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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:
      https://github.com/fleissna/flyEngine

      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.

      Bye,

      Phil
    • 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 ==========  
       
      Renderer.cpp
      #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; }  
      Game.zip
    • 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!
       
      Eric
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OpenGL Does it matter what OpenGL version I learn to use?

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Hi,

Question is in the title.

I've been programming in C/C++/Java for my classes in computer science for a few years now but haven't done anything substantial.

I've been skimming over OpenGL stuff and found it hard to start and realize there's MANY outdated tutorials/books available that may not necessarily apply to the latest version of OpenGL.

My question is -- should I seek out guides/tutorials/documents that talk only about the latest OpenGL or should I simply learn any version that I feel comfortable learning with?

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I would stay clear of any fixed function and immediate mode stuff. I think 3.3 is a reasonable baseline. And if you want to support older systems you can do 2.1 but in a 3.3+ style (with custom attributes, shaders, no matrix stack...).

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Doesn't matter, depends on what guides you find. I think jumping right into shaders might be hard since new OpenGL requires it. Everything translates and of course mobile phones still use older openGL at the moment, so the answer is: doesn't matter much.

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Doesn't matter, depends on what guides you find. I think jumping right into shaders might be hard since new OpenGL requires it. Everything translates and of course mobile phones still use older openGL at the moment, so the answer is: doesn't matter much.


On mobiles, you use OpenGL ES, not OpenGL. They are not the same, although they are similar.
On the desktop, you might have OpenGL ES available as well, but I think the OP is talking about OpenGL. In which case, version 3.3 is a good aim.

If the goal is to just learn the API, it doesn't matter much.

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If you want a spinning triangle or you want to draw some textured sprites as in a tile-based 2D game, it doesn't matter. Otherwise, it makes a huge difference. I would recommend starting to learn OpenGL 3.3 (3.2 if you target Mac), and having an optional look into 4.x (reasons follow).

Versions 3.x and 4.x follow a much more modern model (server-side data buffers) and are usually significantly more efficient. Starting with OpenGL 1.x/2.x you will most probably sooner or later have to "unlearn" everything that is now wrong and learn the proper techniques.

Also, assuming OpenGL 3.x as a minimum requirement has advantages. OpenGL 2.x turns out to be a nightmare when you want to do something "real". The minimum requirements defined by the spec are a joke. Though most hardware supports much better than the minimum, you have no guarantee and you must query every single bit, which isn't all nice and easy. Some hardware just doesn't support more than the bare minimum -- what now?. A lot of the "useful modern" functionality is only available as extension, which further complicates your program, since you have to query for extension presence and write alternative codepaths.
And then, some vendors will just lie to you, directly or indirectly (that is, by following word by word a specification that has been explicitly worded in a deceptive manner). Using extensions properly (and you will need to use many...) can be a real challenge. Writing code (other than some colored triangles) that runs on, say, 1.5 to 2.1 included is... daunting.

Version 3.0 has minimum requirements. There is no such thing as an OpenGL 3.0 graphics card that supports vertex texture fetch with "maximum 0 fetches", or multiple render targets with "max number of targets = 1" or textures no larger than 256x256.

Almost all things that are "just normal" such as reasonably sized textures, framebuffer objects, and at least 4 render targets are mandatory. In other words, as soon as you have version 3.0, you know that you can do most things without having to worry. It will work.
You need very few, if any, extensions in addition. Plus, the ones you will want to use are mostly of the kind "nice to have, but ok if missing". Whereas in 2.x it was more a "oh shit, what now?" situation.

OpenGL 3.1 to 3.3 inclusive add features which may or may not be interesting to you (to me they are), but they run on the same class of hardware. There is however a considerable difference in how parameters are declared between 3.1 and 3.2, which again makes writing a shader that "just runs" on any version an impossible endeavour. Thus, I've decided for myself to just stick with 3.3, which works and has none of the problems. Writing code that works on 3.3 and works the same on 4.x is a breeze.

Now of course Version 4.0 adds more features and 4 is a bigger number than 3, and bigger is always better.
However, do note that Mac currently (to my knowledge) supports none higher than version 3.2 and in general you will need a different class of hardware to run OpenGL 4.x. Not all your customers will have the most recent class of graphics hardware on their system (though you can pretty much assume that OpenGL 3.x is omnipresent with anyone whom you would want as customer nowadays -- someone who wouldn't pay $25 for a graphics card 3 years ago won't pay for your game either!).
Everything in 4.x that doesn't strictly require hardware support is also present as 1:1 identical backtension in 3.x on the major IHVs (backtensions as I call them are really ARB extensions that are 100% identical to core functionality. If only the ARB guys had either been smart enough to name them differently too (BRA would have been nice!) so you have a chance of knowing that functions and constants don't adhere to the ARB's own naming scheme... Edited by samoth

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