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    • By racarate
      Hey everybody!
      I am trying to replicate all these cool on-screen debug visuals I see in all the SIGGRAPH and GDC talks, but I really don't know where to start.  The only resource I know of is almost 16 years old:
      http://number-none.com/product/Interactive Profiling, Part 1/index.html
      Does anybody have a more up-to-date reference?  Do people use minimal UI libraries like Dear ImgGui?  Also, If I am profiling OpenGL ES 3.0 (which doesn't have timer queries) is there really anything I can do to measure performance GPU-wise?  Or should I just chart CPU-side frame time?  I feel like this is something people re-invent for every game there has gotta be a tutorial out there... right?
    • By Achivai
      Hey, I am semi-new to 3d-programming and I've hit a snag. I have one object, let's call it Object A. This object has a long int array of 3d xyz-positions stored in it's vbo as an instanced attribute. I am using these numbers to instance object A a couple of thousand times. So far so good. 
      Now I've hit a point where I want to remove one of these instances of object A while the game is running, but I'm not quite sure how to go about it. At first my thought was to update the instanced attribute of Object A and change the positions to some dummy number that I could catch in the vertex shader and then decide there whether to draw the instance of Object A or not, but I think that would be expensive to do while the game is running, considering that it might have to be done several times every frame in some cases. 
      I'm not sure how to proceed, anyone have any tips?
    • By fleissi
      Hey guys!

      I'm new here and I recently started developing my own rendering engine. It's open source, based on OpenGL/DirectX and C++.
      The full source code is hosted on github:

      I would appreciate if people with experience in game development / engine desgin could take a look at my source code. I'm looking for honest, constructive criticism on how to improve the engine.
      I'm currently writing my master's thesis in computer science and in the recent year I've gone through all the basics about graphics programming, learned DirectX and OpenGL, read some articles on Nvidia GPU Gems, read books and integrated some of this stuff step by step into the engine.

      I know about the basics, but I feel like there is some missing link that I didn't get yet to merge all those little pieces together.

      Features I have so far:
      - Dynamic shader generation based on material properties
      - Dynamic sorting of meshes to be renderd based on shader and material
      - Rendering large amounts of static meshes
      - Hierarchical culling (detail + view frustum)
      - Limited support for dynamic (i.e. moving) meshes
      - Normal, Parallax and Relief Mapping implementations
      - Wind animations based on vertex displacement
      - A very basic integration of the Bullet physics engine
      - Procedural Grass generation
      - Some post processing effects (Depth of Field, Light Volumes, Screen Space Reflections, God Rays)
      - Caching mechanisms for textures, shaders, materials and meshes

      Features I would like to have:
      - Global illumination methods
      - Scalable physics
      - Occlusion culling
      - A nice procedural terrain generator
      - Scripting
      - Level Editing
      - Sound system
      - Optimization techniques

      Books I have so far:
      - Real-Time Rendering Third Edition
      - 3D Game Programming with DirectX 11
      - Vulkan Cookbook (not started yet)

      I hope you guys can take a look at my source code and if you're really motivated, feel free to contribute :-)
      There are some videos on youtube that demonstrate some of the features:
      Procedural grass on the GPU
      Procedural Terrain Engine
      Quadtree detail and view frustum culling

      The long term goal is to turn this into a commercial game engine. I'm aware that this is a very ambitious goal, but I'm sure it's possible if you work hard for it.


    • By tj8146
      I have attached my project in a .zip file if you wish to run it for yourself.
      I am making a simple 2d top-down game and I am trying to run my code to see if my window creation is working and to see if my timer is also working with it. Every time I run it though I get errors. And when I fix those errors, more come, then the same errors keep appearing. I end up just going round in circles.  Is there anyone who could help with this? 
      Errors when I build my code:
      1>Renderer.cpp 1>c:\users\documents\opengl\game\game\renderer.h(15): error C2039: 'string': is not a member of 'std' 1>c:\program files (x86)\windows kits\10\include\10.0.16299.0\ucrt\stddef.h(18): note: see declaration of 'std' 1>c:\users\documents\opengl\game\game\renderer.h(15): error C2061: syntax error: identifier 'string' 1>c:\users\documents\opengl\game\game\renderer.cpp(28): error C2511: 'bool Game::Rendering::initialize(int,int,bool,std::string)': overloaded member function not found in 'Game::Rendering' 1>c:\users\documents\opengl\game\game\renderer.h(9): note: see declaration of 'Game::Rendering' 1>c:\users\documents\opengl\game\game\renderer.cpp(35): error C2597: illegal reference to non-static member 'Game::Rendering::window' 1>c:\users\documents\opengl\game\game\renderer.cpp(36): error C2597: illegal reference to non-static member 'Game::Rendering::window' 1>c:\users\documents\opengl\game\game\renderer.cpp(43): error C2597: illegal reference to non-static member 'Game::Rendering::window' 1>Done building project "Game.vcxproj" -- FAILED. ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========  
      #include <GL/glew.h> #include <GLFW/glfw3.h> #include "Renderer.h" #include "Timer.h" #include <iostream> namespace Game { GLFWwindow* window; /* Initialize the library */ Rendering::Rendering() { mClock = new Clock; } Rendering::~Rendering() { shutdown(); } bool Rendering::initialize(uint width, uint height, bool fullscreen, std::string window_title) { if (!glfwInit()) { return -1; } /* Create a windowed mode window and its OpenGL context */ window = glfwCreateWindow(640, 480, "Hello World", NULL, NULL); if (!window) { glfwTerminate(); return -1; } /* Make the window's context current */ glfwMakeContextCurrent(window); glViewport(0, 0, (GLsizei)width, (GLsizei)height); glOrtho(0, (GLsizei)width, (GLsizei)height, 0, 1, -1); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glfwSwapInterval(1); glEnable(GL_SMOOTH); glEnable(GL_DEPTH_TEST); glEnable(GL_BLEND); glDepthFunc(GL_LEQUAL); glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); glEnable(GL_TEXTURE_2D); glLoadIdentity(); return true; } bool Rendering::render() { /* Loop until the user closes the window */ if (!glfwWindowShouldClose(window)) return false; /* Render here */ mClock->reset(); glfwPollEvents(); if (mClock->step()) { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glfwSwapBuffers(window); mClock->update(); } return true; } void Rendering::shutdown() { glfwDestroyWindow(window); glfwTerminate(); } GLFWwindow* Rendering::getCurrentWindow() { return window; } } Renderer.h
      #pragma once namespace Game { class Clock; class Rendering { public: Rendering(); ~Rendering(); bool initialize(uint width, uint height, bool fullscreen, std::string window_title = "Rendering window"); void shutdown(); bool render(); GLFWwindow* getCurrentWindow(); private: GLFWwindow * window; Clock* mClock; }; } Timer.cpp
      #include <GL/glew.h> #include <GLFW/glfw3.h> #include <time.h> #include "Timer.h" namespace Game { Clock::Clock() : mTicksPerSecond(50), mSkipTics(1000 / mTicksPerSecond), mMaxFrameSkip(10), mLoops(0) { mLastTick = tick(); } Clock::~Clock() { } bool Clock::step() { if (tick() > mLastTick && mLoops < mMaxFrameSkip) return true; return false; } void Clock::reset() { mLoops = 0; } void Clock::update() { mLastTick += mSkipTics; mLoops++; } clock_t Clock::tick() { return clock(); } } TImer.h
      #pragma once #include "Common.h" namespace Game { class Clock { public: Clock(); ~Clock(); void update(); bool step(); void reset(); clock_t tick(); private: uint mTicksPerSecond; ufloat mSkipTics; uint mMaxFrameSkip; uint mLoops; uint mLastTick; }; } Common.h
      #pragma once #include <cstdio> #include <cstdlib> #include <ctime> #include <cstring> #include <cmath> #include <iostream> namespace Game { typedef unsigned char uchar; typedef unsigned short ushort; typedef unsigned int uint; typedef unsigned long ulong; typedef float ufloat; }  
    • By lxjk
      Hi guys,
      There are many ways to do light culling in tile-based shading. I've been playing with this idea for a while, and just want to throw it out there.
      Because tile frustums are general small compared to light radius, I tried using cone test to reduce false positives introduced by commonly used sphere-frustum test.
      On top of that, I use distance to camera rather than depth for near/far test (aka. sliced by spheres).
      This method can be naturally extended to clustered light culling as well.
      The following image shows the general ideas

      Performance-wise I get around 15% improvement over sphere-frustum test. You can also see how a single light performs as the following: from left to right (1) standard rendering of a point light; then tiles passed the test of (2) sphere-frustum test; (3) cone test; (4) spherical-sliced cone test

      I put the details in my blog post (https://lxjk.github.io/2018/03/25/Improve-Tile-based-Light-Culling-with-Spherical-sliced-Cone.html), GLSL source code included!
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OpenGL Terrain Rendering Issue

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Good evening everyone :) Ive just had my first attempt at creating a terrain from a height map (image). I guess its not terrible haha but it not how it should be. Im using OpenGL and Triangle Strips. Here is a screen shot of my terrain looking down on it: So hopefully u can see the liny effect im getting. Below is the code i use for building the terrain. Its not too long so dont be worried :)

public class TerrainBuilder

    public TerrainBuilder()

    public int createDisplayList(String mapFile, GL11 gl){
        int dL = 0;
        int width = getImageWidth(mapFile);
        int height = getImageHeight(mapFile);
        int heightMap[][] = loadMap(mapFile, width, height);

        dL = gl.glGenLists(1);
        gl.glNewList(dL, gl.GL_COMPILE);   

            for(int y = 0; y < height - 2; y++){
                    for(int x = 0; x < width; x++){
                        float xV = x * 2;
                        float yV = (float)(heightMap[y][x]);
                        float zV = -1 * y * 1;
                        float xV1 = x * 2;
                        float yV1 = (float)(heightMap[y + 1][x] );
                        float zV1 = -1 * (y + 1) * 1;
                        float vx = yV * zV1 - zV * yV1;
                        float vy = zV * xV1 - xV * zV1;
                        float vz = xV * yV1 - yV * xV1;
                        float i = (float)Math.sqrt(vx*vx + vy*vy + vz*vz);
                        if(yV < 0 || yV1 < 0){
                            System.out.println("Bellow 0 Y at: " + x + ", " + y);
                        vx = vx / i;
                        vy = vy / i;
                        vz = vz / i;
                        gl.glNormal3f(vx, vy, vz);

                        gl.glTexCoord2f(0.0f, 1.0f);
                        gl.glVertex3f(xV, yV, zV);
                        float nx1 = x * 2;
                        float ny1 = (float)(heightMap[y + 1][x]);
                        float nz1 = -1 * (y + 1) * 1;
                        float nx2 = (x + 1) * 2;
                        float ny2 = (float)(heightMap[y + 2][x]);
                        float nz2 = -1 * (y + 2) * 1;
                        vx = ny1 * nz2 - nz1 * ny2;
                        vy = nz1 * nx2 - nx1 * nz2;
                        vz = nx1 * ny2 - ny1 * nx2;
                        i = (float)Math.sqrt(vx*vx + vy*vy + vz*vz);
                        vx = vx / i;
                        vy = vy / i;
                        vz = vz / i;
                        gl.glNormal3f(vx, vy, vz);
                        gl.glTexCoord2f(0.0f, 0.0f);
                        gl.glVertex3f(xV1, yV1, zV1);
        return dL;
    public int getImageHeight(String file){
        int height = new ImageIcon(file).getIconHeight();
        return height;
    public int getImageWidth(String file){
        int width = new ImageIcon(file).getIconWidth();
        return width;
    public int[][] loadMap(String fileName, int width, int height){
        //Scale 0 - 15
        Image mapImg = new ImageIcon(fileName).getImage();
        int heightMap[][] = new int[height][width];
        BufferedImage map = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics g = map.createGraphics();
        Color color = new Color(map.getRGB(0,0));
        float greyScale = (float)(0.30 * color.getRed() + 0.59 * color.getGreen() + 0.11 * color.getBlue());
        float min = greyScale;
        float max = greyScale;
        g.drawImage(mapImg, 0, 0, null);
        for(int y = 0; y < height; y++){
            for(int x = 0; x < width; x++){
                color = new Color(map.getRGB(x,y));
                greyScale = (float)(0.30 * color.getRed() + 0.59 * color.getGreen() + 0.11 * color.getBlue());
                if(greyScale < min){
                    min = greyScale;
                if(greyScale > max){
                    max = greyScale;
                heightMap[y][x] = (int)greyScale;
        System.out.println("Min: " + min + ", Max: " + max);
        float diff = max - min;
        float scaleSec = diff / 25;
        System.out.println("Scale Sections: " + scaleSec);
        for(int y = 0; y < height; y++){
            for(int x = 0; x < width; x++){
                heightMap[y][x] = (int)(heightMap[y][x] / scaleSec);
        return heightMap;


So yes, im using Java and LWJGL. Im guess the reason i am getting that liney effect is because i may be using the triangle strips incorrectly? Thats just my only thought on wat could be incorrect with my terrain. Im building the terrain with this height map: Any help would be greatly appreciated, Cheers, Nick!!!

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hmm I would bet on a lighting problem. If you try to concentrate on the height, it seems to be continous, So I think there's nothing wrond with the strips iteslf. But the bottom line of vertices in a strip is always black, and I'm pretty sure you made a mistake when you compute the normal of one of the 2 vertex (inside the drawStrip loop)

I tried to understand the code that compute the normal, but I don't understand anything, although I compute normals from a heightfield in my engine ^^
And after more looking of your screenshots, most normals seem wrong.

To compute the normals, you need to take at least 3 points in your heightfiel, but in your code, you only take 2 ...

if you want the normal of vertex[x][y], its as follow :

vertex1 = vector3(x * 2, heightMap[x][y], y * 2);
vertex2 = vector3((x + 1) * 2, heightMap[x + 1][y], y * 2);
vertex3 = vector3(x * 2, heightMap[x][y + 1], (y + 1) * 2);
edge1 = vertex2 - vertex1;
edge2 = vertex3 - vertex1;
normal = normalize(crossProduct(edge1, edge2);

I use pseudo functions to make the understanding simpler. Try that, I really think the problem is with the lighting.

One way to check : disable lighting and siwtch to wireframe display


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Guest Anonymous Poster

Thanks for your replies, just a quick question, how do u switch to wireframe?

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Guest Anonymous Poster

Thanks for your replies, just a quick question, how do u switch to wireframe?

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arg, I didn't realize that you're probably in OpenGL ^^'
in DirectX, it's just a d3dDevice->SetRenderState(D3DRS_FILLMODE, D3DFILL_WIREFRAME); but in OpenGL, you can't (as far as I remember ... didn't code in OpenGL since a looooonng time ^^)

Well, at least, to check if your grid is well drawn (no error in the vertices position, replace the loop that draw the strips by a loop that simply draw the vertices (gl.glBegin(gl.GL_POINT_LIST); or similar) This way, you can see if your vertices are well placed. If it's the case (I believe it is) then, the problem clearly comes from the lighting. So, you'll have to correct the code that compute the normals ^^

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Ok here is a screen from the wireframe view, thanks for the tip btw:

To me it looks like a lighting problem, as suggested by others above, but before i look into the normals can anyone just approve of the diagnosis?

Cheers, Nick :)

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Your texture coordinates are fixed numbers ... and not only that, I only see 0,0 and 0,1 in the code. Neither of these can be right, surely? . . . try disabling textures and rendering it, so that you know for sure it is lighting and not the thing being lit . . .

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