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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 Depth texture seems odd and inaccurate

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I'm working with SharpDX. I've worked pretty extensively with OpenGL, and so far my project with DX11 has worked exactly as expected. However, now I'm working on making a depth buffer that I can also bind to a shader. I've got the shader resource view bound, and it appears to be passed in correctly. However, the range that the values are in seems completely wrong. When I use Graphics Debugger and view the image, the entire depth view is between 0.987 and 0.997. This range does change as the camera moves, and yes I do understand that depth is not linear in view space. The issue is that with my near and far frustums being set at 0.1 -> 200.0, the whole scene (even at 10ish meters) is around .99 in depth. The only way I can get any lower values is to have the camera directly intersect a triangle, at which point it still seems to fade to solid white very rapidly. Even if I don't bind the shader resource view, the issue is still there. Here's the code that creates the depth texture:

var depthTexture = new D3D11.Texture2D(renderer.GetDevice(),
    new D3D11.Texture2DDescription()
        Format = SharpDX.DXGI.Format.R32_Typeless,
        ArraySize = 1,
        MipLevels = 1,
        Width = Camera.GetWidth(),
        Height = Camera.GetHeight(),
        SampleDescription = new SharpDX.DXGI.SampleDescription(1, 0),
        Usage = D3D11.ResourceUsage.Default,
        BindFlags = D3D11.BindFlags.DepthStencil | D3D11.BindFlags.ShaderResource,
        CpuAccessFlags = D3D11.CpuAccessFlags.None,
        OptionFlags = D3D11.ResourceOptionFlags.None

Here's the code that creates the depth stencil view:

D3D11.DepthStencilViewDescription depthDesc = new D3D11.DepthStencilViewDescription()
    Format = SharpDX.DXGI.Format.D32_Float,
    Dimension = D3D11.DepthStencilViewDimension.Texture2D,
    Flags = D3D11.DepthStencilViewFlags.None,

Here's the code that creates the Shader Resource View:

gBufferShaderViews[2] = new D3D11.ShaderResourceView(renderer.GetDevice(), depthTexture, new D3D11.ShaderResourceViewDescription() {
    Format = SharpDX.DXGI.Format.R32_Float,
    Dimension = SharpDX.Direct3D.ShaderResourceViewDimension.Texture2D,
    Texture2D = new D3D11.ShaderResourceViewDescription.Texture2DResource()
        MipLevels = 1,
        MostDetailedMip = 0

And in case it's relevant, here's some code that seems related:

viewport = new Viewport(0, 0, Width, Height);
viewport.MaxDepth = 1.0F;
viewport.MinDepth = 0.0F;

I've tried using R24X8_Typeless / R24_UNorm_X8_Typeless as the format as well, it had the same exact issue, in the exact same range. Is there something I'm missing here? Could it have to do with the projection matrix? I'm using the built-in Matrix.PerspectiveFovLH function that comes with SharpDX, here's the call that builds that:

projection = Matrix.PerspectiveFovLH(fov * 0.0174533F, aspect, zNear, zFar); //The constant is degrees to radians

Ignoring the depth buffer, everything renders fine (including no issues with z-fighting or other depth issues).

Thanks in advance for any help that can be given, if more code is needed just let me know and I'll get it.

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When I use Graphics Debugger and view the image, the entire depth view is between 0.987 and 0.997.

For a 24-bit zbuffer, there's about 17 bits of precision between those two values, which is plenty enough for a zbuffer to be working / not have any z-fighting.

my near and far frustums being set at 0.1 -> 200.0, the whole scene (even at 10ish meters) is around .99 in depth.

That is entirely as expected. Given those numbers, and a 24 bit buffer, at 10 units, the zbuffer value will be 16617752/16777216, or ~0.9905.
You can check the math :)
a = zFar / ( zFar - zNear )
b = ( zFar * zNear ) / ( zNear - zFar )
new_z = a + b / z
z_buffer_value = (2^24) * new_z 
0.9905 ~= (200/(200-0.1)) + ((200*0.1)/(0.1-200)) / 10
You don't have a problem. Everything is working as normal.

and yes I do understand that depth is not linear in view space

This shows exactly how crazy this fact is.
The recommended way to mitigate this is to use a 32-bit floating point depth buffer, and construct your perspective matrix in a way where the far plane is mapped to 0.0 after projection, and the near plane is mapped to 1.0 after projection (opposite of the traditional way of making perspective matrices). The reason behind this choice is that floating point is also not linear -- it has more precision when close to zero. These two non-linear curves then mostly cancel out -- the "reverse" perspective matrix will push most values to be very close to zero, and the floating point format dedicates most bits to representing values that are close to zero... so you end up with something close to linear precision across the entire depth range.
z_buffer_value = (2^24) * ( a + b / z )

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