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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 Mouse Control

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Can somebody help me please. I don't know how to use the wm_message with the mouse. I have the problem when using it with the OpenGl Cordinates. I don't know how to change into the system of OpenGL from the Pixelsystem. What float value has the pixelcordinates as example 245, 318. PLease help me. thx Yosh

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This depends on what you are trying to acheive with the mouse :) If you are attempting to navigate around a 3d world i.e. rotate etc - you just need to rotate your model view matrix by the delta x/ y value of the mouse. If you are trying to select objects then you need to unproject the mouse coordinates (see gluUnproject and google "opengl selection").

Post back what you are trying to acheive and i'll try to help if I get time


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Ok i want to make a menue where i defrine a space with an picture in it. If my mouse cords are in this space which i defined something should happen. but i dont know how to compare the Opengl cords like 1.0f and the pixel cords 315 integer. please help me.



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Opengl cords like 1.0f and the pixel cords 315 integer.

It depends on how you set up you projection matrix. Please post more details.

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Hi yosh,

I'm not sure if this is exactly the right way, but I have worked out this methodology to catch mouse movement, the coordinates, and convert the current 2D Windows mouse position to OpenGL 2D screen coordinates:

// Convert screen coordinates to OpenGL coordinates
void ConvertMousePos(MouseState &mouseState)
GLint viewport[4];
GLdouble mvmatrix[16], projmatrix[16];
GLint realy; // OpenGL y coordinate position
GLdouble glx,gly,glz;

// obtain viewport, modelview, and projection matrix
glGetIntegerv(GL_VIEWPORT, viewport);
glGetDoublev(GL_MODELVIEW_MATRIX, mvmatrix);
glGetDoublev(GL_PROJECTION_MATRIX, projmatrix);
// calculate OpenGL Y position from height of window (viewport[3] is window height in pixels)
realy = (viewport[3] - (GLint) mouseState.y) - 1;
gluUnProject((GLdouble)mouseState.x, (GLdouble)realy, (GLdouble)mouseState.z, mvmatrix, projmatrix, viewport, &glx, &gly, &glz);
mouseState.glx = (GLint)glx; mouseState.gly = (GLint)gly; mouseState.glz = (GLint)glz;

As nefhty says, the viewport orientation determines the realy calculation. Windows has (0,0) top left, whereas I have my OpenGL viewport with (0,0) lower left. This requires me to subtract the OpenGL viewport height (viewport[3]) and subtract the current windows Y location. Draw it on paper and you will get it :-)

I also use a generic struct for storing my mouse state:

// structure for holding current state of the mouse
struct MouseState
int leftButDown; // left mouse button control
int rightButDown; // right mouse button control
int middleButDown; // middle mouse button control
int leftButDblClick; // left mouse button double click control
int rightButDblClick; // right mouse button double click control
int middleButDblClick; // middle mouse button double click control
int x; // mouse position on screen
int y;
int z;
int lastx; // previous mouse position on screen
int lasty;
int lastz;
GLint glx; // OpenGL position in world space
GLint gly;
GLint glz;
GLint lastglx; // Previous OpenGL position in world space
GLint lastgly;
GLint lastglz;
int deltax; // Change in position from last to current
int deltay;
int deltaz;
int deltaglx; // Change in position from last to current in world space
int deltagly;
int deltaglz;

// constructor for mouse state
// initialise member variables
leftButDown = 0; rightButDown = 0; middleButDown = 0;
x = 0; y = 0; z = 0; glz = 0; gly = 0; glz = 0;

and in my WndProc routine I capture the mouse movement messages like this:

static POINT mousePos; // Store mouse coordinates

// detect mouse messages
case WM_LBUTTONDBLCLK: // Left button double click
mouseState.leftButDblClick = true;
// not interested in processing leftButton event for double click
mouseState.leftButDown = false;
return 0;
case WM_RBUTTONDBLCLK: // Right button double click
mouseState.rightButDblClick = true;
// not interested in processing leftButton event for double click
mouseState.rightButDown = false;
return 0;
case WM_LBUTTONDOWN: // Left button down
mouseState.leftButDown = true;
return 0;
case WM_RBUTTONDOWN: // Right button double click
mouseState.rightButDown = true;
return 0;
case WM_MBUTTONDOWN: // Middle button double click
mouseState.middleButDown = true;
return 0;
case WM_LBUTTONUP: // Left button released
mouseState.leftButDown = false;
mouseState.leftButDblClick = false;
return 0;
case WM_RBUTTONUP: // Right button released
mouseState.rightButDown = false;
mouseState.rightButDblClick = false;
return 0;
case WM_MBUTTONUP: // Middle button released
mouseState.middleButDown = false;
return 0;
case WM_MOUSEMOVE: // Mouse movement
// preserve mouse position before new query
mouseState.lastx = mouseState.x; mouseState.lastglx = mouseState.glx;
mouseState.lasty = mouseState.y; mouseState.lastgly = mouseState.gly;
mouseState.lastz = mouseState.z; mouseState.lastglz = mouseState.glz;
// query mouse position and state
ScreenToClient(hWnd, &mousePos);
mouseState.x = mousePos.x;
mouseState.y = mousePos.y;
// get OpenGL coords from current Windows mouse position
// update delta
mouseState.deltax = mouseState.lastx - mouseState.x; mouseState.deltaglx = mouseState.lastglx - mouseState.glx;
mouseState.deltay = mouseState.lasty - mouseState.y; mouseState.deltagly = mouseState.lastgly - mouseState.gly;
mouseState.deltaz = mouseState.lastz - mouseState.z; mouseState.deltaglz = mouseState.lastglz - mouseState.glz;


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Hi, i am having problems to understand the opengl coordinates, i am programing a billiard, and i would like to move the stick aoroud the cue ball.

I have already the equations to do that, but i don't get the rigth coordinates:

glGetDoublev(GL_MODELVIEW_MATRIX, modelMatrix);
glGetDoublev(GL_PROJECTION_MATRIX, projMatrix);
glGetIntegerv(GL_VIEWPORT, viewport);

gluUnProject((float)point.x, (float)point.y, 0.0,
modelMatrix, projMatrix, viewport,
&objx, &objy, &objz);

gluUnProject((float)point.x, (float)point.y, 1,
modelMatrix, projMatrix, viewport,
&objx2, &objy2, &objz2);

If i debug just that, in obj2, or obj1 i get strange results.
What's wrong? And there is not another way to rotate the cuestick without
using gluUnProject with opengl?

Thank you very much

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