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  • How do I implement SkyBox in xna 4.0 Reach Profile (for Windows Phone 7)?

    - by Biny
    I'm trying to Implement SkyBox in my phone game. Most of the samples in the web are for HiDef profile, and they are using custom effects (that not supported on Windows Phone). I've tried to follow this guide. But for some reason my SkyBox is not rendered. This is my SkyBox class: using System; using System.Collections.Generic; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Graphics; using Rocuna.Core; using Rocuna.GameEngine.Graphics; using Rocuna.GameEngine.Graphics.Components; namespace Rocuna.GameEngine.Extension.WP7.Graphics { /// <summary> /// Sky box element for phone games. /// </summary> public class SkyBox : SkyBoxBase { /// <summary> /// Initializes a new instance of the <see cref="SkyBoxBase"/> class. /// </summary> /// <param name="game">The Game that the game component should be attached to.</param> public SkyBox(TextureCube cube, Game game) : base(game) { Cube = cube; CubeFaces = new Texture2D[6]; PositionOffset = new Vector3(20, 20, 20); CreateGraphic(512); StripTexturesFromCube(); InitializeData(Game.GraphicsDevice); } #region Properties /// <summary> /// Gets or sets the position offset. /// </summary> /// <value> /// The position offset. /// </value> public Vector3 PositionOffset { get; set; } /// <summary> /// Gets or sets the position. /// </summary> /// <value> /// The position. /// </value> public Vector3 Position { get; set; } /// <summary> /// Gets or sets the cube. /// </summary> /// <value> /// The cube. /// </value> public TextureCube Cube { get; set; } /// <summary> /// Gets or sets the pixel array. /// </summary> /// <value> /// The pixel array. /// </value> public Color[] PixelArray { get; set; } /// <summary> /// Gets or sets the cube faces. /// </summary> /// <value> /// The cube faces. /// </value> public Texture2D[] CubeFaces { get; set; } /// <summary> /// Gets or sets the vertex buffer. /// </summary> /// <value> /// The vertex buffer. /// </value> public VertexBuffer VertexBuffer { get; set; } /// <summary> /// Gets or sets the index buffer. /// </summary> /// <value> /// The index buffer. /// </value> public IndexBuffer IndexBuffer { get; set; } /// <summary> /// Gets or sets the effect. /// </summary> /// <value> /// The effect. /// </value> public BasicEffect Effect { get; set; } #endregion protected override void LoadContent() { } public override void Update(GameTime gameTime) { var camera = Game.GetService<GraphicManager>().CurrentCamera; this.Position = camera.Position + PositionOffset; base.Update(gameTime); } public override void Draw(GameTime gameTime) { DrawOrder = int.MaxValue; var graphics = Effect.GraphicsDevice; graphics.DepthStencilState = new DepthStencilState() { DepthBufferEnable = false }; graphics.RasterizerState = new RasterizerState() { CullMode = CullMode.None }; graphics.BlendState = new BlendState(); graphics.SamplerStates[0] = SamplerState.AnisotropicClamp; graphics.SetVertexBuffer(VertexBuffer); graphics.Indices = IndexBuffer; Effect.Texture = CubeFaces[0]; Effect.CurrentTechnique.Passes[0].Apply(); graphics.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, _vertices.Count, 0, 2); Effect.Texture = CubeFaces[1]; Effect.CurrentTechnique.Passes[0].Apply(); graphics.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, _vertices.Count, 6, 2); Effect.Texture = CubeFaces[2]; Effect.CurrentTechnique.Passes[0].Apply(); graphics.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, _vertices.Count, 12, 2); Effect.Texture = CubeFaces[3]; Effect.CurrentTechnique.Passes[0].Apply(); graphics.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, _vertices.Count, 18, 2); Effect.Texture = CubeFaces[4]; Effect.CurrentTechnique.Passes[0].Apply(); graphics.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, _vertices.Count, 24, 2); Effect.Texture = CubeFaces[5]; Effect.CurrentTechnique.Passes[0].Apply(); graphics.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, _vertices.Count, 30, 2); base.Draw(gameTime); } #region Fields private List<VertexPositionNormalTexture> _vertices = new List<VertexPositionNormalTexture>(); private List<ushort> _indices = new List<ushort>(); #endregion #region Private methods private void InitializeData(GraphicsDevice graphicsDevice) { VertexBuffer = new VertexBuffer(graphicsDevice, typeof(VertexPositionNormalTexture), _vertices.Count, BufferUsage.None); VertexBuffer.SetData<VertexPositionNormalTexture>(_vertices.ToArray()); // Create an index buffer, and copy our index data into it. IndexBuffer = new IndexBuffer(graphicsDevice, typeof(ushort), _indices.Count, BufferUsage.None); IndexBuffer.SetData<ushort>(_indices.ToArray()); // Create a BasicEffect, which will be used to render the primitive. Effect = new BasicEffect(graphicsDevice); Effect.TextureEnabled = true; Effect.EnableDefaultLighting(); } private void CreateGraphic(float size) { Vector3[] normals = { Vector3.Right, Vector3.Left, Vector3.Up, Vector3.Down, Vector3.Backward, Vector3.Forward, }; Vector2[] textureCoordinates = { Vector2.One, Vector2.UnitY, Vector2.Zero, Vector2.UnitX, Vector2.Zero, Vector2.UnitX, Vector2.One, Vector2.UnitY, Vector2.Zero, Vector2.UnitX, Vector2.One, Vector2.UnitY, Vector2.Zero, Vector2.UnitX, Vector2.One, Vector2.UnitY, Vector2.UnitY, Vector2.Zero, Vector2.UnitX, Vector2.One, Vector2.UnitY, Vector2.Zero, Vector2.UnitX, Vector2.One, }; var index = 0; foreach (var normal in normals) { var side1 = new Vector3(normal.Z, normal.X, normal.Y); var side2 = Vector3.Cross(normal, side1); AddIndex(CurrentVertex + 0); AddIndex(CurrentVertex + 1); AddIndex(CurrentVertex + 2); AddIndex(CurrentVertex + 0); AddIndex(CurrentVertex + 2); AddIndex(CurrentVertex + 3); AddVertex((normal - side1 - side2) * size / 2, normal, textureCoordinates[index++]); AddVertex((normal - side1 + side2) * size / 2, normal, textureCoordinates[index++]); AddVertex((normal + side1 + side2) * size / 2, normal, textureCoordinates[index++]); AddVertex((normal + side1 - side2) * size / 2, normal, textureCoordinates[index++]); } } protected void StripTexturesFromCube() { PixelArray = new Color[Cube.Size * Cube.Size]; for (int s = 0; s < CubeFaces.Length; s++) { CubeFaces[s] = new Texture2D(Game.GraphicsDevice, Cube.Size, Cube.Size, false, SurfaceFormat.Color); switch (s) { case 0: Cube.GetData<Color>(CubeMapFace.PositiveX, PixelArray); CubeFaces[s].SetData<Color>(PixelArray); break; case 1: Cube.GetData(CubeMapFace.NegativeX, PixelArray); CubeFaces[s].SetData(PixelArray); break; case 2: Cube.GetData(CubeMapFace.PositiveY, PixelArray); CubeFaces[s].SetData(PixelArray); break; case 3: Cube.GetData(CubeMapFace.NegativeY, PixelArray); CubeFaces[s].SetData(PixelArray); break; case 4: Cube.GetData(CubeMapFace.PositiveZ, PixelArray); CubeFaces[s].SetData(PixelArray); break; case 5: Cube.GetData(CubeMapFace.NegativeZ, PixelArray); CubeFaces[s].SetData(PixelArray); break; } } } protected void AddVertex(Vector3 position, Vector3 normal, Vector2 textureCoordinates) { _vertices.Add(new VertexPositionNormalTexture(position, normal, textureCoordinates)); } protected void AddIndex(int index) { if (index > ushort.MaxValue) throw new ArgumentOutOfRangeException("index"); _indices.Add((ushort)index); } protected int CurrentVertex { get { return _vertices.Count; } } #endregion } }

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  • Should you create a class within a method?

    - by Amndeep7
    I have made a program using Java that is an implementation of this project: http://nifty.stanford.edu/2009/stone-random-art/sml/index.html. Essentially, you create a mathematical expression and, using the pixel coordinate as input, make a picture. After I initially implemented this in serial, I then implemented it in parallel due to the fact that if the picture size is too large or if the mathematical expression is too complex (especially considering the fact that I made the expression recursively), it takes a really long time. During this process, I realized that I needed two classes which implemented the Runnable interface as I had to put in parameters for the run method, which you aren't allowed to do directly. One of these classes ended up being a medium sized static inner class (not large enough to make an independent class file for it though). The other though, just needed a few parameters to determine some indexes and the size of the for loop that I was making run in parallel - here it is: class DataConversionRunnable implements Runnable { int jj, kk, w; DataConversionRunnable(int column, int matrix, int wid) { jj = column; kk = matrix; w = wid; } public void run() { for(int i = 0; i < w; i++) colorvals[kk][jj][i] = (int) ((raw[kk][jj][i] + 1.0) * 255 / 2.0); increaseCounter(); } } My question is should I make it a static inner class or can I just create it in a method? What is the general programming convention followed in this case?

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  • Optimal sprite size for rotations

    - by Panda Pajama
    I am making a sprite based game, and I have a bunch of images that I get in a ridiculously large resolution and I scale them to the desired sprite size (for example 64x64 pixels) before converting them to a game resource, so when draw my sprite inside the game, I don't have to scale it. However, if I rotate this small sprite inside the game (engine agnostically), some destination pixels will get interpolated, and the sprite will look smudged. This is of course dependent on the rotation angle as well as the interpolation algorithm, but regardless, there is not enough data to correctly sample a specific destination pixel. So there are two solutions I can think of. The first is to use the original huge image, rotate it to the desired angles, and then downscale all the reaulting variations, and put them in an atlas, which has the advantage of being quite simple to implement, but naively consumes twice as much sprite space for each rotation (each rotation must be inscribed in a circle whose diameter is the diagonal of the original sprite's rectangle, whose area is twice of that original rectangle, supposing square sprites). It also has the disadvantage of only having a predefined set of rotations available, which may be okay or not depending on the game. So the other choice would be to store a larger image, and rotate and downscale while rendering, which leads to my question. What is the optimal size for this sprite? Optimal meaning that a larger image will have no effect in the resulting image. This is definitely dependent on the image size, the amount of desired rotations without data loss down to 1/256, which is the minimum representable color difference. I am looking for a theoretical general answer to this problem, because trying a bunch of sizes may be okay, but is far from optimal.

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  • Slick 2d scrolling off screen

    - by Peter
    I have something scrolling in and out of the screen. Now when it goes off screen, I want it to scroll into the screen at another location. What I do is I grab the last pixels at the screens edge using g.copyArea and then g.drawImage on the edge of the screen. And then I do a g.translate to create room for the next row which is next render cycle. My problem is that I get a single pixel row, which is not copied onto the canvas. Where as I want each row to be added and then translated, so that the image that scrolled off screen is recreated on the other side of the screen. Here is my code, maybe there is a better way of doing this, open to any suggests, cause I'm totally stuck @Override public void render(GameContainer gc, Graphics g) throws SlickException { //g.setClip(0, 0, 300, gc.getHeight()); g.translate(0, y); g.drawImage(image,0,200); g.resetTransform(); //g.clearClip(); g.copyArea(rightImage, 0, gc.getHeight() - 1); g.drawImage(rightImage, 300, 0); g.translate(0, y); y=y+3; }

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  • How do client-server cooperation based games like Diablo 3 work?

    - by edgar
    Diablo 3 cooperates with Blizzard servers even during single player games. In fact, Blizzard has had problems with the games "melting their servers." I would like to ask: How do the client and the server communicate? What details does the client leave to the server, and vice versa? What details are redundant - both the client and the server know - and how often do they disagree? The previous paragraph contains the important questions, but I have a few more that I must explain my motivation towards. I am interested in the programming of botting. Ethical botting - I don't plan on actually abusing the automation to run 24/7. I just find it to be a great programming challenge to glean information from a game, and then make decisions from that information. I am stuck in the starting gate. The unofficial questions from this post would be: How can I make a bot (language, tools, libraries)? Can I get information through the communication between client and server, rather than the brute force pixel detection easily used in more static games? There probably is a trust issue, and to that all I can say is that I promise not to abuse the answers. But please feel free to answer any of the questions you feel comfortable with. Thank you!

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  • Recasting and Drawing in SDL

    - by user1078123
    I have some code that essentially draws a column on the screen of a wall in a raycasting-type 3d engine. I am trying to optimize it, as it takes about 10 milliseconds do draw a million pixels using this, and the vast majority of game time is spent in this loop. However, I don't quite understand what's occurring, particularly the recasting (I modified the "pixel manipulation" sample code from the SDL documentation). "canvas" is the surface I am drawing to, and "hello" is the surface containing the texture for the column. int c = (curcol)* canvas->format->BytesPerPixel; void *canvaspixels = canvas->pixels; Uint16 texpitch = hello->pitch; int lim = (drawheight +startdraw) * canvpitch +c + (int) canvaspixels; Uint8 *k = (Uint8 *)hello->pixels + (hit)* hello->format->BytesPerPixel; for (int j= (startdraw)*(canvpitch)+c + (int) canvaspixels; (j< lim); j+= canvpitch){ Uint8 *q = (Uint8 *) ((int(h))*(texpitch)+k); *(Uint32 *)j = *(Uint32 *)q; h += s; } We have void pointers (not sure how those are even represented), 8, 16, and 32 bit ints (h and s are floats), all being intermingled, and while it works, it is quite confusing.

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  • 9 Gigapixel Photo Captures 84 Million Stars

    - by Jason Fitzpatrick
    The European Southern Observatory has released an absolutely enormous picture of the center of the Milky Way captured by their VISTA telescope–the image is 9 gigapixels and captures over 84 million stars. From the press release: The large mirror, wide field of view and very sensitive infrared detectors of ESO’s 4.1-metre Visible and Infrared Survey Telescope for Astronomy (VISTA) make it by far the best tool for this job. The team of astronomers is using data from the VISTA Variables in the Via Lactea programme (VVV), one of six public surveys carried out with VISTA. The data have been used to create a monumental 108 200 by 81 500 pixel colour image containing nearly nine billion pixels. This is one of the biggest astronomical images ever produced. The team has now used these data to compile the largest catalogue of the central concentration of stars in the Milky Way ever created. Want to check out all 9 billion glorious pixels in their uncompressed state? Be prepared to wait a bit, the uncompressed image is available for download but it weighs in at a massive 24.6GB. 84 Million Stars and Counting [via Wired] How Hackers Can Disguise Malicious Programs With Fake File Extensions Can Dust Actually Damage My Computer? What To Do If You Get a Virus on Your Computer

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  • Sponsored Giveaway: Free Copies of WinX DVD Copy Pro for All How-To Geek Readers

    - by The Geek
    Have you ever wanted to make a backup of a DVD, or even rip it to an ISO file to use on your computer without the original optical disc? You can use WinX DVD Copy Pro to make this happen, and we’ve got a giveaway for all HTG readers. To get your free copy, just click through the following link to download and get the license code, as long as you download it by December 20th. In addition, an iPhone / iPad Video Software Pack will be presented as the second round gift from December 21st to January 2nd, 2013. For Windows users: http://www.winxdvd.com/giveaway/ WinX DVD Copy Pro has many features, including this list, which we copied straight from their site: Supports latest released DVDs. Protect your DVD disc from damage. Copy DVD to DVD, ISO image, etc. 9 advanced DVD backup schemes. Support Disney’s Fake, scratched DVDs and Sony ARccOS bad sector. Secure Yourself by Using Two-Step Verification on These 16 Web Services How to Fix a Stuck Pixel on an LCD Monitor How to Factory Reset Your Android Phone or Tablet When It Won’t Boot

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  • Boolean checks with a single quadtree, or multiple quadtrees?

    - by Djentleman
    I'm currently developing a 2D sidescrolling shooter game for PC (think metroidvania but with a lot more happening at once). Using XNA. I'm utilising quadtrees for my spatial partitioning system. All objects will be encompassed by standard bounding geometry (box or sphere) with possible pixel-perfect collision detection implemented after geometry collision (depends on how optimised I can get it). These are my collision scenarios, with < representing object overlap (multiplayer co-op is the reason for the player<player scenario): Collision scenarios (true = collision occurs): Player <> Player = false Enemy <> Enemy = false Player <> Enemy = true PlayerBullet <> Enemy = true PlayerBullet <> Player = false PlayerBullet <> EnemyBullet = true PlayerBullet <> PlayerBullet = false EnemyBullet <> Player = true EnemyBullet <> Enemy = false EnemyBullet <> EnemyBullet = false Player <> Environment = true Enemy <> Environment = true PlayerBullet <> Environment = true EnemyBullet <> Environment = true Going off this information and the fact that were will likely be several hundred objects rendering on-screen at any given time, my question is as follows: Which method is likely to be the most efficient/optimised and why: Using a single quadtree with boolean checks for collision between the different types of objects. Using three quadtrees at once (player, enemy, environment), only testing the player and enemy trees against each other while testing both the player and enemy trees against the environment tree.

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  • how to get the update manager window visible?

    - by Max Waterman
    I can see from the launcher that the Update Manager is running - it has the little triangle by it. However, I am having trouble seeing the window. If I click on it from one desktop, it switches to another, so I assume that the Update Manager has its window on that other desktop, but it still doesn't show anything. If I click alt-tab to switch between apps, I can see that the Update Manager is there, but selecting it just shows me a blank screen. Also, when I select it, while still holding the alt-key, I see the top menu bar switch to 'Update Manager', but when I release alt, it changes back to Ubuntu Desktop. It's almost like the app is off the screen somewhere, perhaps with just a single pixel showing or something like that. disclaimer: One thing that might be affecting things is that I have 'focus follows mouse' configured, which makes things a bit funky with the menu not being on the window, where it should be (perhaps there's a way to put it back with the window?) - I like to be able to type into background windows, and manually control which window is in the foreground.

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  • Frame Independent Movement

    - by ShrimpCrackers
    I've read two other threads here on movement: Time based movement Vs Frame rate based movement?, and Fixed time step vs Variable time step but I think I'm lacking a basic understanding of frame independent movement because I don't understand what either of those threads are talking about. I'm following along with lazyfoo's SDL tutorials and came upon the frame independent lesson. http://lazyfoo.net/SDL_tutorials/lesson32/index.php I'm not sure what the movement part of the code is trying to say but I think it's this (please correct me if I'm wrong): In order to have frame independent movement, we need to find out how far an object (ex. sprite) moves within a certain time frame, for example 1 second. If the dot moves at 200 pixels per second, then I need to calculate how much it moves within that second by multiplying 200 pps by 1/1000 of a second. Is that right? The lesson says: "velocity in pixels per second * time since last frame in seconds. So if the program runs at 200 frames per second: 200 pps * 1/200 seconds = 1 pixel" But...I thought we were multiplying 200 pps by 1/1000th of a second. What is this business with frames per second? I'd appreciate if someone could give me a little bit more detailed explanation as to how frame independent movement works. Thank you.

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  • Moviebarcodes Showcases Entire Movies as Frame-based Barcodes

    - by Jason Fitzpatrick
    If you’ve ever wanted a chance to look at at an entire movie in a single glance, here’s your chance. Moviebarcodes shares mock-barcodes generated by turning each frame of a movie into a thin stripe, offering a glimpse into the color choices and shot lengths in popular movies. The barcode seen above was generated from The Matrix; you can see where the green indicates scenes that were shot inside the matrix and thus given a subtle green tint. In the barcode below, generated from the movie Pleasantville you can see the transition in the movie between the color and black and white scenes. In the case of Pleasantville, elements of the black and white world turning to color represent pivotal moments in the plot development which are now neatly mapped out below: Check out the hundreds of barcodes at the link below; you can even order prints of your favorite movies. Find a great rendering in the mix? Share a link in the comments below. Moviebarcodes [via Cool Inforgraphics] How to Create an Easy Pixel Art Avatar in Photoshop or GIMPInternet Explorer 9 Released: Here’s What You Need To KnowHTG Explains: How Does Email Work?

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  • Big level objects collision system for 2d game

    - by Aristarhys
    I read many variants today and get some knowledge in general, so here is a steps of mine thoughts in pictures (horrible paint.net ones). We need to develop grid system, so we check only thing near, perform simple check to cut out deep check, and at - last deep check like per-pixel collision check. Step 1 - Let p1, p2 are some sprites lets first just check with circle collision - because large distance between p1, p2 this fails and of course so we don't need test more deeply. But if we have not 2, but 20 objects, why we need to even circle test something so far outside of our view. Step 2 - Add basic column system, now we don't bother with p2 if it's in a column far from p1 column, so we even don't do circle test. But p3 is in the same col, so let do circle test, which of course will fail. Step 3 - Lets improve column system to the grid system with grid cell size just like p1, p2, p3 collision boxes, so we cut out things much top or below p1. And this is all great until comes BIG OBJs which is some kind of platforms. They are much bigger then grid cell. Circle test for will be successful, but deep check for whole big obj will fail And that the part I can't get. How do I store the grid position of big object? Like 4 grid coords for big object vertexes? And if one of them close to p1 do circle check for centre of big object then a deep one if succeed? Am I do it wrong? My possible solution:

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  • How-To Geek is Hiring a Geeky Writer – Here Are the Details

    - by The Geek
    Think you have the perfect combination of geek knowledge and writing skills? We’re looking for an experienced writer to join our team, and here are all the details. We need a new writer to cover topics surrounding Windows 7 or 8, home networking, home routers, security, media, troubleshooting, mobile devices, and many similar topics. We are not looking for writers that focus solely on Linux or tech news writers. Please apply if you have the following qualities: You must be a geek at heart. You must be able to put in plenty of time, work, and dedication. If you’re too busy already, don’t apply. You must be able to write articles that are easy to understand. You must be creative. You must generate ideas for articles on your own, and take suggestions like a pro. You must be at least 18 years old. You must have solid English writing skills. You must be able to write tips, how-to articles, explainers, guides, instructional articles, etc. Again, we are not looking for tech news writers. Here’s a couple of our previous articles so you can get an idea of what we’re looking for in terms of quality and content. Please make sure to look through these before you decide to apply. How-to Article: Make Your Own Windows 8 Start Button with Zero Memory Usage Explainer: HTG Explains: When Do You Need to Update Your Drivers? Explainer: HTG Explains: Why Do Hard Drives Show the Wrong Capacity in Windows? How-To Article: How to Factory Reset Your Android Phone or Tablet When It Won’t Boot How to Fix a Stuck Pixel on an LCD Monitor How to Factory Reset Your Android Phone or Tablet When It Won’t Boot Our Geek Trivia App for Windows 8 is Now Available Everywhere

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  • HLSL What you get when you subtract world position from InvertViewProjection.Transform?

    - by cubrman
    In one of NVIDIA's Vertex shaders (the metal one) I found the following code: // transform object normals, tangents, & binormals to world-space: float4x4 WorldITXf : WorldInverseTranspose < string UIWidget="None"; >; // provide tranform from "view" or "eye" coords back to world-space: float4x4 ViewIXf : ViewInverse < string UIWidget="None"; >; ... float4 Po = float4(IN.Position.xyz,1); // homogeneous location coordinates float4 Pw = mul(Po,WorldXf); // convert to "world" space OUT.WorldView = normalize(ViewIXf[3].xyz - Pw.xyz); The term OUT.WorldView is subsequently used in a Pixel Shader to compute lighting: float3 Ln = normalize(IN.LightVec.xyz); float3 Nn = normalize(IN.WorldNormal); float3 Vn = normalize(IN.WorldView); float3 Hn = normalize(Vn + Ln); float4 litV = lit(dot(Ln,Nn),dot(Hn,Nn),SpecExpon); DiffuseContrib = litV.y * Kd * LightColor + AmbiColor; SpecularContrib = litV.z * LightColor; Can anyone tell me what exactly is WorldView here? And why do they add it to the normal?

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  • Processing Kinect v2 Color Streams in Parallel

    - by Chris Gardner
    Originally posted on: http://geekswithblogs.net/freestylecoding/archive/2014/08/20/processing-kinect-v2-color-streams-in-parallel.aspxProcessing Kinect v2 Color Streams in Parallel I've really been enjoying being a part of the Kinect for Windows Developer's Preview. The new hardware has some really impressive capabilities. However, with great power comes great system specs. Unfortunately, my little laptop that could is not 100% up to the task; I've had to get a little creative. The most disappointing thing I've run into is that I can't always cleanly display the color camera stream in managed code. I managed to strip the code down to what I believe is the bear minimum: using( ColorFrame _ColorFrame = e.FrameReference.AcquireFrame() ) { if( null == _ColorFrame ) return;   BitmapToDisplay.Lock(); _ColorFrame.CopyConvertedFrameDataToIntPtr( BitmapToDisplay.BackBuffer, Convert.ToUInt32( BitmapToDisplay.BackBufferStride * BitmapToDisplay.PixelHeight ), ColorImageFormat.Bgra ); BitmapToDisplay.AddDirtyRect( new Int32Rect( 0, 0, _ColorFrame.FrameDescription.Width, _ColorFrame.FrameDescription.Height ) ); BitmapToDisplay.Unlock(); } With this snippet, I'm placing the converted Bgra32 color stream directly on the BackBuffer of the WriteableBitmap. This gives me pretty smooth playback, but I still get the occasional freeze for half a second. After a bit of profiling, I discovered there were a few problems. The first problem is the size of the buffer along with the conversion on the buffer. At this time, the raw image format of the data from the Kinect is Yuy2. This is great for direct video processing. It would be ideal if I had a WriteableVideo object in WPF. However, this is not the case. Further digging led me to the real problem. It appears that the SDK is converting the input serially. Let's think about this for a second. The color camera is a 1080p camera. As we should all know, this give us a native resolution of 1920 x 1080. This produces 2,073,600 pixels. Yuy2 uses 4 bytes per 2 pixel, for a buffer size of 4,147,200 bytes. Bgra32 uses 4 bytes per pixel, for a buffer size of 8,294,400 bytes. The SDK appears to be doing this on one thread. I started wondering if I chould do this better myself. I mean, I have 8 cores in my system. Why can't I use them all? The first problem is converting a Yuy2 frame into a Bgra32 frame. It is NOT trivial. I spent a day of research of just how to do this. In the end, I didn't even produce the best algorithm possible, but it did work. After I managed to get that to work, I knew my next step was the get the conversion operation off the UI Thread. This was a simple process of throwing the work into a Task. Of course, this meant I had to marshal the final write to the WriteableBitmap back to the UI thread. Finally, I needed to vectorize the operation so I could run it safely in parallel. This was, mercifully, not quite as hard as I thought it would be. I had my loop return an index to a pair of pixels. From there, I had to tell the loop to do everything for this pair of pixels. If you're wondering why I did it for pairs of pixels, look back above at the specification for the Yuy2 format. I won't go into full detail on why each 4 bytes contains 2 pixels of information, but rest assured that there is a reason why the format is described in that way. The first working attempt at this algorithm successfully turned my poor laptop into a space heater. I very quickly brought and maintained all 8 cores up to about 97% usage. That's when I remembered that obscure option in the Task Parallel Library where you could limit the amount of parallelism used. After a little trial and error, I discovered 4 parallel tasks was enough for most cases. This yielded the follow code: private byte ClipToByte( int p_ValueToClip ) { return Convert.ToByte( ( p_ValueToClip < byte.MinValue ) ? byte.MinValue : ( ( p_ValueToClip > byte.MaxValue ) ? byte.MaxValue : p_ValueToClip ) ); }   private void ColorFrameArrived( object sender, ColorFrameArrivedEventArgs e ) { if( null == e.FrameReference ) return;   // If you do not dispose of the frame, you never get another one... using( ColorFrame _ColorFrame = e.FrameReference.AcquireFrame() ) { if( null == _ColorFrame ) return;   byte[] _InputImage = new byte[_ColorFrame.FrameDescription.LengthInPixels * _ColorFrame.FrameDescription.BytesPerPixel]; byte[] _OutputImage = new byte[BitmapToDisplay.BackBufferStride * BitmapToDisplay.PixelHeight]; _ColorFrame.CopyRawFrameDataToArray( _InputImage );   Task.Factory.StartNew( () => { ParallelOptions _ParallelOptions = new ParallelOptions(); _ParallelOptions.MaxDegreeOfParallelism = 4;   Parallel.For( 0, Sensor.ColorFrameSource.FrameDescription.LengthInPixels / 2, _ParallelOptions, ( _Index ) => { // See http://msdn.microsoft.com/en-us/library/windows/desktop/dd206750(v=vs.85).aspx int _Y0 = _InputImage[( _Index << 2 ) + 0] - 16; int _U = _InputImage[( _Index << 2 ) + 1] - 128; int _Y1 = _InputImage[( _Index << 2 ) + 2] - 16; int _V = _InputImage[( _Index << 2 ) + 3] - 128;   byte _R = ClipToByte( ( 298 * _Y0 + 409 * _V + 128 ) >> 8 ); byte _G = ClipToByte( ( 298 * _Y0 - 100 * _U - 208 * _V + 128 ) >> 8 ); byte _B = ClipToByte( ( 298 * _Y0 + 516 * _U + 128 ) >> 8 );   _OutputImage[( _Index << 3 ) + 0] = _B; _OutputImage[( _Index << 3 ) + 1] = _G; _OutputImage[( _Index << 3 ) + 2] = _R; _OutputImage[( _Index << 3 ) + 3] = 0xFF; // A   _R = ClipToByte( ( 298 * _Y1 + 409 * _V + 128 ) >> 8 ); _G = ClipToByte( ( 298 * _Y1 - 100 * _U - 208 * _V + 128 ) >> 8 ); _B = ClipToByte( ( 298 * _Y1 + 516 * _U + 128 ) >> 8 );   _OutputImage[( _Index << 3 ) + 4] = _B; _OutputImage[( _Index << 3 ) + 5] = _G; _OutputImage[( _Index << 3 ) + 6] = _R; _OutputImage[( _Index << 3 ) + 7] = 0xFF; } );   Application.Current.Dispatcher.Invoke( () => { BitmapToDisplay.WritePixels( new Int32Rect( 0, 0, Sensor.ColorFrameSource.FrameDescription.Width, Sensor.ColorFrameSource.FrameDescription.Height ), _OutputImage, BitmapToDisplay.BackBufferStride, 0 ); } ); } ); } } This seemed to yield a results I wanted, but there was still the occasional stutter. This lead to what I realized was the second problem. There is a race condition between the UI Thread and me locking the WriteableBitmap so I can write the next frame. Again, I'm writing approximately 8MB to the back buffer. Then, I started thinking I could cheat. The Kinect is running at 30 frames per second. The WPF UI Thread runs at 60 frames per second. This made me not feel bad about exploiting the Composition Thread. I moved the bulk of the code from the FrameArrived handler into CompositionTarget.Rendering. Once I was in there, I polled from a frame, and rendered it if it existed. Since, in theory, I'm only killing the Composition Thread every other hit, I decided I was ok with this for cases where silky smooth video performance REALLY mattered. This ode looked like this: private byte ClipToByte( int p_ValueToClip ) { return Convert.ToByte( ( p_ValueToClip < byte.MinValue ) ? byte.MinValue : ( ( p_ValueToClip > byte.MaxValue ) ? byte.MaxValue : p_ValueToClip ) ); }   void CompositionTarget_Rendering( object sender, EventArgs e ) { using( ColorFrame _ColorFrame = FrameReader.AcquireLatestFrame() ) { if( null == _ColorFrame ) return;   byte[] _InputImage = new byte[_ColorFrame.FrameDescription.LengthInPixels * _ColorFrame.FrameDescription.BytesPerPixel]; byte[] _OutputImage = new byte[BitmapToDisplay.BackBufferStride * BitmapToDisplay.PixelHeight]; _ColorFrame.CopyRawFrameDataToArray( _InputImage );   ParallelOptions _ParallelOptions = new ParallelOptions(); _ParallelOptions.MaxDegreeOfParallelism = 4;   Parallel.For( 0, Sensor.ColorFrameSource.FrameDescription.LengthInPixels / 2, _ParallelOptions, ( _Index ) => { // See http://msdn.microsoft.com/en-us/library/windows/desktop/dd206750(v=vs.85).aspx int _Y0 = _InputImage[( _Index << 2 ) + 0] - 16; int _U = _InputImage[( _Index << 2 ) + 1] - 128; int _Y1 = _InputImage[( _Index << 2 ) + 2] - 16; int _V = _InputImage[( _Index << 2 ) + 3] - 128;   byte _R = ClipToByte( ( 298 * _Y0 + 409 * _V + 128 ) >> 8 ); byte _G = ClipToByte( ( 298 * _Y0 - 100 * _U - 208 * _V + 128 ) >> 8 ); byte _B = ClipToByte( ( 298 * _Y0 + 516 * _U + 128 ) >> 8 );   _OutputImage[( _Index << 3 ) + 0] = _B; _OutputImage[( _Index << 3 ) + 1] = _G; _OutputImage[( _Index << 3 ) + 2] = _R; _OutputImage[( _Index << 3 ) + 3] = 0xFF; // A   _R = ClipToByte( ( 298 * _Y1 + 409 * _V + 128 ) >> 8 ); _G = ClipToByte( ( 298 * _Y1 - 100 * _U - 208 * _V + 128 ) >> 8 ); _B = ClipToByte( ( 298 * _Y1 + 516 * _U + 128 ) >> 8 );   _OutputImage[( _Index << 3 ) + 4] = _B; _OutputImage[( _Index << 3 ) + 5] = _G; _OutputImage[( _Index << 3 ) + 6] = _R; _OutputImage[( _Index << 3 ) + 7] = 0xFF; } );   BitmapToDisplay.WritePixels( new Int32Rect( 0, 0, Sensor.ColorFrameSource.FrameDescription.Width, Sensor.ColorFrameSource.FrameDescription.Height ), _OutputImage, BitmapToDisplay.BackBufferStride, 0 ); } }

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  • Problem with alleg42.dll / program crashes / Allegro & Codeblocks

    - by user24152
    I'm having a serious problem with allegro. The program should display random pixels on the screen and when I build and run it I get the following error message: Below is the full code of my program: #include <stdio.h> #include <stdlib.h> #include <time.h> #include "allegro.h" #define Text_Color_Red makecol(255,0,0) int main() { int ret; int color_depth = 32; int x; int y; int red; int green; int blue; int color; //init allegro allegro_init(); //install keyboard install_keyboard(); //set color depth to 32 bits set_color_depth(color_depth); //init random seed srand(time(NULL)); //init video mode to 640 x 480 ret = set_gfx_mode(GFX_AUTODETECT_WINDOWED,640,480,0,0); if(ret !=0) { allegro_message(allegro_error); return 1; } //Display string textprintf(screen,font,0,0,10,0,Text_Color_Red,"Screen Resolution is: %dx%d -- Press ESC to quit !",SCREEN_W,SCREEN_H); //display pixels until ESC key is pressed //wait for keypress while(!key[KEY_ESC]) { //set a random location x = 10 + rand() % (SCREEN_W-20); y = 10 + rand() % (SCREEN_H-20); //set a random color red = rand() % 255; green = rand() % 255; blue = rand() % 255; color = makecol(red,green,blue); //draw the pixel putpixel(screen, x, y, color); } //quit allegro allegro_exit(); } END_OF_MAIN() Error message: AllegroPixels1.exe has encountered a problem and needs to close. We are sorry for the inconvenience. Error signature: AppName: allegropixels1.exe AppVer: 0.0.0.0 ModName: alleg42.dll ModVer: 4.2.3.0 Offset: 0006c05c I am using Windows XP inside a virtual machine under Parallels 7.0

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  • SEO and external sites that serve responsive images (like Re-SRC)

    - by Baumr
    Re-SRC is a tool that allows you to automatically serve responsive images for your website from their cloud servers. It delivers a new image file each time the browser window (viewport) is resized. To use it in your HTML when linking to an image, you would do the following: <img src="http://app.resrc.it//www.your-domain.com/img/img001.jpg"/> Some more background for SEO considerations: As an example, looking at their demo page's code, the src of the Arc de Triomphe photo — when the browser window is resized to be at a tablet-width — shows this particular file at it's widest. It is found under the following URL: http://app4-uk.resrc.it/s=w560,pd1/ro=h//www.resrc.it/img/demo/demo-image-1.jpg If the viewport is increased to desktop-width, then a smaller image is served in line with the design; see this URL: http://app4-uk.resrc.it/s=w320,pd1/ro=h//www.resrc.it/img/demo/demo-image-1.jpg If I change the viewport to be about half-way between those two, then the image's URL is: http://app4-uk.resrc.it/s=w240,pd1/ro=h//www.resrc.it/img/demo/demo-image-1.jpg In other words, I found that there is a separate file for every 10-pixel increment of the image width. Very cool for saving bandwidth on mobile devices and service responsive/retina images on others, but... Here are two problems I see for SEO: The img on your site, part of your semantic markup, will not be hosted on your site at all, or even a server you control. Any links to these images will pass on "link juice" to Re-SRC's site instead. You are serving a vast array of different image files to different people — some may link to one, others to another size. Then there's the question of what different search engine crawlers will see. Also: There seems to be no fallback option if their servers are down. Do you see any other concerns? Or, perhaps, do you not see those as concerns?

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  • Improving the efficiency of my bloom/glow shader

    - by user1157885
    I'm making a neon style game where everything is glowing but the glow I have is kinda small and I want to know if there's an efficient way to increase the size of it other than increasing the pixel sample iterations. Right now I have something like this: float4 glowColor = tex2D(glowSampler, uvPixel); //Makes the inital lines brighter/closer to white if (glowColor.r != 0 || glowColor.g != 0 || glowColor.b != 0) { glowColor += 0.5; } //Loops over the weights and offsets and samples from the pixels based on those numbers for (int i = 0; i < 20; i++) { glowColor += tex2D(glowSampler, uvPixel + glowOffsets[i] + 0.0018) * glowWeights[i]; } finalColor += glowColor; for the offsets it moves up, down, left and right (5 times each so it loops over 20 times) and the weights just lower the glow amount the further away it gets. The method I was using before to increase it was to increase the number of iterations from 20 to 40 and to increase the size of the offset/weight array but my computer started to have FPS drops when I was doing this so I was wondering how can I make the glow bigger/more vibrant without making it so CPU/Gcard intensive?

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  • Implications of Multiple JobTracker nodes in a Hadoop cluster?

    - by Jim Dennis
    I get the impression that one can, potentially, have multiple JobTracker nodes configured to share the same set of MR (TaskTracker) nodes. I know that, conventionally, all the nodes in a Hadoop cluster should have the same set of configuration files (conventionally under /etc/hadoop/conf/ --- at least for the Cloudera Distribution of Hadoop (CDH). Can we define multiple Job Trackers in mapred-site.xml? Something like: <configuration> <property> <name>mapred.job.tracker</name> <value>jt01.mydomain.not:8021</value> </property> <property> <name>mapred.job.tracker</name> <value>jt02.mydomain.not:8021</value> </property> ... </configuration> Or is there some other allowed syntax for this? What are the implications of doing this. Does each JobTracker get information about the load on each TaskTracker node. In other words can the two JobTracker co-ordinated their scheduling across the TT nodes only based on the gossip information from the TTs or would they need to talk to one another? Is this documented anywhere?

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  • is wisdom of what happens 'behind scenes' (in compiler, external DLLs etc.) important?

    - by I_Question_Things_Deeply
    I have been a computer-fanatic for almost a decade now. I've always loved and wondered how computers work, even from the purest, lowest hardware level to the very smallest pixel on the screen, and all the software around that. That seems to be my problem though ... as I try to write code (I'm pretty fluent at C++) I always sit there enormous amounts of time in front of a text-editor wondering how every line, statement, datum, function, etc. will correspond to every Assembly and machine instruction performed to do absolutely everything necessary for the kernel to allocate memory to run my compiled program, and all of the other hardware being used as well. For example ... I would write cout << "Before memory changed" << endl; and run the debugger to get the Assembly for this, and then try and reverse disassemble the Assembly to machine code based on my ISA, and then research every .dll, library file, linked library, linking process, linker source code of the program, the make file, the kernel I'm using's steps of processing this compilation, the hardware's part aside from the processor (e.g. video card, sound card, chipset, cache latency, byte-sized registers, calling convention use, DDR3 RAM and disk drive, filesystem functioning and so many other things). Am I going about programming wrong? I mean I feel I should know everything that goes on underneath English syntax on a computer program. But the problem is that the more I research every little thing the less I actually accomplish at all. I can never finish anything because of this mentality, yet I feel compelled to know everything... what should I do?

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  • How to run around another football player

    - by Lumis
    I have finished a simple 2D one-on-one indoor football Android game. The thing that it seemed so simple to me, a human being, turned out to be difficult for a computer: how to go around the opponent … At the moment the game logic of the computer player is that if it hits into the human player will step back few points on the pixel greed and then try again to go towards the ball. The problem is if the human player is in-between then the computer player will oscillate in one place, which does not look very nice and the human opponent can use this weakness to control the game. You can see this in the photo – at the moment the computer will go along the red line indefinitely. I tried few ideas but it proved not easy to do it when both the human player and the ball are constantly moving so at each step computer would change directions and “oscillate” again. Once when the computer player reaches the ball it will kick it with certain amount of random strength and direction towards the human’s goal. The question here is how to formulate the logic of going around the ever moving human opponent and how to translate it into the co-ordinate system and frame by frame animation… any suggestions welcome.

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  • What guidelines should be followed when implementing third-party tracking pixels?

    - by Strozykowski
    Background I work on a website that gets a fair amount of traffic, and as such, we have implemented different tracking pixels and techniques across the site for various specific reasons. Because there are many agencies who are sending traffic our way through email campaigns, print ads and SEM, we have agreements with a variety of different outside agencies for tracking these page hits. Consequently, we have tracking pixels which span the entire site, as well as some that are on specific pages only. We have worked to reduce the total number of pixels available on any one page, but occasionally the site is rendered close to unusable when one of these third-party tracking pixels fails to load. This is a huge difficulty on parts of the site where Javascript is needed for functionality built into the page, but is unable to initialize until a 404 is returned on the external tracking pixel. (Sometimes up to 30 seconds later) I have spent some time attempting to research how other firms deal with this sort of instability with third-party components, but have come up a bit short. The plan currently is to implement our own stop-gap method to deal with these external outages, but rather than reinventing the wheel, we wanted to find out how this is dealt with on other sites. Question Is there a good set of guidelines that should be followed when implementing third-party tracking pixels? I would love to see some white papers or other written documents about how other people have dealt with this issue.

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  • Rendering multiple squares fast?

    - by Sam
    so I'm doing my first steps with openGL development on android and I'm kinda stuck at some serious performance issues... What I'm trying to do is render a whole grid of single colored squares on to the screen and I'm getting framerates of ~7FPS. The squares are 9px in size right now with one pixel border in between, so I get a few thousand of them. I have a class "Square" and the Renderer iterates over all Squares every frame and calls the draw() method of each (just the iteration is fast enough, with no openGL code the whole thing runs smootlhy at 60FPS). Right now the draw() method looks like this: // Prepare the square coordinate data GLES20.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX, GLES20.GL_FLOAT, false, vertexStride, vertexBuffer); // Set color for drawing the square GLES20.glUniform4fv(mColorHandle, 1, color, 0); // Draw the square GLES20.glDrawElements(GLES20.GL_TRIANGLES, drawOrder.length, GLES20.GL_UNSIGNED_SHORT, drawListBuffer); So its actually only 3 openGL calls. Everything else (loading shaders, filling buffers, getting appropriate handles, etc.) is done in the Constructor and things like the Program and the handles are also static attributes. What am I missing here, why is it rendering so slow? I've also tried loading the buffer data into VBOs, but this is actually slower... Maybe I did something wrong though. Any help greatly appreciated! :)

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  • Approaches for a clickable map of nations (such as a Risk game) with Spritekit

    - by Vukovitch
    I would like to create a political map where each country is clickable by tapping but I'm not sure the best way to determine which nation was selected. Imagine Risk where each country can be individually clicked to bring up additional information. My current approach is to make a sprite for each nation where every image is the size of the screen The images are mostly transparent except for the country, that way when all of the images are displayed the countries are in the correct place relative to one another. To determine if a click occurs on an individual country I look to see if the tapped location is a non transparent pixel and check that the sprite's name is one of the countries. Additionally the nation needs to glow or something when tapped as an indicator, however my current solution is yet another sprite that is displayed. This seems like a terrible approach and I was wondering what other solutions might achieve the same results. I'm pretty new to SpriteKit so I'm not entirely sure. The other idea I had was creating a single texture where each country is a different shade of gray, then when I get the tap location I do a lookup on the color at that location and get the corresponding country. However, I'm not sure how to create a hilight or glowing country effect with that method.

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