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  • Sudo and startup script

    - by Pitto
    Hello my friends. I have a new asus 1215n and I need to digit commands to enable multitouch. No problem: I've made a script. Since this netbook also need manual activation of the wifi driver the complete script is: #!/bin/bash # # list of synaptics device properties http://www.x.org/archive/X11R7.5/doc/man/man4/synaptics.4.html#sect4 # list current synaptics device properties: xinput list-props '"SynPS/2 Synaptics TouchPad"' # sleep 5 #added delay... xinput set-int-prop "SynPS/2 Synaptics TouchPad" "Device Enabled" 8 1 xinput --set-prop --type=int --format=32 "SynPS/2 Synaptics TouchPad" "Synaptics Two-Finger Pressure" 4 xinput --set-prop --type=int --format=32 "SynPS/2 Synaptics TouchPad" "Synaptics Two-Finger Width" 9 # Below width 1 finger touch, above width simulate 2 finger touch. - value=pad-pixels xinput --set-prop --type=int --format=8 "SynPS/2 Synaptics TouchPad" "Synaptics Edge Scrolling" 1 1 0 # vertical, horizontal, corner - values: 0=disable 1=enable xinput --set-prop --type=int --format=32 "SynPS/2 Synaptics TouchPad" "Synaptics Jumpy Cursor Threshold" 250 # stabilize 2 finger actions - value=pad-pixels #xinput --set-prop --type=int --format=8 "SynPS/2 Synaptics TouchPad" "Synaptics Tap Action" 0 0 0 0 1 2 3 # pad corners rt rb lt lb tap fingers 1 2 3 (can't simulate more then 2 tap fingers AFAIK) - values: 0=disable 1=left 2=middle 3=right etc. (in FF 8=back 9=forward) xinput --set-prop --type=int --format=8 "SynPS/2 Synaptics TouchPad" "Synaptics Two-Finger Scrolling" 1 0 # vertical scrolling, horizontal scrolling - values: 0=disable 1=enable #xinput --set-prop --type=int --format=8 "SynPS/2 Synaptics TouchPad" "Synaptics Circular Scrolling" 1 #xinput --set-prop --type=int --format=8 "SynPS/2 Synaptics TouchPad" "Synaptics Circular Scrolling Trigger" 3 sudo modprobe lib80211 sudo insmod /home/pitto/Drivers/broadcom/wl.ko exit I've saved the script, then put it in my home, then chmod +x scriptname and then added it to startup applications. Then I did: sudo visudo and added this row: myusername ALL=(ALL) NOPASSWD: /home/scriptname rebooted and... Multitouch works but wifi not. When I manually launch the script it asks for sudo password so I thought it was because of modprobe and insmod commands and I've added those commands to sudo visudo. Nothing. What am I doing wrong?

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  • Multitouch script (using xinput) no longer working

    - by Pitto
    #!/bin/bash # # list of synaptics device properties http://www.x.org/archive/X11R7.5/doc/man/man4/synaptics.4.html#sect4 # list current synaptics device properties: xinput list-props '"SynPS/2 Synaptics TouchPad"' # sleep 5 #added delay... xinput set-int-prop "SynPS/2 Synaptics TouchPad" "Device Enabled" 8 1 xinput --set-prop --type=int --format=32 "SynPS/2 Synaptics TouchPad" "Synaptics Two-Finger Pressure" 4 xinput --set-prop --type=int --format=32 "SynPS/2 Synaptics TouchPad" "Synaptics Two-Finger Width" 9 # Below width 1 finger touch, above width simulate 2 finger touch. - value=pad-pixels xinput --set-prop --type=int --format=8 "SynPS/2 Synaptics TouchPad" "Synaptics Edge Scrolling" 1 1 0 # vertical, horizontal, corner - values: 0=disable 1=enable xinput --set-prop --type=int --format=32 "SynPS/2 Synaptics TouchPad" "Synaptics Jumpy Cursor Threshold" 250 # stabilize 2 finger actions - value=pad-pixels #xinput --set-prop --type=int --format=8 "SynPS/2 Synaptics TouchPad" "Synaptics Tap Action" 0 0 0 0 1 2 3 # pad corners rt rb lt lb tap fingers 1 2 3 (can't simulate more then 2 tap fingers AFAIK) - values: 0=disable 1=left 2=middle 3=right etc. (in FF 8=back 9=forward) xinput --set-prop --type=int --format=8 "SynPS/2 Synaptics TouchPad" "Synaptics Two-Finger Scrolling" 1 0 # vertical scrolling, horizontal scrolling - values: 0=disable 1=enable #xinput --set-prop --type=int --format=8 "SynPS/2 Synaptics TouchPad" "Synaptics Circular Scrolling" 1 #xinput --set-prop --type=int --format=8 "SynPS/2 Synaptics TouchPad" "Synaptics Circular Scrolling Trigger" 3 Hello everybody... The above script allowed me to use happily multitouch for a month... Now if I do a two fingers scrolling the mouse cursor just runs on the screen like possessed... Any hints?

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  • Vertex buffer acting strange? [on hold]

    - by Ryan Capote
    I'm having a strange problem, and I don't know what could be causing it. My current code is identical to how I've done this before. I'm trying to render a rectangle using VBO and orthographic projection.   My results:     What I expect: 3x3 rectangle in the top left corner   #include <stdio.h> #include <GL\glew.h> #include <GLFW\glfw3.h> #include "lodepng.h"   static const int FALSE = 0; static const int TRUE = 1;   static const char* VERT_SHADER =     "#version 330\n"       "layout(location=0) in vec4 VertexPosition; "     "layout(location=1) in vec2 UV;"     "uniform mat4 uProjectionMatrix;"     /*"out vec2 TexCoords;"*/       "void main(void) {"     "    gl_Position = uProjectionMatrix*VertexPosition;"     /*"    TexCoords = UV;"*/     "}";   static const char* FRAG_SHADER =     "#version 330\n"       /*"uniform sampler2D uDiffuseTexture;"     "uniform vec4 uColor;"     "in vec2 TexCoords;"*/     "out vec4 FragColor;"       "void main(void) {"    /* "    vec4 texel = texture2D(uDiffuseTexture, TexCoords);"     "    if(texel.a <= 0) {"     "         discard;"     "    }"     "    FragColor = texel;"*/     "    FragColor = vec4(1.f);"     "}";   static int g_running; static GLFWwindow *gl_window; static float gl_projectionMatrix[16];   /*     Structures */ typedef struct _Vertex {     float x, y, z, w;     float u, v; } Vertex;   typedef struct _Position {     float x, y; } Position;   typedef struct _Bitmap {     unsigned char *pixels;     unsigned int width, height; } Bitmap;   typedef struct _Texture {     GLuint id;     unsigned int width, height; } Texture;   typedef struct _VertexBuffer {     GLuint bufferObj, vertexArray; } VertexBuffer;   typedef struct _ShaderProgram {     GLuint vertexShader, fragmentShader, program; } ShaderProgram;   /*   http://en.wikipedia.org/wiki/Orthographic_projection */ void createOrthoProjection(float *projection, float width, float height, float far, float near)  {       const float left = 0;     const float right = width;     const float top = 0;     const float bottom = height;          projection[0] = 2.f / (right - left);     projection[1] = 0.f;     projection[2] = 0.f;     projection[3] = -(right+left) / (right-left);     projection[4] = 0.f;     projection[5] = 2.f / (top - bottom);     projection[6] = 0.f;     projection[7] = -(top + bottom) / (top - bottom);     projection[8] = 0.f;     projection[9] = 0.f;     projection[10] = -2.f / (far-near);     projection[11] = (far+near)/(far-near);     projection[12] = 0.f;     projection[13] = 0.f;     projection[14] = 0.f;     projection[15] = 1.f; }   /*     Textures */ void loadBitmap(const char *filename, Bitmap *bitmap, int *success) {     int error = lodepng_decode32_file(&bitmap->pixels, &bitmap->width, &bitmap->height, filename);       if (error != 0) {         printf("Failed to load bitmap. ");         printf(lodepng_error_text(error));         success = FALSE;         return;     } }   void destroyBitmap(Bitmap *bitmap) {     free(bitmap->pixels); }   void createTexture(Texture *texture, const Bitmap *bitmap) {     texture->id = 0;     glGenTextures(1, &texture->id);     glBindTexture(GL_TEXTURE_2D, texture);       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);       glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, bitmap->width, bitmap->height, 0,              GL_RGBA, GL_UNSIGNED_BYTE, bitmap->pixels);       glBindTexture(GL_TEXTURE_2D, 0); }   void destroyTexture(Texture *texture) {     glDeleteTextures(1, &texture->id);     texture->id = 0; }   /*     Vertex Buffer */ void createVertexBuffer(VertexBuffer *vertexBuffer, Vertex *vertices) {     glGenBuffers(1, &vertexBuffer->bufferObj);     glGenVertexArrays(1, &vertexBuffer->vertexArray);     glBindVertexArray(vertexBuffer->vertexArray);       glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer->bufferObj);     glBufferData(GL_ARRAY_BUFFER, sizeof(Vertex) * 6, (const GLvoid*)vertices, GL_STATIC_DRAW);       const unsigned int uvOffset = sizeof(float) * 4;       glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, sizeof(Vertex), 0);     glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (GLvoid*)uvOffset);       glEnableVertexAttribArray(0);     glEnableVertexAttribArray(1);       glBindBuffer(GL_ARRAY_BUFFER, 0);     glBindVertexArray(0); }   void destroyVertexBuffer(VertexBuffer *vertexBuffer) {     glDeleteBuffers(1, &vertexBuffer->bufferObj);     glDeleteVertexArrays(1, &vertexBuffer->vertexArray); }   void bindVertexBuffer(VertexBuffer *vertexBuffer) {     glBindVertexArray(vertexBuffer->vertexArray);     glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer->bufferObj); }   void drawVertexBufferMode(GLenum mode) {     glDrawArrays(mode, 0, 6); }   void drawVertexBuffer() {     drawVertexBufferMode(GL_TRIANGLES); }   void unbindVertexBuffer() {     glBindVertexArray(0);     glBindBuffer(GL_ARRAY_BUFFER, 0); }   /*     Shaders */ void compileShader(ShaderProgram *shaderProgram, const char *vertexSrc, const char *fragSrc) {     GLenum err;     shaderProgram->vertexShader = glCreateShader(GL_VERTEX_SHADER);     shaderProgram->fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);       if (shaderProgram->vertexShader == 0) {         printf("Failed to create vertex shader.");         return;     }       if (shaderProgram->fragmentShader == 0) {         printf("Failed to create fragment shader.");         return;     }       glShaderSource(shaderProgram->vertexShader, 1, &vertexSrc, NULL);     glCompileShader(shaderProgram->vertexShader);     glGetShaderiv(shaderProgram->vertexShader, GL_COMPILE_STATUS, &err);       if (err != GL_TRUE) {         printf("Failed to compile vertex shader.");         return;     }       glShaderSource(shaderProgram->fragmentShader, 1, &fragSrc, NULL);     glCompileShader(shaderProgram->fragmentShader);     glGetShaderiv(shaderProgram->fragmentShader, GL_COMPILE_STATUS, &err);       if (err != GL_TRUE) {         printf("Failed to compile fragment shader.");         return;     }       shaderProgram->program = glCreateProgram();     glAttachShader(shaderProgram->program, shaderProgram->vertexShader);     glAttachShader(shaderProgram->program, shaderProgram->fragmentShader);     glLinkProgram(shaderProgram->program);          glGetProgramiv(shaderProgram->program, GL_LINK_STATUS, &err);       if (err != GL_TRUE) {         printf("Failed to link shader.");         return;     } }   void destroyShader(ShaderProgram *shaderProgram) {     glDetachShader(shaderProgram->program, shaderProgram->vertexShader);     glDetachShader(shaderProgram->program, shaderProgram->fragmentShader);       glDeleteShader(shaderProgram->vertexShader);     glDeleteShader(shaderProgram->fragmentShader);       glDeleteProgram(shaderProgram->program); }   GLuint getUniformLocation(const char *name, ShaderProgram *program) {     GLuint result = 0;     result = glGetUniformLocation(program->program, name);       return result; }   void setUniformMatrix(float *matrix, const char *name, ShaderProgram *program) {     GLuint loc = getUniformLocation(name, program);       if (loc == -1) {         printf("Failed to get uniform location in setUniformMatrix.\n");         return;     }       glUniformMatrix4fv(loc, 1, GL_FALSE, matrix); }   /*     General functions */ static int isRunning() {     return g_running && !glfwWindowShouldClose(gl_window); }   static void initializeGLFW(GLFWwindow **window, int width, int height, int *success) {     if (!glfwInit()) {         printf("Failed it inialize GLFW.");         *success = FALSE;        return;     }          glfwWindowHint(GLFW_RESIZABLE, 0);     *window = glfwCreateWindow(width, height, "Alignments", NULL, NULL);          if (!*window) {         printf("Failed to create window.");         glfwTerminate();         *success = FALSE;         return;     }          glfwMakeContextCurrent(*window);       GLenum glewErr = glewInit();     if (glewErr != GLEW_OK) {         printf("Failed to initialize GLEW.");         printf(glewGetErrorString(glewErr));         *success = FALSE;         return;     }       glClearColor(0.f, 0.f, 0.f, 1.f);     glViewport(0, 0, width, height);     *success = TRUE; }   int main(int argc, char **argv) {          int err = FALSE;     initializeGLFW(&gl_window, 480, 320, &err);     glDisable(GL_DEPTH_TEST);     if (err == FALSE) {         return 1;     }          createOrthoProjection(gl_projectionMatrix, 480.f, 320.f, 0.f, 1.f);          g_running = TRUE;          ShaderProgram shader;     compileShader(&shader, VERT_SHADER, FRAG_SHADER);     glUseProgram(shader.program);     setUniformMatrix(&gl_projectionMatrix, "uProjectionMatrix", &shader);       Vertex rectangle[6];     VertexBuffer vbo;     rectangle[0] = (Vertex){0.f, 0.f, 0.f, 1.f, 0.f, 0.f}; // Top left     rectangle[1] = (Vertex){3.f, 0.f, 0.f, 1.f, 1.f, 0.f}; // Top right     rectangle[2] = (Vertex){0.f, 3.f, 0.f, 1.f, 0.f, 1.f}; // Bottom left     rectangle[3] = (Vertex){3.f, 0.f, 0.f, 1.f, 1.f, 0.f}; // Top left     rectangle[4] = (Vertex){0.f, 3.f, 0.f, 1.f, 0.f, 1.f}; // Bottom left     rectangle[5] = (Vertex){3.f, 3.f, 0.f, 1.f, 1.f, 1.f}; // Bottom right       createVertexBuffer(&vbo, &rectangle);            bindVertexBuffer(&vbo);          while (isRunning()) {         glClear(GL_COLOR_BUFFER_BIT);         glfwPollEvents();                    drawVertexBuffer();                    glfwSwapBuffers(gl_window);     }          unbindVertexBuffer(&vbo);       glUseProgram(0);     destroyShader(&shader);     destroyVertexBuffer(&vbo);     glfwTerminate();     return 0; }

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  • Convert mkv to mp4 with ffmpeg

    - by JohnS
    When I try converting mkv to mp4 using ffmpeg, the following error occurs: [ipod @ 0x16fa0a0] Application provided invalid, non monotonically increasing dts to muxer in stream 0: -2 = -2 av_interleaved_write_frame(): Invalid argument I used this command to convert the file: ffmpeg -i input.mkv -vcodec copy -acodec copy -absf aac_adtstoasc output.m4v The input file has the following characteristics: mediainfo input.mkv General Unique ID : 200459305952356554213392832683163418790 (0x96CF0ED8DB5914CBB9E18163689280A6) Complete name : input.mkv Format : Matroska Format version : Version 2 File size : 1.46 GiB Duration : 1h 5mn Overall bit rate : 3 168 Kbps Encoded date : UTC 2010-09-26 21:44:02 Writing application : mkvmerge v2.9.5 ('Tu es le seul') built on Jun 17 2009 16:28:30 Writing library : libebml v0.7.8 + libmatroska v0.8.1 Video ID : 1 Format : AVC Format/Info : Advanced Video Codec Format profile : [email protected] Format settings, CABAC : Yes Format settings, ReFrames : 4 frames Codec ID : V_MPEG4/ISO/AVC Duration : 1h 5mn Bit rate : 2 910 Kbps Width : 1 280 pixels Height : 720 pixels Display aspect ratio : 16:9 Frame rate : 25.000 fps Color space : YUV Chroma subsampling : 4:2:0 Bit depth : 8 bits Scan type : Progressive Bits/(Pixel*Frame) : 0.126 Stream size : 1.31 GiB (90%) Writing library : x264 core 105 r1724 b02df7b Encoding settings : cabac=1 / ref=3 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=6 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=0 / chroma_qp_offset=-2 / threads=18 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=0 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc=2pass / mbtree=0 / bitrate=2910 / ratetol=1.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / cplxblur=20.0 / qblur=0.5 / ip_ratio=1.40 / pb_ratio=1.30 / aq=1:1.00 Default : Yes Forced : No Audio ID : 2 Format : AC-3 Format/Info : Audio Coding 3 Mode extension : CM (complete main) Codec ID : A_AC3 Duration : 1h 5mn Bit rate mode : Constant Bit rate : 256 Kbps Channel(s) : 2 channels Channel positions : Front: L R Sampling rate : 48.0 KHz Bit depth : 16 bits Compression mode : Lossy Stream size : 121 MiB (8%) Language : English Default : Yes Forced : No Being new to ffmpeg, I'm not sure what the error means or how to correct it. Thanks!

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  • Textures quality issues with Libgdx

    - by user1876708
    I have drawn several vector objets and characters ( in Adobe Illustrator ) for my game on Android. They are all scalable at any size without any quality losses ( of course it's vector ^^ ). I have tried to simulate my gameboard directly on Illustrator just before setting my assests on libdgx to implement them in my game. I set all the objects at the good size, so that they fit perfectly on my XHDPI device I am running my test on. As you can see it works great ( for me at least ^^ ), the PNG quality is good for me, as expected ! So I have edited all my PNG at this size, set my assets on libgdx and build my game apk. And here is a screenshot of my gameboard ( don't pay attention at the differences of placing and objects, but check at the objets presents on both screenshot ). As you can see, I have a loss of my PNG quality in the game. It can be seen clealry on the hedgehog PNG, but also ( but not as obvious ) on the mushroom ( check at the outline ) and the hole PNG. If you really pay attention, on every objects, you can see pixels that are not visible on my first screenshot. And I just can't figure out why this is happening Oo If you have any ideas, you are very welcome ! Thanks. PS : You can check more clearly the 2 gameboard on this two links ( look at them at 100%, display at high resolution ) : Good quality link, from Illustrator Poor quality link, from the game Second phase of tests : We display an object ( the hedgehog ) on our main menu screen to see how it looks like. The things is that it looks like he is suppose to, which means, high quality with no pixels. The hedgehog PNG is coming from an atlas : layer.addActor(hedgehog); No loss of quality with this method So we think the problem is comming from the method we are using to display it on our gameboard : blocks[9][3] = new Block(TextureUtils.hedgehog, new Vector2(9, 3)); the block is getting the size from the vector we are associating to it, but we have a loss of quality with this method.

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  • Styles of games that work at low-resolution

    - by Brendan Long
    I'm taking a class on compilers, and the goal is to write a compiler for Meggy Jr devices (Arduino). The goal is just to make a simple compilers with loops and variables and stuff. Obviously, that's lame, so the "real goal" is to make an impressive game on the device. The problem is that it only has 64 pixels to work with (technically 72, but the top 8 are single-color and not part of the main display, so they're really only useful for displaying things like money). My problem is thinking of something to do on a device that small. It doesn't really matter if it's original, but it can't be something that's already available. My first idea was "snake", but that comes with the SDK. Same with a side-scrolling shooter. Remaining ideas include a tower defense game (hard to write, hard to control), an RPG (same), tetris (lame).. The problem is that all of the games I like require a high-resolution screen because they have a lot of text. Even a really simple game like nethack would be hard because each creature would be a single color. tl;dr What styles of games require a. No text; and b. Few enough objects that representing them each with a single color is acceptable? EDIT: To clarify, the display is 8x8 for a total of 64 pixels, not 64x64.

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  • Second monitor not detected

    - by configurator
    Note: I've seen this question quite a lot, but in all the cases I could find with answers, the answer was either "I don't know" or "use nvidia-settings (which is irrelevant to me)." I'm using Intel Sandybridge Desktop graphics, with a P8H61-M LE motherboard. How do I get Ubuntu to detect my second monitor? Clicking "Detect Displays" here doesn't do anything. Here's some system info: $ lspci | grep VGA 00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09) $ uname -a Linux clyde 3.5.0-13-generic #13-Ubuntu SMP Tue Aug 28 08:31:47 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux $ hardinfo [copied from the UI] -Display- Resolution : 1920x1080 pixels Vendor : The X.Org Foundation Version : 1.12.3 -Monitors- Monitor 0 : 1920x1080 pixels -Extensions- BIG-REQUESTS Composite DAMAGE DOUBLE-BUFFER DPMS DRI2 GLX Generic Event Extension MIT-SCREEN-SAVER MIT-SHM RANDR RECORD RENDER SECURITY SGI-GLX SHAPE SYNC X-Resource XC-MISC XFIXES XFree86-DGA XFree86-VidModeExtension XINERAMA XInputExtension XKEYBOARD XTEST XVideo -OpenGL- Vendor : Intel Open Source Technology Center Renderer : Mesa DRI Intel(R) Sandybridge Desktop Version : 3.0 Mesa 8.1-devel Direct Rendering : Yes I've tried upgrading everything from ppa:xorg-edgers/ppa and ppa:glasen/intel-driver. I've also installed various tools I've found in other threads (e.g. hardinfo) but they weren't really helpful to me as I don't know what to make of the data. How do I get Ubuntu to detect my second monitor?

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  • Creating a retro-style palette swapping effect in OpenGL

    - by Zack The Human
    I'm working on a Megaman-like game where I need to change the color of certain pixels at runtime. For reference: in Megaman when you change your selected weapon then main character's palette changes to reflect the selected weapon. Not all of the sprite's colors change, only certain ones do. This kind of effect was common and quite easy to do on the NES since the programmer had access to the palette and the logical mapping between pixels and palette indices. On modern hardware, though, this is a bit more challenging because the concept of palettes is not the same. All of my textures are 32-bit and do not use palettes. There are two ways I know of to achieve the effect I want, but I'm curious if there are better ways to achieve this effect easily. The two options I know of are: Use a shader and write some GLSL to perform the "palette swapping" behavior. If shaders are not available (say, because the graphics card doesn't support them) then it is possible to clone the "original" textures and generate different versions with the color changes pre-applied. Ideally I would like to use a shader since it seems straightforward and requires little additional work opposed to the duplicated-texture method. I worry that duplicating textures just to change a color in them is wasting VRAM -- should I not worry about that?

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  • Fixed timestep with interpolation in AS3

    - by Jim Sreven
    I'm trying to implement Glenn Fiedler's popular fixed timestep system as documented here: http://gafferongames.com/game-physics/fix-your-timestep/ In Flash. I'm fairly sure that I've got it set up correctly, along with state interpolation. The result is that if my character is supposed to move at 6 pixels per frame, 35 frames per second = 210 pixels a second, it does exactly that, even if the framerate climbs or falls. The problem is it looks awful. The movement is very stuttery and just doesn't look good. I find that the amount of time in between ENTER_FRAME events, which I'm adding on to my accumulator, averages out to 28.5ms (1000/35) just as it should, but individual frame times vary wildly, sometimes an ENTER_FRAME event will come 16ms after the last, sometimes 42ms. This means that at each graphical redraw the character graphic moves by a different amount, because a different amount of time has passed since the last draw. In theory it should look smooth, but it doesn't at all. In contrast, if I just use the ultra simple system of moving the character 6px every frame, it looks completely smooth, even with these large variances in frame times. How can this be possible? I'm using getTimer() to measure these time differences, are they even reliable?

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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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  • 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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  • 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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  • How to store bitmaps in memory?

    - by Geotarget
    I'm working with general purpose image rendering, and high-performance image processing, and so I need to know how to store bitmaps in-memory. (24bpp/32bpp, compressed/raw, etc) I'm not working with 3D graphics or DirectX / OpenGL rendering and so I don't need to use graphics card compatible bitmap formats. My questions: What is the "usual" or "normal" way to store bitmaps in memory? (in C++ engines/projects?) How to store bitmaps for high-performance algorithms, such that read/write times are the fastest? (fixed array? with/without padding? 24-bpp or 32-bpp?) How to store bitmaps for applications handling a lot of bitmap data, to minimize memory usage? (JPEG? or a faster [de]compression algorithm?) Some possible methods: Use a fixed packed 24-bpp or 32-bpp int[] array and simply access pixels using pointer access, all pixels are allocated in one continuous memory chunk (could be 1-10 MB) Use a form of "sparse" data storage so each line of the bitmap is allocated separately, reusing more memory and requiring smaller contiguous memory segments Store bitmaps in its compressed form (PNG, JPG, GIF, etc) and unpack only when its needed, reducing the amount of memory used. Delete the unpacked data if its not used for 10 secs.

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  • Sampling Heightmap Edges for Normal map

    - by pl12
    I use a Sobel filter to generate normal maps from procedural height maps. The heightmaps are 258x258 pixels. I scale my texture coordinates like so: texCoord = (texCoord * (256/258)) + (1/258) Yet even with this I am left with the following problem: As you can see the edges of the normal map still proves to be problematic. Putting the texture wrap mode to "clamp" also proved no help. EDIT: The Sobel Filter function by sampling the 8 surrounding pixels around a given pixel so that a derivative can be calculated in order to find the "normal" of the given pixel. The texture coordinates are instanced once per quad (for the quadtree that makes up the world) and are created as follows (it is quite possible that the problem results from the way I scale and offset the texCoords as seen above): Java: for(int i = 0; i<vertices.length; i++){ Vector2f coord = new Vector2f((vertices[i].x)/(worldSize), (vertices[i].z)/( worldSize)); texCoords[i] = coord; } the quad used for input here rests on the X0Z plane. 'worldSize' is the diameter of the planet. No negative texCoords are seen as the quad used for input for this method is not centered around the origin. Is there something I am missing here? Thanks.

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  • How can I mark a pixel in the stencil buffer?

    - by János Turánszki
    I never used the stencil buffer for anything until now, but I want to change this. I have an idea of how it should work: the gpu discards or keeps rasterized pixels before the pixel shader based on the stencil buffer value on the given position and some stencil operation. What I don't know is how would I mark a pixel in the stencil buffer with a specific value. For example I draw my scene and want to mark everything which is drawn with a specific material (this material could be looked up from a texture so ideally I should mark the pixel in the pixel shader), so that later when I do some post processing on my scene I would only do it on the marked pixels. I didn't find anything on the internet besides how to set up a stencil buffer and explaining the different stencil operations. I was expecting to find some System-Value semantics like SV_Depth to write to in the pixel shader (because the stencil buffer shares the same resource with the depth buffer in D3D11), but there is no such thing on MSDN. So how should I do this? If I am misunderstanding something please help me clear that up.

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  • Understanding IDAT chunk of PNG file format

    - by DRapp
    From the sample image below, I have a border in yellow just for display purposes only. The actual .png file is a simple black/white image 3 pixels by 3 pixels. I was originally thinking to try as a 2x2, but that would not help trying to interpret low/hi vs hi/low drawing stream. At least this way, I would have two black, one white from the top, or one white, two black from the bottom.. So I read the chunks of data, get to the IDAT chunk, decode that (zlib) and come up with 12 bytes as follows 00 20 00 40 00 80 So, my question, how does the above get broken down into the 3x3 black and white sample... Also, it is saved in palette format and properly recognizes the bit depth of 1 and color palette of 2... color pallet[0] is RGBA all zeros. Palette1 has RGBA of 255, 255, 255, 0 I'll eventually get into the multiple other depth formats later, just wanted to start with what would expect to be the easiest. Part II. Any guidance on handling the other depth formats would help if anything special to be considered especially regarding alpha channel (which I am already looking for in the palette) that might trip me up.

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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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  • Can T520+Bumblebee run an external monitor via DisplayPort?

    - by Fen
    Using 64-bit Ubuntu 11.10 and integrated (Intel) graphics, I can run the 1600x900 laptop display plus a 1600x1200 external monitor connected to the VGA adapter. But my external monitor is 1920x1200 so I have black stripes on each side. I believe the resolution is limited like this as the maximum resolution available from the Intel GPU is 2560x1600 = 4,096,000 pixels and I'm asking for a 3520x1200 = 4,224,000 display (with 1200x300 lost above the laptop screen). At 3200x1200 = 3,840,000 pixels, the Intel GPU seems happy. Under Windows, the same limit exists when using the VGA adapter, but if I turn Optimus on then I can connect the external monitor to the DisplayPort and get its full resolution and an extended desktop. I've seen that Bumblebee can run apps on the DisplayPort using the 'optirun' command. My question is: can Bumblebee run the DisplayPort in concert with the Intel card running the laptop screen creating a large virtual desktop (as on Windows)? If so, are there any pointers to how to do this? I tried once, failed, and dropped back to Integrated Graphics (and black stripes) as I could find no reports of this configuration working.

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  • Recommended formats to store bitmaps in memory?

    - by Geotarget
    I'm working with general purpose image rendering, and high-performance image processing, and so I need to know how to store bitmaps in-memory. (24bpp/32bpp, compressed/raw, etc) I'm not working with 3D graphics or DirectX / OpenGL rendering and so I don't need to use graphics card compatible bitmap formats. My questions: What is the "usual" or "normal" way to store bitmaps in memory? (in C++ engines/projects?) How to store bitmaps for high-performance algorithms, such that read/write times are the fastest? (fixed array? with/without padding? 24-bpp or 32-bpp?) How to store bitmaps for applications handling a lot of bitmap data, to minimize memory usage? (JPEG? or a faster [de]compression algorithm?) Some possible methods: Use a fixed packed 24-bpp or 32-bpp int[] array and simply access pixels using pointer access, all pixels are allocated in one continuous memory chunk (could be 1-10 MB) Use a form of "sparse" data storage so each line of the bitmap is allocated separately, reusing more memory and requiring smaller contiguous memory segments Store bitmaps in its compressed form (PNG, JPG, GIF, etc) and unpack only when its needed, reducing the amount of memory used. Delete the unpacked data if its not used for 10 secs.

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  • Provide A Scrolling "Camera" View Over A 2D Game Map

    - by BitCrash
    I'm in the process of attempting to create a 2D MMO type game with Kryonet and some basic sprites, mostly for my own learning. I have the back end set up great (By my standards) and I'm moving on to actually getting some things drawn onto the map. I cannot for the life of me figure out a solid way to have a "Camera" follow a player around a large area. The view pane for the game is 640 x 480 pixels, and each tile is 32x32 pixels (Thats 20 tiles wide and 15 high for the viewpane) I have tried a couple things to do this, but they did not seem to work out so well. I had a JScrollPane with 9 "Viewpane"-sized canvases in it, and tried to have the JScrollPane move in accordance with the player. The issue came when I reached the end of the JScrollPane. I tried to "Flip" canvases, sending the canvas currrently drawing the player to the middle of the 9 and load the corresponding maps onto the other ones. It was slow and worked poorly. I'm looking for any advice or previous experience with this; any ideas? Thank you! Edit and Clarification: I did not mean to mention Kryonet, I was merely providing peripheral information in case there was something that would help which I could not foresee. Instead of having an array of 9 canvases, why not just have one large canvas loading a large map every once in a while? I'm willing to have "load times" where as with the canvas array I would have none (in theory) to give the user a smooth experience. I could just change the size and location of the map with a modified setBounds() call on the canvas in a layered pane (layered because I have hidden swing items, like inventories and stuff) I'll try it out and post here how it goes for people asking the same question.

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  • Drawning with canvas - problem with sizing [closed]

    - by pioncz
    For example i made 2 canvas with size 500px x 500px and 100px x 100px to see how fillrect works and i found that canvas.fillrect doesnt takes px for arguments, and my question is: how to make pixels as arguments or how to count these arguments for pixels? This is example: <html xmlns="http://www.w3.org/1999/xhtml"> <head> <script type="text/javascript"> function draw() { var canvas = document.getElementById('myCanvas'); var ctx = canvas.getContext('2d'); ctx.fillStyle = '#00f'; ctx.fillRect (0, 0,100, 100); var canvas2 = document.getElementById('myCanvas2'); var ctx2 = canvas2.getContext('2d'); ctx2.fillStyle = '#0f0'; ctx2.fillRect (0, 0, 100, 100); } </script> </head> <body onLoad="draw();"> <canvas id="myCanvas" style="background:black;width:500px;height:500px;display:block;position:absolute;top:0px;left:0px;"> </canvas> <canvas id="myCanvas2" style="background:purple;width:100px;height:100px;display:block;position:absolute;top:0px;left:0px;"> </canvas> </body> </html>

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  • RTS Voxel Engine using LWJGL - Textures glitching

    - by Dieter Hubau
    I'm currently working on an RTS game engine using voxels. I have implemented a basic chunk manager using an Octree of Octrees which contains my voxels (simple square blocks, as in Minecraft). I'm using a Voronoi-based terrain generation to get a simplistic yet relatively realistic heightmap. I have no problem showing a 256*256*256 grid of voxels with a decent framerate (250), because of frustum culling, face culling and only rendering visible blocks. For example, in a random voxel grid of 256*256*256 I generally only render 100k-120k faces, not counting frustum culling. Frustum culling is only called every 100ms, since calling it every frame seemed a bit overkill. Now I have reached the stage of texturing and I'm experiencing some problems: Some experienced people might already see the problem, but if we zoom in, you can see the glitches more clearly: All the seams between my blocks are glitching and kind of 'overlapping' or something. It's much more visible when you're moving around. I'm using a single, simple texture map to draw on my cubes, where each texture is 16*16 pixels big: I have added black edges around the textures to get a kind of cellshaded look, I think it's cool. The texture map has 256 textures of each 16*16 pixels, meaning the total size of my texture map is 256*256 pixels. The code to update the ChunkManager: public void update(ChunkManager chunkManager) { for (Octree<Cube> chunk : chunks) { if (chunk.getId() < 0) { // generate an id for the chunk to be able to call it later chunk.setId(glGenLists(1)); } glNewList(chunk.getId(), GL_COMPILE); glBegin(GL_QUADS); faces += renderChunk(chunk); glEnd(); glEndList(); } } Where my renderChunk method is: private int renderChunk(Octree<Cube> node) { // keep track of the number of visible faces in this chunk int faces = 0; if (!node.isEmpty()) { if (node.isLeaf()) { faces += renderItem(node); } List<Octree<Cube>> children = node.getChildren(); if (children != null && !children.isEmpty()) { for (Octree<Cube> child : children) { faces += renderChunk(child); } } return faces; } Where my renderItem method is the following: private int renderItem(Octree<Cube> node) { Cube cube = node.getItem(-1, -1, -1); int faces = 0; float x = node.getPosition().x; float y = node.getPosition().y; float z = node.getPosition().z; float size = cube.getSize(); Vector3f point1 = new Vector3f(-size + x, -size + y, size + z); Vector3f point2 = new Vector3f(-size + x, size + y, size + z); Vector3f point3 = new Vector3f(size + x, size + y, size + z); Vector3f point4 = new Vector3f(size + x, -size + y, size + z); Vector3f point5 = new Vector3f(-size + x, -size + y, -size + z); Vector3f point6 = new Vector3f(-size + x, size + y, -size + z); Vector3f point7 = new Vector3f(size + x, size + y, -size + z); Vector3f point8 = new Vector3f(size + x, -size + y, -size + z); TextureCoordinates tc = textureManager.getTextureCoordinates(cube.getCubeType()); // front face if (cube.isVisible(CubeSide.FRONT)) { faces++; glTexCoord2f(TEXTURE_U_COORDINATES[tc.u], TEXTURE_V_COORDINATES[tc.v]); glVertex3f(point1.x, point1.y, point1.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u + 1], TEXTURE_V_COORDINATES[tc.v]); glVertex3f(point4.x, point4.y, point4.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u + 1], TEXTURE_V_COORDINATES[tc.v + 1]); glVertex3f(point3.x, point3.y, point3.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u], TEXTURE_V_COORDINATES[tc.v + 1]); glVertex3f(point2.x, point2.y, point2.z); } // back face if (cube.isVisible(CubeSide.BACK)) { faces++; glTexCoord2f(TEXTURE_U_COORDINATES[tc.u + 1], TEXTURE_V_COORDINATES[tc.v]); glVertex3f(point5.x, point5.y, point5.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u + 1], TEXTURE_V_COORDINATES[tc.v + 1]); glVertex3f(point6.x, point6.y, point6.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u], TEXTURE_V_COORDINATES[tc.v + 1]); glVertex3f(point7.x, point7.y, point7.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u], TEXTURE_V_COORDINATES[tc.v]); glVertex3f(point8.x, point8.y, point8.z); } // left face if (cube.isVisible(CubeSide.SIDE_LEFT)) { faces++; glTexCoord2f(TEXTURE_U_COORDINATES[tc.u], TEXTURE_V_COORDINATES[tc.v]); glVertex3f(point5.x, point5.y, point5.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u + 1], TEXTURE_V_COORDINATES[tc.v]); glVertex3f(point1.x, point1.y, point1.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u + 1], TEXTURE_V_COORDINATES[tc.v + 1]); glVertex3f(point2.x, point2.y, point2.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u], TEXTURE_V_COORDINATES[tc.v + 1]); glVertex3f(point6.x, point6.y, point6.z); } // ETC ETC return faces; } When all this is done, I simply render my lists every frame, like this: public void render(ChunkManager chunkManager) { glBindTexture(GL_TEXTURE_2D, textureManager.getCubeTextureId()); // load all chunks from the tree List<Octree<Cube>> chunks = chunkManager.getTree().getAllItems(); for (Octree<Cube> chunk : chunks) { if (frustum.cubeInFrustum(chunk.getPosition(), chunk.getSize() / 2)) { glCallList(chunk.getId()); } } } I don't know if anyone is willing to go through all of this code or maybe you can spot the problem right away, but that is basically the problem, and I can't find a solution :-) Thanks for reading and any help is appreciated!

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  • Camera Projection back Into 3D world, offset error

    - by Anthony
    I'm using XNA to simulate a robot in a 3D world and then do image analysis on what the camera sees. I have my camera looking down in front of the direction that the robot is going, and I have the robot detecting white pixels. I'm trying to take the white pixels that it finds and project them back into the 3D world so that I can see if it is actually detecting the correct pixels. I almost have it working, but there is an offset between where the white is in in the World and were I put my orange triangles (which represent what the robot things is white). /// <summary> /// Takes a bool map of and makes vertex positions based on the map. /// </summary> /// <param name="c"> The bool map</param> private void ProjectBoolMapOnGroundAnthony2(bool[,] c) { float triangleSize = 0.04f; // Point of interest in World W cordinate system. Vector3 pointOfInterest_W = Vector3.Zero; // Point of interest in Robot Cordinate system R Vector3 pointOfInterest_R = Vector3.Zero; // alpha is the angle from the robot camera to where it is looking in the center. //double alpha = Math.Atan(1.8f / 1); /// Matrix representation of the view determined by the position, target, and updirection. Matrix View = ((SimulationMain)Game).mainRobot.robotCameraView.View; /// Matrix representation of the view determined by the angle of the field of view (Pi/4), aspectRatio, nearest plane visible (1), and farthest plane visible (1200) Matrix Projection = ((SimulationMain)Game).mainRobot.robotCameraView.Projection; /// Matrix representing how the real world cordinates differ from that of the rendering by the camera. Matrix World = ((SimulationMain)Game).mainRobot.robotCameraView.World; Plane groundPlan = new Plane(Vector3.UnitZ, 0.0f); for (int x = 0; x < this.screenWidth; x++) { for (int y = 0; y < this.screenHeight; ) { if (c[x, y] == true && this.count1D < 62000) { int j = 1; Vector3 nearPlanePoint = Game.GraphicsDevice.Viewport.Unproject(new Vector3(x, y, 0), Projection, View, World); Vector3 farPlanePoint = Game.GraphicsDevice.Viewport.Unproject(new Vector3(x, y, 1), Projection, View, World); //Vector3 pointOfInterest_W = Vector3.in Ray ray = new Ray(nearPlanePoint, farPlanePoint); pointOfInterest_W = ray.Position + ray.Direction * (float) ray.Intersects(groundPlan); this.vertexArray2[this.count1D + 0].Position.X = pointOfInterest_W.X - triangleSize; this.vertexArray2[this.count1D + 0].Position.Y = pointOfInterest_W.Y - triangleSize * j; this.vertexArray2[this.count1D + 0].Position.Z = pointOfInterest_W.Z; this.vertexArray2[this.count1D + 0].Color = Color.DarkOrange; // Put another vertex a the position but +1 in the X direction triangleSize //this.vertexArray2[this.count1D + 1].Position.X = pointOnGroud.X + 3; //this.vertexArray2[this.count1D + 1].Position.Y = pointOnGroud.Y + j; this.vertexArray2[this.count1D + 1].Position.X = pointOfInterest_W.X; this.vertexArray2[this.count1D + 1].Position.Y = pointOfInterest_W.Y + triangleSize * j; this.vertexArray2[this.count1D + 1].Position.Z = pointOfInterest_W.Z; this.vertexArray2[this.count1D + 1].Color = Color.Red; // Put another vertex a the position but +1 in the X direction //this.vertexArray2[this.count1D + 0].Position.X = pointOnGroud.X; //this.vertexArray2[this.count1D + 0].Position.Y = pointOnGroud.Y + 3 + j; this.vertexArray2[this.count1D + 2].Position.X = pointOfInterest_W.X + triangleSize; this.vertexArray2[this.count1D + 2].Position.Y = pointOfInterest_W.Y - triangleSize * j; this.vertexArray2[this.count1D + 2].Position.Z = pointOfInterest_W.Z; this.vertexArray2[this.count1D + 2].Color = Color.Orange; this.count1D += 3; y += j; } else { y++; } } } } The world is a grass texture with lines on it. The world plane is normal at (0,0,1). Any ideas on why there is an offset? Any Ideas? Thanks for the help, Anthony G.

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  • Which of these algorithms is best for my goal?

    - by JonathonG
    I have created a program that restricts the mouse to a certain region based on a black/white bitmap. The program is 100% functional as-is, but uses an inaccurate, albeit fast, algorithm for repositioning the mouse when it strays outside the area. Currently, when the mouse moves outside the area, basically what happens is this: A line is drawn between a pre-defined static point inside the region and the mouse's new position. The point where that line intersects the edge of the allowed area is found. The mouse is moved to that point. This works, but only works perfectly for a perfect circle with the pre-defined point set in the exact center. Unfortunately, this will never be the case. The application will be used with a variety of rectangles and irregular, amorphous shapes. On such shapes, the point where the line drawn intersects the edge will usually not be the closest point on the shape to the mouse. I need to create a new algorithm that finds the closest point to the mouse's new position on the edge of the allowed area. I have several ideas about this, but I am not sure of their validity, in that they may have far too much overhead. While I am not asking for code, it might help to know that I am using Objective C / Cocoa, developing for OS X, as I feel the language being used might affect the efficiency of potential methods. My ideas are: Using a bit of trigonometry to project lines would work, but that would require some kind of intense algorithm to test every point on every line until it found the edge of the region... That seems too resource intensive since there could be something like 200 lines that would have each have to have as many as 200 pixels checked for black/white.... Using something like an A* pathing algorithm to find the shortest path to a black pixel; however, A* seems resource intensive, even though I could probably restrict it to only checking roughly in one direction. It also seems like it will take more time and effort than I have available to spend on this small portion of the much larger project I am working on, correct me if I am wrong and it would not be a significant amount of code (100 lines or around there). Mapping the border of the region before the application begins running the event tap loop. I think I could accomplish this by using my current line-based algorithm to find an edge point and then initiating an algorithm that checks all 8 pixels around that pixel, finds the next border pixel in one direction, and continues to do this until it comes back to the starting pixel. I could then store that data in an array to be used for the entire duration of the program, and have the mouse re-positioning method check the array for the closest pixel on the border to the mouse target position. That last method would presumably execute it's initial border mapping fairly quickly. (It would only have to map between 2,000 and 8,000 pixels, which means 8,000 to 64,000 checked, and I could even permanently store the data to make launching faster.) However, I am uncertain as to how much overhead it would take to scan through that array for the shortest distance for every single mouse move event... I suppose there could be a shortcut to restrict the number of elements in the array that will be checked to a variable number starting with the intersecting point on the line (from my original algorithm), and raise/lower that number to experiment with the overhead/accuracy tradeoff. Please let me know if I am over thinking this and there is an easier way that will work just fine, or which of these methods would be able to execute something like 30 times per second to keep mouse movement smooth, or if you have a better/faster method. I've posted relevant parts of my code below for reference, and included an example of what the area might look like. (I check for color value against a loaded bitmap that is black/white.) // // This part of my code runs every single time the mouse moves. // CGPoint point = CGEventGetLocation(event); float tX = point.x; float tY = point.y; if( is_in_area(tX,tY, mouse_mask)){ // target is inside O.K. area, do nothing }else{ CGPoint target; //point inside restricted region: float iX = 600; // inside x float iY = 500; // inside y // delta to midpoint between iX,iY and tX,tY float dX; float dY; float accuracy = .5; //accuracy to loop until reached do { dX = (tX-iX)/2; dY = (tY-iY)/2; if(is_in_area((tX-dX),(tY-dY),mouse_mask)){ iX += dX; iY += dY; } else { tX -= dX; tY -= dY; } } while (abs(dX)>accuracy || abs(dY)>accuracy); target = CGPointMake(roundf(tX), roundf(tY)); CGDisplayMoveCursorToPoint(CGMainDisplayID(),target); } Here is "is_in_area(int x, int y)" : bool is_in_area(NSInteger x, NSInteger y, NSBitmapImageRep *mouse_mask){ NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; NSUInteger pixel[4]; [mouse_mask getPixel:pixel atX:x y:y]; if(pixel[0]!= 0){ [pool release]; return false; } [pool release]; return true; }

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  • Applications: The Mathematics of Movement, Part 3

    - by TechTwaddle
    Previously: Part 1, Part 2 As promised in the previous post, this post will cover two variations of the marble move program. The first one, Infinite Move, keeps the marble moving towards the click point, rebounding it off the screen edges and changing its direction when the user clicks again. The second version, Finite Move, is the same as first except that the marble does not move forever. It moves towards the click point, rebounds off the screen edges and slowly comes to rest. The amount of time that it moves depends on the distance between the click point and marble. Infinite Move This case is simple (actually both cases are simple). In this case all we need is the direction information which is exactly what the unit vector stores. So when the user clicks, you calculate the unit vector towards the click point and then keep updating the marbles position like crazy. And, of course, there is no stop condition. There’s a little more additional code in the bounds checking conditions. Whenever the marble goes off the screen boundaries, we need to reverse its direction.  Here is the code for mouse up event and UpdatePosition() method, //stores the unit vector double unitX = 0, unitY = 0; double speed = 6; //speed times the unit vector double incrX = 0, incrY = 0; private void Form1_MouseUp(object sender, MouseEventArgs e) {     double x = e.X - marble1.x;     double y = e.Y - marble1.y;     //calculate distance between click point and current marble position     double lenSqrd = x * x + y * y;     double len = Math.Sqrt(lenSqrd);     //unit vector along the same direction (from marble towards click point)     unitX = x / len;     unitY = y / len;     timer1.Enabled = true; } private void UpdatePosition() {     //amount by which to increment marble position     incrX = speed * unitX;     incrY = speed * unitY;     marble1.x += incrX;     marble1.y += incrY;     //check for bounds     if ((int)marble1.x < MinX + marbleWidth / 2)     {         marble1.x = MinX + marbleWidth / 2;         unitX *= -1;     }     else if ((int)marble1.x > (MaxX - marbleWidth / 2))     {         marble1.x = MaxX - marbleWidth / 2;         unitX *= -1;     }     if ((int)marble1.y < MinY + marbleHeight / 2)     {         marble1.y = MinY + marbleHeight / 2;         unitY *= -1;     }     else if ((int)marble1.y > (MaxY - marbleHeight / 2))     {         marble1.y = MaxY - marbleHeight / 2;         unitY *= -1;     } } So whenever the user clicks we calculate the unit vector along that direction and also the amount by which the marble position needs to be incremented. The speed in this case is fixed at 6. You can experiment with different values. And under bounds checking, whenever the marble position goes out of bounds along the x or y direction we reverse the direction of the unit vector along that direction. Here’s a video of it running;   Finite Move The code for finite move is almost exactly same as that of Infinite Move, except for the difference that the speed is not fixed and there is an end condition, so the marble comes to rest after a while. Code follows, //unit vector along the direction of click point double unitX = 0, unitY = 0; //speed of the marble double speed = 0; private void Form1_MouseUp(object sender, MouseEventArgs e) {     double x = 0, y = 0;     double lengthSqrd = 0, length = 0;     x = e.X - marble1.x;     y = e.Y - marble1.y;     lengthSqrd = x * x + y * y;     //length in pixels (between click point and current marble pos)     length = Math.Sqrt(lengthSqrd);     //unit vector along the same direction as vector(x, y)     unitX = x / length;     unitY = y / length;     speed = length / 12;     timer1.Enabled = true; } private void UpdatePosition() {     marble1.x += speed * unitX;     marble1.y += speed * unitY;     //check for bounds     if ((int)marble1.x < MinX + marbleWidth / 2)     {         marble1.x = MinX + marbleWidth / 2;         unitX *= -1;     }     else if ((int)marble1.x > (MaxX - marbleWidth / 2))     {         marble1.x = MaxX - marbleWidth / 2;         unitX *= -1;     }     if ((int)marble1.y < MinY + marbleHeight / 2)     {         marble1.y = MinY + marbleHeight / 2;         unitY *= -1;     }     else if ((int)marble1.y > (MaxY - marbleHeight / 2))     {         marble1.y = MaxY - marbleHeight / 2;         unitY *= -1;     }     //reduce speed by 3% in every loop     speed = speed * 0.97f;     if ((int)speed <= 0)     {         timer1.Enabled = false;     } } So the only difference is that the speed is calculated as a function of length when the mouse up event occurs. Again, this can be experimented with. Bounds checking is same as before. In the update and draw cycle, we reduce the speed by 3% in every cycle. Since speed is calculated as a function of length, speed = length/12, the amount of time it takes speed to reach zero is directly proportional to length. Note that the speed is in ‘pixels per 40ms’ because the timeout value of the timer is 40ms.  The readability can be improved by representing speed in ‘pixels per second’. This would require you to add some more calculations to the code, which I leave out as an exercise. Here’s a video of this second version,

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