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  • Using Coherence API to get POF bytes

    - by Bruno.Borges
    Someone raised the question on how to use the Coherence API to get the bytes of an object in POF (Portable Object Format) programatically. So I came up with this small code that shows the very cool API simple usage :-)   SimplePofContext spc = new SimplePofContext();    spc.registerUserType(0, User.class, new UserSerializer());    // consider UserSerializer as an implementation of PofSerializer            User u = new User();    u.setId(21);    u.setName("Some Name");    u.setEmail("[email protected]");            ByteArrayOutputStream baos = new ByteArrayOutputStream();    DataOutput dataOutput = new DataOutputStream(baos);    BufferOutput bufferOutput = new WrapperBufferOutput(dataOutput);    spc.serialize(bufferOutput, u);            byte[] byteArray = baos.toByteArray();    System.out.println(Arrays.toString(byteArray));  Easy, isn't?

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  • How do I initialize a Scala map with more than 4 initial elements in Java?

    - by GlenPeterson
    For 4 or fewer elements, something like this works (or at least compiles): import scala.collection.immutable.Map; Map<String,String> HAI_MAP = new Map4<>("Hello", "World", "Happy", "Birthday", "Merry", "XMas", "Bye", "For Now"); For a 5th element I could do this: Map<String,String> b = HAI_MAP.$plus(new Tuple2<>("Later", "Aligator")); But I want to know how to initialize an immutable map with 5 or more elements and I'm flailing in Type-hell. Partial Solution I thought I'd figure this out quickly by compiling what I wanted in Scala, then decompiling the resultant class files. Here's the scala: object JavaMapTest { def main(args: Array[String]) = { val HAI_MAP = Map(("Hello", "World"), ("Happy", "Birthday"), ("Merry", "XMas"), ("Bye", "For Now"), ("Later", "Aligator")) println("My map is: " + HAI_MAP) } } But the decompiler gave me something that has two periods in a row and thus won't compile (I don't think this is valid Java): scala.collection.immutable.Map HAI_MAP = (scala.collection.immutable.Map) scala.Predef..MODULE$.Map().apply(scala.Predef..MODULE$.wrapRefArray( scala.Predef.wrapRefArray( (Object[])new Tuple2[] { new Tuple2("Hello", "World"), new Tuple2("Happy", "Birthday"), new Tuple2("Merry", "XMas"), new Tuple2("Bye", "For Now"), new Tuple2("Later", "Aligator") })); I'm really baffled by the two periods in this: scala.Predef..MODULE$ I asked about it on #java on Freenode and they said the .. looked like a decompiler bug. It doesn't seem to want to compile, so I think they are probably right. I'm running into it when I try to browse interfaces in IntelliJ and am just generally lost. Based on my experimentation, the following is valid: Tuple2[] x = new Tuple2[] { new Tuple2<String,String>("Hello", "World"), new Tuple2<String,String>("Happy", "Birthday"), new Tuple2<String,String>("Merry", "XMas"), new Tuple2<String,String>("Bye", "For Now"), new Tuple2<String,String>("Later", "Aligator") }; scala.collection.mutable.WrappedArray<Tuple2> y = scala.Predef.wrapRefArray(x); There is even a WrappedArray.toMap() method but the types of the signature are complicated and I'm running into the double-period problem there too when I try to research the interfaces from Java.

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  • How do I implement movement in a WPF Adventure game?

    - by ZeroPhase
    I'm working on making a short WPF adventure game. The only major hurdle I have right now is how to animate objects on the screen correctly. I've experimented with DoubleAnimation and ThicknessAnimation both enable movement of the character, but the speed is a bit erratic. The objects I'm trying to move around are labels in a grid, I'm checking the mouse's position in terms of the canvas I have the grid in. Does anyone have any suggestions for coding the movement, while still allowing mouse clicks to pick up items when needed? It would be nice if I could continue using the Visual Studio GUI Editor. By the way, I'm fine with scrapping labels in a grid for a more ideal object to manipulate. Here's my movement code: ThicknessAnimation ta = new ThicknessAnimation(); The event handling movement: private void Hansel_MouseLeftButtonDown(object sender, MouseButtonEventArgs e) { ta.FillBehavior = FillBehavior.HoldEnd; ta.From = Hansel.Margin; double newX = Mouse.GetPosition(PlayArea).X; double newY = Mouse.GetPosition(PlayArea).Y; if (newX < Convert.ToDouble(Hansel.Margin.Left)) { //newX = -1 * newX; ta.To = new Thickness(0, newY, newX, 0); } else if (newY < Convert.ToDouble(Hansel.Margin.Top)) { newY = -1 * newY; } else { ta.To = new Thickness(newX, newY, 0, 0); } ta.Duration = new Duration(TimeSpan.FromSeconds(2)); Hansel.BeginAnimation(Grid.MarginProperty, ta); } ScreenShot with annotations: http://i1118.photobucket.com/albums/k608/sealclubberr/clickToMove_zps9d4a33cc.png ScreenShot with example movement: http://i1118.photobucket.com/albums/k608/sealclubberr/clickToMove_zps51f2359f.jpg

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  • Android Game Development problem with Speed = Distance / Time

    - by Charlton Santana
    I have been coding speed for an object. I have made it so the object will move from one end of the screen to another at a speed depending on the screen size, at the monemt I have made it so it will take one second to pass the screen. So i have worked out the speed in code but when I go to assign the speed it tells me to force close and i do not understand why. Here is the code: MainGame Code: @Override protected void onDraw(Canvas canvas) { setBlockSpeed(getWidth()); } private int blockSpeed; private void setBlockSpeed(int screenWidth){ Log.d(TAG, "screenWidth " + screenWidth); blockSpeed = screenWidth / 100; // 100 is the FPS.. i want it to take 1 second to pass the screen Math.round(blockSpeed); // to make it a whole number block.speed = blockSpeed; // this is line 318!! if i put eg block.speed = 8; it still tells me to force close } Block.java Code: public int speed; public void draw(Canvas canvas) { canvas.drawBitmap(bitmap, x - (bitmap.getWidth() / 2), y - (bitmap.getHeight() / 2), null); if(dontmove == 0){ this.x -= speed; // if it was eg this.x -= 18; it would not have an error } } The exception 06-08 13:22:34.315: E/AndroidRuntime(2801): FATAL EXCEPTION: Thread-11 06-08 13:22:34.315: E/AndroidRuntime(2801): java.lang.NullPointerException 06-08 13:22:34.315: E/AndroidRuntime(2801): at com.charltonsantana.game.MainGame.setBlockSpeed(MainGame.java:318) 06-08 13:22:34.315: E/AndroidRuntime(2801): at com.charltonsantana.game.MainGame.onDraw(MainGame.java:351) 06-08 13:22:34.315: E/AndroidRuntime(2801): at com.charltonsantana.game.MainThread.run(MainThread.java:64)

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  • Getting Unity 3D working on legacy Nvidia card

    - by user69545
    I installed the latest nVIDIA drivers for my FX5500 card. I understand that the X server version does not officially support this driver or card but was wondering what I can do to get compiz running. I have researched for hours on this issue but cannot come up with an answer for myself. I might be doing all this for nothing but I wanted to at least try. Here is the output of my test: mike@mike-linux-box:~$ /usr/lib/nux/unity_support_test -p OpenGL vendor string: NVIDIA Corporation OpenGL renderer string: GeForce FX 5500/AGP/SSE2 OpenGL version string: 2.1.2 NVIDIA 173.14.35 Not software rendered: yes Not blacklisted: no GLX fbconfig: yes GLX texture from pixmap: yes GL npot or rect textures: yes GL vertex program: yes GL fragment program: yes GL vertex buffer object: yes GL framebuffer object: yes GL version is 1.4+: yes Unity 3D supported: no So I was wondering what is the "Not Blacklisted" test? Is this the Nouveau Blacklisting? nVIDIA driver did that automatically. Does this need to be removed? Any help would be appreciated. I just want to run compiz effects. Thanks.

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  • 2D Side scroller collision detection

    - by Shanon Simmonds
    I am trying to do some collision detection between objects and tiles, but the tiles do not have there own x and y position, they are just rendered to the x and y position given, there is an array of integers which has the ids of the tiles to use(which are given from an image and all the different colors are assigned different tiles) int x0 = camera.x / 16; int y0 = camera.y / 16; int x1 = (camera.x + screen.width) / 16; int y1 = (camera.y + screen.height) / 16; for(int y = y0; y < y1; y++) { if(y < 0 || y >= height) continue; // height is the height of the level for(int x = x0; x < x1; x++) { if(x < 0 || x >= width) continue; // width is the width of the level getTile(x, y).render(screen, x * 16, y * 16); } } I tried using the levels getTile method to see if the tile that the object was going to advance to, to see if it was a certain tile, but, it seems to only work in some directions. Any ideas on what I'm doing wrong and fixes would be greatly appreciated. What's wrong is that it doesn't collide properly in every direction and also this is how I tested for a collision in the objects class if(!level.getTile((x + xa) / 16, (y + ya) / 16).isSolid()) { x += xa; y += ya; } EDIT: xa and ya represent the direction as well as the movement, if xa is negative it means the object is moving left, if its positive it is moving right, and same with ya except negative for up, positive for down.

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  • Distinguishing between UI command & domain commands

    - by SonOfPirate
    I am building a WPF client application using the MVVM pattern that provides an interface on top of an existing set of business logic residing in a library which is shared with other applications. The business library followed a domain-driven architecture using CQRS to separate the read and write models (no event sourcing). The combination of technologies and patterns has brought up an interesting conundrum: The MVVM pattern uses the command pattern for handling user-interaction with the view models. .NET provides an ICommand interface which is implemented by most MVVM frameworks, like MVVM Light's RelayCommand and Prism's DelegateCommand. For example, the view model would expose a number of command objects as properties that are bound to the UI and respond when the user performs actions like clicking buttons. Many implementations of the CQRS use the command pattern to isolate and encapsulate individual behaviors. In my business library, we have implemented the write model as command / command-handler pairs. As such, when we want to do some work, such as create a new order, we 'issue' a command (CreateOrderCommand) which is routed to the command-handler responsible for executing the command. This is great, clearly explained in many sources and I am good with it. However, take this scenario: I have a ToolbarViewModel which exposes a CreateNewOrderCommand property. This ICommand object is bound to a button in the UI. When clicked, the UI command creates and issues a new CreateOrderCommand object to the domain which is handled by the CreateOrderCommandHandler. This is difficult to explain to other developers and I am finding myself getting tongue-tied because everything is a command. I'm sure I'm not the first developer to have patterns overlap like this where the naming/terminology also overlap. How have you approached distinguishing your commands used in the UI from those used in the domain? (Edit: I should mention that the business library is UI-agnostic, i.e. no UI technology-specific code exists, or will exists, in this library.)

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  • Farseer tutorial for the absolute beginners

    - by Bil Simser
    This post is inspired (and somewhat a direct copy) of a couple of posts Emanuele Feronato wrote back in 2009 about Box2D (his tutorial was ActionScript 3 based for Box2D, this is C# XNA for the Farseer Physics Engine). Here’s what we’re building: What is Farseer The Farseer Physics Engine is a collision detection system with realistic physics responses to help you easily create simple hobby games or complex simulation systems. Farseer was built as a .NET version of Box2D (based on the Box2D.XNA port of Box2D). While the constructs and syntax has changed over the years, the principles remain the same. This tutorial will walk you through exactly what Emanuele create for Flash but we’ll be doing it using C#, XNA and the Windows Phone platform. The first step is to download the library from its home on CodePlex. If you have NuGet installed, you can install the library itself using the NuGet package that but we’ll also be using some code from the Samples source that can only be obtained by downloading the library. Once you download and unpacked the zip file into a folder and open the solution, this is what you will get: The Samples XNA WP7 project (and content) have all the demos for Farseer. There’s a wealth of info here and great examples to look at to learn. The Farseer Physics XNA WP7 project contains the core libraries that do all the work. DebugView XNA contains an XNA-ready class to let you view debug data and information in the game draw loop (which you can copy into your project or build the source and reference the assembly). The downloaded version has to be compiled as it’s only available in source format so you can do that now if you want (open the solution file and rebuild everything). If you’re using the NuGet package you can just install that. We only need the core library and we’ll be copying in some code from the samples later. Your first Farseer experiment Start Visual Studio and create a new project using the Windows Phone template can call it whatever you want. It’s time to edit Game1.cs 1 public class Game1 : Game 2 { 3 private readonly GraphicsDeviceManager _graphics; 4 private DebugViewXNA _debugView; 5 private Body _floor; 6 private SpriteBatch _spriteBatch; 7 private float _timer; 8 private World _world; 9 10 public Game1() 11 { 12 _graphics = new GraphicsDeviceManager(this) 13 { 14 PreferredBackBufferHeight = 800, 15 PreferredBackBufferWidth = 480, 16 IsFullScreen = true 17 }; 18 19 Content.RootDirectory = "Content"; 20 21 // Frame rate is 30 fps by default for Windows Phone. 22 TargetElapsedTime = TimeSpan.FromTicks(333333); 23 24 // Extend battery life under lock. 25 InactiveSleepTime = TimeSpan.FromSeconds(1); 26 } 27 28 protected override void LoadContent() 29 { 30 // Create a new SpriteBatch, which can be used to draw textures. 31 _spriteBatch = new SpriteBatch(_graphics.GraphicsDevice); 32 33 // Load our font (DebugViewXNA needs it for the DebugPanel) 34 Content.Load<SpriteFont>("font"); 35 36 // Create our World with a gravity of 10 vertical units 37 if (_world == null) 38 { 39 _world = new World(Vector2.UnitY*10); 40 } 41 else 42 { 43 _world.Clear(); 44 } 45 46 if (_debugView == null) 47 { 48 _debugView = new DebugViewXNA(_world); 49 50 // default is shape, controller, joints 51 // we just want shapes to display 52 _debugView.RemoveFlags(DebugViewFlags.Controllers); 53 _debugView.RemoveFlags(DebugViewFlags.Joint); 54 55 _debugView.LoadContent(GraphicsDevice, Content); 56 } 57 58 // Create and position our floor 59 _floor = BodyFactory.CreateRectangle( 60 _world, 61 ConvertUnits.ToSimUnits(480), 62 ConvertUnits.ToSimUnits(50), 63 10f); 64 _floor.Position = ConvertUnits.ToSimUnits(240, 775); 65 _floor.IsStatic = true; 66 _floor.Restitution = 0.2f; 67 _floor.Friction = 0.2f; 68 } 69 70 protected override void Update(GameTime gameTime) 71 { 72 // Allows the game to exit 73 if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed) 74 Exit(); 75 76 // Create a random box every second 77 _timer += (float) gameTime.ElapsedGameTime.TotalSeconds; 78 if (_timer >= 1.0f) 79 { 80 // Reset our timer 81 _timer = 0f; 82 83 // Determine a random size for each box 84 var random = new Random(); 85 var width = random.Next(20, 100); 86 var height = random.Next(20, 100); 87 88 // Create it and store the size in the user data 89 var box = BodyFactory.CreateRectangle( 90 _world, 91 ConvertUnits.ToSimUnits(width), 92 ConvertUnits.ToSimUnits(height), 93 10f, 94 new Point(width, height)); 95 96 box.BodyType = BodyType.Dynamic; 97 box.Restitution = 0.2f; 98 box.Friction = 0.2f; 99 100 // Randomly pick a location along the top to drop it from 101 box.Position = ConvertUnits.ToSimUnits(random.Next(50, 400), 0); 102 } 103 104 // Advance all the elements in the world 105 _world.Step(Math.Min((float) gameTime.ElapsedGameTime.TotalMilliseconds*0.001f, (1f/30f))); 106 107 // Clean up any boxes that have fallen offscreen 108 foreach (var box in from box in _world.BodyList 109 let pos = ConvertUnits.ToDisplayUnits(box.Position) 110 where pos.Y > _graphics.GraphicsDevice.Viewport.Height 111 select box) 112 { 113 _world.RemoveBody(box); 114 } 115 116 base.Update(gameTime); 117 } 118 119 protected override void Draw(GameTime gameTime) 120 { 121 GraphicsDevice.Clear(Color.FromNonPremultiplied(51, 51, 51, 255)); 122 123 _spriteBatch.Begin(); 124 125 var projection = Matrix.CreateOrthographicOffCenter( 126 0f, 127 ConvertUnits.ToSimUnits(_graphics.GraphicsDevice.Viewport.Width), 128 ConvertUnits.ToSimUnits(_graphics.GraphicsDevice.Viewport.Height), 0f, 0f, 129 1f); 130 _debugView.RenderDebugData(ref projection); 131 132 _spriteBatch.End(); 133 134 base.Draw(gameTime); 135 } 136 } 137 Lines 4: Declare the debug view we’ll use for rendering (more on that later). Lines 8: Declare _world variable of type class World. World is the main object to interact with the Farseer engine. It stores all the joints and bodies, and is responsible for stepping through the simulation. Lines 12-17: Create the graphics device we’ll be rendering on. This is an XNA component and we’re just setting it to be the same size as the phone and toggling it to be full screen (no system tray). Lines 34: We create a SpriteFont here by adding it to the project. It’s called “font” because that’s what the DebugView uses but you can name it whatever you want (and if you’re not using DebugView for your production app you might have several fonts). Lines 37-44: We create the physics environment that Farseer uses to contain all the objects by specifying it here. We’re using Vector2.UnitY*10 to represent the gravity to be used in the environment. In other words, 10 units going in a downward motion. Lines 46-56: We create the DebugViewXNA here. This is copied from the […] from the code you downloaded and provides the ability to render all entities onto the screen. In a production release you’ll be doing the rendering yourself of each object but we cheat a bit for the demo and let the DebugView do it for us. The other thing it can provide is to render out a panel of debugging information while the simulation is going on. This is useful in tracking down objects, figuring out how something works, or just keeping track of what’s in the engine. Lines 49-67: Here we create a rigid body (Farseer only supports rigid bodies) to represent the floor that we’ll drop objects onto. We create it by using one of the Farseer factories and specifying the width and height. The ConvertUnits class is copied from the samples code as-is and lets us toggle between display units (pixels) and simulation units (usually metres). We’re creating a floor that’s 480 pixels wide and 50 pixels high (converting them to SimUnits for the engine to understand). We also position it near the bottom of the screen. Values are in metres and when specifying values they refer to the centre of the body object. Lines 77-78: The game Update method fires 30 times a second, too fast to be creating objects this quickly. So we use a variable to track the elapsed seconds since the last update, accumulate that value, then create a new box to drop when 1 second has passed. Lines 89-94: We create a box the same way we created our floor (coming up with a random width and height for the box). Lines 96-101: We set the box to be Dynamic (rather than Static like the floor object) and position it somewhere along the top of the screen. And now you created the world. Gravity does the rest and the boxes fall to the ground. Here’s the result: Farseer Physics Engine Demo using XNA Lines 105: We must update the world at every frame. We do this with the Step method which takes in the time interval. [more] Lines 108-114: Body objects are added to the world but never automatically removed (because Farseer doesn’t know about the display world, it has no idea if an item is on the screen or not). Here we just loop through all the entities and anything that’s dropped off the screen (below the bottom) gets removed from the World. This keeps our entity count down (the simulation never has more than 30 or 40 objects in the world no matter how long you run it for). Too many entities and the app will grind to a halt. Lines 125-130: Farseer knows nothing about the UI so that’s entirely up to you as to how to draw things. Farseer is just tracking the objects and moving them around using the physics engine and it’s rules. You’ll still use XNA to draw items (using the SpriteBatch.Draw method) so you can load up your usual textures and draw items and pirates and dancing zombies all over the screen. Instead in this demo we’re going to cheat a little. In the sample code for Farseer you can download there’s a project called DebugView XNA. This project contains the DebugViewXNA class which just handles iterating through all the bodies in the world and drawing the shapes. So we call the RenderDebugData method here of that class to draw everything correctly. In the case of this demo, we just want to draw Shapes so take a look at the source code for the DebugViewXNA class as to how it extracts all the vertices for the shapes created (in this case simple boxes) and draws them. You’ll learn a *lot* about how Farseer works just by looking at this class. That’s it, that’s all. Simple huh? Hope you enjoy the code and library. Physics is hard and requires some math skills to really grok. The Farseer Physics Engine makes it pretty easy to get up and running and start building games. In future posts we’ll get more in-depth with things you can do with the engine so this is just the beginning. Enjoy!

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  • Philosophy behind the memento pattern

    - by TheSilverBullet
    I have been reading up on memento pattern from various sources of the internet. Differing information from different sources has left me in confusion regarding why this pattern is actually needed. The dofactory implementation says that the primary intention of this pattern is to restore the state of the system. Wiki says that the primary intention is to be able to restore the changes on the system. This gives a different impact - saying that it is possible for a system to have memento implementation with no need to restore. And that ability of restore is a feature of this. OODesign says that It is sometimes necessary to capture the internal state of an object at some point and have the ability to restore the object to that state later in time. Such a case is useful in case of error or failure. So, my question is why exactly do we use this one? Is it to save previous states - or to promote encapsulation between the Caretaker and the Memento? Why is this type of encapsulation so important? Edit: For those visiting, check out this Implementation!

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  • Can not login Dashboard / Unable to find the server at mykeystoneurl

    - by neo0
    I installed Dashboard following this guide: http://wiki.openstack.org/OpenStackDashboard Everything fine, but when I run the server, I can not login with the username and password in DATABASE config in local_settings.py. Here's my config: DATABASES = { 'default': { 'ENGINE': 'django.db.backends.mysql', 'NAME': 'dashboarddb', 'USER': 'nova', 'PASSWORD': 'nova', 'HOST': 'localhost', 'default-character-set': 'utf8' }, } When I run the Dashboard server and enter username + password. It returned this error on browser: Unable to find the server at mykeystoneurl (HTTP 400) And in the command line: DEBUG:openstack_dashboard.settings:Running in debug mode without debug_toolbar. DEBUG:openstack_dashboard.settings:Running in debug mode without debug_toolbar. Validating models... 0 errors found Django version 1.3.1, using settings 'openstack_dashboard.settings' Development server is running at http://0.0.0.0:8888/ Quit the server with CONTROL-C. Request returned failure status. Traceback (most recent call last): File "/home/us/horizon/.venv/src/python-keystoneclient/keystoneclient/client.py", line 121, in request body = json.loads(body) File "/usr/lib/python2.7/json/__init__.py", line 326, in loads return _default_decoder.decode(s) File "/usr/lib/python2.7/json/decoder.py", line 366, in decode obj, end = self.raw_decode(s, idx=_w(s, 0).end()) File "/usr/lib/python2.7/json/decoder.py", line 384, in raw_decode raise ValueError("No JSON object could be decoded") ValueError: No JSON object could be decoded [06/Mar/2012 15:20:03] "POST /auth/login/ HTTP/1.1" 200 3735 I also tried login as "admin" with password is "password" or "secrete" but I didn't work. What's wrong? Thank you!

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  • How to really master ASP.NET MVC?

    - by user1620696
    Some years ago I've worked with web development just using PHP without focus on object orientation and so on. When I knew a little bit about it, and the benefits it brings, I've started moving to ASP.NET MVC. First, I've studied C# in the book Visual C# Step by Step. I've found it a good book for a beginner, and I could learn a lot of this new language with it. Now, when I've came to study ASP.NET MVC, I hadn't so much luck. I've studied on some books that explained MVC well and so on, but then started just saying: "do that, and now that, and then that", and I feel I couldn't really master ASP.NET MVC. I feel this, because when I was reading, I knew how to do the things the book taught, like implementing DI with Ninject and so on, but some time later, without looking at it for some time, I couldn't do it by myself. What I'm trying to say, is that usually I don't know where to start, how to do things in this framework and so on. How can I really master ASP.NET MVC? There is some book, some tutorial series, anything, that can really help with that? I'm pretty happy with the .NET framework, my problem isn't it, my only problem is working with the MVC framework, and applying the techniques from object orientation there. I don't know if this question is on-topic here, but I'm really just looking for some good references, to become better with this framework.

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  • Go/Obj-C style interfaces with ability to extend compiled objects after initial release

    - by Skrylar
    I have a conceptual model for an object system which involves combining Go/Obj-C interfaces/protocols with being able to add virtual methods from any unit, not just the one which defines a class. The idea of this is to allow Ruby-ish open classes so you can take a minimalist approach to library development, and attach on small pieces of functionality as is actually needed by the whole program. Implementation of this involves a table of methods marked virtual in an RTTI table, which system functions are allowed to add to during module initialization. Upon typecasting an object to an interface, a Go-style lookup is done to create a vtable for that particular mapping and pass it off so you can have comparable performance to C/C++. In this case, methods may be added /afterwards/ which were not previously known and these new methods allow newer interfaces to be satisfied; while I like this idea because it seems like it would be very flexible (disregarding the potential for spaghetti code, which can happen with just about any model you use regardless). By wrapping the system calls for binding methods up in a set of clean C-compatible calls, one would also be able to integrate code with shared libraries and retain a decent amount of performance (Go does not do shared linking, and Objective-C does a dynamic lookup on each call.) Is there a valid use-case for this model that would make it worth the extra background plumbing? As much as this Dylan-style extensibility would be nice to have access to, I can't quite bring myself to a use case that would justify the overhead other than "it could make some kinds of code more extensible in future scenarios."

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  • MvcReportViewer v.0.4.0 is available!

    - by Ilya Verbitskiy
    Originally posted on: http://geekswithblogs.net/ilich/archive/2014/06/04/mvcreportviewer-v.0.4.0-is-available.aspxToday I released new version of MvcReportViewer. This release contains mostly bug fixes reported by library users. I am glad to see that Open Source model works and people try to contribute to the project! Thank you everybody for your bug repots and help with the project. Version 0.4.0 Added support for ASP.NET MVC 5 Removed jQuery dependency. I have not tested it on IE8 or earlier versions. Any help with testing is welcome! Fixed problem with SSRS keep-alive cookies. Keep-alive cookies are issued every time a report is opened during a browser session. Many people don't restart their browsers and in my case, Chrome doesn't get rid of the cookie session data on close - had to manually delete them for the reports to start working again. I added KeepSessionAlive control settings to manage SSRS keep-alive behavior. It is set to false by default to fix Bad Request 400: Request Too Long issue. You can find usage example in Fluent.cshtml. Fixed the bug when ReportViewer Control parameters was not parsed when ShowParameterPrompts parameter had not been set. Changed public static MvcReportViewerIframe MvcReportViewer method to use IEnumerable<KeyValuePair<string, object>> reportParameters instead of simple object. The reason is users reported that they mostly use multiple report parameters’ values. Added support for SSRS hosted on Windows Azure. Users should set MvcReportViewer.IsAzureSSRS property to true in Web.config to use Windows Azure authentication. I do not have Windows Azure SSRS and build the code using http://msdn.microsoft.com/en-us/library/gg552871.aspx#Authentication article. It would be nice if somebody from community tested the change or provided me a test report on Windows Azure for testing purposes.

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  • Using runtime generic type reflection to build a smarter DAO

    - by kerry
    Have you ever wished you could get the runtime type of your generic class? I wonder why they didn’t put this in the language. It is possible, however, with reflection: Consider a data access object (DAO) (note: I had to use brackets b/c the arrows were messing with wordpress): public interface Identifiable { public Long getId(); } public interface Dao { public T findById(Long id); public void save(T obj); public void delete(T obj); } Using reflection, we can create a DAO implementation base class, HibernateDao, that will work for any object: import java.lang.reflect.Field; import java.lang.reflect.ParameterizedType; public class HibernateDao implements Dao { private final Class clazz; public HibernateDao(Session session) { // the magic ParameterizedType parameterizedType = (ParameterizedType) clazz.getGenericSuperclass(); return (Class) parameterizedType.getActualTypeArguments()[0]; } public T findById(Long id) { return session.get(clazz, id); } public void save(T obj) { session.saveOrUpdate(obj); } public void delete(T obj) { session.delete(obj); } } Then, all we have to do is extend from the class: public class BookDaoHibernateImpl extends HibernateDao { }

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  • An alternative to multiple inheritance when creating an abstraction layer?

    - by sebf
    In my project I am creating an abstraction layer for some APIs. The purpose of the layer is to make multi-platform easier, and also to simplify the APIs to the feature set that I need while also providing some functionality, the implementation of which will be unique to each platform. At the moment, I have implemented it by defining and abstract class, which has methods which creates objects that implement interfaces. The abstract class and these interfaces define the capabilities of my abstraction layer. The implementation of these in my layer should of course be arbitrary from the POV view of my application, but I have done it, for my first API, by creating chains of subclasses which add more specific functionality as the features of the APIs they expose become less generic. An example would probably demonstrate this better: //The interface as seen by the application interface IGenericResource { byte[] GetSomeData(); } interface ISpecificResourceOne : IGenericResource { int SomePropertyOfResourceOne {get;} } interface ISpecificResourceTwo : IGenericResource { string SomePropertyOfResourceTwo {get;} } public abstract class MyLayer { ISpecificResourceOne CreateResourceOne(); ISpecificResourceTwo CreateResourceTwo(); void UseResourceOne(ISpecificResourceOne one); void UseResourceTwo(ISpecificResourceTwo two); } //The layer as created in my library public class LowLevelResource : IGenericResource { byte[] GetSomeData() {} } public class ResourceOne : LowLevelResource, ISpecificResourceOne { int SomePropertyOfResourceOne {get{}} } public class ResourceTwo : ResourceOne, ISpecificResourceTwo { string SomePropertyOfResourceTwo {get {}} } public partial class Implementation : MyLayer { override UseResourceOne(ISpecificResourceOne one) { DoStuff((ResourceOne)one); } } As can be seen, I am essentially trying to have two inheritance chains on the same object, but of course I can't do this so I simulate the second version with interfaces. The thing is though, I don't like using interfaces for this; it seems wrong, in my mind an interface defines a contract, any class that implements that interface should be able to be used where that interface is used but here that is clearly not the case because the interfaces are being used to allow an object from the layer to masquerade as something else, without the application needing to have access to its definition. What technique would allow me to define a comprehensive, intuitive collection of objects for an abstraction layer, while their implementation remains independent? (Language is C#)

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  • Architecture a for a central renderer rather than self-rendering

    - by The Communist Duck
    For the architectural side of rendering, there's two main ways: having each object render itself, and having a single renderer which renders everything. I'm currently aiming for the second idea, for the following reasons: The list can be sorted to only use shaders once. Else each object would have to bind the shader, because it's not sure if it's active. The objects could be sorted and grouped. Easier to swap APIs. With a few macro lines, it can be easy to swap between a DirectX renderer and an OpenGL renderer (not a reason for my project, but still a good point) Easier to manage rendering code Of course, if anyone has strong recommendations for the first method, I will listen to them. But I was wondering how make this work. First idea The renderer has a list of pointers to the renderable components of each entity, which register themselves on RenderCompoent creation. However, I'm worrying that this may end up as a lot of extra pointer weight. But I can sort the list of pointers every so often. Second idea The entire list of entities is passed to the renderer each render call. The renderer then sorts the list (each call, or maybe once?) and gets what it wants. That's a lot of passing and/or sorting, however. Other ideas ??? PROFIT Anyone got ideas? Thank you.

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  • How to implement child-parent aggregation link in C++?

    - by Giorgio
    Suppose that I have three classes P, C1, C2, composition (strong aggregation) relations between P <>- C1 and P <>- C2, i.e. every instance of P contains an instance of C1 and an instance of C2, which are destroyed when the parent P instance is destroyed. an association relation between instances of C1 and C2 (not necessarily between children of the same P). To implement this, in C++ I normally define three classes P, C1, C2, define two member variables of P of type boost::shared_ptr<C1>, boost::shared_ptr<C2>, and initialize them with newly created objects in P's constructor, implement the relation between C1 and C2 using a boost::weak_ptr<C2> member variable in C1 and a boost::weak_ptr<C1> member variable in C2 that can be set later via appropriate methods, when the relation is established. Now, I also would like to have a link from each C1 and C2 object to its P parent object. What is a good way to implement this? My current idea is to use a simple constant raw pointer (P * const) that is set from the constructor of P (which, in turn, calls the constructors of C1 and C2), i.e. something like: class C1 { public: C1(P * const p, ...) : paren(p) { ... } private: P * const parent; ... }; class P { public: P(...) : childC1(new C1(this, ...)) ... { ... } private: boost::shared_ptr<C1> childC1; ... }; Honestly I see no risk in using a private constant raw pointer in this way but I know that raw pointers are often frowned upon in C++ so I was wondering if there is an alternative solution.

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  • How to fix Java problem installing Matlab 2012a (64-bit) in Ubuntu 12.04 (64 bit)?

    - by Sabyasachi
    I am trying to install Matlab 2012a (64-bit) in Ubuntu 12.04LTS (64-bit). I have installed Java 7. My Java version is: sabyasachi@sabyasachi-ubuntu:~/Downloads/R2012a_UNIX$ java -version java version "1.7.0_05" Java(TM) SE Runtime Environment (build 1.7.0_05-b05) Java HotSpot(TM) 64-Bit Server VM (build 23.1-b03, mixed mode I am getting the following error while installing Matlab: sabyasachi@sabyasachi-ubuntu:~/Downloads/R2012a_UNIX$ ./install Preparing installation files ... Installing ... /tmp/mathworks_18824/sys/java/jre/glnxa64/jre/bin/java: error while loading shared libraries: libjli.so: cannot open shared object file: No such file or directory Finished How can I fix this problem? When I use -v (verbose) option I am getting the following: sabyasachi@sabyasachi-ubuntu:~/Downloads/R2012a_UNIX$ sudo ./install -v Preparing installation files ... -> DVD = /home/sabyasachi/Downloads/R2012a_UNIX -> ARCH = glnxa64 -> DISPLAY = :0 -> TESTONLY = 0 -> JRE_LOC = /tmp/mathworks_26521/sys/java/jre/glnxa64/jre -> LD_LIBRARY_PATH = /tmp/mathworks_26521/bin/glnxa64 Command to run: /tmp/mathworks_26521/sys/java/jre/glnxa64/jre/bin/java -splash:"/home/sabyasachi/Downloads/R2012a_UNIX/java/splash.png" -Djava.ext.dirs=/tmp/mathworks_26521/sys/java/jre/glnxa64/jre/lib/ext:/tmp/mathworks_26521/java/jar:/tmp/mathworks_26521/java/jarext:/tmp/mathworks_26521/java/jarext/axis2/:/tmp/mathworks_26521/java/jarext/guice/:/tmp/mathworks_26521/java/jarext/webservices/ com/mathworks/professionalinstaller/Launcher -root "/home/sabyasachi/Downloads/R2012a_UNIX" -tmpdir "/tmp/mathworks_26521" Installing ... /tmp/mathworks_26521/sys/java/jre/glnxa64/jre/bin/java: error while loading shared libraries: libjli.so: cannot open shared object file: No such file or directory Finished sabyasachi@sabyasachi-ubuntu:~/Downloads/R2012a_UNIX$

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  • OnTrigger not firing consistently

    - by Lautaro
    I have a Prefab called Player which has a Body and a Sword. The game uses 2 instances of Player, Player1 and Player2. I use Player1 to strike Player2. This is code on the sword. My hope is that Sword of Player1 will log on contct with Body of Player2. It happens but only the first hit and then i have to hit several times before another strike is logged. But when i look at log from OnTriggerStay it looks like the TriggerExit is never detected untill long after the sword is gone. void OnTriggerEnter(Collider other) { //Play sound to confirm collision var sm = ObjectDirectory.soundManager; sm.PlaySoundClip(sm.gui_02); Debug.Log(other.name + " - ENTER" ); } void OnTriggerStay(Collider other) { Debug.Log(other.name + " - collision" ); } void OnTriggerExit(Collider other) { Debug.Log(other.name + " - HAS LEFT" ); } DEBUG LOG: Player2 - ENTER UnityEngine.Debug:Log(Object) SwordControl:OnTriggerEnter(Collider) (at Assets/Scripts/SwordControl.cs:28) Player2 - collision UnityEngine.Debug:Log(Object) SwordControl:OnTriggerStay(Collider) (at Assets/Scripts/SwordControl.cs:34) (The last debug log then repeated hundreds of times long after the sword of player 1 had withdrawn and was in no contact with player 2 ) EDIT: Further tests shows that if i move player1 backwards away form player2 i trigger the OnTriggerExit. Even if the sword is not touching Player2 since after the blow. However even after OnTriggerExit it takes many tries untill i can get another blow registered.

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  • Sorting objects before rendering

    - by dreta
    I'm trying to implement a scene graph and in all the articles i've come across there is talk about object sorting. So you'd sort your objects by "material" for example. Now untill i sat down and started implementing it, i kind of took this for granted, because it made sense. But now i'm wondering what does sorting actually change? In my engine, i have a manager for UBOs, i use those to store data that'll be shared between programs, at the moment that only involves time, camera and projection matrices and lights (i'm not worrying about managing which lights affect which objects ATM). Now for each model i have to change the model to world matrix uniform, no sorting is going to change that. So is the jump from changing this matrix to also setting a material for each object that bad? I vaguely remember reading somewhere that each time you change something in the pipeline, it has to get flushed and that can cause performance issues. But for each drawing call i'm setting up a model to world matrix anyway, so what sense does it make to ever be concerned about this? BTW is there any information about whether changing a uniform and calling glBufferSubData is more (or less) expensive.

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  • Finding the shorter turning direction towards a target

    - by A.B.
    I'm trying to implement a type of movement where the object gradually faces the target. The problem I've run into is figuring out which turning direction is faster. The following code works until the object's orientation crosses the -PI or PI threshold, at which point it will start turning into the opposite direction void moveToPoint(sf::Vector2f destination) { if (destination == position) return; auto distance = distanceBetweenPoints(position, destination); auto direction = angleBetweenPoints(position, destination); /// Decides whether incrementing or decrementing orientation is faster /// the next line is the problem if (atan2(sin(direction - rotation), cos(direction - rotation)) > 0 ) { /// Increment rotation rotation += rotation_speed; } else { /// Decrement rotation rotation -= rotation_speed; } if (distance < movement_speed) { position = destination; } else { position.x = position.x + movement_speed*cos(rotation); position.y = position.y + movement_speed*sin(rotation); } updateGraphics(); } 'rotation' and 'rotation_speed' are implemented as custom data type for radians which cannot have values lower than -PI and greater than PI. Any excess or deficit "wraps around". For example, -3.2 becomes ~3.08.

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  • Which Graphics/Geometry abstraction to choose?

    - by Robz
    I've been thinking about the design for a browser app on the HTML5 canvas that simulates a 2D robot zooming around, sensing the world around it. I decided to do this from scratch just for fun. I need shapes, like polygons, circles, and lines in order to model the robot and the world it lives in. These shapes need to be drawn with different appearance attributes, like border/fill style/width/color. I also need to have geometry functions to detect intersections and containment for the robot's sensors and so that the robot doesn't go inside stuff. One idea for functions is to have two totally separate libraries, one to implement graphics (like drawShape(context, shape)) and one for geometry operations (like shapeIntersectsShape(shape1, shape2)). Or, in a more object-oriented approach, the shape objects themselves could implement methods to do their own graphics (shape.draw(context)) and geometry operations (shape1.intersects(shape2)). Then there is the data itself: whether the data to draw a shape and the data to do geometric operations on that shape should be encapsulated within the same object, or be separate structures (where one would contain the other, or both be contained inside another structure). How do existing applications that do graphics/geometry stuff deal with this? Is there one model that is best, or is each good for certain applications? Should the fact that I'm using Javascript instead of a more classical language change how I approach the design?

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  • Interview Questions in OOP

    - by Fero
    Hi all, I faced the below interview questions in OOP under PHP language. Kindly clear my clarifications regarding this. I am very confused. As i am a beginner to OOP i got too confused. Could anyone clarify these things clearly? Difference between Abstract class and interface. Interviewer : Let us consider abstract class contains three abstract methods such as a,b,c and interface contains three methods a,b,c. In this case these do the same functionality. Then why are going for abstract and why are we going for interface. Me : ? static keyword. Interviewer: We call static method without creating object by using scope resolution operator in PHP. As well as we can able to call concrete methods also. Then what is need of static keyword there? Me : .... final keyword. Interviewer: Give me any scenario of using final keyword. Me : For db connection related method Interviewer: Other than that? Me: ... Constructor. Interviewer: What is the use of constructor? Me : There is no need for object to access this. It will call automatically when the class calls. Interviewer: Other than that? Me : .... Thanks in advance...

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  • Rotation and translation like in GTA 1 OpenGL

    - by user1876377
    Okay, so I have a figure in XZ plain. I want to move it forward/backward and rotate at it's own Y axis, then move forward again in the rotation's direction, like the character in GTA 1. Code so far: Init: spaceship_position = glm::vec3(0,0,0); spaceship_rotation = glm::vec3(0,0,0); spaceship_scale = glm::vec3(1, 1, 1); Draw: glm::mat4 transform = glm::scale<float>(spaceship_scale) * glm::rotate<float>(spaceship_rotation.x, 1, 0, 0) * glm::rotate<float>(spaceship_rotation.y, 0, 1, 0) * glm::rotate<float>(spaceship_rotation.z, 0, 0, 1) * glm::translate<float>(spaceship_position); drawMesh(spaceship, texture, transform); Update: switch (key.keysym.sym) { case SDLK_UP: spaceship_position.z += 0.1; break; case SDLK_DOWN: spaceship_position.z -= 0.1; break; case SDLK_LEFT: spaceship_rotation.y += 1; break; case SDLK_RIGHT: spaceship_rotation.y -= 1; break; } So this only moves on the Z axis, but how can I move the object on both Z and X axis where the object is facing?

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  • How to prevent duplicate data access methods that retrieve similar data?

    - by Ronald Wildenberg
    In almost every project I work on with a team, the same problem seems to creep in. Someone writes UI code that needs data and writes a data access method: AssetDto GetAssetById(int assetId) A week later someone else is working on another part of the application and also needs an AssetDto but now including 'approvers' and writes the following: AssetDto GetAssetWithApproversById(int assetId) A month later someone needs an asset but now including the 'questions' (or the 'owners' or the 'running requests', etc): AssetDto GetAssetWithQuestionsById(int assetId) AssetDto GetAssetWithOwnersById(int assetId) AssetDto GetAssetWithRunningRequestsById(int assetId) And it gets even worse when methods like GetAssetWithOwnerAndQuestionsById start to appear. You see the pattern that emerges: an object is attached to a large object graph and you need different parts of this graph in different locations. Of course, I'd like to prevent having a large number of methods that do almost the same. Is it simply a matter of team discipline or is there some pattern I can use to prevent this? In some cases it might make sense to have separate methods, i.e. getting an asset with running requests may be expensive so I do not want to include these all the time. How to handle such cases?

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