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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 Should I start with fixed-function-pipeline OpenGL or the newest possible?

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    Guys, I made a few projects on SDL 1.2 and I decided to jump to 3D programming.
I found that 3D Math Primer book and I swallowed the first 200 pages.

I was bored and I decided to practice a little bit with OpenGL before reading the next chapters.


    I used the lazyfoo OpenGL tutorials which, by the way, are not so good (his SDL tutorials are more than perfect, though). He explained the matrix transformations in the ugliest way possible, good thing I read that math primer book first, so I got what he said. Next, he starts first with some old-pipeline OpenGL stuff, doesn't really explain how all the matrices are interacting with each other and with screen, and not everything is explained properly (or I'm just stupid).


    And I'm wondering, should I continue with his tutorials, although I understand 60-70% of it, or should I see some OpenGL books. And what OpenGL version should I start with, old one first, or directly jump to the newest one?. I have a basic understanding of how objects should be transformed while moving forward or backwards with a player using WASD keys, but I can write only some pseudocode using a piece of paper, can't do it in OpenGL. Until I receive an answer, I will torture myself with those lazyfoo tutorials. So better answer quickly.

Edited by Heelp

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Just to echo what the others have said, It's harder to get started using non-fixed function stuff, a lot harder. I don't know exactly how much code is required to draw just a simple triangle with fixed function compared to non-fixed function but I'm sure it's at least an order of magnitude more to use non-fixed function. Still, there are tutorials out there and you should persevere. Sometimes learning an earlier tech helps towards the newer tech (you can't run before you can walk) but for OpenGL I do not believe that to be the case any. You'll just be learning things that don't transfer and going into later versions of OpenGL with certain expectations that no longer hold true. As for what version I can't really say, 3+ and if you are interested in GLES (mobile development) then 2+. 

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Let me add my comment on the topic.
Although the fixed functionality is deprecated it is still very useful for an introduction to computer graphics. There are several reasons for this:
1. The learning curve is much steeper with new APIs. For the legacy OpenGL you should know only the API. For the modern OpenGL you should also know math and physics, while for the Vulkan you should also know operating systems and how HW works.
2. The number code lines increase exponentially. For the triangle drawing in the legacy OpenGL one needs a dozen lines of code, about 400 lines in modern OpenGL and about 1000 in Vulkan.
3. Being overwhelmed with non-graphics topics, the beginner usually misses the main concepts like transformations, lighting, texturing etc.
That's why I'm still teaching legacy OpenGL in the first course of Computer Graphics, while the programmable pipeline is left for the advanced course (next year, after passing the first one). So far it works well.

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    Ok guys, thanks a lot for all the answers. There is so much stuff going on in games, now I understand why all the guys in my class jump straight to the web-related stuff, lol. I can't believe that there are people out there who are game developers. That must be soooo coool!


    Back to the topic, I did some 5-6 tutorials with the old OpenGL, now the next best step seems to be to read "Learning Modern 3D Graphics Programming" (why do people use the word "modern" in a book, I've always wondered). Nevermind, hope I don't have problems.


    Aks9, I never knew there was a Computer graphics course, that teaches OpenGL. There isn't a Computer Graphics course in my university, but I see online that there are even courses for undergraduates, not only for post-grads.Which provokes my next question: Did I mess up choosing Computer Science course instead of Computer Graphics? Is it possible to do game-related stuff with Computer Science degree, or should I find some major in Computer Graphics or something? There are some articles on the internet, but are kind of outdated, that's why I ask here.

Edited by Heelp

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Is it possible to do game-related stuff with Computer Science degree, or should I find some major in Computer Graphics or something? There are some articles on the internet, but are kind of outdated, that's why I ask here.

A proper university undergraduate degree is not job training.  A degree in computer science will give you the foundation to do many things once you enter the vocational world, and remember, you are not a career, and jobs change radically faster than you realize.


You can devote your spare energy to doing game development and building your own portfolio without getting formal vocational training in a post-secondary institution. Once you graduate, you can then either choose specialization in grad school (which is sort of like vocational training for academia), attend a vocational school or college for formal job training in game development, or start marketing your skills and talent using your hobby portfolio.  Your computer science degree will still serve you well in 20 years while robots program all the quantum biocomputer implants we will rely on as we relax in our autonomous flying cars.


But I'd recommend starting with OpenGL 2 and the Red Book because first you need to learn about the graphics pipeline, basic 3D game program structure and dataflow, vertexes drawing and transforms, colour, textures, and all the basics before you open up the engine and see how the buffers and shaders work inside.  Consider what you write using OpenGL 2 as throwaway, but what you learn is not throwaway.  Your target will be to learn OpenGL 3.5 and OpenGL ES 2 and use that for writing games that are not throwway.

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Ok, thanks for info, man, really. I'm gonna hit the books hard now. Will post my demo here after 1 or 2 months, show my progress :cool: .

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    Back to the topic, I did some 5-6 tutorials with the old OpenGL, now the next best step seems to be to read "Learning Modern 3D Graphics Programming" (why do people use the word "modern" in a book, I've always wondered). Nevermind, hope I don't have problems.
Thats a really nice online book thingy. It teaches pure "core" OpenGL, so no deprecated stuff at all. It also nails down the math nicely. 

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