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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 What OpenGL Implementation Do Real Games Use?

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Since there are many official (and unofficial) desktop OpenGL implementations, which do actual 3D games use? GLUT? FreeGLUT? Mesa3D?


Which performs the best?

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Neither GLUT nor FreeGLUT are OpenGL implementations. They are windowing layers for OpenGL. Mesa3D is a software implementation that provides limited possibilities for hardware acceleration.


If you're on Windows, there's pretty much only one sensible option; you use the default implementation that the operating system provides. The benefit with using that implementation is that each hardware manufacturer provides their own hardware driver for it. Just link the standard opengl32.lib that ships with your compiler to use it.

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Mesa3D is the primary implementation of OpenGL on UNIX and supports several hardware graphics adapters (More than the default implementation in Windows infact).

But, yes it can also be compiled to be software only. Edited by Karsten_

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Define what an “actual” 3D game is?
Low-level indie games could use anything.  Many people use wrappers such as SDL or SMFL, but this is mainly just for helping them through the learning process or to get quick but not-so-serious results.
Medium-level indie games get closer to the direct API of choice, but it is not consistent enough to say what they “commonly” use, and at this point the target platform becomes much more of a decision-maker.  Of course the mobile industry is booming so it is worth mentioning that for mobile platforms they will all be using raw OpenGL ES 2.0.
But at this level those who are developing for Windows start to lean more towards DirectX and start to grow their own cross-platform engine (assuming you are not interesting in those who are using Unity 3D, Unreal Engine, etc., since you seem to want to get hands-on with your work).
At this level it is not always feasible in terms of skill or finances to make a DirectX port of an existing OpenGL engine, but even those who stick to OpenGL start to tend more towards raw OpenGL (no wrappers, just raw OpenGL).
At the AAA end of the scale things become more consistent but there is still no single answer.
By this point OpenGL is rarely used at all except for OpenGL ES 2.0 for mobiles.  Consoles and hand-helds (such as Nintendo 3DS) often provide an OpenGL (or OpenGL ES 2.0) layer but developers avoid this for performance reasons—it is always faster to use the native API.
That carries over to PC, in which the native API is DirectX.  As a result, most “actual” games (you didn’t define it so I can only assume what you meant) for the desktop market use DirectX when possible and OpenGL when no other options are available, and they strictly use raw OpenGL.
Generally the big game developers prefer to avoid OpenGL altogether if possible because it is like developing for Android—there are too many inconsistent implementations across vendors and the drivers are usually shoddy.  What works on one machine is guaranteed not to work on some other machine out there.
Another reason is that with the expectations on today’s graphics, they will require OpenGL 4.3, which requires users of Windows to upgrade manually if they have not already on Windows.
Valve is trying to put an end to this situation, and we may well start to see much better drivers (which means performance) and more consistent results in the future.
OpenGL is worth learning for 2 reasons:
  • There may be a surge in OpenGL games if Valve is successful in its Linux pursuit.
  • The mobile industry is booming and is a great place to start making your own indie games.
But if we assume that by “actual” you meant “AAA”, while there are always exceptions, the main answer is that they are using DirectX 11 first, then DirectX 9, then raw OpenGL if targeting Linux or Macintosh.  Generally speaking.
And which implementation?  I think you meant to answer which version.  You don’t get to pick your implementation—that is up to the vendors to implement.
The version you want is up to you.  Lower versions work across more machines, but your graphics will be pretty poor.  If you want compute shaders you will need core version 4.3 or GL_ARB_compute_shader extension.  If you use extensions, prepare for headaches as you implement all the fall-backs for unsupported features.  One more reason why the big guys stay away from OpenGL when possible.
L. Spiro Edited by L. Spiro

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As far as I know it is like this:


In *nix world you get: Mesa (up to 3.1 spec), proprietary GPU driver's implementation (up to 4.3 for nVidia, 4.2 for AMD) and OSS driver's implementation (i have no idea, enough to play Quake3 based games).

In Windows you get: Microsoft implementation (1.1 spec) and GPU driver's implementation (up to 4.3 for nVidia, 4.2 for AMD).

In OSX you get: Apple's implementation (up to 3.2 for everyone).


EDIT: Corrected Mesa's and Apple's spec implementations.

Edited by TheChubu

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In OSX you get: Apple's implementation (up to 3.1 for everyone).

OS X 10.8 (Mountain Lion) supports OpenGL 3.2 core with some OpenGL 3.3 features as extensions.

L. Spiro

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Just to clarify to MrJoshL, we don't really "choose" what implementation to use (unless we want to force software rendering and we explicitly do so)


If we want hardware acceleration (aka get access to GPU), we'll just load the OpenGL implementation that is installed in the system (for NVIDIA cards, it's NVIDIA's, for ATI cards, it's ATI's). Since they're implementations, they implement everything they're supposed to, otherwise we would get a crash or a "cannot load routine from library" error and exit.


In Windows, the OGL system is called OpenGL "ICD" (Installable Client Driver). When the driver (ati, nvidia, intel, sis, s3, powervr, 3dfx, etc) didn't provide an OpenGL implementation, the application will be routed to a software implementation developed by Microsoft which is very outdated (supports 1.1 spec) so if you're using something higher, your application it will just fail to load (it's as if DirectX wouldn't be installed for Direct3D games)

When the driver did provide the implementation, the ICD will route to the driver's DLL.


In Linux, something very similar happens. Most distros ship the Mesa software implementation (which is usually very up to date), and if you install proprietary drivers, the installation messes with distro's folders & symbolic links to use the driver's OGL implementation instead of Mesa's.

Every now and then the installer (either driver's or distro's package manager) may mess the installation and try to mix Mesa dlls with driver's and X11 will crash when launching a GL application (been there....... multiple times). The situation has improved a lot though, in the last couple of years.


In Mac, I have no idea how it works, but afaik Apple controls the implementation being shipped.



You can of course ship your game with Mesa DLLs (since it's the only implementation I'm aware of that could be licensed for that) and always use Mesa's implementation, but almost nobody would like to do that.


GLUT & FreeGLUT are layers that simplify the creation of a GL context, and may deal with all this trouble (i.e. not having the right ICD installed, not having required GL version, loading extensions, etc) because this is all messing with DLL & function loading that has nothing to do with rendering triangles to the screen.

Edit: We just want to load the installed implementation and start rendering with hardware acceleration.

Edited by Matias Goldberg

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