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• How do I make my applet turn the user's input into an integer and compare it to the computer's random number?

  - by Kitteran

  I'm in beginning programming and I don't fully understand applets yet. However, (with some help from internet tutorials) I was able to create an applet that plays a game of guess with the user. The applet compiles fine, but when it runs, this error message appears: "Exception in thread "main" java.lang.NumberFormatException: For input string: "" at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48) at java.lang.Integer.parseInt(Integer.java:470) at java.lang.Integer.parseInt(Integer.java:499) at Guess.createUserInterface(Guess.java:101) at Guess.<init>(Guess.java:31) at Guess.main(Guess.java:129)" I've tried moving the "userguess = Integer.parseInt( t1.getText() );" on line 101 to multiple places, but I still get the same error. Can anyone tell me what I'm doing wrong? The Code: // Creates the game GUI. import javax.swing.*; import java.awt.*; import java.awt.event.*; public class Guess extends JFrame{ private JLabel userinputJLabel; private JLabel lowerboundsJLabel; private JLabel upperboundsJLabel; private JLabel computertalkJLabel; private JButton guessJButton; private JPanel guessJPanel; static int computernum; int userguess; static void declare() { computernum = (int) (100 * Math.random()) + 1; //random number picked (1-100) } // no-argument constructor public Guess() { createUserInterface(); } // create and position GUI components private void createUserInterface() { // get content pane and set its layout Container contentPane = getContentPane(); contentPane.setLayout( null ); contentPane.setBackground( Color.white ); // set up userinputJLabel userinputJLabel = new JLabel(); userinputJLabel.setText( "Enter Guess Here -->" ); userinputJLabel.setBounds( 0, 65, 120, 50 ); userinputJLabel.setHorizontalAlignment( JLabel.CENTER ); userinputJLabel.setBackground( Color.white ); userinputJLabel.setOpaque( true ); contentPane.add( userinputJLabel ); // set up lowerboundsJLabel lowerboundsJLabel = new JLabel(); lowerboundsJLabel.setText( "Lower Bounds Of Guess = 1" ); lowerboundsJLabel.setBounds( 0, 0, 170, 50 ); lowerboundsJLabel.setHorizontalAlignment( JLabel.CENTER ); lowerboundsJLabel.setBackground( Color.white ); lowerboundsJLabel.setOpaque( true ); contentPane.add( lowerboundsJLabel ); // set up upperboundsJLabel upperboundsJLabel = new JLabel(); upperboundsJLabel.setText( "Upper Bounds Of Guess = 100" ); upperboundsJLabel.setBounds( 250, 0, 170, 50 ); upperboundsJLabel.setHorizontalAlignment( JLabel.CENTER ); upperboundsJLabel.setBackground( Color.white ); upperboundsJLabel.setOpaque( true ); contentPane.add( upperboundsJLabel ); // set up computertalkJLabel computertalkJLabel = new JLabel(); computertalkJLabel.setText( "Computer Says:" ); computertalkJLabel.setBounds( 0, 130, 100, 50 ); //format (x, y, width, height) computertalkJLabel.setHorizontalAlignment( JLabel.CENTER ); computertalkJLabel.setBackground( Color.white ); computertalkJLabel.setOpaque( true ); contentPane.add( computertalkJLabel ); //Set up guess jbutton guessJButton = new JButton(); guessJButton.setText( "Enter" ); guessJButton.setBounds( 250, 78, 100, 30 ); contentPane.add( guessJButton ); guessJButton.addActionListener( new ActionListener() // anonymous inner class { // event handler called when Guess button is pressed public void actionPerformed( ActionEvent event ) { guessActionPerformed( event ); } } // end anonymous inner class ); // end call to addActionListener // set properties of application's window setTitle( "Guess Game" ); // set title bar text setSize( 500, 500 ); // set window size setVisible( true ); // display window //create text field TextField t1 = new TextField(); // Blank text field for user input t1.setBounds( 135, 78, 100, 30 ); contentPane.add( t1 ); userguess = Integer.parseInt( t1.getText() ); //create section for computertalk Label computertalkLabel = new Label(""); computertalkLabel.setBounds( 115, 130, 300, 50); contentPane.add( computertalkLabel ); } // Display computer reactions to user guess private void guessActionPerformed( ActionEvent event ) { if (userguess > computernum) //if statements (computer's reactions to user guess) computertalkJLabel.setText( "Computer Says: Too High" ); else if (userguess < computernum) computertalkJLabel.setText( "Computer Says: Too Low" ); else if (userguess == computernum) computertalkJLabel.setText( "Computer Says:You Win!" ); else computertalkJLabel.setText( "Computer Says: Error" ); } // end method oneJButtonActionPerformed // end method createUserInterface // main method public static void main( String args[] ) { Guess application = new Guess(); application.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE); } // end method main } // end class Phone

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• Initializing and drawing a mesh using OpenTK

  - by Boreal

  I'm implementing a "Mesh" class to use in my OpenTK game. You pass in a vertex array and an index array, and then you can call Mesh.Draw() to draw it using a shader. I've heard VBO's and VAO's are the way to go for this approach, but nowhere have I found a guide that shows how to get Data Video Memory Shader. Can someone give me a quick rundown of how this works? EDIT: So far, I have this: struct Vertex { public Vector3 position; public Vector3 normal; public Vector3 color; public static int memSize = 9 * sizeof(float); public static byte[] memOffset = { 0, 3 * sizeof(float), 6 * sizeof(float) }; } class Mesh { private uint vbo; private uint ibo; // stores the numbers of vertices and indices private int numVertices; private int numIndices; public Mesh(int numVertices, Vertex[] vertices, int numIndices, ushort[] indices) { // set numbers this.numVertices = numVertices; this.numIndices = numIndices; // generate buffers GL.GenBuffers(1, out vbo); GL.GenBuffers(1, out ibo); GL.BindBuffer(BufferTarget.ArrayBuffer, vbo); GL.BindBuffer(BufferTarget.ElementArrayBuffer, ibo); // send data to the buffers GL.BufferData(BufferTarget.ArrayBuffer, new IntPtr(Vertex.memSize * numVertices), vertices, BufferUsageHint.StaticDraw); GL.BufferData(BufferTarget.ElementArrayBuffer, new IntPtr(sizeof(ushort) * numIndices), indices, BufferUsageHint.StaticDraw); } public void Render() { // bind buffers GL.BindBuffer(BufferTarget.ArrayBuffer, vbo); GL.BindBuffer(BufferTarget.ElementArrayBuffer, ibo); // define offsets GL.VertexPointer(3, VertexPointerType.Float, Vertex.memSize, new IntPtr(Vertex.memOffset[0])); GL.NormalPointer(NormalPointerType.Float, Vertex.memSize, new IntPtr(Vertex.memOffset[1])); GL.ColorPointer(3, ColorPointerType.Float, Vertex.memSize, new IntPtr(Vertex.memOffset[2])); // draw GL.DrawElements(BeginMode.Triangles, numIndices, DrawElementsType.UnsignedInt, (IntPtr)0); } } class Application : GameWindow { Mesh triangle; protected override void OnLoad(EventArgs e) { base.OnLoad(e); GL.ClearColor(0.1f, 0.2f, 0.5f, 0.0f); GL.Enable(EnableCap.DepthTest); GL.Enable(EnableCap.VertexArray); GL.Enable(EnableCap.NormalArray); GL.Enable(EnableCap.ColorArray); Vertex v0 = new Vertex(); v0.position = new Vector3(-1.0f, -1.0f, 4.0f); v0.normal = new Vector3(0.0f, 0.0f, -1.0f); v0.color = new Vector3(1.0f, 1.0f, 0.0f); Vertex v1 = new Vertex(); v1.position = new Vector3(1.0f, -1.0f, 4.0f); v1.normal = new Vector3(0.0f, 0.0f, -1.0f); v1.color = new Vector3(1.0f, 0.0f, 0.0f); Vertex v2 = new Vertex(); v2.position = new Vector3(0.0f, 1.0f, 4.0f); v2.normal = new Vector3(0.0f, 0.0f, -1.0f); v2.color = new Vector3(0.2f, 0.9f, 1.0f); Vertex[] va = { v0, v1, v2 }; ushort[] ia = { 0, 1, 2 }; triangle = new Mesh(3, va, 3, ia); } protected override void OnRenderFrame(FrameEventArgs e) { base.OnRenderFrame(e); GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit); Matrix4 modelview = Matrix4.LookAt(Vector3.Zero, Vector3.UnitZ, Vector3.UnitY); GL.MatrixMode(MatrixMode.Modelview); GL.LoadMatrix(ref modelview); triangle.Render(); SwapBuffers(); } } It doesn't draw anything.

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• The Incremental Architect&rsquo;s Napkin - #5 - Design functions for extensibility and readability

  - by Ralf Westphal

  Originally posted on: http://geekswithblogs.net/theArchitectsNapkin/archive/2014/08/24/the-incremental-architectrsquos-napkin---5---design-functions-for.aspx The functionality of programs is entered via Entry Points. So what we´re talking about when designing software is a bunch of functions handling the requests represented by and flowing in through those Entry Points. Designing software thus consists of at least three phases: Analyzing the requirements to find the Entry Points and their signatures Designing the functionality to be executed when those Entry Points get triggered Implementing the functionality according to the design aka coding I presume, you´re familiar with phase 1 in some way. And I guess you´re proficient in implementing functionality in some programming language. But in my experience developers in general are not experienced in going through an explicit phase 2. “Designing functionality? What´s that supposed to mean?” you might already have thought. Here´s my definition: To design functionality (or functional design for short) means thinking about… well, functions. You find a solution for what´s supposed to happen when an Entry Point gets triggered in terms of functions. A conceptual solution that is, because those functions only exist in your head (or on paper) during this phase. But you may have guess that, because it´s “design” not “coding”. And here is, what functional design is not: It´s not about logic. Logic is expressions (e.g. +, -, && etc.) and control statements (e.g. if, switch, for, while etc.). Also I consider calling external APIs as logic. It´s equally basic. It´s what code needs to do in order to deliver some functionality or quality. Logic is what´s doing that needs to be done by software. Transformations are either done through expressions or API-calls. And then there is alternative control flow depending on the result of some expression. Basically it´s just jumps in Assembler, sometimes to go forward (if, switch), sometimes to go backward (for, while, do). But calling your own function is not logic. It´s not necessary to produce any outcome. Functionality is not enhanced by adding functions (subroutine calls) to your code. Nor is quality increased by adding functions. No performance gain, no higher scalability etc. through functions. Functions are not relevant to functionality. Strange, isn´t it. What they are important for is security of investment. By introducing functions into our code we can become more productive (re-use) and can increase evolvability (higher unterstandability, easier to keep code consistent). That´s no small feat, however. Evolvable code can hardly be overestimated. That´s why to me functional design is so important. It´s at the core of software development. To sum this up: Functional design is on a level of abstraction above (!) logical design or algorithmic design. Functional design is only done until you get to a point where each function is so simple you are very confident you can easily code it. Functional design an logical design (which mostly is coding, but can also be done using pseudo code or flow charts) are complementary. Software needs both. If you start coding right away you end up in a tangled mess very quickly. Then you need back out through refactoring. Functional design on the other hand is bloodless without actual code. It´s just a theory with no experiments to prove it. But how to do functional design? An example of functional design Let´s assume a program to de-duplicate strings. The user enters a number of strings separated by commas, e.g. a, b, a, c, d, b, e, c, a. And the program is supposed to clear this list of all doubles, e.g. a, b, c, d, e. There is only one Entry Point to this program: the user triggers the de-duplication by starting the program with the string list on the command line C:\>deduplicate "a, b, a, c, d, b, e, c, a" a, b, c, d, e …or by clicking on a GUI button. This leads to the Entry Point function to get called. It´s the program´s main function in case of the batch version or a button click event handler in the GUI version. That´s the physical Entry Point so to speak. It´s inevitable. What then happens is a three step process: Transform the input data from the user into a request. Call the request handler. Transform the output of the request handler into a tangible result for the user. Or to phrase it a bit more generally: Accept input. Transform input into output. Present output. This does not mean any of these steps requires a lot of effort. Maybe it´s just one line of code to accomplish it. Nevertheless it´s a distinct step in doing the processing behind an Entry Point. Call it an aspect or a responsibility - and you will realize it most likely deserves a function of its own to satisfy the Single Responsibility Principle (SRP). Interestingly the above list of steps is already functional design. There is no logic, but nevertheless the solution is described - albeit on a higher level of abstraction than you might have done yourself. But it´s still on a meta-level. The application to the domain at hand is easy, though: Accept string list from command line De-duplicate Present de-duplicated strings on standard output And this concrete list of processing steps can easily be transformed into code:static void Main(string[] args) { var input = Accept_string_list(args); var output = Deduplicate(input); Present_deduplicated_string_list(output); } Instead of a big problem there are three much smaller problems now. If you think each of those is trivial to implement, then go for it. You can stop the functional design at this point. But maybe, just maybe, you´re not so sure how to go about with the de-duplication for example. Then just implement what´s easy right now, e.g.private static string Accept_string_list(string[] args) { return args[0]; } private static void Present_deduplicated_string_list( string[] output) { var line = string.Join(", ", output); Console.WriteLine(line); } Accept_string_list() contains logic in the form of an API-call. Present_deduplicated_string_list() contains logic in the form of an expression and an API-call. And then repeat the functional design for the remaining processing step. What´s left is the domain logic: de-duplicating a list of strings. How should that be done? Without any logic at our disposal during functional design you´re left with just functions. So which functions could make up the de-duplication? Here´s a suggestion: De-duplicate Parse the input string into a true list of strings. Register each string in a dictionary/map/set. That way duplicates get cast away. Transform the data structure into a list of unique strings. Processing step 2 obviously was the core of the solution. That´s where real creativity was needed. That´s the core of the domain. But now after this refinement the implementation of each step is easy again:private static string[] Parse_string_list(string input) { return input.Split(',') .Select(s => s.Trim()) .ToArray(); } private static Dictionary<string,object> Compile_unique_strings(string[] strings) { return strings.Aggregate( new Dictionary<string, object>(), (agg, s) => { agg[s] = null; return agg; }); } private static string[] Serialize_unique_strings( Dictionary<string,object> dict) { return dict.Keys.ToArray(); } With these three additional functions Main() now looks like this:static void Main(string[] args) { var input = Accept_string_list(args); var strings = Parse_string_list(input); var dict = Compile_unique_strings(strings); var output = Serialize_unique_strings(dict); Present_deduplicated_string_list(output); } I think that´s very understandable code: just read it from top to bottom and you know how the solution to the problem works. It´s a mirror image of the initial design: Accept string list from command line Parse the input string into a true list of strings. Register each string in a dictionary/map/set. That way duplicates get cast away. Transform the data structure into a list of unique strings. Present de-duplicated strings on standard output You can even re-generate the design by just looking at the code. Code and functional design thus are always in sync - if you follow some simple rules. But about that later. And as a bonus: all the functions making up the process are small - which means easy to understand, too. So much for an initial concrete example. Now it´s time for some theory. Because there is method to this madness ;-) The above has only scratched the surface. Introducing Flow Design Functional design starts with a given function, the Entry Point. Its goal is to describe the behavior of the program when the Entry Point is triggered using a process, not an algorithm. An algorithm consists of logic, a process on the other hand consists just of steps or stages. Each processing step transforms input into output or a side effect. Also it might access resources, e.g. a printer, a database, or just memory. Processing steps thus can rely on state of some sort. This is different from Functional Programming, where functions are supposed to not be stateful and not cause side effects.[1] In its simplest form a process can be written as a bullet point list of steps, e.g. Get data from user Output result to user Transform data Parse data Map result for output Such a compilation of steps - possibly on different levels of abstraction - often is the first artifact of functional design. It can be generated by a team in an initial design brainstorming. Next comes ordering the steps. What should happen first, what next etc.? Get data from user Parse data Transform data Map result for output Output result to user That´s great for a start into functional design. It´s better than starting to code right away on a given function using TDD. Please get me right: TDD is a valuable practice. But it can be unnecessarily hard if the scope of a functionn is too large. But how do you know beforehand without investing some thinking? And how to do this thinking in a systematic fashion? My recommendation: For any given function you´re supposed to implement first do a functional design. Then, once you´re confident you know the processing steps - which are pretty small - refine and code them using TDD. You´ll see that´s much, much easier - and leads to cleaner code right away. For more information on this approach I call “Informed TDD” read my book of the same title. Thinking before coding is smart. And writing down the solution as a bunch of functions possibly is the simplest thing you can do, I´d say. It´s more according to the KISS (Keep It Simple, Stupid) principle than returning constants or other trivial stuff TDD development often is started with. So far so good. A simple ordered list of processing steps will do to start with functional design. As shown in the above example such steps can easily be translated into functions. Moving from design to coding thus is simple. However, such a list does not scale. Processing is not always that simple to be captured in a list. And then the list is just text. Again. Like code. That means the design is lacking visuality. Textual representations need more parsing by your brain than visual representations. Plus they are limited in their “dimensionality”: text just has one dimension, it´s sequential. Alternatives and parallelism are hard to encode in text. In addition the functional design using numbered lists lacks data. It´s not visible what´s the input, output, and state of the processing steps. That´s why functional design should be done using a lightweight visual notation. No tool is necessary to draw such designs. Use pen and paper; a flipchart, a whiteboard, or even a napkin is sufficient. Visualizing processes The building block of the functional design notation is a functional unit. I mostly draw it like this: Something is done, it´s clear what goes in, it´s clear what comes out, and it´s clear what the processing step requires in terms of state or hardware. Whenever input flows into a functional unit it gets processed and output is produced and/or a side effect occurs. Flowing data is the driver of something happening. That´s why I call this approach to functional design Flow Design. It´s about data flow instead of control flow. Control flow like in algorithms is of no concern to functional design. Thinking about control flow simply is too low level. Once you start with control flow you easily get bogged down by tons of details. That´s what you want to avoid during design. Design is supposed to be quick, broad brush, abstract. It should give overview. But what about all the details? As Robert C. Martin rightly said: “Programming is abot detail”. Detail is a matter of code. Once you start coding the processing steps you designed you can worry about all the detail you want. Functional design does not eliminate all the nitty gritty. It just postpones tackling them. To me that´s also an example of the SRP. Function design has the responsibility to come up with a solution to a problem posed by a single function (Entry Point). And later coding has the responsibility to implement the solution down to the last detail (i.e. statement, API-call). TDD unfortunately mixes both responsibilities. It´s just coding - and thereby trying to find detailed implementations (green phase) plus getting the design right (refactoring). To me that´s one reason why TDD has failed to deliver on its promise for many developers. Using functional units as building blocks of functional design processes can be depicted very easily. Here´s the initial process for the example problem: For each processing step draw a functional unit and label it. Choose a verb or an “action phrase” as a label, not a noun. Functional design is about activities, not state or structure. Then make the output of an upstream step the input of a downstream step. Finally think about the data that should flow between the functional units. Write the data above the arrows connecting the functional units in the direction of the data flow. Enclose the data description in brackets. That way you can clearly see if all flows have already been specified. Empty brackets mean “no data is flowing”, but nevertheless a signal is sent. A name like “list” or “strings” in brackets describes the data content. Use lower case labels for that purpose. A name starting with an upper case letter like “String” or “Customer” on the other hand signifies a data type. If you like, you also can combine descriptions with data types by separating them with a colon, e.g. (list:string) or (strings:string[]). But these are just suggestions from my practice with Flow Design. You can do it differently, if you like. Just be sure to be consistent. Flows wired-up in this manner I call one-dimensional (1D). Each functional unit just has one input and/or one output. A functional unit without an output is possible. It´s like a black hole sucking up input without producing any output. Instead it produces side effects. A functional unit without an input, though, does make much sense. When should it start to work? What´s the trigger? That´s why in the above process even the first processing step has an input. If you like, view such 1D-flows as pipelines. Data is flowing through them from left to right. But as you can see, it´s not always the same data. It get´s transformed along its passage: (args) becomes a (list) which is turned into (strings). The Principle of Mutual Oblivion A very characteristic trait of flows put together from function units is: no functional units knows another one. They are all completely independent of each other. Functional units don´t know where their input is coming from (or even when it´s gonna arrive). They just specify a range of values they can process. And they promise a certain behavior upon input arriving. Also they don´t know where their output is going. They just produce it in their own time independent of other functional units. That means at least conceptually all functional units work in parallel. Functional units don´t know their “deployment context”. They now nothing about the overall flow they are place in. They are just consuming input from some upstream, and producing output for some downstream. That makes functional units very easy to test. At least as long as they don´t depend on state or resources. I call this the Principle of Mutual Oblivion (PoMO). Functional units are oblivious of others as well as an overall context/purpose. They are just parts of a whole focused on a single responsibility. How the whole is built, how a larger goal is achieved, is of no concern to the single functional units. By building software in such a manner, functional design interestingly follows nature. Nature´s building blocks for organisms also follow the PoMO. The cells forming your body do not know each other. Take a nerve cell “controlling” a muscle cell for example:[2] The nerve cell does not know anything about muscle cells, let alone the specific muscel cell it is “attached to”. Likewise the muscle cell does not know anything about nerve cells, let a lone a specific nerve cell “attached to” it. Saying “the nerve cell is controlling the muscle cell” thus only makes sense when viewing both from the outside. “Control” is a concept of the whole, not of its parts. Control is created by wiring-up parts in a certain way. Both cells are mutually oblivious. Both just follow a contract. One produces Acetylcholine (ACh) as output, the other consumes ACh as input. Where the ACh is going, where it´s coming from neither cell cares about. Million years of evolution have led to this kind of division of labor. And million years of evolution have produced organism designs (DNA) which lead to the production of these different cell types (and many others) and also to their co-location. The result: the overall behavior of an organism. How and why this happened in nature is a mystery. For our software, though, it´s clear: functional and quality requirements needs to be fulfilled. So we as developers have to become “intelligent designers” of “software cells” which we put together to form a “software organism” which responds in satisfying ways to triggers from it´s environment. My bet is: If nature gets complex organisms working by following the PoMO, who are we to not apply this recipe for success to our much simpler “machines”? So my rule is: Wherever there is functionality to be delivered, because there is a clear Entry Point into software, design the functionality like nature would do it. Build it from mutually oblivious functional units. That´s what Flow Design is about. In that way it´s even universal, I´d say. Its notation can also be applied to biology: Never mind labeling the functional units with nouns. That´s ok in Flow Design. You´ll do that occassionally for functional units on a higher level of abstraction or when their purpose is close to hardware. Getting a cockroach to roam your bedroom takes 1,000,000 nerve cells (neurons). Getting the de-duplication program to do its job just takes 5 “software cells” (functional units). Both, though, follow the same basic principle. Translating functional units into code Moving from functional design to code is no rocket science. In fact it´s straightforward. There are two simple rules: Translate an input port to a function. Translate an output port either to a return statement in that function or to a function pointer visible to that function. The simplest translation of a functional unit is a function. That´s what you saw in the above example. Functions are mutually oblivious. That why Functional Programming likes them so much. It makes them composable. Which is the reason, nature works according to the PoMO. Let´s be clear about one thing: There is no dependency injection in nature. For all of an organism´s complexity no DI container is used. Behavior is the result of smooth cooperation between mutually oblivious building blocks. Functions will often be the adequate translation for the functional units in your designs. But not always. Take for example the case, where a processing step should not always produce an output. Maybe the purpose is to filter input. Here the functional unit consumes words and produces words. But it does not pass along every word flowing in. Some words are swallowed. Think of a spell checker. It probably should not check acronyms for correctness. There are too many of them. Or words with no more than two letters. Such words are called “stop words”. In the above picture the optionality of the output is signified by the astrisk outside the brackets. It means: Any number of (word) data items can flow from the functional unit for each input data item. It might be none or one or even more. This I call a stream of data. Such behavior cannot be translated into a function where output is generated with return. Because a function always needs to return a value. So the output port is translated into a function pointer or continuation which gets passed to the subroutine when called:[3]void filter_stop_words( string word, Action<string> onNoStopWord) { if (...check if not a stop word...) onNoStopWord(word); } If you want to be nitpicky you might call such a function pointer parameter an injection. And technically you´re right. Conceptually, though, it´s not an injection. Because the subroutine is not functionally dependent on the continuation. Firstly continuations are procedures, i.e. subroutines without a return type. Remember: Flow Design is about unidirectional data flow. Secondly the name of the formal parameter is chosen in a way as to not assume anything about downstream processing steps. onNoStopWord describes a situation (or event) within the functional unit only. Translating output ports into function pointers helps keeping functional units mutually oblivious in cases where output is optional or produced asynchronically. Either pass the function pointer to the function upon call. Or make it global by putting it on the encompassing class. Then it´s called an event. In C# that´s even an explicit feature.class Filter { public void filter_stop_words( string word) { if (...check if not a stop word...) onNoStopWord(word); } public event Action<string> onNoStopWord; } When to use a continuation and when to use an event dependens on how a functional unit is used in flows and how it´s packed together with others into classes. You´ll see examples further down the Flow Design road. Another example of 1D functional design Let´s see Flow Design once more in action using the visual notation. How about the famous word wrap kata? Robert C. Martin has posted a much cited solution including an extensive reasoning behind his TDD approach. So maybe you want to compare it to Flow Design. The function signature given is:string WordWrap(string text, int maxLineLength) {...} That´s not an Entry Point since we don´t see an application with an environment and users. Nevertheless it´s a function which is supposed to provide a certain functionality. The text passed in has to be reformatted. The input is a single line of arbitrary length consisting of words separated by spaces. The output should consist of one or more lines of a maximum length specified. If a word is longer than a the maximum line length it can be split in multiple parts each fitting in a line. Flow Design Let´s start by brainstorming the process to accomplish the feat of reformatting the text. What´s needed? Words need to be assembled into lines Words need to be extracted from the input text The resulting lines need to be assembled into the output text Words too long to fit in a line need to be split Does sound about right? I guess so. And it shows a kind of priority. Long words are a special case. So maybe there is a hint for an incremental design here. First let´s tackle “average words” (words not longer than a line). Here´s the Flow Design for this increment: The the first three bullet points turned into functional units with explicit data added. As the signature requires a text is transformed into another text. See the input of the first functional unit and the output of the last functional unit. In between no text flows, but words and lines. That´s good to see because thereby the domain is clearly represented in the design. The requirements are talking about words and lines and here they are. But note the asterisk! It´s not outside the brackets but inside. That means it´s not a stream of words or lines, but lists or sequences. For each text a sequence of words is output. For each sequence of words a sequence of lines is produced. The asterisk is used to abstract from the concrete implementation. Like with streams. Whether the list of words gets implemented as an array or an IEnumerable is not important during design. It´s an implementation detail. Does any processing step require further refinement? I don´t think so. They all look pretty “atomic” to me. And if not… I can always backtrack and refine a process step using functional design later once I´ve gained more insight into a sub-problem. Implementation The implementation is straightforward as you can imagine. The processing steps can all be translated into functions. Each can be tested easily and separately. Each has a focused responsibility. And the process flow becomes just a sequence of function calls: Easy to understand. It clearly states how word wrapping works - on a high level of abstraction. And it´s easy to evolve as you´ll see. Flow Design - Increment 2 So far only texts consisting of “average words” are wrapped correctly. Words not fitting in a line will result in lines too long. Wrapping long words is a feature of the requested functionality. Whether it´s there or not makes a difference to the user. To quickly get feedback I decided to first implement a solution without this feature. But now it´s time to add it to deliver the full scope. Fortunately Flow Design automatically leads to code following the Open Closed Principle (OCP). It´s easy to extend it - instead of changing well tested code. How´s that possible? Flow Design allows for extension of functionality by inserting functional units into the flow. That way existing functional units need not be changed. The data flow arrow between functional units is a natural extension point. No need to resort to the Strategy Pattern. No need to think ahead where extions might need to be made in the future. I just “phase in” the remaining processing step: Since neither Extract words nor Reformat know of their environment neither needs to be touched due to the “detour”. The new processing step accepts the output of the existing upstream step and produces data compatible with the existing downstream step. Implementation - Increment 2 A trivial implementation checking the assumption if this works does not do anything to split long words. The input is just passed on: Note how clean WordWrap() stays. The solution is easy to understand. A developer looking at this code sometime in the future, when a new feature needs to be build in, quickly sees how long words are dealt with. Compare this to Robert C. Martin´s solution:[4] How does this solution handle long words? Long words are not even part of the domain language present in the code. At least I need considerable time to understand the approach. Admittedly the Flow Design solution with the full implementation of long word splitting is longer than Robert C. Martin´s. At least it seems. Because his solution does not cover all the “word wrap situations” the Flow Design solution handles. Some lines would need to be added to be on par, I guess. But even then… Is a difference in LOC that important as long as it´s in the same ball park? I value understandability and openness for extension higher than saving on the last line of code. Simplicity is not just less code, it´s also clarity in design. But don´t take my word for it. Try Flow Design on larger problems and compare for yourself. What´s the easier, more straightforward way to clean code? And keep in mind: You ain´t seen all yet ;-) There´s more to Flow Design than described in this chapter. In closing I hope I was able to give you a impression of functional design that makes you hungry for more. To me it´s an inevitable step in software development. Jumping from requirements to code does not scale. And it leads to dirty code all to quickly. Some thought should be invested first. Where there is a clear Entry Point visible, it´s functionality should be designed using data flows. Because with data flows abstraction is possible. For more background on why that´s necessary read my blog article here. For now let me point out to you - if you haven´t already noticed - that Flow Design is a general purpose declarative language. It´s “programming by intention” (Shalloway et al.). Just write down how you think the solution should work on a high level of abstraction. This breaks down a large problem in smaller problems. And by following the PoMO the solutions to those smaller problems are independent of each other. So they are easy to test. Or you could even think about getting them implemented in parallel by different team members. Flow Design not only increases evolvability, but also helps becoming more productive. All team members can participate in functional design. This goes beyon collective code ownership. We´re talking collective design/architecture ownership. Because with Flow Design there is a common visual language to talk about functional design - which is the foundation for all other design activities.   PS: If you like what you read, consider getting my ebook “The Incremental Architekt´s Napkin”. It´s where I compile all the articles in this series for easier reading. I like the strictness of Function Programming - but I also find it quite hard to live by. And it certainly is not what millions of programmers are used to. Also to me it seems, the real world is full of state and side effects. So why give them such a bad image? That´s why functional design takes a more pragmatic approach. State and side effects are ok for processing steps - but be sure to follow the SRP. Don´t put too much of it into a single processing step. ? Image taken from www.physioweb.org ? My code samples are written in C#. C# sports typed function pointers called delegates. Action is such a function pointer type matching functions with signature void someName(T t). Other languages provide similar ways to work with functions as first class citizens - even Java now in version 8. I trust you find a way to map this detail of my translation to your favorite programming language. I know it works for Java, C++, Ruby, JavaScript, Python, Go. And if you´re using a Functional Programming language it´s of course a no brainer. ? Taken from his blog post “The Craftsman 62, The Dark Path”. ?

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• Exploring packages in code

  In my previous post Searching for tasks with code you can see how to explore the control flow side of packages, drilling down through containers, task, and event handlers, but it didn’t cover the data flow. I recently saw a post on the MSDN forum asking how to edit an existing package programmatically, and the sticking point was how to find the the data flow and the components inside. This post builds on some of the previous code and shows how you can explore all objects inside a package. I took the sample Task Search application I’d written previously, and came up with a totally pointless little console application that just walks through the package and writes out the basic type and name of every object it finds, starting with the package itself e.g. Package – MyPackage . The sample package we used last time showed nested objects as well an event handler; a OnPreExecute event tucked away on the task SQL In FEL. The output of this sample tool would look like this: PackageObjects v1.0.0.0 (1.0.0.26627) Copyright (C) 2009 Konesans Ltd Processing File - Z:\Users\Darren Green\Documents\Visual Studio 2005\Projects\SSISTestProject\EventsAndContainersWithExe cSQLForSearch.dtsx Package - EventsAndContainersWithExecSQLForSearch For Loop - FOR Counter Loop Task - SQL In Counter Loop Sequence Container - SEQ For Each Loop Wrapper For Each Loop - FEL Simple Loop Task - SQL In FEL Task - SQL On Pre Execute for FEL SQL Task Sequence Container - SEQ Top Level Sequence Container - SEQ Nested Lvl 1 Sequence Container - SEQ Nested Lvl 2 Task - SQL In Nested Lvl 2 Task - SQL In Nested Lvl 1 #1 Task - SQL In Nested Lvl 1 #2 Connection Manager – LocalHost The code is very similar to what we had previously, but there are a couple of extra bits to deal with connections and to look more closely at a task and see if it is a Data Flow task. For connections your just examine the package's Connections collection as shown in the abridged snippets below. First you can see the call to the ProcessConnections method, followed by the method itself. // Load the package file Application application = new Application(); using (Package package = application.LoadPackage(filename, null)) { // Write out the package name Console.WriteLine("Package - {0}", package.Name); ... More ... // Look and the connections ProcessConnections(package.Connections); } private static void ProcessConnections(Connections connections) { foreach (ConnectionManager connectionManager in connections) { Console.WriteLine("Connection Manager - {0}", connectionManager.Name); } } What we didn’t see in the sample output above was anything to do with the Data Flow, but rest assured the code now handles it too. The following snippet shows how each task is examined to see if it is a Data Flow task, and if so we can then loop through all of the components inside the data flow. private static void ProcessTaskHost(TaskHost taskHost) { if (taskHost == null) { return; } Console.WriteLine("Task - {0}", taskHost.Name); // Check if the task is a Data Flow task MainPipe pipeline = taskHost.InnerObject as MainPipe; if (pipeline != null) { ProcessPipeline(pipeline); } } private static void ProcessPipeline(MainPipe pipeline) { foreach (IDTSComponentMetaData90 componentMetadata in pipeline.ComponentMetaDataCollection) { Console.WriteLine("Pipeline Component - {0}", componentMetadata.Name); // If you wish to make changes to the component then you should really use the managed wrapper. // CManagedComponentWrapper wrapper = componentMetadata.Instantiate(); // wrapper.SetComponentProperty("PropertyName", "Value"); } } Hopefully you can see how we get a reference to the Data Flow task, and then use the ComponentMetaDataCollection to find out what components we have inside the pipeline. If you wanted to know more about the component you could look at the ObjectType or ComponentClassID properties. After that it gets a bit harder and you should get a reference to the wrapper object as the comment suggest and start using the properties, just like you would in the create packages samples, see our Code Development category for some for these examples. Download Sample code project PackageObjects.zip (5KB)

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• ASP.NET Web API - Screencast series with downloadable sample code - Part 1

  - by Jon Galloway

  There's a lot of great ASP.NET Web API content on the ASP.NET website at http://asp.net/web-api. I mentioned my screencast series in original announcement post, but we've since added the sample code so I thought it was worth pointing the series out specifically. This is an introductory screencast series that walks through from File / New Project to some more advanced scenarios like Custom Validation and Authorization. The screencast videos are all short (3-5 minutes) and the sample code for the series is both available for download and browsable online. I did the screencasts, but the samples were written by the ASP.NET Web API team. So - let's watch them together! Grab some popcorn and pay attention, because these are short. After each video, I'll talk about what I thought was important. I'm embedding the videos using HTML5 (MP4) with Silverlight fallback, but if something goes wrong or your browser / device / whatever doesn't support them, I'll include the link to where the videos are more professionally hosted on the ASP.NET site. Note also if you're following along with the samples that, since Part 1 just looks at the File / New Project step, the screencast part numbers are one ahead of the sample part numbers - so screencast 4 matches with sample code demo 3. Note: I started this as one long post for all 6 parts, but as it grew over 2000 words I figured it'd be better to break it up. Part 1: Your First Web API [Video and code on the ASP.NET site] This screencast starts with an overview of why you'd want to use ASP.NET Web API: Reach more clients (thinking beyond the browser to mobile clients, other applications, etc.) Scale (who doesn't love the cloud?!) Embrace HTTP (a focus on HTTP both on client and server really simplifies and focuses service interactions) Next, I start a new ASP.NET Web API application and show some of the basics of the ApiController. We don't write any new code in this first step, just look at the example controller that's created by File / New Project. using System; using System.Collections.Generic; using System.Linq; using System.Net.Http; using System.Web.Http; namespace NewProject_Mvc4BetaWebApi.Controllers { public class ValuesController : ApiController { // GET /api/values public IEnumerable<string> Get() { return new string[] { "value1", "value2" }; } // GET /api/values/5 public string Get(int id) { return "value"; } // POST /api/values public void Post(string value) { } // PUT /api/values/5 public void Put(int id, string value) { } // DELETE /api/values/5 public void Delete(int id) { } } } Finally, we walk through testing the output of this API controller using browser tools. There are several ways you can test API output, including Fiddler (as described by Scott Hanselman in this post) and built-in developer tools available in all modern browsers. For simplicity I used Internet Explorer 9 F12 developer tools, but you're of course welcome to use whatever you'd like. A few important things to note: This class derives from an ApiController base class, not the standard ASP.NET MVC Controller base class. They're similar in places where API's and HTML returning controller uses are similar, and different where API and HTML use differ. A good example of where those things are different is in the routing conventions. In an HTTP controller, there's no need for an "action" to be specified, since the HTTP verbs are the actions. We don't need to do anything to map verbs to actions; when a request comes in to /api/values/5 with the DELETE HTTP verb, it'll automatically be handled by the Delete method in an ApiController. The comments above the API methods show sample URL's and HTTP verbs, so we can test out the first two GET methods by browsing to the site in IE9, hitting F12 to bring up the tools, and entering /api/values in the URL: That sample action returns a list of values. To get just one value back, we'd browse to /values/5: That's it for Part 1. In Part 2 we'll look at getting data (beyond hardcoded strings) and start building out a sample application.

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• Endless terrain in jMonkey using TerrainGrid fails to render

  - by nightcrawler23

  I have started to learn game development using jMonkey engine. I am able to create single tile of terrain using TerrainQuad but as the next step I'm stuck at making it infinite. I have gone through the wiki and want to use the TerrainGrid class but my code does not seem to work. I have looked around on the web and searched other forums but cannot find any other code example to help. I believe in the below code, ImageTileLoader returns an image which is the heightmap for that tile. I have modified it to return the same image every time. But all I see is a black window. The Namer method is not even called. terrain = new TerrainGrid("terrain", patchSize, 513, new ImageTileLoader(assetManager, new Namer() { public String getName(int x, int y) { //return "Scenes/TerrainMountains/terrain_" + x + "_" + y + ".png"; System.out.println("X = " + x + ", Y = " + y); return "Textures/heightmap.png"; } })); These are my sources: jMonkeyEngine 3 Tutorial (10) - Hello Terrain TerrainGridTest.java ImageTileLoader This is the result when i use TerrainQuad: , My full code: // Sample 10 - How to create fast-rendering terrains from heightmaps, and how to // use texture splatting to make the terrain look good. public class HelloTerrain extends SimpleApplication { private TerrainQuad terrain; Material mat_terrain; private float grassScale = 64; private float dirtScale = 32; private float rockScale = 64; public static void main(String[] args) { HelloTerrain app = new HelloTerrain(); app.start(); } private FractalSum base; private PerturbFilter perturb; private OptimizedErode therm; private SmoothFilter smooth; private IterativeFilter iterate; @Override public void simpleInitApp() { flyCam.setMoveSpeed(200); initMaterial(); AbstractHeightMap heightmap = null; Texture heightMapImage = assetManager.loadTexture("Textures/heightmap.png"); heightmap = new ImageBasedHeightMap(heightMapImage.getImage()); heightmap.load(); int patchSize = 65; //terrain = new TerrainQuad("my terrain", patchSize, 513, heightmap.getHeightMap()); // * This Works but below doesnt work* terrain = new TerrainGrid("terrain", patchSize, 513, new ImageTileLoader(assetManager, new Namer() { public String getName(int x, int y) { //return "Scenes/TerrainMountains/terrain_" + x + "_" + y + ".png"; System.out.println("X = " + x + ", Y = " + y); return "Textures/heightmap.png"; // set to return the sme hieghtmap image. } })); terrain.setMaterial(mat_terrain); terrain.setLocalTranslation(0,-100, 0); terrain.setLocalScale(2f, 1f, 2f); rootNode.attachChild(terrain); TerrainLodControl control = new TerrainLodControl(terrain, getCamera()); terrain.addControl(control); } public void initMaterial() { // TERRAIN TEXTURE material this.mat_terrain = new Material(this.assetManager, "Common/MatDefs/Terrain/HeightBasedTerrain.j3md"); // GRASS texture Texture grass = this.assetManager.loadTexture("Textures/white.png"); grass.setWrap(WrapMode.Repeat); this.mat_terrain.setTexture("region1ColorMap", grass); this.mat_terrain.setVector3("region1", new Vector3f(-10, 0, this.grassScale)); // DIRT texture Texture dirt = this.assetManager.loadTexture("Textures/white.png"); dirt.setWrap(WrapMode.Repeat); this.mat_terrain.setTexture("region2ColorMap", dirt); this.mat_terrain.setVector3("region2", new Vector3f(0, 900, this.dirtScale)); Texture building = this.assetManager.loadTexture("Textures/building.png"); building.setWrap(WrapMode.Repeat); this.mat_terrain.setTexture("slopeColorMap", building); this.mat_terrain.setFloat("slopeTileFactor", 32); this.mat_terrain.setFloat("terrainSize", 513); } }

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• asynchrony is viral

  - by Daniel Moth

  It is becoming hard to write code today without introducing some form of asynchrony and, if you are using .NET (e.g. for Windows Phone 8 or Windows Store apps), that means sooner or later you have to await something and mark your method as async. My most recent examples included introducing speech recognition in my Translator By Moth phone app where I had to await mySpeechRecognizerUI.RecognizeWithUIAsync() and when moving that code base to a Windows Store project just to show a MessageBox I had to await myMessageDialog.ShowAsync(). Any time you need to invoke an asynchronous method in your code, you have a choice to make: kick off the operation but don’t wait for it to complete (otherwise known as fire-and-forget), synchronously wait for it to complete (which will entail blocking, which can be bad, especially on a UI thread), or asynchronously wait for it to complete before continuing on with the rest of the method’s work. In most cases, you want the latter, and the await keyword makes that trivial to implement.  When you use the magical await keyword in front of an API call, then you typically have to make additional changes to your code: This await usage is within a method of course, and now you have to annotate that method with async. Furthermore, you have to change the return type of the method you just annotated so it returns a Task (if it previously returned void), or Task<myOldReturnType> (if it previously returned myOldReturnType). Note that if it returns void, in some cases you could cheat and stop there. Furthermore, any method that called this method you just annotated with async will now also be invoking an asynchronous operation, so you have to make that change in the body of the caller method to introduce the await keyword before the call to the method. …you guessed it, you now have to change this caller method to be annotated with async and have its return types tweaked... …and it goes on virally… At some point you reach the root of your user code, e.g. a GUI event handler, and whoever calls that void method can already deal with the fact that you marked it as async and the viral introduction of the keywords stops there… This is all wonderful progress and a very powerful mechanism, and I just wish someone had written a refactoring tool to take care of this… anyone? I mentioned earlier that you have a choice when invoking an asynchronous operation. If the first time you encounter this you wish to localize the impact of all these changes and essentially try to turn the asynchronous behavior into synchronous by blocking - don't! For reasons why you don't want to do that, read Toub's excellent blog post (and check out the rest of his blog with gems on async programming starting with the Async FAQ). Just embrace the pattern knowing that when you use one instance of an await, you'll propagate the change all the way to the root user code method, e.g. typically an event handler. Related aside: I just finished re-writing my MessageBox wrapper class for Phone projects, including making it work in Windows Store projects, and it does expect you to use it with an await :-). I'll share that in an upcoming post for those of you that have the same need… Comments about this post by Daniel Moth welcome at the original blog.

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• Tuple in C# 4.0

  - by Jalpesh P. Vadgama

  C# 4.0 language includes a new feature called Tuple. Tuple provides us a way of grouping elements of different data type. That enables us to use it a lots places at practical world like we can store a coordinates of graphs etc. In C# 4.0 we can create Tuple with Create method. This Create method offer 8 overload like following. So you can group maximum 8 data types with a Tuple. Followings are overloads of a data type. Create(T1)- Which represents a tuple of size 1 Create(T1,T2)- Which represents a tuple of size 2 Create(T1,T2,T3) – Which represents a tuple of size 3 Create(T1,T2,T3,T4) – Which represents a tuple of size 4 Create(T1,T2,T3,T4,T5) – Which represents a tuple of size 5 Create(T1,T2,T3,T4,T5,T6) – Which represents a tuple of size 6 Create(T1,T2,T3,T4,T5,T6,T7) – Which represents a tuple of size 7 Create(T1,T2,T3,T4,T5,T6,T7,T8) – Which represents a tuple of size 8 Following are some example code for tuple. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace TupleExample { class Program { static void Main(string[] args) { var tuple = System.Tuple.Create<string, string, string>("Jalpesh", "P", "Vadgama"); Console.WriteLine(tuple); var t = System.Tuple.Create<int, string>(1, "Jalpesh"); Console.WriteLine(t); } } } Following is a output of above as expected. You can also access values insides Tuple with ItemN property. Where N represents particular number of item in tuple. Following is an example of it. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace TupleExample { class Program { static void Main(string[] args) { var tuple = System.Tuple.Create<string, string, string>("Jalpesh", "P", "Vadgama"); Console.WriteLine(tuple.Item1); Console.WriteLine(tuple.Item2); Console.WriteLine(tuple.Item3); } } } Here you can see I have printed items with Item1,Item2 and Item3 . Following is the output of above code.   Even we can create a nested tuple also following is code for nested tuple. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace TupleExample { class Program { static void Main(string[] args) { var tuple = System.Tuple.Create(1,"Jalpesh",new Tuple<string,string>("P","Vadgama")); Console.WriteLine(tuple.Item1); Console.WriteLine(tuple.Item2); Console.WriteLine(tuple.Item3); } } } Following is a output above code as expected. As you can see there are unlimited possibilities we can do lots of things with Tuple. Hope you liked it. Stay tuned for more. Till then Happy Programming!!

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• SQL Server &ndash; Undelete a Table and Restore a Single Table from Backup

  - by Mladen Prajdic

  This post is part of the monthly community event called T-SQL Tuesday started by Adam Machanic (blog|twitter) and hosted by someone else each month. This month the host is Sankar Reddy (blog|twitter) and the topic is Misconceptions in SQL Server. You can follow posts for this theme on Twitter by looking at #TSQL2sDay hashtag. Let me start by saying: This code is a crazy hack that is to never be used unless you really, really have to. Really! And I don’t think there’s a time when you would really have to use it for real. Because it’s a hack there are number of things that can go wrong so play with it knowing that. I’ve managed to totally corrupt one database. :) Oh… and for those saying: yeah yeah.. you have a single table in a file group and you’re restoring that, I say “nay nay” to you. As we all know SQL Server can’t do single table restores from backup. This is kind of a obvious thing due to different relational integrity (RI) concerns. Since we have to maintain that we have to restore all tables represented in a RI graph. For this exercise i say BAH! to those concerns. Note that this method “works” only for simple tables that don’t have LOB and off rows data. The code can be expanded to include those but I’ve tried to leave things “simple”. Note that for this to work our table needs to be relatively static data-wise. This doesn’t work for OLTP table. Products are a perfect example of static data. They don’t change much between backups, pretty much everything depends on them and their table is one of those tables that are relatively easy to accidentally delete everything from. This only works if the database is in Full or Bulk-Logged recovery mode for tables where the contents have been deleted or truncated but NOT when a table was dropped. Everything we’ll talk about has to be done before the data pages are reused for other purposes. After deletion or truncation the pages are marked as reusable so you have to act fast. The best thing probably is to put the database into single user mode ASAP while you’re performing this procedure and return it to multi user after you’re done. How do we do it? We will be using an undocumented but known DBCC commands: DBCC PAGE, an undocumented function sys.fn_dblog and a little known DATABASE RESTORE PAGE option. All tests will be on a copy of Production.Product table in AdventureWorks database called Production.Product1 because the original table has FK constraints that prevent us from truncating it for testing. -- create a duplicate table. This doesn't preserve indexes!SELECT *INTO AdventureWorks.Production.Product1FROM AdventureWorks.Production.Product   After we run this code take a full back to perform further testing.   First let’s see what the difference between DELETE and TRUNCATE is when it comes to logging. With DELETE every row deletion is logged in the transaction log. With TRUNCATE only whole data page deallocations are logged in the transaction log. Getting deleted data pages is simple. All we have to look for is row delete entry in the sys.fn_dblog output. But getting data pages that were truncated from the transaction log presents a bit of an interesting problem. I will not go into depths of IAM(Index Allocation Map) and PFS (Page Free Space) pages but suffice to say that every IAM page has intervals that tell us which data pages are allocated for a table and which aren’t. If we deep dive into the sys.fn_dblog output we can see that once you truncate a table all the pages in all the intervals are deallocated and this is shown in the PFS page transaction log entry as deallocation of pages. For every 8 pages in the same extent there is one PFS page row in the transaction log. This row holds information about all 8 pages in CSV format which means we can get to this data with some parsing. A great help for parsing this stuff is Peter Debetta’s handy function dbo.HexStrToVarBin that converts hexadecimal string into a varbinary value that can be easily converted to integer tus giving us a readable page number. The shortened (columns removed) sys.fn_dblog output for a PFS page with CSV data for 1 extent (8 data pages) looks like this: -- [Page ID] is displayed in hex format. -- To convert it to readable int we'll use dbo.HexStrToVarBin function found at -- http://sqlblog.com/blogs/peter_debetta/archive/2007/03/09/t-sql-convert-hex-string-to-varbinary.aspx -- This function must be installed in the master databaseSELECT Context, AllocUnitName, [Page ID], DescriptionFROM sys.fn_dblog(NULL, NULL)WHERE [Current LSN] = '00000031:00000a46:007d' The pages at the end marked with 0x00—> are pages that are allocated in the extent but are not part of a table. We can inspect the raw content of each data page with a DBCC PAGE command: -- we need this trace flag to redirect output to the query window.DBCC TRACEON (3604); -- WITH TABLERESULTS gives us data in table format instead of message format-- we use format option 3 because it's the easiest to read and manipulate further onDBCC PAGE (AdventureWorks, 1, 613, 3) WITH TABLERESULTS   Since the DBACC PAGE output can be quite extensive I won’t put it here. You can see an example of it in the link at the beginning of this section. Getting deleted data back When we run a delete statement every row to be deleted is marked as a ghost record. A background process periodically cleans up those rows. A huge misconception is that the data is actually removed. It’s not. Only the pointers to the rows are removed while the data itself is still on the data page. We just can’t access it with normal means. To get those pointers back we need to restore every deleted page using the RESTORE PAGE option mentioned above. This restore must be done from a full backup, followed by any differential and log backups that you may have. This is necessary to bring the pages up to the same point in time as the rest of the data.  However the restore doesn’t magically connect the restored page back to the original table. It simply replaces the current page with the one from the backup. After the restore we use the DBCC PAGE to read data directly from all data pages and insert that data into a temporary table. To finish the RESTORE PAGE  procedure we finally have to take a tail log backup (simple backup of the transaction log) and restore it back. We can now insert data from the temporary table to our original table by hand. Getting truncated data back When we run a truncate the truncated data pages aren’t touched at all. Even the pointers to rows stay unchanged. Because of this getting data back from truncated table is simple. we just have to find out which pages belonged to our table and use DBCC PAGE to read data off of them. No restore is necessary. Turns out that the problems we had with finding the data pages is alleviated by not having to do a RESTORE PAGE procedure. Stop stalling… show me The Code! This is the code for getting back deleted and truncated data back. It’s commented in all the right places so don’t be afraid to take a closer look. Make sure you have a full backup before trying this out. Also I suggest that the last step of backing and restoring the tail log is performed by hand. USE masterGOIF OBJECT_ID('dbo.HexStrToVarBin') IS NULL RAISERROR ('No dbo.HexStrToVarBin installed. Go to http://sqlblog.com/blogs/peter_debetta/archive/2007/03/09/t-sql-convert-hex-string-to-varbinary.aspx and install it in master database' , 18, 1) SET NOCOUNT ONBEGIN TRY DECLARE @dbName VARCHAR(1000), @schemaName VARCHAR(1000), @tableName VARCHAR(1000), @fullBackupName VARCHAR(1000), @undeletedTableName VARCHAR(1000), @sql VARCHAR(MAX), @tableWasTruncated bit; /* THE FIRST LINE ARE OUR INPUT PARAMETERS In this case we're trying to recover Production.Product1 table in AdventureWorks database. My full backup of AdventureWorks database is at e:\AW.bak */ SELECT @dbName = 'AdventureWorks', @schemaName = 'Production', @tableName = 'Product1', @fullBackupName = 'e:\AW.bak', @undeletedTableName = '##' + @tableName + '_Undeleted', @tableWasTruncated = 0, -- copy the structure from original table to a temp table that we'll fill with restored data @sql = 'IF OBJECT_ID(''tempdb..' + @undeletedTableName + ''') IS NOT NULL DROP TABLE ' + @undeletedTableName + ' SELECT *' + ' INTO ' + @undeletedTableName + ' FROM [' + @dbName + '].[' + @schemaName + '].[' + @tableName + ']' + ' WHERE 1 = 0' EXEC (@sql) IF OBJECT_ID('tempdb..#PagesToRestore') IS NOT NULL DROP TABLE #PagesToRestore /* FIND DATA PAGES WE NEED TO RESTORE*/ CREATE TABLE #PagesToRestore ([ID] INT IDENTITY(1,1), [FileID] INT, [PageID] INT, [SQLtoExec] VARCHAR(1000)) -- DBCC PACE statement to run later RAISERROR ('Looking for deleted pages...', 10, 1) -- use T-LOG direct read to get deleted data pages INSERT INTO #PagesToRestore([FileID], [PageID], [SQLtoExec]) EXEC('USE [' + @dbName + '];SELECT FileID, PageID, ''DBCC TRACEON (3604); DBCC PAGE ([' + @dbName + '], '' + FileID + '', '' + PageID + '', 3) WITH TABLERESULTS'' as SQLToExecFROM (SELECT DISTINCT LEFT([Page ID], 4) AS FileID, CONVERT(VARCHAR(100), ' + 'CONVERT(INT, master.dbo.HexStrToVarBin(SUBSTRING([Page ID], 6, 20)))) AS PageIDFROM sys.fn_dblog(NULL, NULL)WHERE AllocUnitName LIKE ''%' + @schemaName + '.' + @tableName + '%'' ' + 'AND Context IN (''LCX_MARK_AS_GHOST'', ''LCX_HEAP'') AND Operation in (''LOP_DELETE_ROWS''))t');SELECT *FROM #PagesToRestore -- if upper EXEC returns 0 rows it means the table was truncated so find truncated pages IF (SELECT COUNT(*) FROM #PagesToRestore) = 0 BEGIN RAISERROR ('No deleted pages found. Looking for truncated pages...', 10, 1) -- use T-LOG read to get truncated data pages INSERT INTO #PagesToRestore([FileID], [PageID], [SQLtoExec]) -- dark magic happens here -- because truncation simply deallocates pages we have to find out which pages were deallocated. -- we can find this out by looking at the PFS page row's Description column. -- for every deallocated extent the Description has a CSV of 8 pages in that extent. -- then it's just a matter of parsing it. -- we also remove the pages in the extent that weren't allocated to the table itself -- marked with '0x00-->00' EXEC ('USE [' + @dbName + '];DECLARE @truncatedPages TABLE(DeallocatedPages VARCHAR(8000), IsMultipleDeallocs BIT);INSERT INTO @truncatedPagesSELECT REPLACE(REPLACE(Description, ''Deallocated '', ''Y''), ''0x00-->00 '', ''N'') + '';'' AS DeallocatedPages, CHARINDEX('';'', Description) AS IsMultipleDeallocsFROM (SELECT DISTINCT LEFT([Page ID], 4) AS FileID, CONVERT(VARCHAR(100), CONVERT(INT, master.dbo.HexStrToVarBin(SUBSTRING([Page ID], 6, 20)))) AS PageID, DescriptionFROM sys.fn_dblog(NULL, NULL)WHERE Context IN (''LCX_PFS'') AND Description LIKE ''Deallocated%'' AND AllocUnitName LIKE ''%' + @schemaName + '.' + @tableName + '%'') t;SELECT FileID, PageID , ''DBCC TRACEON (3604); DBCC PAGE ([' + @dbName + '], '' + FileID + '', '' + PageID + '', 3) WITH TABLERESULTS'' as SQLToExecFROM (SELECT LEFT(PageAndFile, 1) as WasPageAllocatedToTable , SUBSTRING(PageAndFile, 2, CHARINDEX('':'', PageAndFile) - 2 ) as FileID , CONVERT(VARCHAR(100), CONVERT(INT, master.dbo.HexStrToVarBin(SUBSTRING(PageAndFile, CHARINDEX('':'', PageAndFile) + 1, LEN(PageAndFile))))) as PageIDFROM ( SELECT SUBSTRING(DeallocatedPages, delimPosStart, delimPosEnd - delimPosStart) as PageAndFile, IsMultipleDeallocs FROM ( SELECT *, CHARINDEX('';'', DeallocatedPages)*(N-1) + 1 AS delimPosStart, CHARINDEX('';'', DeallocatedPages)*N AS delimPosEnd FROM @truncatedPages t1 CROSS APPLY (SELECT TOP (case when t1.IsMultipleDeallocs = 1 then 8 else 1 end) ROW_NUMBER() OVER(ORDER BY number) as N FROM master..spt_values) t2 )t)t)tWHERE WasPageAllocatedToTable = ''Y''') SELECT @tableWasTruncated = 1 END DECLARE @lastID INT, @pagesCount INT SELECT @lastID = 1, @pagesCount = COUNT(*) FROM #PagesToRestore SELECT @sql = 'Number of pages to restore: ' + CONVERT(VARCHAR(10), @pagesCount) IF @pagesCount = 0 RAISERROR ('No data pages to restore.', 18, 1) ELSE RAISERROR (@sql, 10, 1) -- If the table was truncated we'll read the data directly from data pages without restoring from backup IF @tableWasTruncated = 0 BEGIN -- RESTORE DATA PAGES FROM FULL BACKUP IN BATCHES OF 200 WHILE @lastID <= @pagesCount BEGIN -- create CSV string of pages to restore SELECT @sql = STUFF((SELECT ',' + CONVERT(VARCHAR(100), FileID) + ':' + CONVERT(VARCHAR(100), PageID) FROM #PagesToRestore WHERE ID BETWEEN @lastID AND @lastID + 200 ORDER BY ID FOR XML PATH('')), 1, 1, '') SELECT @sql = 'RESTORE DATABASE [' + @dbName + '] PAGE = ''' + @sql + ''' FROM DISK = ''' + @fullBackupName + '''' RAISERROR ('Starting RESTORE command:' , 10, 1) WITH NOWAIT; RAISERROR (@sql , 10, 1) WITH NOWAIT; EXEC(@sql); RAISERROR ('Restore DONE' , 10, 1) WITH NOWAIT; SELECT @lastID = @lastID + 200 END /* If you have any differential or transaction log backups you should restore them here to bring the previously restored data pages up to date */ END DECLARE @dbccSinglePage TABLE ( [ParentObject] NVARCHAR(500), [Object] NVARCHAR(500), [Field] NVARCHAR(500), [VALUE] NVARCHAR(MAX) ) DECLARE @cols NVARCHAR(MAX), @paramDefinition NVARCHAR(500), @SQLtoExec VARCHAR(1000), @FileID VARCHAR(100), @PageID VARCHAR(100), @i INT = 1 -- Get deleted table columns from information_schema view -- Need sp_executeSQL because database name can't be passed in as variable SELECT @cols = 'select @cols = STUFF((SELECT '', ['' + COLUMN_NAME + '']''FROM ' + @dbName + '.INFORMATION_SCHEMA.COLUMNSWHERE TABLE_NAME = ''' + @tableName + ''' AND TABLE_SCHEMA = ''' + @schemaName + '''ORDER BY ORDINAL_POSITIONFOR XML PATH('''')), 1, 2, '''')', @paramDefinition = N'@cols nvarchar(max) OUTPUT' EXECUTE sp_executesql @cols, @paramDefinition, @cols = @cols OUTPUT -- Loop through all the restored data pages, -- read data from them and insert them into temp table -- which you can then insert into the orignial deleted table DECLARE dbccPageCursor CURSOR GLOBAL FORWARD_ONLY FOR SELECT [FileID], [PageID], [SQLtoExec] FROM #PagesToRestore ORDER BY [FileID], [PageID] OPEN dbccPageCursor; FETCH NEXT FROM dbccPageCursor INTO @FileID, @PageID, @SQLtoExec; WHILE @@FETCH_STATUS = 0 BEGIN RAISERROR ('---------------------------------------------', 10, 1) WITH NOWAIT; SELECT @sql = 'Loop iteration: ' + CONVERT(VARCHAR(10), @i); RAISERROR (@sql, 10, 1) WITH NOWAIT; SELECT @sql = 'Running: ' + @SQLtoExec RAISERROR (@sql, 10, 1) WITH NOWAIT; -- if something goes wrong with DBCC execution or data gathering, skip it but print error BEGIN TRY INSERT INTO @dbccSinglePage EXEC (@SQLtoExec) -- make the data insert magic happen here IF (SELECT CONVERT(BIGINT, [VALUE]) FROM @dbccSinglePage WHERE [Field] LIKE '%Metadata: ObjectId%') = OBJECT_ID('['+@dbName+'].['+@schemaName +'].['+@tableName+']') BEGIN DELETE @dbccSinglePage WHERE NOT ([ParentObject] LIKE 'Slot % Offset %' AND [Object] LIKE 'Slot % Column %') SELECT @sql = 'USE tempdb; ' + 'IF (OBJECTPROPERTY(object_id(''' + @undeletedTableName + '''), ''TableHasIdentity'') = 1) ' + 'SET IDENTITY_INSERT ' + @undeletedTableName + ' ON; ' + 'INSERT INTO ' + @undeletedTableName + '(' + @cols + ') ' + STUFF((SELECT ' UNION ALL SELECT ' + STUFF((SELECT ', ' + CASE WHEN VALUE = '[NULL]' THEN 'NULL' ELSE '''' + [VALUE] + '''' END FROM ( -- the unicorn help here to correctly set ordinal numbers of columns in a data page -- it's turning STRING order into INT order (1,10,11,2,21 into 1,2,..10,11...21) SELECT [ParentObject], [Object], Field, VALUE, RIGHT('00000' + O1, 6) AS ParentObjectOrder, RIGHT('00000' + REVERSE(LEFT(O2, CHARINDEX(' ', O2)-1)), 6) AS ObjectOrder FROM ( SELECT [ParentObject], [Object], Field, VALUE, REPLACE(LEFT([ParentObject], CHARINDEX('Offset', [ParentObject])-1), 'Slot ', '') AS O1, REVERSE(LEFT([Object], CHARINDEX('Offset ', [Object])-2)) AS O2 FROM @dbccSinglePage WHERE t.ParentObject = ParentObject )t)t ORDER BY ParentObjectOrder, ObjectOrder FOR XML PATH('')), 1, 2, '') FROM @dbccSinglePage t GROUP BY ParentObject FOR XML PATH('') ), 1, 11, '') + ';' RAISERROR (@sql, 10, 1) WITH NOWAIT; EXEC (@sql) END END TRY BEGIN CATCH SELECT @sql = 'ERROR!!!' + CHAR(10) + CHAR(13) + 'ErrorNumber: ' + ERROR_NUMBER() + '; ErrorMessage' + ERROR_MESSAGE() + CHAR(10) + CHAR(13) + 'FileID: ' + @FileID + '; PageID: ' + @PageID RAISERROR (@sql, 10, 1) WITH NOWAIT; END CATCH DELETE @dbccSinglePage SELECT @sql = 'Pages left to process: ' + CONVERT(VARCHAR(10), @pagesCount - @i) + CHAR(10) + CHAR(13) + CHAR(10) + CHAR(13) + CHAR(10) + CHAR(13), @i = @i+1 RAISERROR (@sql, 10, 1) WITH NOWAIT; FETCH NEXT FROM dbccPageCursor INTO @FileID, @PageID, @SQLtoExec; END CLOSE dbccPageCursor; DEALLOCATE dbccPageCursor; EXEC ('SELECT ''' + @undeletedTableName + ''' as TableName; SELECT * FROM ' + @undeletedTableName)END TRYBEGIN CATCH SELECT ERROR_NUMBER() AS ErrorNumber, ERROR_MESSAGE() AS ErrorMessage IF CURSOR_STATUS ('global', 'dbccPageCursor') >= 0 BEGIN CLOSE dbccPageCursor; DEALLOCATE dbccPageCursor; ENDEND CATCH-- if the table was deleted we need to finish the restore page sequenceIF @tableWasTruncated = 0BEGIN -- take a log tail backup and then restore it to complete page restore process DECLARE @currentDate VARCHAR(30) SELECT @currentDate = CONVERT(VARCHAR(30), GETDATE(), 112) RAISERROR ('Starting Log Tail backup to c:\Temp ...', 10, 1) WITH NOWAIT; PRINT ('BACKUP LOG [' + @dbName + '] TO DISK = ''c:\Temp\' + @dbName + '_TailLogBackup_' + @currentDate + '.trn''') EXEC ('BACKUP LOG [' + @dbName + '] TO DISK = ''c:\Temp\' + @dbName + '_TailLogBackup_' + @currentDate + '.trn''') RAISERROR ('Log Tail backup done.', 10, 1) WITH NOWAIT; RAISERROR ('Starting Log Tail restore from c:\Temp ...', 10, 1) WITH NOWAIT; PRINT ('RESTORE LOG [' + @dbName + '] FROM DISK = ''c:\Temp\' + @dbName + '_TailLogBackup_' + @currentDate + '.trn''') EXEC ('RESTORE LOG [' + @dbName + '] FROM DISK = ''c:\Temp\' + @dbName + '_TailLogBackup_' + @currentDate + '.trn''') RAISERROR ('Log Tail restore done.', 10, 1) WITH NOWAIT;END-- The last step is manual. Insert data from our temporary table to the original deleted table The misconception here is that you can do a single table restore properly in SQL Server. You can't. But with little experimentation you can get pretty close to it. One way to possible remove a dependency on a backup to retrieve deleted pages is to quickly run a similar script to the upper one that gets data directly from data pages while the rows are still marked as ghost records. It could be done if we could beat the ghost record cleanup task.

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• Exploring packages in code

  In my previous post Searching for tasks with code you can see how to explore the control flow side of packages, drilling down through containers, task, and event handlers, but it didn’t cover the data flow. I recently saw a post on the MSDN forum asking how to edit an existing package programmatically, and the sticking point was how to find the the data flow and the components inside. This post builds on some of the previous code and shows how you can explore all objects inside a package. I took the sample Task Search application I’d written previously, and came up with a totally pointless little console application that just walks through the package and writes out the basic type and name of every object it finds, starting with the package itself e.g. Package – MyPackage . The sample package we used last time showed nested objects as well an event handler; a OnPreExecute event tucked away on the task SQL In FEL. The output of this sample tool would look like this: PackageObjects v1.0.0.0 (1.0.0.26627) Copyright (C) 2009 Konesans Ltd Processing File - Z:\Users\Darren Green\Documents\Visual Studio 2005\Projects\SSISTestProject\EventsAndContainersWithExe cSQLForSearch.dtsx Package - EventsAndContainersWithExecSQLForSearch For Loop - FOR Counter Loop Task - SQL In Counter Loop Sequence Container - SEQ For Each Loop Wrapper For Each Loop - FEL Simple Loop Task - SQL In FEL Task - SQL On Pre Execute for FEL SQL Task Sequence Container - SEQ Top Level Sequence Container - SEQ Nested Lvl 1 Sequence Container - SEQ Nested Lvl 2 Task - SQL In Nested Lvl 2 Task - SQL In Nested Lvl 1 #1 Task - SQL In Nested Lvl 1 #2 Connection Manager – LocalHost The code is very similar to what we had previously, but there are a couple of extra bits to deal with connections and to look more closely at a task and see if it is a Data Flow task. For connections your just examine the package's Connections collection as shown in the abridged snippets below. First you can see the call to the ProcessConnections method, followed by the method itself. // Load the package file Application application = new Application(); using (Package package = application.LoadPackage(filename, null)) { // Write out the package name Console.WriteLine("Package - {0}", package.Name); ... More ... // Look and the connections ProcessConnections(package.Connections); } private static void ProcessConnections(Connections connections) { foreach (ConnectionManager connectionManager in connections) { Console.WriteLine("Connection Manager - {0}", connectionManager.Name); } } What we didn’t see in the sample output above was anything to do with the Data Flow, but rest assured the code now handles it too. The following snippet shows how each task is examined to see if it is a Data Flow task, and if so we can then loop through all of the components inside the data flow. private static void ProcessTaskHost(TaskHost taskHost) { if (taskHost == null) { return; } Console.WriteLine("Task - {0}", taskHost.Name); // Check if the task is a Data Flow task MainPipe pipeline = taskHost.InnerObject as MainPipe; if (pipeline != null) { ProcessPipeline(pipeline); } } private static void ProcessPipeline(MainPipe pipeline) { foreach (IDTSComponentMetaData90 componentMetadata in pipeline.ComponentMetaDataCollection) { Console.WriteLine("Pipeline Component - {0}", componentMetadata.Name); // If you wish to make changes to the component then you should really use the managed wrapper. // CManagedComponentWrapper wrapper = componentMetadata.Instantiate(); // wrapper.SetComponentProperty("PropertyName", "Value"); } } Hopefully you can see how we get a reference to the Data Flow task, and then use the ComponentMetaDataCollection to find out what components we have inside the pipeline. If you wanted to know more about the component you could look at the ObjectType or ComponentClassID properties. After that it gets a bit harder and you should get a reference to the wrapper object as the comment suggest and start using the properties, just like you would in the create packages samples, see our Code Development category for some for these examples. Download Sample code project PackageObjects.zip (5KB)

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• How do I implement a quaternion based camera?

  - by kudor gyozo

  I looked at several tutorials about this and when I thought I understood I tried to implement a quaternion based camera. The problem is it doesn't work correctly, after rotating for approx. 10 degrees it jumps back to -10 degrees. I have no idea what's wrong. I'm using openTK and it already has a quaternion class. I'm a noob at opengl, I'm doing this just for fun, and don't really understand quaternions, so probably I'm doing something stupid here. Here is some code: (Actually almost all the code except the methods that load and draw a vbo (it is taken from an OpenTK sample that demonstrates vbo-s)) I load a cube into a vbo and initialize the quaternion for the camera protected override void OnLoad(EventArgs e) { base.OnLoad(e); cameraPos = new Vector3(0, 0, 7); cameraRot = Quaternion.FromAxisAngle(new Vector3(0,0,-1), 0); GL.ClearColor(System.Drawing.Color.MidnightBlue); GL.Enable(EnableCap.DepthTest); vbo = LoadVBO(CubeVertices, CubeElements); } I load a perspective projection here. This is loaded at the beginning and every time I resize the window. protected override void OnResize(EventArgs e) { base.OnResize(e); GL.Viewport(0, 0, Width, Height); float aspect_ratio = Width / (float)Height; Matrix4 perpective = Matrix4.CreatePerspectiveFieldOfView(MathHelper.PiOver4, aspect_ratio, 1, 64); GL.MatrixMode(MatrixMode.Projection); GL.LoadMatrix(ref perpective); } Here I get the last rotation value and create a new quaternion that represents only the last rotation and multiply it with the camera quaternion. After this I transform this into axis-angle so that opengl can use it. (This is how I understood it from several online quaternion tutorials) protected override void OnRenderFrame(FrameEventArgs e) { base.OnRenderFrame(e); GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit); double speed = 1; double rx = 0, ry = 0; if (Keyboard[Key.A]) { ry = -speed * e.Time; } if (Keyboard[Key.D]) { ry = +speed * e.Time; } if (Keyboard[Key.W]) { rx = +speed * e.Time; } if (Keyboard[Key.S]) { rx = -speed * e.Time; } Quaternion tmpQuat = Quaternion.FromAxisAngle(new Vector3(0,1,0), (float)ry); cameraRot = tmpQuat * cameraRot; cameraRot.Normalize(); GL.MatrixMode(MatrixMode.Modelview); GL.LoadIdentity(); Vector3 axis; float angle; cameraRot.ToAxisAngle(out axis, out angle); GL.Rotate(angle, axis); GL.Translate(-cameraPos); Draw(vbo); SwapBuffers(); } Here are 2 images to explain better: I rotate a while and from this: it jumps into this Any help is appreciated. Update1: I add these to a streamwriter that writes into a file: sw.WriteLine("camerarot: X:{0} Y:{1} Z:{2} W:{3} L:{4}", cameraRot.X, cameraRot.Y, cameraRot.Z, cameraRot.W, cameraRot.Length); sw.WriteLine("ry: {0}", ry); The log is available here: http://www.pasteall.org/26133/text. At line 770 the cube jumps from right to left, when camerarot.Y changes signs. I don't know if this is normal. Update2 Here is the complete project.

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• LibGDX Box2D Body and Sprite AND DebugRenderer out of sync

  - by Free Lancer

  I am having a couple issues with Box2D bodies. I have a GameObject holding a Sprite and Body. I use a ShapeRenderer to draw an outline of the Body's and Sprite's bounding boxes. I also added a Box2DDebugRenderer to make sure everything's lining up properly. My problem is the Sprite and Body at first overlap perfectly, but as I turn the Body moves a bit off the sprite then comes back when the Car is facing either North or South. Here's an image of what I mean: (Not sure what that line is, first time to show up) BLUE is the Body, RED is the Sprite, PURPLE is the Box2DDebugRenderer. Also, you probably noticed a purple square in the top right corner. Well that's the Car drawn by the Box2D Debug Renderer. I thought it might be the camera but I've been playing with the Cameras for hours and nothing seems to work. All give me weird results. Here's my code: Screen: public void show() { // --------------------- SETUP ALL THE CAMERA STUFF ------------------------------ // battleStage = new Stage( 720, 480, false ); // Setup the camera. In Box2D we operate on a meter scale, pixels won't do it. So we use // an Orthographic camera with a Viewport of 24 meters in width and 16 meters in height. battleStage.setCamera( new OrthographicCamera( CAM_METER_WIDTH, CAM_METER_HEIGHT ) ); battleStage.getCamera().position.set( CAM_METER_WIDTH / 2, CAM_METER_HEIGHT / 2, 0 ); // The Box2D Debug Renderer will handle rendering all physics objects for debugging debugger = new Box2DDebugRenderer( true, true, true, true ); //debugCam = new OrthographicCamera( CAM_METER_WIDTH, CAM_METER_HEIGHT ); } public void render(float delta) { // Update the Physics World, use 1/45 for something around 45 Frames/Second for mobile devices physicsWorld.step( 1/45.0f, 8, 3 ); // 1/45 for devices // Set the Camera matrices and clear the screen Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT); battleStage.getCamera().update(); // Draw game objects here battleStage.act(delta); battleStage.draw(); // Again update the Camera matrices and call the debug renderer debugCam.update(); debugger.render( physicsWorld, debugCam.combined); // Vehicle handles its own interaction with the HUD // update all Actors movements in the game Stage hudStage.act( delta ); // Draw each Actor onto the Scene at their new positions hudStage.draw(); } Car: (extends Actor) public Car( Texture texture, float posX, float posY, World world ) { super( "Car" ); mSprite = new Sprite( texture ); mSprite.setSize( WIDTH * Consts.PIXEL_METER_RATIO, HEIGHT * Consts.PIXEL_METER_RATIO ); mSprite.setOrigin( mSprite.getWidth()/2, mSprite.getHeight()/2); // set the origin to be at the center of the body mSprite.setPosition( posX * Consts.PIXEL_METER_RATIO, posY * Consts.PIXEL_METER_RATIO ); // place the car in the center of the game map FixtureDef carFixtureDef = new FixtureDef(); mBody = Physics.createBoxBody( BodyType.DynamicBody, carFixtureDef, mSprite ); } public void draw() { mSprite.setPosition( mBody.getPosition().x * Consts.PIXEL_METER_RATIO, mBody.getPosition().y * Consts.PIXEL_METER_RATIO ); mSprite.setRotation( MathUtils.radiansToDegrees * mBody.getAngle() ); // draw the sprite mSprite.draw( batch ); } Physics: (Create the Body) public static Body createBoxBody( final BodyType pBodyType, final FixtureDef pFixtureDef, Sprite pSprite ) { float pRotation = 0; float pWidth = pSprite.getWidth(); float pHeight = pSprite.getHeight(); final BodyDef boxBodyDef = new BodyDef(); boxBodyDef.type = pBodyType; boxBodyDef.position.x = pSprite.getX() / Consts.PIXEL_METER_RATIO; boxBodyDef.position.y = pSprite.getY() / Consts.PIXEL_METER_RATIO; // Temporary Box shape of the Body final PolygonShape boxPoly = new PolygonShape(); final float halfWidth = pWidth * 0.5f / Consts.PIXEL_METER_RATIO; final float halfHeight = pHeight * 0.5f / Consts.PIXEL_METER_RATIO; boxPoly.setAsBox( halfWidth, halfHeight ); // set the anchor point to be the center of the sprite pFixtureDef.shape = boxPoly; final Body boxBody = BattleScreen.getPhysicsWorld().createBody(boxBodyDef); boxBody.createFixture(pFixtureDef); } Sorry for all the code and long description but it's hard to pin down what exactly might be causing the problem.

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• In GLSL is it possible to offset vertices based on height map colour?

  - by Rob

  I am attempting to generate some terrain based upon a heightmap. I have generated a 32 x 32 grid and a corresponding height map - In my vertex shader I am trying to offset the position of the Y axis based upon the colour of the heightmap, white vertices being higher than black ones. //Vertex Shader Code #version 330 uniform mat4 modelMatrix; uniform mat4 viewMatrix; uniform mat4 projectionMatrix; uniform sampler2D heightmap; layout (location=0) in vec4 vertexPos; layout (location=1) in vec4 vertexColour; layout (location=3) in vec2 vertexTextureCoord; layout (location=4) in float offset; out vec4 fragCol; out vec4 fragPos; out vec2 fragTex; void main() { // Retreive the current pixel's colour vec4 hmColour = texture(heightmap,vertexTextureCoord); // Offset the y position by the value of current texel's colour value ? vec4 offset = vec4(vertexPos.x , vertexPos.y + hmColour.r, vertexPos.z , 1.0); // Final Position gl_Position = projectionMatrix * viewMatrix * modelMatrix * offset; // Data sent to Fragment Shader. fragCol = vertexColour; fragPos = vertexPos; fragTex = vertexTextureCoord; } However the code I have produced only creates a grid with none of the y vertices higher than any others. This is the C++ code that generates the grid and texture co-orientates which I believe to be correct as the texture is mapped to the grid, hence the white blob in the middle. The grid-lines are generated in the fragment shader, sorry for any confusion. I have tried multiplying the r value of hmColour by 1000 unfortunately that had no effect. The only other problem it could be is that the texture coordinate data is incorrect ? for (int z = 0; z < MAP_Z ; z++) { for(int x = 0; x < MAP_X ; x++) { //Generate Vertex Buffer vertexData[iVertex++] = float (x) * MAP_X; vertexData[iVertex++] = 0; vertexData[iVertex++] = -(float) (z) * MAP_Z; //Colour Buffer NOT NEEDED colourData[iColour++] = 255.0f; // R colourData[iColour++] = 1.0f; // G colourData[iColour++] = 0.0f; // B //Texture Buffer textureData[iTexture++] = (float ) x * (1.0f / MAP_X); textureData[iTexture++] = (float ) z * (1.0f / MAP_Z); } } The heightmap texture I am trying to use appears like so (without grid-lines). This is the corresponding fragment shader // Fragment Shader Code #version 330 uniform sampler2D hmTexture; layout (location=0) out vec4 fragColour; in vec2 fragTex; in vec4 pos; void main(void) { vec2 line = fragTex * 32; // Without Gridlines fragColour = texture(hmTexture,fragTex); // With grid lines // + mix(vec4(0.0, 0.0, 1.0, 0.0), vec4(1.0, 1.0, 1.0, 1.0), // smoothstep(0.05,fract(line.y), 0.99) * smoothstep(0.05,fract(line.x),0.99)); }

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• Problem with AssetManager while loading a Model type

  - by user1204548

  Today I've tried the AssetManager for the first time with .g3db files and I'm having some problems. Exception in thread "LWJGL Application" com.badlogic.gdx.utils.GdxRuntimeException: com.badlogic.gdx.utils.GdxRuntimeException: Couldn't load dependencies of asset: data/data at com.badlogic.gdx.assets.AssetManager.handleTaskError(AssetManager.java:508) at com.badlogic.gdx.assets.AssetManager.update(AssetManager.java:342) at com.lostchg.martagdx3d.MartaGame.render(MartaGame.java:78) at com.badlogic.gdx.Game.render(Game.java:46) at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:207) at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:114) Caused by: com.badlogic.gdx.utils.GdxRuntimeException: Couldn't load dependencies of asset: data/data at com.badlogic.gdx.assets.AssetLoadingTask.handleAsyncLoader(AssetLoadingTask.java:119) at com.badlogic.gdx.assets.AssetLoadingTask.update(AssetLoadingTask.java:89) at com.badlogic.gdx.assets.AssetManager.updateTask(AssetManager.java:445) at com.badlogic.gdx.assets.AssetManager.update(AssetManager.java:340) ... 4 more Caused by: com.badlogic.gdx.utils.GdxRuntimeException: com.badlogic.gdx.utils.GdxRuntimeException: Couldn't load file: data/data at com.badlogic.gdx.utils.async.AsyncResult.get(AsyncResult.java:31) at com.badlogic.gdx.assets.AssetLoadingTask.handleAsyncLoader(AssetLoadingTask.java:117) ... 7 more Caused by: com.badlogic.gdx.utils.GdxRuntimeException: Couldn't load file: data/data at com.badlogic.gdx.graphics.Pixmap.<init>(Pixmap.java:140) at com.badlogic.gdx.assets.loaders.TextureLoader.loadAsync(TextureLoader.java:72) at com.badlogic.gdx.assets.loaders.TextureLoader.loadAsync(TextureLoader.java:41) at com.badlogic.gdx.assets.AssetLoadingTask.call(AssetLoadingTask.java:69) at com.badlogic.gdx.assets.AssetLoadingTask.call(AssetLoadingTask.java:34) at com.badlogic.gdx.utils.async.AsyncExecutor$2.call(AsyncExecutor.java:49) at java.util.concurrent.FutureTask.run(Unknown Source) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: com.badlogic.gdx.utils.GdxRuntimeException: File not found: data\data (Internal) at com.badlogic.gdx.files.FileHandle.read(FileHandle.java:132) at com.badlogic.gdx.files.FileHandle.length(FileHandle.java:586) at com.badlogic.gdx.files.FileHandle.readBytes(FileHandle.java:220) at com.badlogic.gdx.graphics.Pixmap.<init>(Pixmap.java:137) ... 9 more Why it tries to load that unexisting file? It seems that the AssetManager manages to load my .g3db file at first, because earlier the java console threw some errors related to the textures associated to the 3D scene having to be a power of 2. Relevant code: public void show() { ... assets = new AssetManager(); assets.load("data/levelprueba2.g3db", Model.class); loading = true; ... } private void doneLoading() { Model model = assets.get("data/levelprueba2.g3db", Model.class); for (int i = 0; i < model.nodes.size; i++) { String id = model.nodes.get(i).id; ModelInstance instance = new ModelInstance(model, id); Node node = instance.getNode(id); instance.transform.set(node.globalTransform); node.translation.set(0,0,0); node.scale.set(1,1,1); node.rotation.idt(); instance.calculateTransforms(); instances.add(instance); } loading = false; } public void render(float delta) { super.render(delta); if (loading && assets.update()) doneLoading(); ... } The error points to the line with the assets.update() method. Please, help! Sorry for my bad English and my amateurish doubts.

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• MvcExtensions - ActionFilter

  - by kazimanzurrashid

  One of the thing that people often complains is dependency injection in Action Filters. Since the standard way of applying action filters is to either decorate the Controller or the Action methods, there is no way you can inject dependencies in the action filter constructors. There are quite a few posts on this subject, which shows the property injection with a custom action invoker, but all of them suffers from the same small bug (you will find the BuildUp is called more than once if the filter implements multiple interface e.g. both IActionFilter and IResultFilter). The MvcExtensions supports both property injection as well as fluent filter configuration api. There are a number of benefits of this fluent filter configuration api over the regular attribute based filter decoration. You can pass your dependencies in the constructor rather than property. Lets say, you want to create an action filter which will update the User Last Activity Date, you can create a filter like the following: public class UpdateUserLastActivityAttribute : FilterAttribute, IResultFilter { public UpdateUserLastActivityAttribute(IUserService userService) { Check.Argument.IsNotNull(userService, "userService"); UserService = userService; } public IUserService UserService { get; private set; } public void OnResultExecuting(ResultExecutingContext filterContext) { // Do nothing, just sleep. } public void OnResultExecuted(ResultExecutedContext filterContext) { Check.Argument.IsNotNull(filterContext, "filterContext"); string userName = filterContext.HttpContext.User.Identity.IsAuthenticated ? filterContext.HttpContext.User.Identity.Name : null; if (!string.IsNullOrEmpty(userName)) { UserService.UpdateLastActivity(userName); } } } As you can see, it is nothing different than a regular filter except that we are passing the dependency in the constructor. Next, we have to configure this filter for which Controller/Action methods will execute: public class ConfigureFilters : ConfigureFiltersBase { protected override void Configure(IFilterRegistry registry) { registry.Register<HomeController, UpdateUserLastActivityAttribute>(); } } You can register more than one filter for the same Controller/Action Methods: registry.Register<HomeController, UpdateUserLastActivityAttribute, CompressAttribute>(); You can register the filters for a specific Action method instead of the whole controller: registry.Register<HomeController, UpdateUserLastActivityAttribute, CompressAttribute>(c => c.Index()); You can even set various properties of the filter: registry.Register<ControlPanelController, CustomAuthorizeAttribute>( attribute => { attribute.AllowedRole = Role.Administrator; }); The Fluent Filter registration also reduces the number of base controllers in your application. It is very common that we create a base controller and decorate it with action filters and then we create concrete controller(s) so that the base controllers action filters are also executed in the concrete controller. You can do the  same with a single line statement with the fluent filter registration: Registering the Filters for All Controllers: registry.Register<ElmahHandleErrorAttribute>(new TypeCatalogBuilder().Add(GetType().Assembly).Include(type => typeof(Controller).IsAssignableFrom(type))); Registering Filters for selected Controllers: registry.Register<ElmahHandleErrorAttribute>(new TypeCatalogBuilder().Add(GetType().Assembly).Include(type => typeof(Controller).IsAssignableFrom(type) && (type.Name.StartsWith("Home") || type.Name.StartsWith("Post")))); You can also use the built-in filters in the fluent registration, for example: registry.Register<HomeController, OutputCacheAttribute>(attribute => { attribute.Duration = 60; }); With the fluent filter configuration you can even apply filters to controllers that source code is not available to you (may be the controller is a part of a third part component). That’s it for today, in the next post we will discuss about the Model binding support in MvcExtensions. So stay tuned.

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• OpenGL slower than Canvas

  - by VanDir

  Up to 3 days ago I used a Canvas in a SurfaceView to do all the graphics operations but now I switched to OpenGL because my game went from 60FPS to 30/45 with the increase of the sprites in some levels. However, I find myself disappointed because OpenGL now reaches around 40/50 FPS at all levels. Surely (I hope) I'm doing something wrong. How can I increase the performance at stable 60FPS? My game is pretty simple and I can not believe that it is impossible to reach them. I use 2D sprite texture applied to a square for all the objects. I use a transparent GLSurfaceView, the real background is applied in a ImageView behind the GLSurfaceView. Some code public MyGLSurfaceView(Context context, AttributeSet attrs) { super(context); setZOrderOnTop(true); setEGLConfigChooser(8, 8, 8, 8, 0, 0); getHolder().setFormat(PixelFormat.RGBA_8888); mRenderer = new ClearRenderer(getContext()); setRenderer(mRenderer); setLongClickable(true); setFocusable(true); } public void onSurfaceCreated(final GL10 gl, EGLConfig config) { gl.glEnable(GL10.GL_TEXTURE_2D); gl.glShadeModel(GL10.GL_SMOOTH); gl.glDisable(GL10.GL_DEPTH_TEST); gl.glDepthMask(false); gl.glEnable(GL10.GL_ALPHA_TEST); gl.glAlphaFunc(GL10.GL_GREATER, 0); gl.glEnable(GL10.GL_BLEND); gl.glBlendFunc(GL10.GL_ONE, GL10.GL_ONE_MINUS_SRC_ALPHA); gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST); } public void onSurfaceChanged(GL10 gl, int width, int height) { gl.glViewport(0, 0, width, height); gl.glMatrixMode(GL10.GL_PROJECTION); gl.glLoadIdentity(); gl.glOrthof(0, width, height, 0, -1f, 1f); gl.glMatrixMode(GL10.GL_MODELVIEW); gl.glLoadIdentity(); } public void onDrawFrame(GL10 gl) { gl.glClear(GL10.GL_COLOR_BUFFER_BIT); gl.glMatrixMode(GL10.GL_MODELVIEW); gl.glLoadIdentity(); gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY); // Draw all the graphic object. for (byte i = 0; i < mGame.numberOfObjects(); i++){ mGame.getObject(i).draw(gl); } // Disable the client state before leaving gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY); } mGame.getObject(i).draw(gl) is for all the objects like this: /* HERE there is always a translatef and scalef transformation and sometimes rotatef */ gl.glBindTexture(GL10.GL_TEXTURE_2D, mTexPointer[0]); // Point to our vertex buffer gl.glVertexPointer(3, GL10.GL_FLOAT, 0, mVertexBuffer); gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, mTextureBuffer); // Draw the vertices as triangle strip gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, mVertices.length / 3); EDIT: After some test it seems to be due to the transparent GLSurfaceView. If I delete this line of code: setEGLConfigChooser(8, 8, 8, 8, 0, 0); the background becomes all black but I reach 60 fps. What can I do?

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• Unit Testing DateTime – The Crazy Way

  - by João Angelo

  We all know that the process of unit testing code that depends on DateTime, particularly the current time provided through the static properties (Now, UtcNow and Today), it’s a PITA. If you go ask how to unit test DateTime.Now on stackoverflow I’ll bet that you’ll get two kind of answers: Encapsulate the current time in your own interface and use a standard mocking framework; Pull out the big guns like Typemock Isolator, JustMock or Microsoft Moles/Fakes and mock the static property directly. Now each alternative has is pros and cons and I would have to say that I glean more to the second approach because the first adds a layer of abstraction just for the sake of testability. However, the second approach depends on commercial tools that not every shop wants to buy or in the not so friendly Microsoft Moles. (Sidenote: Moles is now named Fakes and it will ship with VS 2012) This tends to leave people without an acceptable and simple solution so after reading another of these types of questions in SO I came up with yet another alternative, one based on the first alternative that I presented here but tries really hard to not get in your way with yet another layer of abstraction. So, without further dues, I present you, the Tardis. The Tardis is single section of conditionally compiled code that overrides the meaning of the DateTime expression inside a single class. You still get the normal coding experience of using DateTime all over the place, but in a DEBUG compilation your tests will be able to mock every static method or property of the DateTime class. An example follows, while the full Tardis code can be downloaded from GitHub: using System; using NSubstitute; using NUnit.Framework; using Tardis; public class Example { public Example() : this(string.Empty) { } public Example(string title) { #if DEBUG this.DateTime = DateTimeProvider.Default; this.Initialize(title); } internal IDateTimeProvider DateTime { get; set; } internal Example(string title, IDateTimeProvider provider) { this.DateTime = provider; #endif this.Initialize(title); } private void Initialize(string title) { this.Title = title; this.CreatedAt = DateTime.UtcNow; } private string title; public string Title { get { return this.title; } set { this.title = value; this.UpdatedAt = DateTime.UtcNow; } } public DateTime CreatedAt { get; private set; } public DateTime UpdatedAt { get; private set; } } public class TExample { public void T001() { // Arrange var tardis = Substitute.For<IDateTimeProvider>(); tardis.UtcNow.Returns(new DateTime(2000, 1, 1, 6, 6, 6)); // Act var sut = new Example("Title", tardis); // Assert Assert.That(sut.CreatedAt, Is.EqualTo(tardis.UtcNow)); } public void T002() { // Arrange var tardis = Substitute.For<IDateTimeProvider>(); var sut = new Example("Title", tardis); tardis.UtcNow.Returns(new DateTime(2000, 1, 1, 6, 6, 6)); // Act sut.Title = "Updated"; // Assert Assert.That(sut.UpdatedAt, Is.EqualTo(tardis.UtcNow)); } } This approach is also suitable for other similar classes with commonly used static methods or properties like the ConfigurationManager class.

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• Tile engine Texture not updating when numbers in array change

  - by Corey

  I draw my map from a txt file. I am using java with slick2d library. When I print the array the number changes in the array, but the texture doesn't change. public class Tiles { public Image[] tiles = new Image[5]; public int[][] map = new int[64][64]; public Image grass, dirt, fence, mound; private SpriteSheet tileSheet; public int tileWidth = 32; public int tileHeight = 32; public void init() throws IOException, SlickException { tileSheet = new SpriteSheet("assets/tiles.png", tileWidth, tileHeight); grass = tileSheet.getSprite(0, 0); dirt = tileSheet.getSprite(7, 7); fence = tileSheet.getSprite(2, 0); mound = tileSheet.getSprite(2, 6); tiles[0] = grass; tiles[1] = dirt; tiles[2] = fence; tiles[3] = mound; int x=0, y=0; BufferedReader in = new BufferedReader(new FileReader("assets/map.dat")); String line; while ((line = in.readLine()) != null) { String[] values = line.split(","); x = 0; for (String str : values) { int str_int = Integer.parseInt(str); map[x][y]=str_int; //System.out.print(map[x][y] + " "); x++; } //System.out.println(""); y++; } in.close(); } public void update(GameContainer gc) { } public void render(GameContainer gc) { for(int y = 0; y < map.length; y++) { for(int x = 0; x < map[0].length; x ++) { int textureIndex = map[x][y]; Image texture = tiles[textureIndex]; texture.draw(x*tileWidth,y*tileHeight); } } } } Mouse Picking Where I change the number in the array Input input = gc.getInput(); gc.getInput().setOffset(cameraX-400, cameraY-300); float mouseX = input.getMouseX(); float mouseY = input.getMouseY(); double mousetileX = Math.floor((double)mouseX/tiles.tileWidth); double mousetileY = Math.floor((double)mouseY/tiles.tileHeight); double playertileX = Math.floor(playerX/tiles.tileWidth); double playertileY = Math.floor(playerY/tiles.tileHeight); double lengthX = Math.abs((float)playertileX - mousetileX); double lengthY = Math.abs((float)playertileY - mousetileY); double distance = Math.sqrt((lengthX*lengthX)+(lengthY*lengthY)); if(input.isMousePressed(Input.MOUSE_LEFT_BUTTON) && distance < 4) { System.out.println("Clicked"); if(tiles.map[(int)mousetileX][(int)mousetileY] == 1) { tiles.map[(int)mousetileX][(int)mousetileY] = 0; } } I never ask a question until I have tried to figure it out myself. I have been stuck with this problem for two weeks. It's not like this site is made for asking questions or anything. So if you actually try to help me instead of telling me to use a debugger thank you. You either get told you have too much or too little code. Nothing is never enough for the people on here it's as bad as something like reddit. Idk what is wrong all my textures work when I render them it just doesn't update when the number in the array changes. I am obviously debugging when I say that I was printing the array and the number is changing like it should, so it's not a problem with my mouse picking code. It is a problem with my textures, but I don't know what because they all render correctly. That is why I need help.

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• GLSL subroutine not being used

  - by amoffat

  I'm using a gaussian blur fragment shader. In it, I thought it would be concise to include 2 subroutines: one for selecting the horizontal texture coordinate offsets, and another for the vertical texture coordinate offsets. This way, I just have one gaussian blur shader to manage. Here is the code for my shader. The {{NAME}} bits are template placeholders that I substitute in at shader compile time: #version 420 subroutine vec2 sample_coord_type(int i); subroutine uniform sample_coord_type sample_coord; in vec2 texcoord; out vec3 color; uniform sampler2D tex; uniform int texture_size; const float offsets[{{NUM_SAMPLES}}] = float[]({{SAMPLE_OFFSETS}}); const float weights[{{NUM_SAMPLES}}] = float[]({{SAMPLE_WEIGHTS}}); subroutine(sample_coord_type) vec2 vertical_coord(int i) { return vec2(0.0, offsets[i] / texture_size); } subroutine(sample_coord_type) vec2 horizontal_coord(int i) { //return vec2(offsets[i] / texture_size, 0.0); return vec2(0.0, 0.0); // just for testing if this subroutine gets used } void main(void) { color = vec3(0.0); for (int i=0; i<{{NUM_SAMPLES}}; i++) { color += texture(tex, texcoord + sample_coord(i)).rgb * weights[i]; color += texture(tex, texcoord - sample_coord(i)).rgb * weights[i]; } } Here is my code for selecting the subroutine: blur_program->start(); blur_program->set_subroutine("sample_coord", "vertical_coord", GL_FRAGMENT_SHADER); blur_program->set_int("texture_size", width); blur_program->set_texture("tex", *deferred_output); blur_program->draw(); // draws a quad for the fragment shader to run on and: void ShaderProgram::set_subroutine(constr name, constr routine, GLenum target) { GLuint routine_index = glGetSubroutineIndex(id, target, routine.c_str()); GLuint uniform_index = glGetSubroutineUniformLocation(id, target, name.c_str()); glUniformSubroutinesuiv(target, 1, &routine_index); // debugging int num_subs; glGetActiveSubroutineUniformiv(id, target, uniform_index, GL_NUM_COMPATIBLE_SUBROUTINES, &num_subs); std::cout << uniform_index << " " << routine_index << " " << num_subs << "\n"; } I've checked for errors, and there are none. When I pass in vertical_coord as the routine to use, my scene is blurred vertically, as it should be. The routine_index variable is also 1 (which is weird, because vertical_coord subroutine is the first listed in the shader code...but no matter, maybe the compiler is switching things around) However, when I pass in horizontal_coord, my scene is STILL blurred vertically, even though the value of routine_index is 0, suggesting that a different subroutine is being used. Yet the horizontal_coord subroutine explicitly does not blur. What's more is, whichever subroutine comes first in the shader, is the subroutine that the shader uses permanently. Right now, vertical_coord comes first, so the shader blurs vertically always. If I put horizontal_coord first, the scene is unblurred, as expected, but then I cannot select the vertical_coord subroutine! :) Also, the value of num_subs is 2, suggesting that there are 2 subroutines compatible with my sample_coord subroutine uniform. Just to re-iterate, all of my return values are fine, and there are no glGetError() errors happening. Any ideas?

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• Android - passing data between Activities

  - by Bill Osuch

  (To follow along with this, you should understand the basics of starting new activities: Link ) The easiest way to pass data from one activity to another is to create your own custom bundle and pass it to your new class. First, create two new activities called Search and SearchResults (make sure you add the second one you create to the AndroidManifest.xml file!), and create xml layout files for each. Search's file should look like this: <?xml version="1.0" encoding="utf-8"?> <LinearLayout     xmlns:android="http://schemas.android.com/apk/res/android"     android:layout_width="fill_parent"     android:layout_height="fill_parent"     android:orientation="vertical">     <TextView          android:layout_width="fill_parent"      android:layout_height="wrap_content"      android:text="Name:"/>     <EditText                android:id="@+id/edittext"         android:layout_width="fill_parent"         android:layout_height="wrap_content"/>     <TextView          android:layout_width="fill_parent"         android:layout_height="wrap_content"         android:text="ID Number:"/>     <EditText                android:id="@+id/edittext2"                android:layout_width="fill_parent"                android:layout_height="wrap_content"/>     <Button           android:id="@+id/btnSearch"          android:layout_width="fill_parent"         android:layout_height="wrap_content"         android:text="Search" /> </LinearLayout> and SearchResult's should look like this: <?xml version="1.0" encoding="utf-8"?> <LinearLayout     xmlns:android="http://schemas.android.com/apk/res/android"     android:layout_width="fill_parent"     android:layout_height="fill_parent"     android:orientation="vertical">     <TextView          android:id="@+id/txtName"         android:layout_width="fill_parent"         android:layout_height="wrap_content"/>     <TextView          android:id="@+id/txtState"         android:layout_width="fill_parent"         android:layout_height="wrap_content"         android:text="No data"/> </LinearLayout> Next, we'll override the OnCreate method of Search: @Override public void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.search);     Button search = (Button) findViewById(R.id.btnSearch);     search.setOnClickListener(new View.OnClickListener() {         public void onClick(View view) {                           Intent intent = new Intent(Search.this, SearchResults.class);              Bundle b = new Bundle();                           EditText txt1 = (EditText) findViewById(R.id.edittext);             EditText txt2 = (EditText) findViewById(R.id.edittext2);                                      b.putString("name", txt1.getText().toString());             b.putInt("state", Integer.parseInt(txt2.getText().toString()));                              //Add the set of extended data to the intent and start it             intent.putExtras(b);             startActivity(intent);          }     }); } This is very similar to the previous example, except here we're creating our own bundle, adding some key/value pairs to it, and adding it to the intent. Now, to retrieve the data, we just need to grab the Bundle that was passed to the new Activity and extract our values from it: @Override public void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.search_results);     Bundle b = getIntent().getExtras();     int value = b.getInt("state", 0);     String name = b.getString("name");             TextView vw1 = (TextView) findViewById(R.id.txtName);     TextView vw2 = (TextView) findViewById(R.id.txtState);             vw1.setText("Name: " + name);     vw2.setText("State: " + String.valueOf(value)); }

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• How to switch between views in android?

  - by aurezza

  I've tried several methods to switch between two views in my program. I've tried creating a new thread then have the view run for 5 seconds before creating intent to start my main activity. This is the code snippet from the said view class: mHelpThread = new Thread(){ @Override public void run(){ try { synchronized(this){ // Wait given period of time or exit on touch wait(5000); } } catch(InterruptedException ex){ } finish(); // Run next activity Intent intent = new Intent(Intent.ACTION_MAIN, null); intent.addCategory(Intent.CATEGORY_HOME); startActivity(intent); //stop(); } }; mHelpThread.start(); I can access the said view without error but it doesn't disappear after 5 seconds nor did it switched to main view when I even utilized an onTouchEvent() to detect touch on the screen of which it should have automatically closed. I've also tried adding a button on the said view to manually switch to main view: @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.help); final HelpView helpView = this; final Button btnback = (Button) findViewById(R.id.back); btnback.setOnClickListener(new View.OnClickListener(){ public void onClick(View v) { Intent intent = new Intent(helpView, MainActivity.class); startActivity(intent); } }); } These codes worked, though, for creating a launcher for my program. So I thought that it would work the same if I added an option for help/rules(for the game) that would switch to another view. I've only since started using eclipse for android so pardon my lack of knowledge. Here is also the snippet from my manifest: <uses-sdk android:minSdkVersion="11" android:targetSdkVersion="15" /> <application android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > <activity android:name="MainActivity" android:label="@string/title_activity_main"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.DEFAULT"/> </intent-filter> <intent-filter></intent-filter> </activity> <activity android:name="SplashScreen" android:theme="@style/Theme.Transparent"> <intent-filter> <action android:name="android.intent.action.MAIN"/> <category android:name="android.intent.category.LAUNCHER"/> </intent-filter> </activity> <activity android:name="HelpView" android:theme="@style/Theme.Transparent"> <intent-filter> <action android:name="android.intent.action.MAIN"/> <category android:name="android.intent.category.DEFAULT"/> </intent-filter> <intent-filter></intent-filter> </activity> </application>

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• Two small issues with Windows Phone 7 ApplicationBar buttons (and workaround)

  - by Laurent Bugnion

  When you work with the ApplicationBar in Windows Phone 7, you notice very fast that it is not quite a component like the others. For example, the ApplicationBarIconButton element is not a dependency object, which causes issues because it is not possible to add attached properties to it. Here are two other issues I stumbled upon, and what workaround I used to make it work anyway. Finding a button by name returns null Since the ApplicationBar is not in the tree of the Silverlight page, finding an element by name fails. For example consider the following code: <phoneNavigation:PhoneApplicationPage.ApplicationBar> <shell:ApplicationBar> <shell:ApplicationBar.Buttons> <shell:ApplicationBarIconButton IconUri="/Resources/edit.png" Click="EditButtonClick" x:Name="EditButton"/> <shell:ApplicationBarIconButton IconUri="/Resources/cancel.png" Click="CancelButtonClick" x:Name="CancelButton"/> </shell:ApplicationBar.Buttons> </shell:ApplicationBar> </phoneNavigation:PhoneApplicationPage.ApplicationBar> with private void EditButtonClick( object sender, EventArgs e) { CancelButton.IsEnabled = false; // Fails, CancelButton is always null } The CancelButton, even though it is named through an x:Name attribute, and even though it appears in Intellisense in the code behind, is null when it is needed. To solve the issue, I use the following code: public enum IconButton { Edit = 0, Cancel = 1 } public ApplicationBarIconButton GetButton( IconButton which) { return ApplicationBar.Buttons[(int) which] as ApplicationBarIconButton; } private void EditButtonClick( object sender, EventArgs e) { GetButton(IconButton.Cancel).IsEnabled = false; } Updating a Binding when the icon button is clicked In Silverlight, a Binding on a TextBox’s Text property can only be updated in two circumstances: When the TextBox loses the focus. Explicitly by placing a call in code. In WPF, there is a third option, updating the Binding every time that the Text property changes (i.e. every time that the user types a character). Unfortunately this option is not available in Silverlight). To select option 1, 2 (and in WPF, 3), you use the Mode property of the Binding class. The issue here is that pressing a button on the ApplicationBar does not remove the focus from the TextBox where the user is currently typing. If the button is a Save button, this is super annoying: The Binding does not get updated on the data object, the object is saved anyway with the old state, and noone understands what just happened. In order to solve this, you can make sure that the Binding is updated explicitly when the button is pressed, with the following code: private void SaveButtonClick(object sender, EventArgs e) { // Force update binding first var binding = MessageTextBox.GetBindingExpression( TextBox.TextProperty); binding.UpdateSource(); // Property was updated for sure, now we can save var vm = DataContext as MainViewModel; vm.Save(); } Obviously this is less maintainable than the usual way to do things in Silverlight. So be careful when using the ApplicationBar and remember that it is not a Silverlight element like the others!! Happy coding! Laurent   Laurent Bugnion (GalaSoft) Subscribe | Twitter | Facebook | Flickr | LinkedIn

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• C++ problem with assimp 3D model loader

  - by Brendan Webster

  In my game I have model loading functions for Assimp model loading library. I can load the model and render it, but the model displays incorrectly. The models load in as if they were using a seperate projection matrix. I have looked over my code over and over again, but I probably keep on missing the obvious reason why this is happening. Here is an image of my game: It's simply a 6 sided cube, but it's off big time! Here are my code snippets for rendering the cube to the screen: void C_MediaLoader::display(void) { float tmp; glTranslatef(0,0,0); // rotate it around the y axis glRotatef(angle,0.f,0.f,1.f); glColor4f(1,1,1,1); // scale the whole asset to fit into our view frustum tmp = scene_max.x-scene_min.x; tmp = aisgl_max(scene_max.y - scene_min.y,tmp); tmp = aisgl_max(scene_max.z - scene_min.z,tmp); tmp = (1.f / tmp); glScalef(tmp/5, tmp/5, tmp/5); // center the model //glTranslatef( -scene_center.x, -scene_center.y, -scene_center.z ); // if the display list has not been made yet, create a new one and // fill it with scene contents if(scene_list == 0) { scene_list = glGenLists(1); glNewList(scene_list, GL_COMPILE); // now begin at the root node of the imported data and traverse // the scenegraph by multiplying subsequent local transforms // together on GL's matrix stack. recursive_render(scene, scene->mRootNode); glEndList(); } glCallList(scene_list); } void C_MediaLoader::recursive_render (const struct aiScene *sc, const struct aiNode* nd) { unsigned int i; unsigned int n = 0, t; struct aiMatrix4x4 m = nd->mTransformation; // update transform aiTransposeMatrix4(&m); glPushMatrix(); glMultMatrixf((float*)&m); // draw all meshes assigned to this node for (; n < nd->mNumMeshes; ++n) { const struct aiMesh* mesh = scene->mMeshes[nd->mMeshes[n]]; apply_material(sc->mMaterials[mesh->mMaterialIndex]); if(mesh->mNormals == NULL) { glDisable(GL_LIGHTING); } else { glEnable(GL_LIGHTING); } for (t = 0; t < mesh->mNumFaces; ++t) { const struct aiFace* face = &mesh->mFaces[t]; GLenum face_mode; switch(face->mNumIndices) { case 1: face_mode = GL_POINTS; break; case 2: face_mode = GL_LINES; break; case 3: face_mode = GL_TRIANGLES; break; default: face_mode = GL_POLYGON; break; } glBegin(face_mode); for(i = 0; i < face->mNumIndices; i++) { int index = face->mIndices[i]; if(mesh->mColors[0] != NULL) glColor4fv((GLfloat*)&mesh->mColors[0][index]); if(mesh->mNormals != NULL) glNormal3fv(&mesh->mNormals[index].x); glVertex3fv(&mesh->mVertices[index].x); } glEnd(); } } // draw all children for (n = 0; n < nd->mNumChildren; ++n) { recursive_render(sc, nd->mChildren[n]); } glPopMatrix(); } Sorry there is so much code to look through, but I really cannot find the problem, and I would love to have help.

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• Flash Actionscript 3.0 Game Projectile Creation

  - by Christian Basar

  I have been creating a side-scrolling Actionscript 3.0 game. In this game I want the Player to be able to shoot blow darts as weapons. I had some trouble getting the darts to be created in the right place (in front of the player), but eventually got it working with some help from this page (please look at it for background information on this problem): http://stackoverflow.com/questions/8031553/flash-actionscript-3-0-game-projectile-creation I got the darts to be created in the right place (near the player) and a 'movePlayerDarts()' function moves them. But I actually have a new problem. When the player moves after firing a dart, the dart tries to follow him! If the player jumps, the dart rises up. If the player moves to the left, the dart moves slightly to the left. Obviously, there is some code somewhere which is telling the darts to follow the player. I do not see how, unless the 'playerDartContainer' has something to do with that. But the container is always at position (0,0) and it does not move. Also, as a test I traced a dart's 'y' coordinate within the constantly-running 'movePlayerDarts()' function. As you can see, that function constantly moves the dart down the y axis by increasing its y-coordinate value. But when I jump, the 'y' coordinate being traced is never reduced, even though the dart clearly looks like it's rising! If anybody has any suggestions, I'd appreciate them! Here is the code I use to create the darts: // This function creates a dart public function createDart():void { if (playerDartContainer.numChildren <= 4) { // Play dart shooting sound sndDartShootIns.play(); // Create a new 'PlayerDart' object playerDart = new PlayerDart(); // Set the new dart's initial position and direction depending on the player's direction // Player's facing right if (player.scaleX == 1) { // Create dart in front of player's dart gun playerDart.x = player.x + 12; playerDart.y = player.y - 85; // Dart faces right, too playerDart.scaleX = 1; } // Player's facing left else if (player.scaleX == -1) { // Create dart in front of player's dart gun playerDart.x = player.x - 12; playerDart.y = player.y - 85; // Dart faces left, too playerDart.scaleX = -1; } playerDartContainer.addChild(playerDart); } } // End of 'createDart()' function This code is the EnterFrameHandler for the player darts: // In every frame, call 'movePlayerDarts()' to move the darts within the 'playerDartContainer' public function playerDartEnterFrameHandler(event:Event):void { // Only move the Player's darts if their container has at least one dart within if (playerDartContainer.numChildren > 0) { movePlayerDarts(); } } And finally, this is the code that actually moves all of the player's darts: // Move all of the Player's darts public function movePlayerDarts():void { for (var pdIns:int = 0; pdIns < playerDartContainer.numChildren; pdIns++) { // Set the Player Dart 'instance' variable to equal the current PlayerDart playerDartIns = PlayerDart(playerDartContainer.getChildAt(pdIns)); // Move the current dart in the direction it was shot. The dart's 'x-scale' // factor is multiplied by its speed (5) to move the dart in its correct // direction. If the 'x-scale' factor is -1, the dart is pointing left (as // seen in the 'createDart()' function. (-1 * 5 = -5), so the dart will go // to left at a rate of 5. The opposite is true for the right-ward facing // darts playerDartIns.x += playerDartIns.scaleX * 1; // Make gravity work on the dart playerDartIns.y += 0.7; //playerDartIns.y += 1; // What if the dart hits the ground? if (HitTest.intersects(playerDartIns, floor, this)) { playerDartContainer.removeChild(playerDartIns); } //trace("Dart x: " + playerDartIns.x); trace("Dart y: " + playerDartIns.y); } }

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• How to raycast select a scaled OBB?

  - by user3254944

  I have the OBB picking code to select an OBB with code inspired from Real time Rendering 3 and opengl-tutorial.org. I can successfully select objects that have been moved or rotated. However, I cant correctly select an object that has been scaled. The bounding box scales right, but the I can only select the object in a thin strip on its center. How do I fix the checkForHits() function to allow it to read the scaling that I passed to it in the raycast matrix? void GLWidget::selectObjRaycast() { glm::vec2 mouse = (glm::vec2(mousePos.x(), mousePos.y()) / glm::vec2(this->width(), this->height())) * 2.0f - 1.0f; mouse.y *= -1; glm::mat4 toWorld = glm::inverse(ProjectionM * ViewM); glm::vec4 from = toWorld * glm::vec4(mouse, -1.0f, 1.0f); glm::vec4 to = toWorld * glm::vec4(mouse, 1.0f, 1.0f); from /= from.w; to /= to.w; fromAABB = glm::vec3(from); toAABB = glm::normalize(glm::vec3(to - from)); checkForHits(); } void GLWidget::checkForHits() { for (int i = 0; i < myWin.myEtc->allObj.size(); ++i) //check for hits on each obj's bb { bool miss = 0; float tMin = 0.0f; float tMax = 100000.0f; glm::vec3 bbPos(myWin.myEtc->allObj[i]->raycastM[3].x, myWin.myEtc->allObj[i]->raycastM[3].y, myWin.myEtc->allObj[i]->raycastM[3].z); glm::vec3 delta = bbPos - fromAABB; for (int j = 0; j < 3; ++j) { glm::vec3 axis(myWin.myEtc->allObj[i]->raycastM[j].x, myWin.myEtc->allObj[i]->raycastM[j].y, myWin.myEtc->allObj[i]->raycastM[j].z); float e = glm::dot(axis, delta); float f = glm::dot(toAABB, axis); if (fabs(f) > 0.001f) { float t1 = (e + myWin.myEtc->allObj[i]->bbMin[j]) / f; float t2 = (e + myWin.myEtc->allObj[i]->bbMax[j]) / f; if (t1 > t2) { float w = t1; t1 = t2; t2 = w; } if (t2 < tMax) tMax = t2; if (t1 > tMin) tMin = t1; if (tMax < tMin) miss = 1; } else { if (-e + myWin.myEtc->allObj[i]->bbMin[j] > 0.0f || -e + myWin.myEtc->allObj[i]->bbMax[j] < 0.0f) miss = 1; } } if (miss == 0) { intersection_distance = tMin; myWin.myEtc->sel.push_back(myWin.myEtc->allObj[i]); myWin.myEtc->allObj[i]->highlight = myWin.myGLHelp->highlight; break; } } } void Object::render(glm::mat4 PV) { scaleM = glm::scale(glm::mat4(), s->val_3); r_quat = glm::quat(glm::radians(r->val_3)); rotationM = glm::toMat4(r_quat); translationM = glm::translate(glm::mat4(), t->val_3); transLocal1M = glm::translate(glm::mat4(), -rsPivot->val_3); transLocal2M = glm::translate(glm::mat4(), rsPivot->val_3); raycastM = translationM * transLocal2M * rotationM * scaleM * transLocal1M; // MVP = PV * translationM * transLocal2M * rotationM * scaleM * transLocal1M; }

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