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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 D3D12 atrocious performance

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I'm getting about 10 FPS with only about 20 draw calls of very small meshes.


Clearly I'm doing something very very wrong.


Is there an issue with populating a single command list to draw 20 items?  I figured even if that isn't optimal, it shouldn't be THIS terrible.  At this point my iPad running OpenGL ES is outperforming my d3d12 engine by a massive margin.


The following code runs before most of my draw calls to set up necessary state:  


Sorry for the messed up tab spacings

	void CoreStateMachine::prepareToDraw()
		auto cl = continueRenderingCommands();

		//prepare any buffers required by current shader program
		auto prog = currentProgram;

				prog->globalCBuffer = make_shared<BufferArray>();
				prog->globalCBufferDirty = true;
				//this should be cleaned up at some point
				prog->globalCBuffer = make_shared<BufferArray>();
				prog->globalCBufferDirty = true;

				prog->globalCBuffer->provideData(0, prog->globalCBufferSize, prog->globalCBufferData, BufferArray::UT_DYNAMIC);
				prog->globalCBufferDirty = false;

			cl->SetGraphicsRootConstantBufferView(2, prog->globalCBuffer->buffers[0]->GetGPUVirtualAddress());

		auto currentVA = VertexArray::current();
		assert(currentVA != nullptr);

		device->CopyDescriptorsSimple(textureTableSize, cbSrvHeaps[descriptorHeapIndex]->hCPU(textureTableIndex), cpuCbSrvHeap->hCPU(0), D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV);
		device->CopyDescriptorsSimple(textureTableSize, samplerHeaps[descriptorHeapIndex]->hCPU(textureTableIndex), cpuSamplerHeap->hCPU(0), D3D12_DESCRIPTOR_HEAP_TYPE_SAMPLER);

      ID3D12DescriptorHeap *descHeaps[] = { cbSrvHeaps[descriptorHeapIndex]->get(), samplerHeaps[descriptorHeapIndex]->get() };
      cl->SetDescriptorHeaps(ARRAYSIZE(descHeaps), descHeaps);
      descriptorHeapsChanged = false;

		//might be smarter to set this up earlier if I can.. not sure what the tradeoff is here
			pipelineState = nullptr;
		ThrowIfFailed(device->CreateGraphicsPipelineState(&psoDesc, IID_PPV_ARGS(&pipelineState)));


      cl->SetGraphicsRootDescriptorTable(0, cbSrvHeaps[descriptorHeapIndex]->hGPU(textureTableIndex));
      cl->SetGraphicsRootDescriptorTable(1, samplerHeaps[descriptorHeapIndex]->hGPU(textureTableIndex));
      descriptorTablesChanged = false;

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Thanks.   You're so right.  I just came to this.  My arch isn't setup well for caching PSOs but after refactoring some stuff, fingers crossed, I'll get some good draw call performance.

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omfg.  here's another tip.  DON'T test performance with debug builds.  I forgot about how bad the performance of MSVC generated debug builds are.  Doing a release build shot the performance of the whole system up to max FPS


Spent the last hour chasing around a phantom

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omfg.  here's another tip.  DON'T test performance with debug builds.  I forgot about how bad the performance of MSVC generated debug builds are.  Doing a release build shot the performance of the whole system up to max FPS


Spent the last hour chasing around a phantom


I wrote a massive nest of inter-related entities involving thousands of STL containers and a half-assed messaging/scheduling system for school once. The time to simulate a single day in debug was about 2 minutes. The time in release was about 10 seconds.

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It may be time to give up on d3d12.  My opengl system massively outperforms it with a drastically simpler architecture, even on a freaking ipad.  I thought I'd be able to get performance gains without dicking around too much - that was the appeal of d3d12 and the coming vulkan to me.  But man... 7 days in a row of staying up til 2am... and I still don't have it.  This just plainly is not worth it for me.  


My system changes "uniform" global constants very often and at unpredictable times.  At a high level, the kind of "precomputation" that d3d12 would need to be fast just isnt there.  It feels like instanced rendering all over again.  I can't seem to find a way to efficiently copy the needed cbuffer data before draw calls in a way that doesn't hurt performance.


I know my code is suboptimal, but I expected to outperform opengl at the very least with this kind of baseline.


very dissapointing...

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Without trying to be too dismissive of your technical abilities, I feel pretty confident in saying that the fault probably lies at your door rather than any shortcomings in the API.


The ability to rapidly "map" and set new constants very quickly is one of the key areas that has become a lot faster in D3D12. The simplest scheme to be able efficiently update constants is simply to allocate two chunks of memory, each large enough to hold all the constants that need to be written for a single frame. You can persistently map a buffer for the lifetime of the application and need only memcpy your constants to a monotonically increasing address during the frame before switching to the other of the two buffers for the following frame. 


Perhaps you could explain how you've implemented constant updates?

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It may be time to give up on d3d12.  My opengl system massively outperforms it with a drastically simpler architecture, even on a freaking ipad.  I thought I'd be able to get performance gains without dicking around too much - that was the appeal of d3d12 and the coming vulkan to me.


This is very important right here. D3D12, Vulkan (and Mantle) do not exist to make a programmer's life easier, they exist to get the most out of your hardware when you need it, at the cost of the developer having to take on a lot more work to get the rendering side of your application in a stable state.


If you can comfortably do whatever your application needs to do with OpenGL/D3D11, then by all means keep using those APIs; the new generation of APIs is not meant as a replacement for these, but as an alternative.


If you feel that your application can't get to the point where you want it to be because the runtime itself is holding you back then you'll want to spend your time getting intimate with D3D12 or Vulkan.


Remember that these new APIs are not a magic wand you can wave at your application to suddenly make things run faster (even though Microsoft's marketing department would like you to believe that), nor do they magically push your GPU into overdrive so it can suddenly process a lot more data. These APIs were designed by and for those people who needed to push things to the limit and those people who felt confident enough in their knowledge of the inner workings of both graphics hardware and modern rendering engines to be able to make better low level decisions than any D3D11/OpenGL driver ever could.

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