corresponding to each key is stored in the same index as the key in the values array. In this example, the value for key item 5 is 'z', and for key item 8 is 'm'. Whenever an item is inserted or removed from the SortedList, a binary search is run on the keys array to find the correct index, then all the items in the arrays are shifted to accomodate the new or removed item. For example, if the key 3 was removed, a binary search would be run to find the array index the item was at, then everything above that index would be moved down by one: and then if the key/value pair {7, 'f'} was added, a binary search would be run on the keys to find the index to insert the new item, and everything above that index would be moved up to accomodate the new item: If another item was then added, both arrays would be resized (to a length of 10) before the new item was added to the arrays. As you can see, any insertions or removals in the middle of the list require a proportion of the array contents to be moved; an O(n) operation. However, if the insertion or removal is at the end of the array (ie the largest key), then it's only O(log n); the cost of the binary search to determine it does actually need to be added to the end (excluding the occasional O(n) cost of resizing the arrays to fit more items). As a side effect of using backing arrays, SortedList offers IList Keys and Values views that simply use the backing keys or values arrays, as well as various methods utilising the array index of stored items, which SortedDictionary does not (and cannot) offer. The Comparison So, when should you use one and not the other? Well, here's the important differences: Memory usage SortedDictionary and SortedList have got very different memory profiles. SortedDictionary... has a memory overhead of one object instance, a bool, and two references per item. On 64-bit systems, this adds up to ~40 bytes, not including the stored item and the reference to it from the Node object. stores the items in separate objects that can be spread all over the heap. This helps to keep memory fragmentation low, as the individual node objects can be allocated wherever there's a spare 60 bytes. In contrast, SortedList... has no additional overhead per item (only the reference to it in the array entries), however the backing arrays can be significantly larger than you need; every time the arrays are resized they double in size. That means that if you add 513 items to a SortedList, the backing arrays will each have a length of 1024. To conteract this, the TrimExcess method resizes the arrays back down to the actual size needed, or you can simply assign list.Capacity = list.Count. stores its items in a continuous block in memory. If the list stores thousands of items, this can cause significant problems with Large Object Heap memory fragmentation as the array resizes, which SortedDictionary doesn't have. Performance Operations on a SortedDictionary always have O(log n) performance, regardless of where in the collection you're adding or removing items. In contrast, SortedList has O(n) performance when you're altering the middle of the collection. If you're adding or removing from the end (ie the largest item), then performance is O(log n), same as SortedDictionary (in practice, it will likely be slightly faster, due to the array items all being in the same area in memory, also called locality of reference). So, when should you use one and not the other? As always with these sort of things, there are no hard-and-fast rules. But generally, if you: need to access items using their index within the collection are populating the dictionary all at once from sorted data aren't adding or removing keys once it's populated then use a SortedList. But if you: don't know how many items are going to be in the dictionary are populating the dictionary from random, unsorted data are adding & removing items randomly then use a SortedDictionary. The default (again, there's no definite rules on these sort of things!) should be to use SortedDictionary, unless there's a good reason to use SortedList, due to the bad performance of SortedList when altering the middle of the collection.

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  • xml file save/read error (making a highscore system for XNA game)

    - by Eddy
    i get an error after i write player name to the file for second or third time (An unhandled exception of type 'System.InvalidOperationException' occurred in System.Xml.dll Additional information: There is an error in XML document (18, 17).) (in highscores load method In data = (HighScoreData)serializer.Deserialize(stream); it stops) the problem is that some how it adds additional "" at the end of my .dat file could anyone tell me how to fix this? the file before save looks: <?xml version="1.0"?> <HighScoreData xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <PlayerName> <string>neil</string> <string>shawn</string> <string>mark</string> <string>cindy</string> <string>sam</string> </PlayerName> <Score> <int>200</int> <int>180</int> <int>150</int> <int>100</int> <int>50</int> </Score> <Count>5</Count> </HighScoreData> the file after save looks: <?xml version="1.0"?> <HighScoreData xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <PlayerName> <string>Nick</string> <string>Nick</string> <string>neil</string> <string>shawn</string> <string>mark</string> </PlayerName> <Score> <int>210</int> <int>210</int> <int>200</int> <int>180</int> <int>150</int> </Score> <Count>5</Count> </HighScoreData>> the part of my code that does all of save load to xml is: DECLARATIONS PART [Serializable] public struct HighScoreData { public string[] PlayerName; public int[] Score; public int Count; public HighScoreData(int count) { PlayerName = new string[count]; Score = new int[count]; Count = count; } } IAsyncResult result = null; bool inputName; HighScoreData data; int Score = 0; public string NAME; public string HighScoresFilename = "highscores.dat"; Game1 constructor public Game1() { graphics = new GraphicsDeviceManager(this); Content.RootDirectory = "Content"; Width = graphics.PreferredBackBufferWidth = 960; Height = graphics.PreferredBackBufferHeight =640; GamerServicesComponent GSC = new GamerServicesComponent(this); Components.Add(GSC); } Inicialize function (end of it) protected override void Initialize() { //other game code base.Initialize(); string fullpath =Path.Combine(HighScoresFilename); if (!File.Exists(fullpath)) { //If the file doesn't exist, make a fake one... // Create the data to save data = new HighScoreData(5); data.PlayerName[0] = "neil"; data.Score[0] = 200; data.PlayerName[1] = "shawn"; data.Score[1] = 180; data.PlayerName[2] = "mark"; data.Score[2] = 150; data.PlayerName[3] = "cindy"; data.Score[3] = 100; data.PlayerName[4] = "sam"; data.Score[4] = 50; SaveHighScores(data, HighScoresFilename); } } all methods for loading saving and output public static void SaveHighScores(HighScoreData data, string filename) { // Get the path of the save game string fullpath = Path.Combine("highscores.dat"); // Open the file, creating it if necessary FileStream stream = File.Open(fullpath, FileMode.OpenOrCreate); try { // Convert the object to XML data and put it in the stream XmlSerializer serializer = new XmlSerializer(typeof(HighScoreData)); serializer.Serialize(stream, data); } finally { // Close the file stream.Close(); } } /* Load highscores */ public static HighScoreData LoadHighScores(string filename) { HighScoreData data; // Get the path of the save game string fullpath = Path.Combine("highscores.dat"); // Open the file FileStream stream = File.Open(fullpath, FileMode.OpenOrCreate, FileAccess.Read); try { // Read the data from the file XmlSerializer serializer = new XmlSerializer(typeof(HighScoreData)); data = (HighScoreData)serializer.Deserialize(stream);//this is the line // where program gives an error } finally { // Close the file stream.Close(); } return (data); } /* Save player highscore when game ends */ private void SaveHighScore() { // Create the data to saved HighScoreData data = LoadHighScores(HighScoresFilename); int scoreIndex = -1; for (int i = 0; i < data.Count ; i++) { if (Score > data.Score[i]) { scoreIndex = i; break; } } if (scoreIndex > -1) { //New high score found ... do swaps for (int i = data.Count - 1; i > scoreIndex; i--) { data.PlayerName[i] = data.PlayerName[i - 1]; data.Score[i] = data.Score[i - 1]; } data.PlayerName[scoreIndex] = NAME; //Retrieve User Name Here data.Score[scoreIndex] = Score; // Retrieve score here SaveHighScores(data, HighScoresFilename); } } /* Iterate through data if highscore is called and make the string to be saved*/ public string makeHighScoreString() { // Create the data to save HighScoreData data2 = LoadHighScores(HighScoresFilename); // Create scoreBoardString string scoreBoardString = "Highscores:\n\n"; for (int i = 0; i<5;i++) { scoreBoardString = scoreBoardString + data2.PlayerName[i] + "-" + data2.Score[i] + "\n"; } return scoreBoardString; } when ill make this work i will start this code when i call game over (now i start it when i press some buttons, so i could test it faster) public void InputYourName() { if (result == null && !Guide.IsVisible) { string title = "Name"; string description = "Write your name in order to save your Score"; string defaultText = "Nick"; PlayerIndex playerIndex = new PlayerIndex(); result= Guide.BeginShowKeyboardInput(playerIndex, title, description, defaultText, null, null); // NAME = result.ToString(); } if (result != null && result.IsCompleted) { NAME = Guide.EndShowKeyboardInput(result); result = null; inputName = false; SaveHighScore(); } } this where i call output to the screen (ill call this in highscores meniu section when i am done with debugging) spriteBatch.DrawString(Font1, "" + makeHighScoreString(),new Vector2(500,200), Color.White); }

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  • Anatomy of a .NET Assembly - CLR metadata 1

    - by Simon Cooper
    Before we look at the bytes comprising the CLR-specific data inside an assembly, we first need to understand the logical format of the metadata (For this post I only be looking at simple pure-IL assemblies; mixed-mode assemblies & other things complicates things quite a bit). Metadata streams Most of the CLR-specific data inside an assembly is inside one of 5 streams, which are analogous to the sections in a PE file. The name of each section in a PE file starts with a ., and the name of each stream in the CLR metadata starts with a #. All but one of the streams are heaps, which store unstructured binary data. The predefined streams are: #~ Also called the metadata stream, this stream stores all the information on the types, methods, fields, properties and events in the assembly. Unlike the other streams, the metadata stream has predefined contents & structure. #Strings This heap is where all the namespace, type & member names are stored. It is referenced extensively from the #~ stream, as we'll be looking at later. #US Also known as the user string heap, this stream stores all the strings used in code directly. All the strings you embed in your source code end up in here. This stream is only referenced from method bodies. #GUID This heap exclusively stores GUIDs used throughout the assembly. #Blob This heap is for storing pure binary data - method signatures, generic instantiations, that sort of thing. Items inside the heaps (#Strings, #US, #GUID and #Blob) are indexed using a simple binary offset from the start of the heap. At that offset is a coded integer giving the length of that item, then the item's bytes immediately follow. The #GUID stream is slightly different, in that GUIDs are all 16 bytes long, so a length isn't required. Metadata tables The #~ stream contains all the assembly metadata. The metadata is organised into 45 tables, which are binary arrays of predefined structures containing information on various aspects of the metadata. Each entry in a table is called a row, and the rows are simply concatentated together in the file on disk. For example, each row in the TypeRef table contains: A reference to where the type is defined (most of the time, a row in the AssemblyRef table). An offset into the #Strings heap with the name of the type An offset into the #Strings heap with the namespace of the type. in that order. The important tables are (with their table number in hex): 0x2: TypeDef 0x4: FieldDef 0x6: MethodDef 0x14: EventDef 0x17: PropertyDef Contains basic information on all the types, fields, methods, events and properties defined in the assembly. 0x1: TypeRef The details of all the referenced types defined in other assemblies. 0xa: MemberRef The details of all the referenced members of types defined in other assemblies. 0x9: InterfaceImpl Links the types defined in the assembly with the interfaces that type implements. 0xc: CustomAttribute Contains information on all the attributes applied to elements in this assembly, from method parameters to the assembly itself. 0x18: MethodSemantics Links properties and events with the methods that comprise the get/set or add/remove methods of the property or method. 0x1b: TypeSpec 0x2b: MethodSpec These tables provide instantiations of generic types and methods for each usage within the assembly. There are several ways to reference a single row within a table. The simplest is to simply specify the 1-based row index (RID). The indexes are 1-based so a value of 0 can represent 'null'. In this case, which table the row index refers to is inferred from the context. If the table can't be determined from the context, then a particular row is specified using a token. This is a 4-byte value with the most significant byte specifying the table, and the other 3 specifying the 1-based RID within that table. This is generally how a metadata table row is referenced from the instruction stream in method bodies. The third way is to use a coded token, which we will look at in the next post. So, back to the bytes Now we've got a rough idea of how the metadata is logically arranged, we can now look at the bytes comprising the start of the CLR data within an assembly: The first 8 bytes of the .text section are used by the CLR loader stub. After that, the CLR-specific data starts with the CLI header. I've highlighted the important bytes in the diagram. In order, they are: The size of the header. As the header is a fixed size, this is always 0x48. The CLR major version. This is always 2, even for .NET 4 assemblies. The CLR minor version. This is always 5, even for .NET 4 assemblies, and seems to be ignored by the runtime. The RVA and size of the metadata header. In the diagram, the RVA 0x20e4 corresponds to the file offset 0x2e4 Various flags specifying if this assembly is pure-IL, whether it is strong name signed, and whether it should be run as 32-bit (this is how the CLR differentiates between x86 and AnyCPU assemblies). A token pointing to the entrypoint of the assembly. In this case, 06 (the last byte) refers to the MethodDef table, and 01 00 00 refers to to the first row in that table. (after a gap) RVA of the strong name signature hash, which comes straight after the CLI header. The RVA 0x2050 corresponds to file offset 0x250. The rest of the CLI header is mainly used in mixed-mode assemblies, and so is zeroed in this pure-IL assembly. After the CLI header comes the strong name hash, which is a SHA-1 hash of the assembly using the strong name key. After that comes the bodies of all the methods in the assembly concatentated together. Each method body starts off with a header, which I'll be looking at later. As you can see, this is a very small assembly with only 2 methods (an instance constructor and a Main method). After that, near the end of the .text section, comes the metadata, containing a metadata header and the 5 streams discussed above. We'll be looking at this in the next post. Conclusion The CLI header data doesn't have much to it, but we've covered some concepts that will be important in later posts - the logical structure of the CLR metadata and the overall layout of CLR data within the .text section. Next, I'll have a look at the contents of the #~ stream, and how the table data is arranged on disk.

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  • C# Performance Pitfall – Interop Scenarios Change the Rules

    - by Reed
    C# and .NET, overall, really do have fantastic performance in my opinion.  That being said, the performance characteristics dramatically differ from native programming, and take some relearning if you’re used to doing performance optimization in most other languages, especially C, C++, and similar.  However, there are times when revisiting tricks learned in native code play a critical role in performance optimization in C#. I recently ran across a nasty scenario that illustrated to me how dangerous following any fixed rules for optimization can be… The rules in C# when optimizing code are very different than C or C++.  Often, they’re exactly backwards.  For example, in C and C++, lifting a variable out of loops in order to avoid memory allocations often can have huge advantages.  If some function within a call graph is allocating memory dynamically, and that gets called in a loop, it can dramatically slow down a routine. This can be a tricky bottleneck to track down, even with a profiler.  Looking at the memory allocation graph is usually the key for spotting this routine, as it’s often “hidden” deep in call graph.  For example, while optimizing some of my scientific routines, I ran into a situation where I had a loop similar to: for (i=0; i<numberToProcess; ++i) { // Do some work ProcessElement(element[i]); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This loop was at a fairly high level in the call graph, and often could take many hours to complete, depending on the input data.  As such, any performance optimization we could achieve would be greatly appreciated by our users. After a fair bit of profiling, I noticed that a couple of function calls down the call graph (inside of ProcessElement), there was some code that effectively was doing: // Allocate some data required DataStructure* data = new DataStructure(num); // Call into a subroutine that passed around and manipulated this data highly CallSubroutine(data); // Read and use some values from here double values = data->Foo; // Cleanup delete data; // ... return bar; Normally, if “DataStructure” was a simple data type, I could just allocate it on the stack.  However, it’s constructor, internally, allocated it’s own memory using new, so this wouldn’t eliminate the problem.  In this case, however, I could change the call signatures to allow the pointer to the data structure to be passed into ProcessElement and through the call graph, allowing the inner routine to reuse the same “data” memory instead of allocating.  At the highest level, my code effectively changed to something like: DataStructure* data = new DataStructure(numberToProcess); for (i=0; i<numberToProcess; ++i) { // Do some work ProcessElement(element[i], data); } delete data; Granted, this dramatically reduced the maintainability of the code, so it wasn’t something I wanted to do unless there was a significant benefit.  In this case, after profiling the new version, I found that it increased the overall performance dramatically – my main test case went from 35 minutes runtime down to 21 minutes.  This was such a significant improvement, I felt it was worth the reduction in maintainability. In C and C++, it’s generally a good idea (for performance) to: Reduce the number of memory allocations as much as possible, Use fewer, larger memory allocations instead of many smaller ones, and Allocate as high up the call stack as possible, and reuse memory I’ve seen many people try to make similar optimizations in C# code.  For good or bad, this is typically not a good idea.  The garbage collector in .NET completely changes the rules here. In C#, reallocating memory in a loop is not always a bad idea.  In this scenario, for example, I may have been much better off leaving the original code alone.  The reason for this is the garbage collector.  The GC in .NET is incredibly effective, and leaving the allocation deep inside the call stack has some huge advantages.  First and foremost, it tends to make the code more maintainable – passing around object references tends to couple the methods together more than necessary, and overall increase the complexity of the code.  This is something that should be avoided unless there is a significant reason.  Second, (unlike C and C++) memory allocation of a single object in C# is normally cheap and fast.  Finally, and most critically, there is a large advantage to having short lived objects.  If you lift a variable out of the loop and reuse the memory, its much more likely that object will get promoted to Gen1 (or worse, Gen2).  This can cause expensive compaction operations to be required, and also lead to (at least temporary) memory fragmentation as well as more costly collections later. As such, I’ve found that it’s often (though not always) faster to leave memory allocations where you’d naturally place them – deep inside of the call graph, inside of the loops.  This causes the objects to stay very short lived, which in turn increases the efficiency of the garbage collector, and can dramatically improve the overall performance of the routine as a whole. In C#, I tend to: Keep variable declarations in the tightest scope possible Declare and allocate objects at usage While this tends to cause some of the same goals (reducing unnecessary allocations, etc), the goal here is a bit different – it’s about keeping the objects rooted for as little time as possible in order to (attempt) to keep them completely in Gen0, or worst case, Gen1.  It also has the huge advantage of keeping the code very maintainable – objects are used and “released” as soon as possible, which keeps the code very clean.  It does, however, often have the side effect of causing more allocations to occur, but keeping the objects rooted for a much shorter time. Now – nowhere here am I suggesting that these rules are hard, fast rules that are always true.  That being said, my time spent optimizing over the years encourages me to naturally write code that follows the above guidelines, then profile and adjust as necessary.  In my current project, however, I ran across one of those nasty little pitfalls that’s something to keep in mind – interop changes the rules. In this case, I was dealing with an API that, internally, used some COM objects.  In this case, these COM objects were leading to native allocations (most likely C++) occurring in a loop deep in my call graph.  Even though I was writing nice, clean managed code, the normal managed code rules for performance no longer apply.  After profiling to find the bottleneck in my code, I realized that my inner loop, a innocuous looking block of C# code, was effectively causing a set of native memory allocations in every iteration.  This required going back to a “native programming” mindset for optimization.  Lifting these variables and reusing them took a 1:10 routine down to 0:20 – again, a very worthwhile improvement. Overall, the lessons here are: Always profile if you suspect a performance problem – don’t assume any rule is correct, or any code is efficient just because it looks like it should be Remember to check memory allocations when profiling, not just CPU cycles Interop scenarios often cause managed code to act very differently than “normal” managed code. Native code can be hidden very cleverly inside of managed wrappers

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  • Custom Lookup Provider For NetBeans Platform CRUD Tutorial

    - by Geertjan
    For a long time I've been planning to rewrite the second part of the NetBeans Platform CRUD Application Tutorial to integrate the loosely coupled capabilities introduced in a seperate series of articles based on articles by Antonio Vieiro (a great series, by the way). Nothing like getting into the Lookup stuff right from the get go (rather than as an afterthought)! The question, of course, is how to integrate the loosely coupled capabilities in a logical way within that tutorial. Today I worked through the tutorial from scratch, up until the point where the prototype is completed, i.e., there's a JTextArea displaying data pulled from a database. That brought me to the place where I needed to be. In fact, as soon as the prototype is completed, i.e., the database connection has been shown to work, the whole story about Lookup.Provider and InstanceContent should be introduced, so that all the subsequent sections, i.e., everything within "Integrating CRUD Functionality" will be done by adding new capabilities to the Lookup.Provider. However, before I perform open heart surgery on that tutorial, I'd like to run the scenario by all those reading this blog who understand what I'm trying to do! (I.e., probably anyone who has read this far into this blog entry.) So, this is what I propose should happen and in this order: Point out the fact that right now the database access code is found directly within our TopComponent. Not good. Because you're mixing view code with data code and, ideally, the developers creating the user interface wouldn't need to know anything about the data access layer. Better to separate out the data access code into a separate class, within the CustomerLibrary module, i.e., far away from the module providing the user interface, with this content: public class CustomerDataAccess { public List<Customer> getAllCustomers() { return Persistence.createEntityManagerFactory("CustomerLibraryPU"). createEntityManager().createNamedQuery("Customer.findAll").getResultList(); } } Point out the fact that there is a concept of "Lookup" (which readers of the tutorial should know about since they should have followed the NetBeans Platform Quick Start), which is a registry into which objects can be published and to which other objects can be listening. In the same way as a TopComponent provides a Lookup, as demonstrated in the NetBeans Platform Quick Start, your own object can also provide a Lookup. So, therefore, let's provide a Lookup for Customer objects.  import org.openide.util.Lookup; import org.openide.util.lookup.AbstractLookup; import org.openide.util.lookup.InstanceContent; public class CustomerLookupProvider implements Lookup.Provider { private Lookup lookup; private InstanceContent instanceContent; public CustomerLookupProvider() { // Create an InstanceContent to hold capabilities... instanceContent = new InstanceContent(); // Create an AbstractLookup to expose the InstanceContent... lookup = new AbstractLookup(instanceContent); // Add a "Read" capability to the Lookup of the provider: //...to come... // Add a "Update" capability to the Lookup of the provider: //...to come... // Add a "Create" capability to the Lookup of the provider: //...to come... // Add a "Delete" capability to the Lookup of the provider: //...to come... } @Override public Lookup getLookup() { return lookup; } } Point out the fact that, in the same way as we can publish an object into the Lookup of a TopComponent, we can now also publish an object into the Lookup of our CustomerLookupProvider. Instead of publishing a String, as in the NetBeans Platform Quick Start, we'll publish an instance of our own type. And here is the type: public interface ReadCapability { public void read() throws Exception; } And here is an implementation of our type added to our Lookup: public class CustomerLookupProvider implements Lookup.Provider { private Set<Customer> customerSet; private Lookup lookup; private InstanceContent instanceContent; public CustomerLookupProvider() { customerSet = new HashSet<Customer>(); // Create an InstanceContent to hold capabilities... instanceContent = new InstanceContent(); // Create an AbstractLookup to expose the InstanceContent... lookup = new AbstractLookup(instanceContent); // Add a "Read" capability to the Lookup of the provider: instanceContent.add(new ReadCapability() { @Override public void read() throws Exception { ProgressHandle handle = ProgressHandleFactory.createHandle("Loading..."); handle.start(); customerSet.addAll(new CustomerDataAccess().getAllCustomers()); handle.finish(); } }); // Add a "Update" capability to the Lookup of the provider: //...to come... // Add a "Create" capability to the Lookup of the provider: //...to come... // Add a "Delete" capability to the Lookup of the provider: //...to come... } @Override public Lookup getLookup() { return lookup; } public Set<Customer> getCustomers() { return customerSet; } } Point out that we can now create a new instance of our Lookup (in some other module, so long as it has a dependency on the module providing the CustomerLookupProvider and the ReadCapability), retrieve the ReadCapability, and then do something with the customers that are returned, here in the rewritten constructor of the TopComponent, without needing to know anything about how the database access is actually achieved since that is hidden in the implementation of our type, above: public CustomerViewerTopComponent() { initComponents(); setName(Bundle.CTL_CustomerViewerTopComponent()); setToolTipText(Bundle.HINT_CustomerViewerTopComponent()); // EntityManager entityManager = Persistence.createEntityManagerFactory("CustomerLibraryPU").createEntityManager(); // Query query = entityManager.createNamedQuery("Customer.findAll"); // List<Customer> resultList = query.getResultList(); // for (Customer c : resultList) { // jTextArea1.append(c.getName() + " (" + c.getCity() + ")" + "\n"); // } CustomerLookupProvider lookup = new CustomerLookupProvider(); ReadCapability rc = lookup.getLookup().lookup(ReadCapability.class); try { rc.read(); for (Customer c : lookup.getCustomers()) { jTextArea1.append(c.getName() + " (" + c.getCity() + ")" + "\n"); } } catch (Exception ex) { Exceptions.printStackTrace(ex); } } Does the above make as much sense to others as it does to me, including the naming of the classes? Feedback would be appreciated! Then I'll integrate into the tutorial and do the same for the other sections, i.e., "Create", "Update", and "Delete". (By the way, of course, the tutorial ends up showing that, rather than using a JTextArea to display data, you can use Nodes and explorer views to do so.)

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  • tile_static, tile_barrier, and tiled matrix multiplication with C++ AMP

    - by Daniel Moth
    We ended the previous post with a mechanical transformation of the C++ AMP matrix multiplication example to the tiled model and in the process introduced tiled_index and tiled_grid. This is part 2. tile_static memory You all know that in regular CPU code, static variables have the same value regardless of which thread accesses the static variable. This is in contrast with non-static local variables, where each thread has its own copy. Back to C++ AMP, the same rules apply and each thread has its own value for local variables in your lambda, whereas all threads see the same global memory, which is the data they have access to via the array and array_view. In addition, on an accelerator like the GPU, there is a programmable cache, a third kind of memory type if you'd like to think of it that way (some call it shared memory, others call it scratchpad memory). Variables stored in that memory share the same value for every thread in the same tile. So, when you use the tiled model, you can have variables where each thread in the same tile sees the same value for that variable, that threads from other tiles do not. The new storage class for local variables introduced for this purpose is called tile_static. You can only use tile_static in restrict(direct3d) functions, and only when explicitly using the tiled model. What this looks like in code should be no surprise, but here is a snippet to confirm your mental image, using a good old regular C array // each tile of threads has its own copy of locA, // shared among the threads of the tile tile_static float locA[16][16]; Note that tile_static variables are scoped and have the lifetime of the tile, and they cannot have constructors or destructors. tile_barrier In amp.h one of the types introduced is tile_barrier. You cannot construct this object yourself (although if you had one, you could use a copy constructor to create another one). So how do you get one of these? You get it, from a tiled_index object. Beyond the 4 properties returning index objects, tiled_index has another property, barrier, that returns a tile_barrier object. The tile_barrier class exposes a single member, the method wait. 15: // Given a tiled_index object named t_idx 16: t_idx.barrier.wait(); 17: // more code …in the code above, all threads in the tile will reach line 16 before a single one progresses to line 17. Note that all threads must be able to reach the barrier, i.e. if you had branchy code in such a way which meant that there is a chance that not all threads could reach line 16, then the code above would be illegal. Tiled Matrix Multiplication Example – part 2 So now that we added to our understanding the concepts of tile_static and tile_barrier, let me obfuscate rewrite the matrix multiplication code so that it takes advantage of tiling. Before you start reading this, I suggest you get a cup of your favorite non-alcoholic beverage to enjoy while you try to fully understand the code. 01: void MatrixMultiplyTiled(vector<float>& vC, const vector<float>& vA, const vector<float>& vB, int M, int N, int W) 02: { 03: static const int TS = 16; 04: array_view<const float,2> a(M, W, vA); 05: array_view<const float,2> b(W, N, vB); 06: array_view<writeonly<float>,2> c(M,N,vC); 07: parallel_for_each(c.grid.tile< TS, TS >(), 08: [=] (tiled_index< TS, TS> t_idx) restrict(direct3d) 09: { 10: int row = t_idx.local[0]; int col = t_idx.local[1]; 11: float sum = 0.0f; 12: for (int i = 0; i < W; i += TS) { 13: tile_static float locA[TS][TS], locB[TS][TS]; 14: locA[row][col] = a(t_idx.global[0], col + i); 15: locB[row][col] = b(row + i, t_idx.global[1]); 16: t_idx.barrier.wait(); 17: for (int k = 0; k < TS; k++) 18: sum += locA[row][k] * locB[k][col]; 19: t_idx.barrier.wait(); 20: } 21: c[t_idx.global] = sum; 22: }); 23: } Notice that all the code up to line 9 is the same as per the changes we made in part 1 of tiling introduction. If you squint, the body of the lambda itself preserves the original algorithm on lines 10, 11, and 17, 18, and 21. The difference being that those lines use new indexing and the tile_static arrays; the tile_static arrays are declared and initialized on the brand new lines 13-15. On those lines we copy from the global memory represented by the array_view objects (a and b), to the tile_static vanilla arrays (locA and locB) – we are copying enough to fit a tile. Because in the code that follows on line 18 we expect the data for this tile to be in the tile_static storage, we need to synchronize the threads within each tile with a barrier, which we do on line 16 (to avoid accessing uninitialized memory on line 18). We also need to synchronize the threads within a tile on line 19, again to avoid the race between lines 14, 15 (retrieving the next set of data for each tile and overwriting the previous set) and line 18 (not being done processing the previous set of data). Luckily, as part of the awesome C++ AMP debugger in Visual Studio there is an option that helps you find such races, but that is a story for another blog post another time. May I suggest reading the next section, and then coming back to re-read and walk through this code with pen and paper to really grok what is going on, if you haven't already? Cool. Why would I introduce this tiling complexity into my code? Funny you should ask that, I was just about to tell you. There is only one reason we tiled our extent, had to deal with finding a good tile size, ensure the number of threads we schedule are correctly divisible with the tile size, had to use a tiled_index instead of a normal index, and had to understand tile_barrier and to figure out where we need to use it, and double the size of our lambda in terms of lines of code: the reason is to be able to use tile_static memory. Why do we want to use tile_static memory? Because accessing tile_static memory is around 10 times faster than accessing the global memory on an accelerator like the GPU, e.g. in the code above, if you can get 150GB/second accessing data from the array_view a, you can get 1500GB/second accessing the tile_static array locA. And since by definition you are dealing with really large data sets, the savings really pay off. We have seen tiled implementations being twice as fast as their non-tiled counterparts. Now, some algorithms will not have performance benefits from tiling (and in fact may deteriorate), e.g. algorithms that require you to go only once to global memory will not benefit from tiling, since with tiling you already have to fetch the data once from global memory! Other algorithms may benefit, but you may decide that you are happy with your code being 150 times faster than the serial-version you had, and you do not need to invest to make it 250 times faster. Also algorithms with more than 3 dimensions, which C++ AMP supports in the non-tiled model, cannot be tiled. Also note that in future releases, we may invest in making the non-tiled model, which already uses tiling under the covers, go the extra step and use tile_static memory on your behalf, but it is obviously way to early to commit to anything like that, and we certainly don't do any of that today. Comments about this post by Daniel Moth welcome at the original blog.

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  • Consuming the Amazon S3 service from a Win8 Metro Application

    - by cibrax
    As many of the existing Http APIs for Cloud Services, AWS also provides a set of different platform SDKs for hiding many of complexities present in the APIs. While there is a platform SDK for .NET, which is open source and available in C#, that SDK does not work in Win8 Metro Applications for the changes introduced in WinRT. WinRT offers a complete different set of APIs for doing I/O operations such as doing http calls or using cryptography for signing or encrypting data, two aspects that are absolutely necessary for consuming AWS. All the I/O APIs available as part of WinRT are asynchronous, and uses the TPL model for .NET applications (HTML and JavaScript Metro applications use a model based in promises, which is similar concept).  In the case of S3, the http Authorization header is used for two purposes, authenticating clients and make sure the messages were not altered while they were in transit. For doing that, it uses a signature or hash of the message content and some of the headers using a symmetric key (That's just one of the available mechanisms). Windows Azure for example also uses the same mechanism in many of its APIs. There are three challenges that any developer working for first time in Metro will have to face to consume S3, the new WinRT APIs, the asynchronous nature of them and the complexity introduced for generating the Authorization header. Having said that, I decided to write this post with some of the gotchas I found myself trying to consume this Amazon service. 1. Generating the signature for the Authorization header All the cryptography APIs in WinRT are available under Windows.Security.Cryptography namespace. Many of operations available in these APIs uses the concept of buffers (IBuffer) for representing a chunk of binary data. As you will see in the example below, these buffers are mainly generated with the use of static methods in a WinRT class CryptographicBuffer available as part of the namespace previously mentioned. private string DeriveAuthToken(string resource, string httpMethod, string timestamp) { var stringToSign = string.Format("{0}\n" + "\n" + "\n" + "\n" + "x-amz-date:{1}\n" + "/{2}/", httpMethod, timestamp, resource); var algorithm = MacAlgorithmProvider.OpenAlgorithm("HMAC_SHA1"); var keyMaterial = CryptographicBuffer.CreateFromByteArray(Encoding.UTF8.GetBytes(this.secret)); var hmacKey = algorithm.CreateKey(keyMaterial); var signature = CryptographicEngine.Sign( hmacKey, CryptographicBuffer.CreateFromByteArray(Encoding.UTF8.GetBytes(stringToSign)) ); return CryptographicBuffer.EncodeToBase64String(signature); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The algorithm that determines the information or content you need to use for generating the signature is very well described as part of the AWS documentation. In this case, this method is generating a signature required for creating a new bucket. A HmacSha1 hash is computed using a secret or symetric key provided by AWS in the management console. 2. Sending an Http Request to the S3 service WinRT also ships with the System.Net.Http.HttpClient that was first introduced some months ago with ASP.NET Web API. This client provides a rich interface on top the traditional WebHttpRequest class, and also solves some of limitations found in this last one. There are a few things that don't work with a raw WebHttpRequest such as setting the Host header, which is something absolutely required for consuming S3. Also, HttpClient is more friendly for doing unit tests, as it receives a HttpMessageHandler as part of the constructor that can fake to emulate a real http call. This is how the code for consuming the service with HttpClient looks like, public async Task<S3Response> CreateBucket(string name, string region = null, params string[] acl) { var timestamp = string.Format("{0:r}", DateTime.UtcNow); var auth = DeriveAuthToken(name, "PUT", timestamp); var request = new HttpRequestMessage(HttpMethod.Put, "http://s3.amazonaws.com/"); request.Headers.Host = string.Format("{0}.s3.amazonaws.com", name); request.Headers.TryAddWithoutValidation("Authorization", "AWS " + this.key + ":" + auth); request.Headers.Add("x-amz-date", timestamp); var client = new HttpClient(); var response = await client.SendAsync(request); return new S3Response { Succeed = response.StatusCode == HttpStatusCode.OK, Message = (response.Content != null) ? await response.Content.ReadAsStringAsync() : null }; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } You will notice a few additional things in this code. By default, HttpClient validates the values for some well-know headers, and Authorization is one of them. It won't allow you to set a value with ":" on it, which is something that S3 expects. However, that's not a problem at all, as you can skip the validation by using the TryAddWithoutValidation method. Also, the code is heavily relying on the new async and await keywords to transform all the asynchronous calls into synchronous ones. In case you would want to unit test this code and faking the call to the real S3 service, you should have to modify it to inject a custom HttpMessageHandler into the HttpClient. The following implementation illustrates this concept, In case you would want to unit test this code and faking the call to the real S3 service, you should have to modify it to inject a custom HttpMessageHandler into the HttpClient. The following implementation illustrates this concept, public class FakeHttpMessageHandler : HttpMessageHandler { HttpResponseMessage response; public FakeHttpMessageHandler(HttpResponseMessage response) { this.response = response; } protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, System.Threading.CancellationToken cancellationToken) { var tcs = new TaskCompletionSource<HttpResponseMessage>(); tcs.SetResult(response); return tcs.Task; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } You can use this handler for injecting any response while you are unit testing the code.

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  • Consuming the Amazon S3 service from a Win8 Metro Application

    - by cibrax
    As many of the existing Http APIs for Cloud Services, AWS also provides a set of different platform SDKs for hiding many of complexities present in the APIs. While there is a platform SDK for .NET, which is open source and available in C#, that SDK does not work in Win8 Metro Applications for the changes introduced in WinRT. WinRT offers a complete different set of APIs for doing I/O operations such as doing http calls or using cryptography for signing or encrypting data, two aspects that are absolutely necessary for consuming AWS. All the I/O APIs available as part of WinRT are asynchronous, and uses the TPL model for .NET applications (HTML and JavaScript Metro applications use a model based in promises, which is similar concept).  In the case of S3, the http Authorization header is used for two purposes, authenticating clients and make sure the messages were not altered while they were in transit. For doing that, it uses a signature or hash of the message content and some of the headers using a symmetric key (That's just one of the available mechanisms). Windows Azure for example also uses the same mechanism in many of its APIs. There are three challenges that any developer working for first time in Metro will have to face to consume S3, the new WinRT APIs, the asynchronous nature of them and the complexity introduced for generating the Authorization header. Having said that, I decided to write this post with some of the gotchas I found myself trying to consume this Amazon service. 1. Generating the signature for the Authorization header All the cryptography APIs in WinRT are available under Windows.Security.Cryptography namespace. Many of operations available in these APIs uses the concept of buffers (IBuffer) for representing a chunk of binary data. As you will see in the example below, these buffers are mainly generated with the use of static methods in a WinRT class CryptographicBuffer available as part of the namespace previously mentioned. private string DeriveAuthToken(string resource, string httpMethod, string timestamp) { var stringToSign = string.Format("{0}\n" + "\n" + "\n" + "\n" + "x-amz-date:{1}\n" + "/{2}/", httpMethod, timestamp, resource); var algorithm = MacAlgorithmProvider.OpenAlgorithm("HMAC_SHA1"); var keyMaterial = CryptographicBuffer.CreateFromByteArray(Encoding.UTF8.GetBytes(this.secret)); var hmacKey = algorithm.CreateKey(keyMaterial); var signature = CryptographicEngine.Sign( hmacKey, CryptographicBuffer.CreateFromByteArray(Encoding.UTF8.GetBytes(stringToSign)) ); return CryptographicBuffer.EncodeToBase64String(signature); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The algorithm that determines the information or content you need to use for generating the signature is very well described as part of the AWS documentation. In this case, this method is generating a signature required for creating a new bucket. A HmacSha1 hash is computed using a secret or symetric key provided by AWS in the management console. 2. Sending an Http Request to the S3 service WinRT also ships with the System.Net.Http.HttpClient that was first introduced some months ago with ASP.NET Web API. This client provides a rich interface on top the traditional WebHttpRequest class, and also solves some of limitations found in this last one. There are a few things that don't work with a raw WebHttpRequest such as setting the Host header, which is something absolutely required for consuming S3. Also, HttpClient is more friendly for doing unit tests, as it receives a HttpMessageHandler as part of the constructor that can fake to emulate a real http call. This is how the code for consuming the service with HttpClient looks like, public async Task<S3Response> CreateBucket(string name, string region = null, params string[] acl) { var timestamp = string.Format("{0:r}", DateTime.UtcNow); var auth = DeriveAuthToken(name, "PUT", timestamp); var request = new HttpRequestMessage(HttpMethod.Put, "http://s3.amazonaws.com/"); request.Headers.Host = string.Format("{0}.s3.amazonaws.com", name); request.Headers.TryAddWithoutValidation("Authorization", "AWS " + this.key + ":" + auth); request.Headers.Add("x-amz-date", timestamp); var client = new HttpClient(); var response = await client.SendAsync(request); return new S3Response { Succeed = response.StatusCode == HttpStatusCode.OK, Message = (response.Content != null) ? await response.Content.ReadAsStringAsync() : null }; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } You will notice a few additional things in this code. By default, HttpClient validates the values for some well-know headers, and Authorization is one of them. It won't allow you to set a value with ":" on it, which is something that S3 expects. However, that's not a problem at all, as you can skip the validation by using the TryAddWithoutValidation method. Also, the code is heavily relying on the new async and await keywords to transform all the asynchronous calls into synchronous ones. In case you would want to unit test this code and faking the call to the real S3 service, you should have to modify it to inject a custom HttpMessageHandler into the HttpClient. The following implementation illustrates this concept, In case you would want to unit test this code and faking the call to the real S3 service, you should have to modify it to inject a custom HttpMessageHandler into the HttpClient. The following implementation illustrates this concept, public class FakeHttpMessageHandler : HttpMessageHandler { HttpResponseMessage response; public FakeHttpMessageHandler(HttpResponseMessage response) { this.response = response; } protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, System.Threading.CancellationToken cancellationToken) { var tcs = new TaskCompletionSource<HttpResponseMessage>(); tcs.SetResult(response); return tcs.Task; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } You can use this handler for injecting any response while you are unit testing the code.

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  • Use a Fake Http Channel to Unit Test with HttpClient

    - by Steve Michelotti
    Applications get data from lots of different sources. The most common is to get data from a database or a web service. Typically, we encapsulate calls to a database in a Repository object and we create some sort of IRepository interface as an abstraction to decouple between layers and enable easier unit testing by leveraging faking and mocking. This works great for database interaction. However, when consuming a RESTful web service, this is is not always the best approach. The WCF Web APIs that are available on CodePlex (current drop is Preview 3) provide a variety of features to make building HTTP REST services more robust. When you download the latest bits, you’ll also find a new HttpClient which has been updated for .NET 4.0 as compared to the one that shipped for 3.5 in the original REST Starter Kit. The HttpClient currently provides the best API for consuming REST services on the .NET platform and the WCF Web APIs provide a number of extension methods which extend HttpClient and make it even easier to use. Let’s say you have a client application that is consuming an HTTP service – this could be Silverlight, WPF, or any UI technology but for my example I’ll use an MVC application: 1: using System; 2: using System.Net.Http; 3: using System.Web.Mvc; 4: using FakeChannelExample.Models; 5: using Microsoft.Runtime.Serialization; 6:   7: namespace FakeChannelExample.Controllers 8: { 9: public class HomeController : Controller 10: { 11: private readonly HttpClient httpClient; 12:   13: public HomeController(HttpClient httpClient) 14: { 15: this.httpClient = httpClient; 16: } 17:   18: public ActionResult Index() 19: { 20: var response = httpClient.Get("Person(1)"); 21: var person = response.Content.ReadAsDataContract<Person>(); 22:   23: this.ViewBag.Message = person.FirstName + " " + person.LastName; 24: 25: return View(); 26: } 27: } 28: } On line #20 of the code above you can see I’m performing an HTTP GET request to a Person resource exposed by an HTTP service. On line #21, I use the ReadAsDataContract() extension method provided by the WCF Web APIs to serialize to a Person object. In this example, the HttpClient is being passed into the constructor by MVC’s dependency resolver – in this case, I’m using StructureMap as an IoC and my StructureMap initialization code looks like this: 1: using StructureMap; 2: using System.Net.Http; 3:   4: namespace FakeChannelExample 5: { 6: public static class IoC 7: { 8: public static IContainer Initialize() 9: { 10: ObjectFactory.Initialize(x => 11: { 12: x.For<HttpClient>().Use(() => new HttpClient("http://localhost:31614/")); 13: }); 14: return ObjectFactory.Container; 15: } 16: } 17: } My controller code currently depends on a concrete instance of the HttpClient. Now I *could* create some sort of interface and wrap the HttpClient in this interface and use that object inside my controller instead – however, there are a few why reasons that is not desirable: For one thing, the API provided by the HttpClient provides nice features for dealing with HTTP services. I don’t really *want* these to look like C# RPC method calls – when HTTP services have REST features, I may want to inspect HTTP response headers and hypermedia contained within the message so that I can make intelligent decisions as to what to do next in my workflow (although I don’t happen to be doing these things in my example above) – this type of workflow is common in hypermedia REST scenarios. If I just encapsulate HttpClient behind some IRepository interface and make it look like a C# RPC method call, it will become difficult to take advantage of these types of things. Second, it could get pretty mind-numbing to have to create interfaces all over the place just to wrap the HttpClient. Then you’re probably going to have to hard-code HTTP knowledge into your code to formulate requests rather than just “following the links” that the hypermedia in a message might provide. Third, at first glance it might appear that we need to create an interface to facilitate unit testing, but actually it’s unnecessary. Even though the code above is dependent on a concrete type, it’s actually very easy to fake the data in a unit test. The HttpClient provides a Channel property (of type HttpMessageChannel) which allows you to create a fake message channel which can be leveraged in unit testing. In this case, what I want is to be able to write a unit test that just returns fake data. I also want this to be as re-usable as possible for my unit testing. I want to be able to write a unit test that looks like this: 1: [TestClass] 2: public class HomeControllerTest 3: { 4: [TestMethod] 5: public void Index() 6: { 7: // Arrange 8: var httpClient = new HttpClient("http://foo.com"); 9: httpClient.Channel = new FakeHttpChannel<Person>(new Person { FirstName = "Joe", LastName = "Blow" }); 10:   11: HomeController controller = new HomeController(httpClient); 12:   13: // Act 14: ViewResult result = controller.Index() as ViewResult; 15:   16: // Assert 17: Assert.AreEqual("Joe Blow", result.ViewBag.Message); 18: } 19: } Notice on line #9, I’m setting the Channel property of the HttpClient to be a fake channel. I’m also specifying the fake object that I want to be in the response on my “fake” Http request. I don’t need to rely on any mocking frameworks to do this. All I need is my FakeHttpChannel. The code to do this is not complex: 1: using System; 2: using System.IO; 3: using System.Net.Http; 4: using System.Runtime.Serialization; 5: using System.Threading; 6: using FakeChannelExample.Models; 7:   8: namespace FakeChannelExample.Tests 9: { 10: public class FakeHttpChannel<T> : HttpClientChannel 11: { 12: private T responseObject; 13:   14: public FakeHttpChannel(T responseObject) 15: { 16: this.responseObject = responseObject; 17: } 18:   19: protected override HttpResponseMessage Send(HttpRequestMessage request, CancellationToken cancellationToken) 20: { 21: return new HttpResponseMessage() 22: { 23: RequestMessage = request, 24: Content = new StreamContent(this.GetContentStream()) 25: }; 26: } 27:   28: private Stream GetContentStream() 29: { 30: var serializer = new DataContractSerializer(typeof(T)); 31: Stream stream = new MemoryStream(); 32: serializer.WriteObject(stream, this.responseObject); 33: stream.Position = 0; 34: return stream; 35: } 36: } 37: } The HttpClientChannel provides a Send() method which you can override to return any HttpResponseMessage that you want. You can see I’m using the DataContractSerializer to serialize the object and write it to a stream. That’s all you need to do. In the example above, the only thing I’ve chosen to do is to provide a way to return different response objects. But there are many more features you could add to your own re-usable FakeHttpChannel. For example, you might want to provide the ability to add HTTP headers to the message. You might want to use a different serializer other than the DataContractSerializer. You might want to provide custom hypermedia in the response as well as just an object or set HTTP response codes. This list goes on. This is the just one example of the really cool features being added to the next version of WCF to enable various HTTP scenarios. The code sample for this post can be downloaded here.

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  • RiverTrail - JavaScript GPPGU Data Parallelism

    - by JoshReuben
    Where is WebCL ? The Khronos WebCL working group is working on a JavaScript binding to the OpenCL standard so that HTML 5 compliant browsers can host GPGPU web apps – e.g. for image processing or physics for WebGL games - http://www.khronos.org/webcl/ . While Nokia & Samsung have some protype WebCL APIs, Intel has one-upped them with a higher level of abstraction: RiverTrail. Intro to RiverTrail Intel Labs JavaScript RiverTrail provides GPU accelerated SIMD data-parallelism in web applications via a familiar JavaScript programming paradigm. It extends JavaScript with simple deterministic data-parallel constructs that are translated at runtime into a low-level hardware abstraction layer. With its high-level JS API, programmers do not have to learn a new language or explicitly manage threads, orchestrate shared data synchronization or scheduling. It has been proposed as a draft specification to ECMA a (known as ECMA strawman). RiverTrail runs in all popular browsers (except I.E. of course). To get started, download a prebuilt version https://github.com/downloads/RiverTrail/RiverTrail/rivertrail-0.17.xpi , install Intel's OpenCL SDK http://www.intel.com/go/opencl and try out the interactive River Trail shell http://rivertrail.github.com/interactive For a video overview, see  http://www.youtube.com/watch?v=jueg6zB5XaM . ParallelArray the ParallelArray type is the central component of this API & is a JS object that contains ordered collections of scalars – i.e. multidimensional uniform arrays. A shape property describes the dimensionality and size– e.g. a 2D RGBA image will have shape [height, width, 4]. ParallelArrays are immutable & fluent – they are manipulated by invoking methods on them which produce new ParallelArray objects. ParallelArray supports several constructors over arrays, functions & even the canvas. // Create an empty Parallel Array var pa = new ParallelArray(); // pa0 = <>   // Create a ParallelArray out of a nested JS array. // Note that the inner arrays are also ParallelArrays var pa = new ParallelArray([ [0,1], [2,3], [4,5] ]); // pa1 = <<0,1>, <2,3>, <4.5>>   // Create a two-dimensional ParallelArray with shape [3, 2] using the comprehension constructor var pa = new ParallelArray([3, 2], function(iv){return iv[0] * iv[1];}); // pa7 = <<0,0>, <0,1>, <0,2>>   // Create a ParallelArray from canvas.  This creates a PA with shape [w, h, 4], var pa = new ParallelArray(canvas); // pa8 = CanvasPixelArray   ParallelArray exposes fluent API functions that take an elemental JS function for data manipulation: map, combine, scan, filter, and scatter that return a new ParallelArray. Other functions are scalar - reduce  returns a scalar value & get returns the value located at a given index. The onus is on the developer to ensure that the elemental function does not defeat data parallelization optimization (avoid global var manipulation, recursion). For reduce & scan, order is not guaranteed - the onus is on the dev to provide an elemental function that is commutative and associative so that scan will be deterministic – E.g. Sum is associative, but Avg is not. map Applies a provided elemental function to each element of the source array and stores the result in the corresponding position in the result array. The map method is shape preserving & index free - can not inspect neighboring values. // Adding one to each element. var source = new ParallelArray([1,2,3,4,5]); var plusOne = source.map(function inc(v) {     return v+1; }); //<2,3,4,5,6> combine Combine is similar to map, except an index is provided. This allows elemental functions to access elements from the source array relative to the one at the current index position. While the map method operates on the outermost dimension only, combine, can choose how deep to traverse - it provides a depth argument to specify the number of dimensions it iterates over. The elemental function of combine accesses the source array & the current index within it - element is computed by calling the get method of the source ParallelArray object with index i as argument. It requires more code but is more expressive. var source = new ParallelArray([1,2,3,4,5]); var plusOne = source.combine(function inc(i) { return this.get(i)+1; }); reduce reduces the elements from an array to a single scalar result – e.g. Sum. // Calculate the sum of the elements var source = new ParallelArray([1,2,3,4,5]); var sum = source.reduce(function plus(a,b) { return a+b; }); scan Like reduce, but stores the intermediate results – return a ParallelArray whose ith elements is the results of using the elemental function to reduce the elements between 0 and I in the original ParallelArray. // do a partial sum var source = new ParallelArray([1,2,3,4,5]); var psum = source.scan(function plus(a,b) { return a+b; }); //<1, 3, 6, 10, 15> scatter a reordering function - specify for a certain source index where it should be stored in the result array. An optional conflict function can prevent an exception if two source values are assigned the same position of the result: var source = new ParallelArray([1,2,3,4,5]); var reorder = source.scatter([4,0,3,1,2]); // <2, 4, 5, 3, 1> // if there is a conflict use the max. use 33 as a default value. var reorder = source.scatter([4,0,3,4,2], 33, function max(a, b) {return a>b?a:b; }); //<2, 33, 5, 3, 4> filter // filter out values that are not even var source = new ParallelArray([1,2,3,4,5]); var even = source.filter(function even(iv) { return (this.get(iv) % 2) == 0; }); // <2,4> Flatten used to collapse the outer dimensions of an array into a single dimension. pa = new ParallelArray([ [1,2], [3,4] ]); // <<1,2>,<3,4>> pa.flatten(); // <1,2,3,4> Partition used to restore the original shape of the array. var pa = new ParallelArray([1,2,3,4]); // <1,2,3,4> pa.partition(2); // <<1,2>,<3,4>> Get return value found at the indices or undefined if no such value exists. var pa = new ParallelArray([0,1,2,3,4], [10,11,12,13,14], [20,21,22,23,24]) pa.get([1,1]); // 11 pa.get([1]); // <10,11,12,13,14>

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  • Refactoring FizzBuzz

    - by MarkPearl
    A few years ago I blogger about FizzBuzz, at the time the post was prompted by Scott Hanselman who had podcasted about how surprized he was that some programmers could not even solve the FizzBuzz problem within a reasonable period of time during a job interview. At the time I thought I would give the problem a go in F# and sure enough the solution was fairly simple – I then also did a basic solution in C# but never posted it. Since then I have learned that being able to solve a problem and how you solve the problem are two totally different things. Today I decided to give the problem a retry and see if I had learnt anything new in the last year or so. Here is how my solution looked after refactoring… Solution 1 – Cheap and Nasty public class FizzBuzzCalculator { public string NumberFormat(int number) { var numDivisibleBy3 = (number % 3) == 0; var numDivisibleBy5 = (number % 5) == 0; if (numDivisibleBy3 && numDivisibleBy5) return String.Format("{0} FizzBuz", number); else if (numDivisibleBy3) return String.Format("{0} Fizz", number); else if (numDivisibleBy5) return String.Format("{0} Buz", number); return number.ToString(); } } class Program { static void Main(string[] args) { var fizzBuzz = new FizzBuzzCalculator(); for (int i = 0; i < 100; i++) { Console.WriteLine(fizzBuzz.NumberFormat(i)); } } } My first attempt I just looked at solving the problem – it works, and could be an acceptable solution but tonight I thought I would see how far  I could refactor it… The section I decided to focus on was the mass of if..else code in the NumberFormat method. Solution 2 – Replacing If…Else with a Dictionary public class FizzBuzzCalculator { private readonly Dictionary<Tuple<bool, bool>, string> _mappings; public FizzBuzzCalculator(Dictionary<Tuple<bool, bool>, string> mappings) { _mappings = mappings; } public string NumberFormat(int number) { var numDivisibleBy3 = (number % 3) == 0; var numDivisibleBy5 = (number % 5) == 0; var mappedKey = new Tuple<bool, bool>(numDivisibleBy3, numDivisibleBy5); return String.Format("{0} {1}", number, _mappings[mappedKey]); } } class Program { static void Main(string[] args) { var mappings = new Dictionary<Tuple<bool, bool>, string> { { new Tuple<bool, bool>(true, true), "- FizzBuzz"}, { new Tuple<bool, bool>(true, false), "- Fizz"}, { new Tuple<bool, bool>(false, true), "- Buzz"}, { new Tuple<bool, bool>(false, false), ""} }; var fizzBuzz = new FizzBuzzCalculator(mappings); for (int i = 0; i < 100; i++) { Console.WriteLine(fizzBuzz.NumberFormat(i)); } Console.ReadLine(); } } In my second attempt I looked at removing the if else in the NumberFormat method. A dictionary proved to be useful for this – I added a constructor to the class and injected the dictionary mapping. One could argue that this is totally overkill, but if I was going to use this code in a large system an approach like this makes it easy to put this data in a configuration file, which would up its OC (Open for extensibility, closed for modification principle). I could of course take the OC principle even further – the check for divisibility by 3 and 5 is tightly coupled to this class. If I wanted to make it 4 instead of 3, I would need to adjust this class. This introduces my third refactoring. Solution 3 – Introducing Delegates and Injecting them into the class public delegate bool FizzBuzzComparison(int number); public class FizzBuzzCalculator { private readonly Dictionary<Tuple<bool, bool>, string> _mappings; private readonly FizzBuzzComparison _comparison1; private readonly FizzBuzzComparison _comparison2; public FizzBuzzCalculator(Dictionary<Tuple<bool, bool>, string> mappings, FizzBuzzComparison comparison1, FizzBuzzComparison comparison2) { _mappings = mappings; _comparison1 = comparison1; _comparison2 = comparison2; } public string NumberFormat(int number) { var mappedKey = new Tuple<bool, bool>(_comparison1(number), _comparison2(number)); return String.Format("{0} {1}", number, _mappings[mappedKey]); } } class Program { private static bool DivisibleByNum(int number, int divisor) { return number % divisor == 0; } public static bool Divisibleby3(int number) { return number % 3 == 0; } public static bool Divisibleby5(int number) { return number % 5 == 0; } static void Main(string[] args) { var mappings = new Dictionary<Tuple<bool, bool>, string> { { new Tuple<bool, bool>(true, true), "- FizzBuzz"}, { new Tuple<bool, bool>(true, false), "- Fizz"}, { new Tuple<bool, bool>(false, true), "- Buzz"}, { new Tuple<bool, bool>(false, false), ""} }; var fizzBuzz = new FizzBuzzCalculator(mappings, Divisibleby3, Divisibleby5); for (int i = 0; i < 100; i++) { Console.WriteLine(fizzBuzz.NumberFormat(i)); } Console.ReadLine(); } } I have taken this one step further and introduced delegates that are injected into the FizzBuzz Calculator class, from an OC principle perspective it has probably made it more compliant than the previous Solution 2, but there seems to be a lot of noise. Anonymous Delegates increase the readability level, which is what I have done in Solution 4. Solution 4 – Anon Delegates public delegate bool FizzBuzzComparison(int number); public class FizzBuzzCalculator { private readonly Dictionary<Tuple<bool, bool>, string> _mappings; private readonly FizzBuzzComparison _comparison1; private readonly FizzBuzzComparison _comparison2; public FizzBuzzCalculator(Dictionary<Tuple<bool, bool>, string> mappings, FizzBuzzComparison comparison1, FizzBuzzComparison comparison2) { _mappings = mappings; _comparison1 = comparison1; _comparison2 = comparison2; } public string NumberFormat(int number) { var mappedKey = new Tuple<bool, bool>(_comparison1(number), _comparison2(number)); return String.Format("{0} {1}", number, _mappings[mappedKey]); } } class Program { static void Main(string[] args) { var mappings = new Dictionary<Tuple<bool, bool>, string> { { new Tuple<bool, bool>(true, true), "- FizzBuzz"}, { new Tuple<bool, bool>(true, false), "- Fizz"}, { new Tuple<bool, bool>(false, true), "- Buzz"}, { new Tuple<bool, bool>(false, false), ""} }; var fizzBuzz = new FizzBuzzCalculator(mappings, (n) => n % 3 == 0, (n) => n % 5 == 0); for (int i = 0; i < 100; i++) { Console.WriteLine(fizzBuzz.NumberFormat(i)); } Console.ReadLine(); } }   Using the anonymous delegates I think the noise level has now been reduced. This is where I am going to end this post, I have gone through 4 iterations of the code from the initial solution using If..Else to delegates and dictionaries. I think each approach would have it’s pro’s and con’s and depending on the intention of where the code would be used would be a large determining factor. If you can think of an alternative way to do FizzBuzz, add a comment!

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  • &lt;%: %&gt;, HtmlEncode, IHtmlString and MvcHtmlString

    - by Shaun
    One of my colleague and friend, Robin is playing and struggling with the ASP.NET MVC 2 on a project these days while I’m struggling with a annoying client. Since it’s his first time to use ASP.NET MVC he was meetings with a lot of problem and I was very happy to share my experience to him. Yesterday he asked me when he attempted to insert a <br /> element into his page he found that the page was rendered like this which is bad. He found his <br /> was shown as a part of the string rather than creating a new line. After checked a bit in his code I found that it’s because he utilized a new ASP.NET markup supported in .NET 4.0 – “<%: %>”. If you have been using ASP.NET MVC 1 or in .NET 3.5 world it would be very common that using <%= %> to show something on the page from the backend code. But when you do it you must ensure that the string that are going to be displayed should be Html-safe, which means all the Html markups must be encoded. Otherwise this might cause an XSS (cross-site scripting) problem. So that you’d better use the code like this below to display anything on the page. In .NET 4.0 Microsoft introduced a new markup to solve this problem which is <%: %>. It will encode the content automatically so that you will no need to check and verify your code manually for the XSS issue mentioned below. But this also means that it will encode all things, include the Html element you want to be rendered. So I changed his code like this and it worked well. After helped him solved this problem and finished a spreadsheet for my boring project I considered a bit more on the <%: %>. Since it will encode all thing why it renders correctly when we use “<%: Html.TextBox(“name”) %>” to show a text box? As you know the Html.TextBox will render a “<input name="name" id="name" type="text"/>” element on the page. If <%: %> will encode everything it should not display a text box. So I dig into the source code of the MVC and found some comments in the class MvcHtmlString. 1: // In ASP.NET 4, a new syntax <%: %> is being introduced in WebForms pages, where <%: expression %> is equivalent to 2: // <%= HttpUtility.HtmlEncode(expression) %>. The intent of this is to reduce common causes of XSS vulnerabilities 3: // in WebForms pages (WebForms views in the case of MVC). This involves the addition of an interface 4: // System.Web.IHtmlString and a static method overload System.Web.HttpUtility::HtmlEncode(object). The interface 5: // definition is roughly: 6: // public interface IHtmlString { 7: // string ToHtmlString(); 8: // } 9: // And the HtmlEncode(object) logic is roughly: 10: // - If the input argument is an IHtmlString, return argument.ToHtmlString(), 11: // - Otherwise, return HtmlEncode(Convert.ToString(argument)). 12: // 13: // Unfortunately this has the effect that calling <%: Html.SomeHelper() %> in an MVC application running on .NET 4 14: // will end up encoding output that is already HTML-safe. As a result, we're changing out HTML helpers to return 15: // MvcHtmlString where appropriate. <%= Html.SomeHelper() %> will continue to work in both .NET 3.5 and .NET 4, but 16: // changing the return types to MvcHtmlString has the added benefit that <%: Html.SomeHelper() %> will also work 17: // properly in .NET 4 rather than resulting in a double-encoded output. MVC developers in .NET 4 will then be able 18: // to use the <%: %> syntax almost everywhere instead of having to remember where to use <%= %> and where to use 19: // <%: %>. This should help developers craft more secure web applications by default. 20: // 21: // To create an MvcHtmlString, use the static Create() method instead of calling the protected constructor. The comment said the encoding rule of the <%: %> would be: If the type of the content is IHtmlString it will NOT encode since the IHtmlString indicates that it’s Html-safe. Otherwise it will use HtmlEncode to encode the content. If we check the return type of the Html.TextBox method we will find that it’s MvcHtmlString, which was implemented the IHtmlString interface dynamically. That is the reason why the “<input name="name" id="name" type="text"/>” was not encoded by <%: %>. So if we want to tell ASP.NET MVC, or I should say the ASP.NET runtime that the content is Html-safe and no need, or should not be encoded we can convert the content into IHtmlString. So another resolution would be like this. Also we can create an extension method as well for better developing experience. 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Web; 5: using System.Web.Mvc; 6:  7: namespace ShaunXu.Blogs.IHtmlStringIssue 8: { 9: public static class Helpers 10: { 11: public static MvcHtmlString IsHtmlSafe(this string content) 12: { 13: return MvcHtmlString.Create(content); 14: } 15: } 16: } Then the view would be like this. And the page rendered correctly.         Summary In this post I explained a bit about the new markup in .NET 4.0 – <%: %> and its usage. I also explained a bit about how to control the page content, whether it should be encoded or not. We can see the ASP.NET MVC gives us more points to control the web pages.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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  • GLSL compiler messages from different vendors [on hold]

    - by revers
    I'm writing a GLSL shader editor and I want to parse GLSL compiler messages to make hyperlinks to invalid lines in a shader code. I know that these messages are vendor specific but currently I have access only to AMD's video cards. I want to handle at least NVidia's and Intel's hardware, apart from AMD's. If you have video card from different vendor than AMD, could you please give me the output of following C++ program: #include <GL/glew.h> #include <GL/freeglut.h> #include <iostream> using namespace std; #define STRINGIFY(X) #X static const char* fs = STRINGIFY( out vec4 out_Color; mat4 m; void main() { vec3 v3 = vec3(1.0); vec2 v2 = v3; out_Color = vec4(5.0 * v2.x, 1.0); vec3 k = 3.0; float = 5; } ); static const char* vs = STRINGIFY( in vec3 in_Position; void main() { vec3 v(5); gl_Position = vec4(in_Position, 1.0); } ); void printShaderInfoLog(GLint shader) { int infoLogLen = 0; int charsWritten = 0; GLchar *infoLog; glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &infoLogLen); if (infoLogLen > 0) { infoLog = new GLchar[infoLogLen]; glGetShaderInfoLog(shader, infoLogLen, &charsWritten, infoLog); cout << "Log:\n" << infoLog << endl; delete [] infoLog; } } void printProgramInfoLog(GLint program) { int infoLogLen = 0; int charsWritten = 0; GLchar *infoLog; glGetProgramiv(program, GL_INFO_LOG_LENGTH, &infoLogLen); if (infoLogLen > 0) { infoLog = new GLchar[infoLogLen]; glGetProgramInfoLog(program, infoLogLen, &charsWritten, infoLog); cout << "Program log:\n" << infoLog << endl; delete [] infoLog; } } void initShaders() { GLuint v = glCreateShader(GL_VERTEX_SHADER); GLuint f = glCreateShader(GL_FRAGMENT_SHADER); GLint vlen = strlen(vs); GLint flen = strlen(fs); glShaderSource(v, 1, &vs, &vlen); glShaderSource(f, 1, &fs, &flen); GLint compiled; glCompileShader(v); bool succ = true; glGetShaderiv(v, GL_COMPILE_STATUS, &compiled); if (!compiled) { cout << "Vertex shader not compiled." << endl; succ = false; } printShaderInfoLog(v); glCompileShader(f); glGetShaderiv(f, GL_COMPILE_STATUS, &compiled); if (!compiled) { cout << "Fragment shader not compiled." << endl; succ = false; } printShaderInfoLog(f); GLuint p = glCreateProgram(); glAttachShader(p, v); glAttachShader(p, f); glLinkProgram(p); glUseProgram(p); printProgramInfoLog(p); if (!succ) { exit(-1); } delete [] vs; delete [] fs; } int main(int argc, char* argv[]) { glutInit(&argc, argv); glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA); glutInitWindowSize(600, 600); glutCreateWindow("Triangle Test"); glewInit(); GLenum err = glewInit(); if (GLEW_OK != err) { cout << "glewInit failed, aborting." << endl; exit(1); } cout << "Using GLEW " << glewGetString(GLEW_VERSION) << endl; const GLubyte* renderer = glGetString(GL_RENDERER); const GLubyte* vendor = glGetString(GL_VENDOR); const GLubyte* version = glGetString(GL_VERSION); const GLubyte* glslVersion = glGetString(GL_SHADING_LANGUAGE_VERSION); GLint major, minor; glGetIntegerv(GL_MAJOR_VERSION, &major); glGetIntegerv(GL_MINOR_VERSION, &minor); cout << "GL Vendor : " << vendor << endl; cout << "GL Renderer : " << renderer << endl; cout << "GL Version : " << version << endl; cout << "GL Version : " << major << "." << minor << endl; cout << "GLSL Version : " << glslVersion << endl; initShaders(); return 0; } On my video card it gives: Status: Using GLEW 1.7.0 GL Vendor : ATI Technologies Inc. GL Renderer : ATI Radeon HD 4250 GL Version : 3.3.11631 Compatibility Profile Context GL Version : 3.3 GLSL Version : 3.30 Vertex shader not compiled. Log: Vertex shader failed to compile with the following errors: ERROR: 0:1: error(#132) Syntax error: '5' parse error ERROR: error(#273) 1 compilation errors. No code generated Fragment shader not compiled. Log: Fragment shader failed to compile with the following errors: WARNING: 0:1: warning(#402) Implicit truncation of vector from size 3 to size 2. ERROR: 0:1: error(#174) Not enough data provided for construction constructor WARNING: 0:1: warning(#402) Implicit truncation of vector from size 1 to size 3. ERROR: 0:1: error(#132) Syntax error: '=' parse error ERROR: error(#273) 2 compilation errors. No code generated Program log: Vertex and Fragment shader(s) were not successfully compiled before glLinkProgram() was called. Link failed. Or if you like, you could give me other compiler messages than proposed by me. To summarize, the question is: What are GLSL compiler messages formats (INFOs, WARNINGs, ERRORs) for different vendors? Please give me examples or pattern explanation. EDIT: Ok, it seems that this question is too broad, then shortly: How does NVidia's and Intel's GLSL compilers present ERROR and WARNING messages? AMD/ATI uses patterns like this: ERROR: <position>:<line_number>: <message> WARNING: <position>:<line_number>: <message> (examples are above).

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  • Recursion in the form of a Recursive Func&lt;T, T&gt;

    - by ToStringTheory
    I gotta admit, I am kind of surprised that I didn’t realize I could do this sooner.  I recently had a problem which required a recursive function call to come up with the answer.  After some time messing around with a recursive method, and creating an API that I was not happy with, I was able to create an API that I enjoy, and seems intuitive. Introduction To bring it to a simple example, consider the summation to n: A mathematically identical formula is: In a .NET function, this can be represented by a function: Func<int, int> summation = x => x*(x+1)/2 Calling summation with an input integer will yield the summation to that number: var sum10 = summation(4); //sum10 would be equal to 10 But what if I wanted to get a second level summation…  First some to n, and then use that argument as the input to the same function, to find the second level summation: So as an easy example, calculate the summation to 3, which yields 6.  Then calculate the summation to 6 which yields 21. Represented as a mathematical formula - So what if I wanted to represent this as .NET functions.  I can always do: //using the summation formula from above var sum3 = summation(3); //sets sum3 to 6 var sum3_2 = summation(sum3); //sets sum3 to 21 I could always create a while loop to perform the calculations too: Func<int, int> summation = x => x*(x+1)/2; //for the interests of a smaller example, using shorthand int sumResultTo = 3; int level = 2; while(level-- > 0) { sumResultTo = summation(sumResultTo); } //sumResultTo is equal to 21 now. Or express it as a for-loop, method calls, etc…  I really didn’t like any of the options that I tried.  Then it dawned on me – since I was using a Func<T, T> anyways, why not use the Func’s output from one call as the input as another directly. Some Code So, I decided that I wanted a recursion class.  Something that I would be generic and reusable in case I ever wanted to do something like this again. It is limited to only the Func<T1, T2> level of Func, and T1 must be the same as T2. The first thing in this class is a private field for the function: private readonly Func<T, T> _functionToRecurse; So, I since I want the function to be unchangeable, I have defined it as readonly.  Therefore my constructor looks like: public Recursion(Func<T, T> functionToRecurse) { if (functionToRecurse == null) { throw new ArgumentNullException("functionToRecurse", "The function to recurse can not be null"); } _functionToRecurse = functionToRecurse; } Simple enough.  If you have any questions, feel free to post them in the comments, and I will be sure to answer them. Next, I want enough. If be able to get the result of a function dependent on how many levels of recursion: private Func<T, T> GetXLevel(int level) { if (level < 1) { throw new ArgumentOutOfRangeException("level", level, "The level of recursion must be greater than 0"); } if (level == 1) return _functionToRecurse; return _GetXLevel(level - 1, _functionToRecurse); } So, if you pass in 1 for the level, you get just the Func<T,T> back.  If you say that you want to go deeper down the rabbit hole, it calls a method which accepts the level it is at, and the function which it needs to use to recurse further: private Func<T, T> _GetXLevel(int level, Func<T, T> prevFunc) { if (level == 1) return y => prevFunc(_functionToRecurse(y)); return _GetXLevel(level - 1, y => prevFunc(_functionToRecurse(y))); } That is really all that is needed for this class. If I exposed the GetXLevel function publicly, I could use that to get the function for a level, and pass in the argument..  But I wanted something better.  So, I used the ‘this’ array operator for the class: public Func<T,T> this[int level] { get { if (level < 1) { throw new ArgumentOutOfRangeException("level", level, "The level of recursion must be greater than 0"); } return this.GetXLevel(level); } } So, using the same example above of finding the second recursion of the summation of 3: var summator = new Recursion<int>(x => (x * (x + 1)) / 2); var sum_3_level2 = summator[2](3); //yields 21 You can even find just store the delegate to the second level summation, and use it multiple times: var summator = new Recursion<int>(x => (x * (x + 1)) / 2); var sum_level2 = summator[2]; var sum_3_level2 = sum_level2(3); //yields 21 var sum_4_level2 = sum_level2(4); //yields 55 var sum_5_level2 = sum_level2(5); //yields 120 Full Code Don’t think I was just going to hold off on the full file together and make you do the hard work…  Copy this into a new class file: public class Recursion<T> { private readonly Func<T, T> _functionToRecurse; public Recursion(Func<T, T> functionToRecurse) { if (functionToRecurse == null) { throw new ArgumentNullException("functionToRecurse", "The function to recurse can not be null"); } _functionToRecurse = functionToRecurse; } public Func<T,T> this[int level] { get { if (level < 1) { throw new ArgumentOutOfRangeException("level", level, "The level of recursion must be greater than 0"); } return this.GetXLevel(level); } } private Func<T, T> GetXLevel(int level) { if (level < 1) { throw new ArgumentOutOfRangeException("level", level, "The level of recursion must be greater than 0"); } if (level == 1) return _functionToRecurse; return _GetXLevel(level - 1, _functionToRecurse); } private Func<T, T> _GetXLevel(int level, Func<T, T> prevFunc) { if (level == 1) return y => prevFunc(_functionToRecurse(y)); return _GetXLevel(level - 1, y => prevFunc(_functionToRecurse(y))); } } Conclusion The great thing about this class, is that it can be used with any function with same input/output parameters.  I strived to find an implementation that I found clean and useful, and I finally settled on this.  If you have feedback – good or bad, I would love to hear it!

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  • Struct Method for Loops Problem

    - by Annalyne
    I have tried numerous times how to make a do-while loop using the float constructor for my code but it seems it does not work properly as I wanted. For summary, I am making a TBRPG in C++ and I encountered few problems. But before that, let me post my code. #include <iostream> #include <string> #include <ctime> #include <cstdlib> using namespace std; int char_level = 1; //the starting level of the character. string town; //town string town_name; //the name of the town the character is in. string charname; //holds the character's name upon the start of the game int gems = 0; //holds the value of the games the character has. const int MAX_ITEMS = 15; //max items the character can carry string inventory [MAX_ITEMS]; //the inventory of the character in game int itemnum = 0; //number of items that the character has. bool GameOver = false; //boolean intended for the game over scr. string monsterTroop [] = {"Slime", "Zombie", "Imp", "Sahaguin, Hounds, Vampire"}; //monster name float monsterTroopHealth [] = {5.0f, 10.0f, 15.0f, 20.0f, 25.0f}; // the health of the monsters int monLifeBox; //life carrier of the game's enemy troops int enemNumber; //enemy number //inventory[itemnum++] = "Sword"; class RPG_Game_Enemy { public: void enemyAppear () { srand(time(0)); enemNumber = 1+(rand()%3); if (enemNumber == 1) cout << monsterTroop[1]; //monster troop 1 else if (enemNumber == 2) cout << monsterTroop[2]; //monster troop 2 else if (enemNumber == 3) cout << monsterTroop[3]; //monster troop 3 else if (enemNumber == 4) cout << monsterTroop[4]; //monster troop 4 } void enemDefeat () { cout << "The foe has been defeated. You are victorious." << endl; } void enemyDies() { //if the enemy dies: //collapse declaration cout << "The foe vanished and you are victorious!" << endl; } }; class RPG_Scene_Battle { public: RPG_Scene_Battle(float ini_health) : health (ini_health){}; float getHealth() { return health; } void setHealth(float rpg_val){ health = rpg_val;}; private: float health; }; //---------------------------------------------------------------// // Conduct Damage for the Scene Battle's Damage //---------------------------------------------------------------// float conductDamage(RPG_Scene_Battle rpg_tr, float damage) { rpg_tr.setHealth(rpg_tr.getHealth() - damage); return rpg_tr.getHealth(); }; // ------------------------------------------------------------- // void RPG_Scene_DisplayItem () { cout << "Items: \n"; for (int i=0; i < itemnum; ++i) cout << inventory[i] <<endl; }; In this code I have so far, the problem I have is the battle scene. For example, the player battles a Ghost with 10 HP, when I use a do while loop to subtract the HP of the character and the enemy, it only deducts once in the do while. Some people said I should use a struct, but I have no idea how to make it. Is there a way someone can display a code how to implement it on my game? Edit: I made the do-while by far like this: do RPG_Scene_Battle (player, 20.0f); RPG_Scene_Battle (enemy, 10.0f); cout << "Battle starts!" <<endl; cout << "You used a blade skill and deducted 2 hit points to the enemy!" conductDamage (enemy, 2.0f); while (enemy!=0) also, I made something like this: #include <iostream> using namespace std; int gems = 0; class Entity { public: Entity(float startingHealth) : health(startingHealth){}; // initialize health float getHealth(){return health;} void setHealth(float value){ health = value;}; private: float health; }; float subtractHealthFrom(Entity& ent, float damage) { ent.setHealth(ent.getHealth() - damage); return ent.getHealth(); }; int main () { Entity character(10.0f); Entity enemy(10.0f); cout << "Hero Life: "; cout << subtractHealthFrom(character, 2.0f) <<endl; cout << "Monster Life: "; cout << subtractHealthFrom(enemy, 2.0f) <<endl; cout << "Hero Life: "; cout << subtractHealthFrom(character, 2.0f) <<endl; cout << "Monster Life: "; cout << subtractHealthFrom(enemy, 2.0f) <<endl; }; Struct method, they say, should solve this problem. How can I continously deduct hp from the enemy? Whenever I deduct something, it would return to its original value -_-

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  • OpenGL loading functions error [on hold]

    - by Ghilliedrone
    I'm new to OpenGL, and I bought a book on it for beginners. I finished writing the sample code for making a context/window. I get an error on this line at the part PFNWGLCREATECONTEXTATTRIBSARBPROC, saying "Error: expected a ')'": typedef HGLRC(APIENTRYP PFNWGLCREATECONTEXTATTRIBSARBPROC)(HDC, HGLRC, const int*); Replacing it or adding a ")" makes it error, but the error disappears when I use the OpenGL headers included in the books CD, which are OpenGL 3.0. I would like a way to make this work with the newest gl.h/wglext.h and without libraries. Here's the rest of the class if it's needed: #include <ctime> #include <windows.h> #include <iostream> #include <gl\GL.h> #include <gl\wglext.h> #include "Example.h" #include "GLWindow.h" typedef HGLRC(APIENTRYP PFNWGLCREATECONTEXTATTRIBSARBPROC)(HDC, HGLRC, const int*); PFNWGLCREATECONTEXTATTRIBSARBPROC wglCreateContextAttribsARB = NULL; bool GLWindow::create(int width, int height, int bpp, bool fullscreen) { DWORD dwExStyle; //Window Extended Style DWORD dwStyle; //Window Style m_isFullscreen = fullscreen;//Store the fullscreen flag m_windowRect.left = 0L; m_windowRect.right = (long)width; m_windowRect.top = 0L; m_windowRect.bottom = (long)height;//Set bottom to height // fill out the window class structure m_windowClass.cbSize = sizeof(WNDCLASSEX); m_windowClass.style = CS_HREDRAW | CS_VREDRAW; m_windowClass.lpfnWndProc = GLWindow::StaticWndProc; //We set our static method as the event handler m_windowClass.cbClsExtra = 0; m_windowClass.cbWndExtra = 0; m_windowClass.hInstance = m_hinstance; m_windowClass.hIcon = LoadIcon(NULL, IDI_APPLICATION); // default icon m_windowClass.hCursor = LoadCursor(NULL, IDC_ARROW); // default arrow m_windowClass.hbrBackground = NULL; // don't need background m_windowClass.lpszMenuName = NULL; // no menu m_windowClass.lpszClassName = (LPCWSTR)"GLClass"; m_windowClass.hIconSm = LoadIcon(NULL, IDI_WINLOGO); // windows logo small icon if (!RegisterClassEx(&m_windowClass)) { MessageBox(NULL, (LPCWSTR)"Failed to register window class", NULL, MB_OK); return false; } if (m_isFullscreen)//If we are fullscreen, we need to change the display { DEVMODE dmScreenSettings; //Device mode memset(&dmScreenSettings, 0, sizeof(dmScreenSettings)); dmScreenSettings.dmSize = sizeof(dmScreenSettings); dmScreenSettings.dmPelsWidth = width; //Screen width dmScreenSettings.dmPelsHeight = height; //Screen height dmScreenSettings.dmBitsPerPel = bpp; //Bits per pixel dmScreenSettings.dmFields = DM_BITSPERPEL | DM_PELSWIDTH | DM_PELSHEIGHT; if (ChangeDisplaySettings(&dmScreenSettings, CDS_FULLSCREEN) != DISP_CHANGE_SUCCESSFUL) { MessageBox(NULL, (LPCWSTR)"Display mode failed", NULL, MB_OK); m_isFullscreen = false; } } if (m_isFullscreen) //Is it fullscreen? { dwExStyle = WS_EX_APPWINDOW; //Window Extended Style dwStyle = WS_POPUP; //Windows Style ShowCursor(false); //Hide mouse pointer } else { dwExStyle = WS_EX_APPWINDOW | WS_EX_WINDOWEDGE; //Window Exteneded Style dwStyle = WS_OVERLAPPEDWINDOW; //Windows Style } AdjustWindowRectEx(&m_windowRect, dwStyle, false, dwExStyle); //Adjust window to true requested size //Class registered, so now create window m_hwnd = CreateWindowEx(NULL, //Extended Style (LPCWSTR)"GLClass", //Class name (LPCWSTR)"Chapter 2", //App name dwStyle | WS_CLIPCHILDREN | WS_CLIPSIBLINGS, 0, 0, //x, y coordinates m_windowRect.right - m_windowRect.left, m_windowRect.bottom - m_windowRect.top, //Width and height NULL, //Handle to parent NULL, //Handle to menu m_hinstance, //Application instance this); //Pass a pointer to the GLWindow here //Check if window creation failed, hwnd would equal NULL if (!m_hwnd) { return 0; } m_hdc = GetDC(m_hwnd); ShowWindow(m_hwnd, SW_SHOW); UpdateWindow(m_hwnd); m_lastTime = GetTickCount() / 1000.0f; return true; } LRESULT CALLBACK GLWindow::StaticWndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam) { GLWindow* window = nullptr; //If this is the create message if (uMsg == WM_CREATE) { //Get the pointer we stored during create window = (GLWindow*)((LPCREATESTRUCT)lParam)->lpCreateParams; //Associate the window pointer with the hwnd for the other events to access SetWindowLongPtr(hWnd, GWL_USERDATA, (LONG_PTR)window); } else { //If this is not a creation event, then we should have stored a pointer to the window window = (GLWindow*)GetWindowLongPtr(hWnd, GWL_USERDATA); if (!window) { //Do the default event handling return DefWindowProc(hWnd, uMsg, wParam, lParam); } } //Call our window's member WndProc(allows us to access member variables) return window->WndProc(hWnd, uMsg, wParam, lParam); } LRESULT GLWindow::WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam) { switch (uMsg) { case WM_CREATE: { m_hdc = GetDC(hWnd); setupPixelFormat(); //Set the version that we want, in this case 3.0 int attribs[] = { WGL_CONTEXT_MAJOR_VERSION_ARB, 3, WGL_CONTEXT_MINOR_VERSION_ARB, 0, 0}; //Create temporary context so we can get a pointer to the function HGLRC tmpContext = wglCreateContext(m_hdc); //Make the context current wglMakeCurrent(m_hdc, tmpContext); //Get the function pointer wglCreateContextAttribsARB = (PFNWGLCREATECONTEXTATTRIBSARBPROC)wglGetProcAddress("wglCreateContextAttribsARB"); //If this is NULL then OpenGl 3.0 is not supported if (!wglCreateContextAttribsARB) { MessageBox(NULL, (LPCWSTR)"OpenGL 3.0 is not supported", (LPCWSTR)"An error occured", MB_ICONERROR | MB_OK); DestroyWindow(hWnd); return 0; } //Create an OpenGL 3.0 context using the new function m_hglrc = wglCreateContextAttribsARB(m_hdc, 0, attribs); //Delete the temporary context wglDeleteContext(tmpContext); //Make the GL3 context current wglMakeCurrent(m_hdc, m_hglrc); m_isRunning = true; } break; case WM_DESTROY: //Window destroy case WM_CLOSE: //Windows is closing wglMakeCurrent(m_hdc, NULL); wglDeleteContext(m_hglrc); m_isRunning = false; //Stop the main loop PostQuitMessage(0); break; case WM_SIZE: { int height = HIWORD(lParam); //Get height and width int width = LOWORD(lParam); getAttachedExample()->onResize(width, height); //Call the example's resize method } break; case WM_KEYDOWN: if (wParam == VK_ESCAPE) //If the escape key was pressed { DestroyWindow(m_hwnd); } break; default: break; } return DefWindowProc(hWnd, uMsg, wParam, lParam); } void GLWindow::processEvents() { MSG msg; //While there are messages in the queue, store them in msg while (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)) { //Process the messages TranslateMessage(&msg); DispatchMessage(&msg); } } Here is the header: #pragma once #include <ctime> #include <windows.h> class Example;//Declare our example class class GLWindow { public: GLWindow(HINSTANCE hInstance); //default constructor bool create(int width, int height, int bpp, bool fullscreen); void destroy(); void processEvents(); void attachExample(Example* example); bool isRunning(); //Is the window running? void swapBuffers() { SwapBuffers(m_hdc); } static LRESULT CALLBACK StaticWndProc(HWND wnd, UINT msg, WPARAM wParam, LPARAM lParam); LRESULT CALLBACK WndProc(HWND wnd, UINT msg, WPARAM wParam, LPARAM lParam); float getElapsedSeconds(); private: Example* m_example; //A link to the example program bool m_isRunning; //Is the window still running? bool m_isFullscreen; HWND m_hwnd; //Window handle HGLRC m_hglrc; //Rendering context HDC m_hdc; //Device context RECT m_windowRect; //Window bounds HINSTANCE m_hinstance; //Application instance WNDCLASSEX m_windowClass; void setupPixelFormat(void); Example* getAttachedExample() { return m_example; } float m_lastTime; };

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  • Rotate triangle so that its tip points in the direction of the point on the screen that we last touched

    - by Sid
    OpenGL ES - Android. Hello all, I am unable to rotate the triangle accordingly in such a way that its tip always points to my finger. What i did : Constructed a triangle in by GL.GL_TRIANGLES. Added touch events to it. I can rotate the triangle along my Z-axis successfully. Even made the vector class for it. What i need : Each time when I touch the screen, I want to rotate the triangle to face the touch point. Need some help. Here's what i implemented. I wonder that where i am going wrong? My code : public class Graphic2DTriangle { private FloatBuffer vertexBuffer; private ByteBuffer indexBuffer; private float[] vertices = { -1.0f,-1.0f, 0.0f, 2.0f, 0.0f, 0.0f, -1.0f, 1.0f, 0.0f }; private byte[] indices = { 0, 1, 2 }; public Graphic2DTriangle() { ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length * 4); vbb.order(ByteOrder.nativeOrder()); // Use native byte order vertexBuffer = vbb.asFloatBuffer(); // Convert byte buffer to float vertexBuffer.put(vertices); // Copy data into buffer vertexBuffer.position(0); // Rewind // Setup index-array buffer. Indices in byte. indexBuffer = ByteBuffer.allocateDirect(indices.length); indexBuffer.put(indices); indexBuffer.position(0); } public void draw(GL10 gl) { gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer); gl.glDrawElements(GL10.GL_TRIANGLES, indices.length, GL10.GL_UNSIGNED_BYTE, indexBuffer); gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); } } My SurfaceView class where i've done some Touch Events. public class BallThrowGLSurfaceView extends GLSurfaceView{ MySquareRender _renderObj; View _viewObj; float oldX,oldY,dX,dY; final float TOUCH_SCALE_FACTOR = 0.6f; Vector2 touchPos = new Vector2(); float angle=0; public BallThrowGLSurfaceView(Context context) { super(context); // TODO Auto-generated constructor stub _renderObj = new MySquareRender(context); this.setRenderer(_renderObj); this.setRenderMode(RENDERMODE_WHEN_DIRTY); } @Override public boolean onTouchEvent(MotionEvent event) { // TODO Auto-generated method stub touchPos.x = event.getX(); touchPos.y = event.getY(); Log.i("Co-ord", touchPos.x+"hh"+touchPos.y); switch(event.getAction()){ case MotionEvent.ACTION_MOVE : dX = touchPos.x - oldX; dY = touchPos.y - oldY; if(touchPos.y > getHeight()/2){ dX = dX*-1; } if(touchPos.x < getWidth()/2){ dY = dY*-1; } _renderObj.mAngle += (dX+dY) * TOUCH_SCALE_FACTOR; requestRender(); Log.i("AngleCo-ord", _renderObj.mAngle +"hh"); } oldX = touchPos.x; oldY = touchPos.y; Log.i("OldCo-ord", oldX+" hh "+oldY); return true; } } Last but not the least. My vector2 class. public class Vector2 { public static float TO_RADIANS = (1 / 180.0f) * (float) Math.PI; public static float TO_DEGREES = (1 / (float) Math.PI) * 180; public float x, y; public Vector2() { } public Vector2(float x, float y) { this.x = x; this.y = y; } public Vector2(Vector2 other) { this.x = other.x; this.y = other.y; } public Vector2 cpy() { return new Vector2(x, y); } public Vector2 set(float x, float y) { this.x = x; this.y = y; return this; } public Vector2 set(Vector2 other) { this.x = other.x; this.y = other.y; return this; } public Vector2 add(float x, float y) { this.x += x; this.y += y; return this; } public Vector2 add(Vector2 other) { this.x += other.x; this.y += other.y; return this; } public Vector2 sub(float x, float y) { this.x -= x; this.y -= y; return this; } public Vector2 sub(Vector2 other) { this.x -= other.x; this.y -= other.y; return this; } public Vector2 mul(float scalar) { this.x *= scalar; this.y *= scalar; return this; } public float len() { return FloatMath.sqrt(x * x + y * y); } public Vector2 nor() { float len = len(); if (len != 0) { this.x /= len; this.y /= len; } return this; } public float angle() { float angle = (float) Math.atan2(y, x) * TO_DEGREES; if (angle < 0) angle += 360; return angle; } public Vector2 rotate(float angle) { float rad = angle * TO_RADIANS; float cos = FloatMath.cos(rad); float sin = FloatMath.sin(rad); float newX = this.x * cos - this.y * sin; float newY = this.x * sin + this.y * cos; this.x = newX; this.y = newY; return this; } public float dist(Vector2 other) { float distX = this.x - other.x; float distY = this.y - other.y; return FloatMath.sqrt(distX * distX + distY * distY); } public float dist(float x, float y) { float distX = this.x - x; float distY = this.y - y; return FloatMath.sqrt(distX * distX + distY * distY); } public float distSquared(Vector2 other) { float distX = this.x - other.x; float distY = this.y - other.y; return distX * distX + distY * distY; } public float distSquared(float x, float y) { float distX = this.x - x; float distY = this.y - y; return distX * distX + distY * distY; } } PS : i am able to handle the touch events. I can rotate the triangle with the touch of my finger. But i want that ONE VERTEX of the triangle should point at my finger position respective of the position of my finger.

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  • how to use 3D map Actionscript class in mxml file for display map.

    - by nemade-vipin
    hello friends, I have created the application in which I have to use 3D map Action Script class in mxml file to display a map in form. that is in tab navigator last tab. My ActionScript 3D map class is(FlyingDirections):- package src.SBTSCoreObject { import src.SBTSCoreObject.JSONDecoder; import com.google.maps.InfoWindowOptions; import com.google.maps.LatLng; import com.google.maps.LatLngBounds; import com.google.maps.Map3D; import com.google.maps.MapEvent; import com.google.maps.MapOptions; import com.google.maps.MapType; import com.google.maps.MapUtil; import com.google.maps.View; import com.google.maps.controls.NavigationControl; import com.google.maps.geom.Attitude; import com.google.maps.interfaces.IPolyline; import com.google.maps.overlays.Marker; import com.google.maps.overlays.MarkerOptions; import com.google.maps.services.Directions; import com.google.maps.services.DirectionsEvent; import com.google.maps.services.Route; import flash.display.Bitmap; import flash.display.DisplayObject; import flash.display.DisplayObjectContainer; import flash.display.Loader; import flash.display.LoaderInfo; import flash.display.Sprite; import flash.events.Event; import flash.events.IOErrorEvent; import flash.events.MouseEvent; import flash.events.TimerEvent; import flash.filters.DropShadowFilter; import flash.geom.Point; import flash.net.URLLoader; import flash.net.URLRequest; import flash.net.navigateToURL; import flash.text.TextField; import flash.text.TextFieldAutoSize; import flash.text.TextFormat; import flash.utils.Timer; import flash.utils.getTimer; public class FlyingDirections extends Map3D { /** * Panoramio home page. */ private static const PANORAMIO_HOME:String = "http://www.panoramio.com/"; /** * The icon for the car. */ [Embed("assets/car-icon-24px.png")] private static const Car:Class; /** * The Panoramio icon. */ [Embed("assets/iw_panoramio.png")] private static const PanoramioIcon:Class; /** * We animate a zoom in to the start the route before the car starts * to move. This constant sets the time in seconds over which this * zoom occurs. */ private static const LEAD_IN_DURATION:Number = 3; /** * Duration of the trip in seconds. */ private static const TRIP_DURATION:Number = 40; /** * Constants that define the geometry of the Panoramio image markers. */ private static const BORDER_T:Number = 3; private static const BORDER_L:Number = 10; private static const BORDER_R:Number = 10; private static const BORDER_B:Number = 3; private static const GAP_T:Number = 2; private static const GAP_B:Number = 1; private static const IMAGE_SCALE:Number = 1; /** * Trajectory that the camera follows over time. Each element is an object * containing properties used to generate parameter values for flyTo(..). * fraction = 0 corresponds to the start of the trip; fraction = 1 * correspondsto the end of the trip. */ private var FLY_TRAJECTORY:Array = [ { fraction: 0, zoom: 6, attitude: new Attitude(0, 0, 0) }, { fraction: 0.2, zoom: 8.5, attitude: new Attitude(30, 30, 0) }, { fraction: 0.5, zoom: 9, attitude: new Attitude(30, 40, 0) }, { fraction: 1, zoom: 8, attitude: new Attitude(50, 50, 0) }, { fraction: 1.1, zoom: 8, attitude: new Attitude(130, 50, 0) }, { fraction: 1.2, zoom: 8, attitude: new Attitude(220, 50, 0) }, ]; /** * Number of panaramio photos for which we load data. We&apos;ll select a * subset of these approximately evenly spaced along the route. */ private static const NUM_GEOTAGGED_PHOTOS:int = 50; /** * Number of panaramio photos that we actually show. */ private static const NUM_SHOWN_PHOTOS:int = 7; /** * Scaling between real trip time and animation time. */ private static const SCALE_TIME:Number = 0.001; /** * getTimer() value at the instant that we start the trip. If this is 0 then * we have not yet started the car moving. */ private var startTimer:int = 0; /** * The current route. */ private var route:Route; /** * The polyline for the route. */ private var polyline:IPolyline; /** * The car marker. */ private var marker:Marker; /** * The cumulative duration in seconds over each step in the route. * cumulativeStepDuration[0] is 0; cumulativeStepDuration[1] adds the * duration of step 0; cumulativeStepDuration[2] adds the duration * of step 1; etc. */ private var cumulativeStepDuration:/*Number*/Array = []; /** * The cumulative distance in metres over each vertex in the route polyline. * cumulativeVertexDistance[0] is 0; cumulativeVertexDistance[1] adds the * distance to vertex 1; cumulativeVertexDistance[2] adds the distance to * vertex 2; etc. */ private var cumulativeVertexDistance:Array; /** * Array of photos loaded from Panoramio. This array has the same format as * the &apos;photos&apos; property within the JSON returned by the Panoramio API * (see http://www.panoramio.com/api/), with additional properties added to * individual photo elements to hold the loader structures that fetch * the actual images. */ private var photos:Array = []; /** * Array of polyline vertices, where each element is in world coordinates. * Several computations can be faster if we can use world coordinates * instead of LatLng coordinates. */ private var worldPoly:/*Point*/Array; /** * Whether the start button has been pressed. */ private var startButtonPressed:Boolean = false; /** * Saved event from onDirectionsSuccess call. */ private var directionsSuccessEvent:DirectionsEvent = null; /** * Start button. */ private var startButton:Sprite; /** * Alpha value used for the Panoramio image markers. */ private var markerAlpha:Number = 0; /** * Index of the current driving direction step. Used to update the * info window content each time we progress to a new step. */ private var currentStepIndex:int = -1; /** * The fly directions map constructor. * * @constructor */ public function FlyingDirections() { key="ABQIAAAA7QUChpcnvnmXxsjC7s1fCxQGj0PqsCtxKvarsoS-iqLdqZSKfxTd7Xf-2rEc_PC9o8IsJde80Wnj4g"; super(); addEventListener(MapEvent.MAP_PREINITIALIZE, onMapPreinitialize); addEventListener(MapEvent.MAP_READY, onMapReady); } /** * Handles map preintialize. Initializes the map center and zoom level. * * @param event The map event. */ private function onMapPreinitialize(event:MapEvent):void { setInitOptions(new MapOptions({ center: new LatLng(-26.1, 135.1), zoom: 4, viewMode: View.VIEWMODE_PERSPECTIVE, mapType:MapType.PHYSICAL_MAP_TYPE })); } /** * Handles map ready and looks up directions. * * @param event The map event. */ private function onMapReady(event:MapEvent):void { enableScrollWheelZoom(); enableContinuousZoom(); addControl(new NavigationControl()); // The driving animation will be updated on every frame. addEventListener(Event.ENTER_FRAME, enterFrame); addStartButton(); // We start the directions loading now, so that we&apos;re ready to go when // the user hits the start button. var directions:Directions = new Directions(); directions.addEventListener( DirectionsEvent.DIRECTIONS_SUCCESS, onDirectionsSuccess); directions.addEventListener( DirectionsEvent.DIRECTIONS_FAILURE, onDirectionsFailure); directions.load("48 Pirrama Rd, Pyrmont, NSW to Byron Bay, NSW"); } /** * Adds a big blue start button. */ private function addStartButton():void { startButton = new Sprite(); startButton.buttonMode = true; startButton.addEventListener(MouseEvent.CLICK, onStartClick); startButton.graphics.beginFill(0x1871ce); startButton.graphics.drawRoundRect(0, 0, 150, 100, 10, 10); startButton.graphics.endFill(); var startField:TextField = new TextField(); startField.autoSize = TextFieldAutoSize.LEFT; startField.defaultTextFormat = new TextFormat("_sans", 20, 0xffffff, true); startField.text = "Start!"; startButton.addChild(startField); startField.x = 0.5 * (startButton.width - startField.width); startField.y = 0.5 * (startButton.height - startField.height); startButton.filters = [ new DropShadowFilter() ]; var container:DisplayObjectContainer = getDisplayObject() as DisplayObjectContainer; container.addChild(startButton); startButton.x = 0.5 * (container.width - startButton.width); startButton.y = 0.5 * (container.height - startButton.height); var panoField:TextField = new TextField(); panoField.autoSize = TextFieldAutoSize.LEFT; panoField.defaultTextFormat = new TextFormat("_sans", 11, 0x000000, true); panoField.text = "Photos provided by Panoramio are under the copyright of their owners."; container.addChild(panoField); panoField.x = container.width - panoField.width - 5; panoField.y = 5; } /** * Handles directions success. Starts flying the route if everything * is ready. * * @param event The directions event. */ private function onDirectionsSuccess(event:DirectionsEvent):void { directionsSuccessEvent = event; flyRouteIfReady(); } /** * Handles click on the start button. Starts flying the route if everything * is ready. */ private function onStartClick(event:MouseEvent):void { startButton.removeEventListener(MouseEvent.CLICK, onStartClick); var container:DisplayObjectContainer = getDisplayObject() as DisplayObjectContainer; container.removeChild(startButton); startButtonPressed = true; flyRouteIfReady(); } /** * If we have loaded the directions and the start button has been pressed * start flying the directions route. */ private function flyRouteIfReady():void { if (!directionsSuccessEvent || !startButtonPressed) { return; } var directions:Directions = directionsSuccessEvent.directions; // Extract the route. route = directions.getRoute(0); // Draws the polyline showing the route. polyline = directions.createPolyline(); addOverlay(directions.createPolyline()); // Creates a car marker that is moved along the route. var car:DisplayObject = new Car(); marker = new Marker(route.startGeocode.point, new MarkerOptions({ icon: car, iconOffset: new Point(-car.width / 2, -car.height) })); addOverlay(marker); transformPolyToWorld(); createCumulativeArrays(); // Load Panoramio data for the region covered by the route. loadPanoramioData(directions.bounds); var duration:Number = route.duration; // Start a timer that will trigger the car moving after the lead in time. var leadInTimer:Timer = new Timer(LEAD_IN_DURATION * 1000, 1); leadInTimer.addEventListener(TimerEvent.TIMER, onLeadInDone); leadInTimer.start(); var flyTime:Number = -LEAD_IN_DURATION; // Set up the camera flight trajectory. for each (var flyStep:Object in FLY_TRAJECTORY) { var time:Number = flyStep.fraction * duration; var center:LatLng = latLngAt(time); var scaledTime:Number = time * SCALE_TIME; var zoom:Number = flyStep.zoom; var attitude:Attitude = flyStep.attitude; var elapsed:Number = scaledTime - flyTime; flyTime = scaledTime; flyTo(center, zoom, attitude, elapsed); } } /** * Loads Panoramio data for the route bounds. We load data about more photos * than we need, then select a subset lying along the route. * @param bounds Bounds within which to fetch images. */ private function loadPanoramioData(bounds:LatLngBounds):void { var params:Object = { order: "popularity", set: "full", from: "0", to: NUM_GEOTAGGED_PHOTOS.toString(10), size: "small", minx: bounds.getWest(), miny: bounds.getSouth(), maxx: bounds.getEast(), maxy: bounds.getNorth() }; var loader:URLLoader = new URLLoader(); var request:URLRequest = new URLRequest( "http://www.panoramio.com/map/get_panoramas.php?" + paramsToString(params)); loader.addEventListener(Event.COMPLETE, onPanoramioDataLoaded); loader.addEventListener(IOErrorEvent.IO_ERROR, onPanoramioDataFailed); loader.load(request); } /** * Transforms the route polyline to world coordinates. */ private function transformPolyToWorld():void { var numVertices:int = polyline.getVertexCount(); worldPoly = new Array(numVertices); for (var i:int = 0; i < numVertices; ++i) { var vertex:LatLng = polyline.getVertex(i); worldPoly[i] = fromLatLngToPoint(vertex, 0); } } /** * Returns the time at which the route approaches closest to the * given point. * @param world Point in world coordinates. * @return Route time at which the closest approach occurs. */ private function getTimeOfClosestApproach(world:Point):Number { var minDistSqr:Number = Number.MAX_VALUE; var numVertices:int = worldPoly.length; var x:Number = world.x; var y:Number = world.y; var minVertex:int = 0; for (var i:int = 0; i < numVertices; ++i) { var dx:Number = worldPoly[i].x - x; var dy:Number = worldPoly[i].y - y; var distSqr:Number = dx * dx + dy * dy; if (distSqr < minDistSqr) { minDistSqr = distSqr; minVertex = i; } } return cumulativeVertexDistance[minVertex]; } /** * Returns the array index of the first element that compares greater than * the given value. * @param ordered Ordered array of elements. * @param value Value to use for comparison. * @return Array index of the first element that compares greater than * the given value. */ private function upperBound(ordered:Array, value:Number, first:int=0, last:int=-1):int { if (last < 0) { last = ordered.length; } var count:int = last - first; var index:int; while (count > 0) { var step:int = count >> 1; index = first + step; if (value >= ordered[index]) { first = index + 1; count -= step - 1; } else { count = step; } } return first; } /** * Selects up to a given number of photos approximately evenly spaced along * the route. * @param ordered Array of photos, each of which is an object with * a property &apos;closestTime&apos;. * @param number Number of photos to select. */ private function selectEvenlySpacedPhotos(ordered:Array, number:int):Array { var start:Number = cumulativeVertexDistance[0]; var end:Number = cumulativeVertexDistance[cumulativeVertexDistance.length - 2]; var closestTimes:Array = []; for each (var photo:Object in ordered) { closestTimes.push(photo.closestTime); } var selectedPhotos:Array = []; for (var i:int = 0; i < number; ++i) { var idealTime:Number = start + ((end - start) * (i + 0.5) / number); var index:int = upperBound(closestTimes, idealTime); if (index < 1) { index = 0; } else if (index >= ordered.length) { index = ordered.length - 1; } else { var errorToPrev:Number = Math.abs(idealTime - closestTimes[index - 1]); var errorToNext:Number = Math.abs(idealTime - closestTimes[index]); if (errorToPrev < errorToNext) { --index; } } selectedPhotos.push(ordered[index]); } return selectedPhotos; } /** * Handles completion of loading the Panoramio index data. Selects from the * returned photo indices a subset of those that lie along the route and * initiates load of each of these. * @param event Load completion event. */ private function onPanoramioDataLoaded(event:Event):void { var loader:URLLoader = event.target as URLLoader; var decoder:JSONDecoder = new JSONDecoder(loader.data as String); var allPhotos:Array = decoder.getValue().photos; for each (var photo:Object in allPhotos) { var latLng:LatLng = new LatLng(photo.latitude, photo.longitude); photo.closestTime = getTimeOfClosestApproach(fromLatLngToPoint(latLng, 0)); } allPhotos.sortOn("closestTime", Array.NUMERIC); photos = selectEvenlySpacedPhotos(allPhotos, NUM_SHOWN_PHOTOS); for each (photo in photos) { var photoLoader:Loader = new Loader(); // The images aren&apos;t on panoramio.com: we can&apos;t acquire pixel access // using "new LoaderContext(true)". photoLoader.load( new URLRequest(photo.photo_file_url)); photo.loader = photoLoader; // Save the loader info: we use this to find the original element when // the load completes. photo.loaderInfo = photoLoader.contentLoaderInfo; photoLoader.contentLoaderInfo.addEventListener( Event.COMPLETE, onPhotoLoaded); } } /** * Creates a MouseEvent listener function that will navigate to the given * URL in a new window. * @param url URL to which to navigate. */ private function createOnClickUrlOpener(url:String):Function { return function(event:MouseEvent):void { navigateToURL(new URLRequest(url)); }; } /** * Handles completion of loading an individual Panoramio image. * Adds a custom marker that displays the image. Initially this is made * invisible so that it can be faded in as needed. * @param event Load completion event. */ private function onPhotoLoaded(event:Event):void { var loaderInfo:LoaderInfo = event.target as LoaderInfo; // We need to find which photo element this image corresponds to. for each (var photo:Object in photos) { if (loaderInfo == photo.loaderInfo) { var imageMarker:Sprite = createImageMarker(photo.loader, photo.owner_name, photo.owner_url); var options:MarkerOptions = new MarkerOptions({ icon: imageMarker, hasShadow: true, iconAlignment: MarkerOptions.ALIGN_BOTTOM | MarkerOptions.ALIGN_LEFT }); var latLng:LatLng = new LatLng(photo.latitude, photo.longitude); var marker:Marker = new Marker(latLng, options); photo.marker = marker; addOverlay(marker); // A hack: we add the actual image after the overlay has been added, // which creates the shadow, so that the shadow is valid even if we // don&apos;t have security privileges to generate the shadow from the // image. marker.foreground.visible = false; marker.shadow.alpha = 0; var imageHolder:Sprite = new Sprite(); imageHolder.addChild(photo.loader); imageHolder.buttonMode = true; imageHolder.addEventListener( MouseEvent.CLICK, createOnClickUrlOpener(photo.photo_url)); imageMarker.addChild(imageHolder); return; } } trace("An image was loaded which could not be found in the photo array."); } /** * Creates a custom marker showing an image. */ private function createImageMarker(child:DisplayObject, ownerName:String, ownerUrl:String):Sprite { var content:Sprite = new Sprite(); var panoramioIcon:Bitmap = new PanoramioIcon(); var iconHolder:Sprite = new Sprite(); iconHolder.addChild(panoramioIcon); iconHolder.buttonMode = true; iconHolder.addEventListener(MouseEvent.CLICK, onPanoramioIconClick); panoramioIcon.x = BORDER_L; panoramioIcon.y = BORDER_T; content.addChild(iconHolder); // NOTE: we add the image as a child only after we&apos;ve added the marker // to the map. Currently the API requires this if it&apos;s to generate the // shadow for unprivileged content. // Shrink the image, so that it doesn&apos;t obcure too much screen space. // Ideally, we&apos;d subsample, but we don&apos;t have pixel level access. child.scaleX = IMAGE_SCALE; child.scaleY = IMAGE_SCALE; var imageW:Number = child.width; var imageH:Number = child.height; child.x = BORDER_L + 30; child.y = BORDER_T + iconHolder.height + GAP_T; var authorField:TextField = new TextField(); authorField.autoSize = TextFieldAutoSize.LEFT; authorField.defaultTextFormat = new TextFormat("_sans", 12); authorField.text = "author:"; content.addChild(authorField); authorField.x = BORDER_L; authorField.y = BORDER_T + iconHolder.height + GAP_T + imageH + GAP_B; var ownerField:TextField = new TextField(); ownerField.autoSize = TextFieldAutoSize.LEFT; var textFormat:TextFormat = new TextFormat("_sans", 14, 0x0e5f9a); ownerField.defaultTextFormat = textFormat; ownerField.htmlText = "<a href=\"" + ownerUrl + "\" target=\"_blank\">" + ownerName + "</a>"; content.addChild(ownerField); ownerField.x = BORDER_L + authorField.width; ownerField.y = BORDER_T + iconHolder.height + GAP_T + imageH + GAP_B; var totalW:Number = BORDER_L + Math.max(imageW, ownerField.width + authorField.width) + BORDER_R; var totalH:Number = BORDER_T + iconHolder.height + GAP_T + imageH + GAP_B + ownerField.height + BORDER_B; content.graphics.beginFill(0xffffff); content.graphics.drawRoundRect(0, 0, totalW, totalH, 10, 10); content.graphics.endFill(); var marker:Sprite = new Sprite(); marker.addChild(content); content.x = 30; content.y = 0; marker.graphics.lineStyle(); marker.graphics.beginFill(0xff0000); marker.graphics.drawCircle(0, totalH + 30, 3); marker.graphics.endFill(); marker.graphics.lineStyle(2, 0xffffff); marker.graphics.moveTo(30 + 10, totalH - 10); marker.graphics.lineTo(0, totalH + 30); return marker; } /** * Handles click on the Panoramio icon. */ private function onPanoramioIconClick(event:MouseEvent):void { navigateToURL(new URLRequest(PANORAMIO_HOME)); } /** * Handles failure of a Panoramio image load. */ private function onPanoramioDataFailed(event:IOErrorEvent):void { trace("Load of image failed: " + event); } /** * Returns a string containing cgi query parameters. * @param Associative array mapping query parameter key to value. * @return String containing cgi query parameters. */ private static function paramsToString(params:Object):String { var result:String = ""; var separator:String = ""; for (var key:String in params) { result += separator + encodeURIComponent(key) + "=" + encodeURIComponent(params[key]); separator = "&"; } return result; } /** * Called once the lead-in flight is done. Starts the car driving along * the route and starts a timer to begin fade in of the Panoramio * images in 1.5 seconds. */ private function onLeadInDone(event:Event):void { // Set startTimer non-zero so that the car starts to move. startTimer = getTimer(); // Start a timer that will fade in the Panoramio images. var fadeInTimer:Timer = new Timer(1500, 1); fadeInTimer.addEventListener(TimerEvent.TIMER, onFadeInTimer); fadeInTimer.start(); } /** * Handles the fade in timer&apos;s TIMER event. Sets markerAlpha above zero * which causes the frame enter handler to fade in the markers. */ private function onFadeInTimer(event:Event):void { markerAlpha = 0.01; } /** * The end time of the flight. */ private function get endTime():Number { if (!cumulativeStepDuration || cumulativeStepDuration.length == 0) { return startTimer; } return startTimer + cumulativeStepDuration[cumulativeStepDuration.length - 1]; } /** * Creates the cumulative arrays, cumulativeStepDuration and * cumulativeVertexDistance. */ private function createCumulativeArrays():void { cumulativeStepDuration = new Array(route.numSteps + 1); cumulativeVertexDistance = new Array(polyline.getVertexCount() + 1); var polylineTotal:Number = 0; var total:Number = 0; var numVertices:int = polyline.getVertexCount(); for (var stepIndex:int = 0; stepIndex < route.numSteps; ++stepIndex) { cumulativeStepDuration[stepIndex] = total; total += route.getStep(stepIndex).duration; var startVertex:int = stepIndex >= 0 ? route.getStep(stepIndex).polylineIndex : 0; var endVertex:int = stepIndex < (route.numSteps - 1) ? route.getStep(stepIndex + 1).polylineIndex : numVertices; var duration:Number = route.getStep(stepIndex).duration; var stepVertices:int = endVertex - startVertex; var latLng:LatLng = polyline.getVertex(startVertex); for (var vertex:int = startVertex; vertex < endVertex; ++vertex) { cumulativeVertexDistance[vertex] = polylineTotal; if (vertex < numVertices - 1) { var nextLatLng:LatLng = polyline.getVertex(vertex + 1); polylineTotal += nextLatLng.distanceFrom(latLng); } latLng = nextLatLng; } } cumulativeStepDuration[stepIndex] = total; } /** * Opens the info window above the car icon that details the given * step of the driving directions. * @param stepIndex Index of the current step. */ private function openInfoForStep(stepIndex:int):void { // Sets the content of the info window. var content:String; if (stepIndex >= route.numSteps) { content = "<b>" + route.endGeocode.address + "</b>" + "<br /><br />" + route.summaryHtml; } else { content = "<b>" + stepIndex + ".</b> " + route.getStep(stepIndex).descriptionHtml; } marker.openInfoWindow(new InfoWindowOptions({ contentHTML: content })); } /** * Displays the driving directions step appropriate for the given time. * Opens the info window showing the step instructions each time we * progress to a new step. * @param time Time for which to display the step. */ private function displayStepAt(time:Number):void { var stepIndex:int = upperBound(cumulativeStepDuration, time) - 1; var minStepIndex:int = 0; var maxStepIndex:int = route.numSteps - 1; if (stepIndex >= 0 && stepIndex <= maxStepIndex && currentStepIndex != stepIndex) { openInfoForStep(stepIndex); currentStepIndex = stepIndex; } } /** * Returns the LatLng at which the car should be positioned at the given * time. * @param time Time for which LatLng should be found. * @return LatLng. */ private function latLngAt(time:Number):LatLng { var stepIndex:int = upperBound(cumulativeStepDuration, time) - 1; var minStepIndex:int = 0; var maxStepIndex:int = route.numSteps - 1; if (stepIndex < minStepIndex) { return route.startGeocode.point; } else if (stepIndex > maxStepIndex) { return route.endGeocode.point; } var stepStart:Number = cumulativeStepDuration[stepIndex]; var stepEnd:Number = cumulativeStepDuration[stepIndex + 1]; var stepFraction:Number = (time - stepStart) / (stepEnd - stepStart); var startVertex:int = route.getStep(stepIndex).polylineIndex; var endVertex:int = (stepIndex + 1) < route.numSteps ? route.getStep(stepIndex + 1).polylineIndex : polyline.getVertexCount(); var stepVertices:int = endVertex - startVertex; var stepLeng

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  • WCF on Windows Phone 7 (Silverlight 4)

    - by Igor Zevaka
    Has anyone been able to communicate using WCF on Windows Phone Series 7 emulator? I've been trying for the past two days and it's just happening for me. I can get a normal Silverlight control to work in both Silverlight 3 and Silverlight 4, but not the phone version. Here are two versions that I've tried: Version 1 - Using Async Pattern BasicHttpBinding basicHttpBinding = new BasicHttpBinding(); EndpointAddress endpointAddress = new EndpointAddress("http://localhost/wcf/Authentication.svc"); Wcf.IAuthentication auth1 = new ChannelFactory<Wcf.IAuthentication>(basicHttpBinding, endpointAddress).CreateChannel(endpointAddress); AsyncCallback callback = (result) => { Action<string> write = (str) => { this.Dispatcher.BeginInvoke(delegate { //Display something }); }; try { Wcf.IAuthentication auth = result.AsyncState as Wcf.IAuthentication; Wcf.AuthenticationResponse response = auth.EndLogin(result); write(response.Success.ToString()); } catch (Exception ex) { write(ex.Message); System.Diagnostics.Debug.WriteLine(ex.Message); } }; auth1.BeginLogin("user0", "test0", callback, auth1); This version breaks on this line: Wcf.IAuthentication auth1 = new ChannelFactory<Wcf.IAuthentication>(basicHttpBinding, endpointAddress).CreateChannel(endpointAddress); Throwing System.NotSupportedException. The exception is not very descriptive and the callstack is equally not very helpful: at System.ServiceModel.DiagnosticUtility.ExceptionUtility.BuildMessage(Exception x) at System.ServiceModel.DiagnosticUtility.ExceptionUtility.LogException(Exception x) at System.ServiceModel.DiagnosticUtility.ExceptionUtility.ThrowHelperError(Exception e) at System.ServiceModel.ChannelFactory`1.CreateChannel(EndpointAddress address) at WindowsPhoneApplication2.MainPage.DoLogin() .... Version 2 - Blocking WCF call Here is the version that doesn't use the async pattern. [System.ServiceModel.ServiceContract] public interface IAuthentication { [System.ServiceModel.OperationContract] AuthenticationResponse Login(string user, string password); } public class WcfClientBase<TChannel> : System.ServiceModel.ClientBase<TChannel> where TChannel : class { public WcfClientBase(string name, bool streaming) : base(GetBinding(streaming), GetEndpoint(name)) { ClientCredentials.UserName.UserName = WcfConfig.UserName; ClientCredentials.UserName.Password = WcfConfig.Password; } public WcfClientBase(string name) : this(name, false) {} private static System.ServiceModel.Channels.Binding GetBinding(bool streaming) { System.ServiceModel.BasicHttpBinding binding = new System.ServiceModel.BasicHttpBinding(); binding.MaxReceivedMessageSize = 1073741824; if(streaming) { //binding.TransferMode = System.ServiceModel.TransferMode.Streamed; } /*if(XXXURLXXX.StartsWith("https")) { binding.Security.Mode = BasicHttpSecurityMode.Transport; binding.Security.Transport.ClientCredentialType = HttpClientCredentialType.None; }*/ return binding; } private static System.ServiceModel.EndpointAddress GetEndpoint(string name) { return new System.ServiceModel.EndpointAddress(WcfConfig.Endpoint + name + ".svc"); } protected override TChannel CreateChannel() { throw new System.NotImplementedException(); } } auth.Login("test0", "password0"); This version crashes in System.ServiceModel.ClientBase<TChannel> constructor. The call stack is a bit different: at System.Reflection.MethodInfo.get_ReturnParameter() at System.ServiceModel.Description.ServiceReflector.HasNoDisposableParameters(MethodInfo methodInfo) at System.ServiceModel.Description.TypeLoader.CreateOperationDescription(ContractDescription contractDescription, MethodInfo methodInfo, MessageDirection direction, ContractReflectionInfo reflectionInfo, ContractDescription declaringContract) at System.ServiceModel.Description.TypeLoader.CreateOperationDescriptions(ContractDescription contractDescription, ContractReflectionInfo reflectionInfo, Type contractToGetMethodsFrom, ContractDescription declaringContract, MessageDirection direction) at System.ServiceModel.Description.TypeLoader.CreateContractDescription(ServiceContractAttribute contractAttr, Type contractType, Type serviceType, ContractReflectionInfo& reflectionInfo, Object serviceImplementation) at System.ServiceModel.Description.TypeLoader.LoadContractDescriptionHelper(Type contractType, Type serviceType, Object serviceImplementation) at System.ServiceModel.Description.TypeLoader.LoadContractDescription(Type contractType) at System.ServiceModel.ChannelFactory1.CreateDescription() at System.ServiceModel.ChannelFactory.InitializeEndpoint(Binding binding, EndpointAddress address) at System.ServiceModel.ChannelFactory1..ctor(Binding binding, EndpointAddress remoteAddress) at System.ServiceModel.ClientBase1..ctor(Binding binding, EndpointAddress remoteAddress) at Wcf.WcfClientBase1..ctor(String name, Boolean streaming) at Wcf.WcfClientBase`1..ctor(String name) at Wcf.AuthenticationClient..ctor() at WindowsPhoneApplication2.MainPage.DoLogin() ... Any ideas?

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