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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 How do I determine the maximum VBO size?

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I was playing around with some old maze generation code and tried to generate a maze 10000 x 10000 cells in size. The algorithm had no trouble generating the maze, but sending the VBO with 400,000,000+ vertices to the graphics card caused a crash. I didn't think of it at the time, but with 24 bytes per vertex, that totaled over 9.6 billion bytes of data. This exercise was, of course, unnecessary and a waste of time, but it did bring up something that I hadn't considered before.... How does one determine if the data being sent will fit into the graphics card's RAM prior to sending it? If sending too much data will cause a crash, then it is important to know before hand. I know that my graphics card has xx total VRAM, but not all of that space is available to me.

 

Does OpenGL provide some mechanism to get this information? I am aware that it would be dependent on the card manufacturer, but the driver should make this information available to the API, I would think. I've search OpenGL's documentation, but I cannot seem to find anything. Maybe this is something that is only available through the OS?

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Does OpenGL provide some mechanism to get this information? I am aware that it would be dependent on the card manufacturer, but the driver should make this information available to the API, I would think. I've search OpenGL's documentation, but I cannot seem to find anything. Maybe this is something that is only available through the OS?

There isn't really a fixed amount that is available. 

 

The card has some fixed total storage, given by the amount of video RAM. From that you need to subtract the space taken by shaders, textures, vertex buffers, and any framebuffers. And each of those is per application which shares the GPU.

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I googled this and didn't find any documentation regarding a limit on VBO size.  I also read that if there's not enough memory for a VBO, then it will be placed in system memory.  

 

Also, I wanted to ask you this, are those 400,000,000+ primitives always within your viewing frustum?  I really hope you're culling everything you're camera isn't facing! wink.png

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There are several ways to get information about memory allocation through the API. NVX_gpu_memory_info and ATI_meminfo are some of the extensions for that.

I tried to summarize main aspects of those extensions in OpenGL Insights, Chapter 38, pg.535-540.

 

There is a limit in size of objects in graphics card memory. It depends on graphics card memory size, driver policy, and probably architecture. Different vendors also expose different policies. NV, for example, won't draw objects that cannot fit into the dedicated graphics memory, while AMD allows drawing directly from the shared system memory. This shouldn't be accepted as absolute truth, but that's just the behavior of drivers and cards I had tested.

 

In any case, splitting gigantic VBOs into smaller chunks enables more efficient memory management. At the cost of reducing performance, the sum of dedicated and shared memory can be used for storing graphics objects.

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Thanks for the replies. This was me being bored and not an actual project. If it had been an actual project I would have divided up the maze into zones and only displayed the zones visible in the frustum.

I am curious why the program crashed at glBufferData with a bad_alloc exception? If the VBO could have been placed in system memory, of which I have 16 GB, there shouldn't be an issue. Odd. Maybe a driver issue?

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If it was a 32-bit program then I'd expect a failure, but definitely not a crash; even if 64-bit you should not have crashed - glBufferData is specified to generate GL_OUT_OF_MEMORY if the requested size can't be allocated.  Almost certainly a driver bug (although I don't expect that there are too many people creating > 9gb buffers so the code path for this may not be robustly tested in any driver!)

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If it was a 32-bit program then I'd expect a failure, but definitely not a crash; even if 64-bit you should not have crashed - glBufferData is specified to generate GL_OUT_OF_MEMORY if the requested size can't be allocated.  Almost certainly a driver bug (although I don't expect that there are too many people creating > 9gb buffers so the code path for this may not be robustly tested in any driver!)

That is what I was thinking. Thanks for the answer.

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Thanks for the replies. This was me being bored and not an actual project. If it had been an actual project I would have divided up the maze into zones and only displayed the zones visible in the frustum.

I am curious why the program crashed at glBufferData with a bad_alloc exception? If the VBO could have been placed in system memory, of which I have 16 GB, there shouldn't be an issue. Odd. Maybe a driver issue?

That 9GB VBO cannot be allocated by any mean. Shared system memory is not the same as system memory. Take a look at your graphics card's control panel. It is probably less than 2GB. Second, transferring data from CPU memory to GPU memory goes through two phases - copying from application memory space to driver memory space, and copying from driver memory space to device. Allocating objects that are bigger than a dedicated or shared graphics memory is nonsense by any mean. That's probably why vendors (you didn't mentioned which) have "forgotten" to catch the exception, as mhagain said.

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Well... I tried to allocate 16 million vertices, 11 floats for each, 704Mb, and my GTX 560 Ti with 1Gb failed miserably :D So I wouldn't even try with 400 million.

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