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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 Logical Operation Style Alpha Blending in D3D

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In OpenGL, one can do logical operations such as OR/XOR/Invert to current fragment and the value in the framebuffer correspondingly. I'm asking if there is any similar operations in D3D. Thanks a lot! [Edited by - NicholasYang on October 29, 2007 9:36:52 PM]

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There is a group of render states in D3D9 (or Output Merger stage in D3D10) that control how the new fragments are combined with the existing ones.

You use color blending by manipulating the following render states:
D3DRS_BLENDFACTOR
D3DRS_SRCBLEND
D3DRS_DESTBLEND
...and the corresponding states for alpha channel combiners.

It is easy to use the inverse of either source or destination, but bitwise operations are not directly supported using the standard blending scheme. Instead, you could use a render-target texture as a temporary surface and use pixel shaders to implement custom blending (on modern cards, you can run just about any logic there).

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Quote:
Original post by Nik02
There is a group of render states in D3D9 (or Output Merger stage in D3D10) that control how the new fragments are combined with the existing ones.

You use color blending by manipulating the following render states:
D3DRS_BLENDFACTOR
D3DRS_SRCBLEND
D3DRS_DESTBLEND
...and the corresponding states for alpha channel combiners.

It is easy to use the inverse of either source or destination, but bitwise operations are not directly supported using the standard blending scheme. Instead, you could use a render-target texture as a temporary surface and use pixel shaders to implement custom blending (on modern cards, you can run just about any logic there).


Thanks for your suggestion! But there is something more complicated that custom blending could not do. For example, I want to do an operation that is very similar to Alpha Blending. The difference between them is that, I want the operator to be a logical operator, EX. XOR/OR. I could not afford to render one layer to a surface and then render another and after several layers are ready, use a pixel shader to combine them. This is very inefficient.
What can I do in D3D to implement this ?

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Prior to Direct3D 10 (which introduces a 32bit integer instruction set) you can't really do proper logical or bitwise operations in a pixel shader. You can fudge the results by being clever and hoping that floating point precision doesn't bite you, but ultimately it's still a hack.

Quote:
I could not afford to render one layer to a surface and then render another and after several layers are ready, use a pixel shader to combine them. This is very inefficient.
Are you sure? I'm not saying you're wrong as such, but the style of architecture Niko proposed is fairly common place in D3D rendering (breaking down complex operations into many smaller ones) and isn't always bad for performance.

GPU's have pretty complex performance characteristics, so something that sounds bad on paper isn't necessarily bad in practice (and vice versa)...

hth
Jack

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Quote:
Original post by jollyjeffers
Prior to Direct3D 10 (which introduces a 32bit integer instruction set) you can't really do proper logical or bitwise operations in a pixel shader. You can fudge the results by being clever and hoping that floating point precision doesn't bite you, but ultimately it's still a hack.


It should be easy to get a logical operation done in D3D9 by use of a 256 x 256 x 8-bit lookup texture. You'd just need 3 lookups per pixel (one for each channel). I suspect it would be quicker than the floating point maths, and it's certainly less dependant on precision.

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Yup, the look-up table approach is a good one provided you can fit everything into a texture (e.g. 8-12bit resolution) and don't mind trading arithmetic performance for bandwidth and memory consumption.

I've found it to work quite well for factorising other rendering functions, but equally I've seen reports of it being quicker to brute force the arithmetic and save bandwidth and memory for other things... YMMV [smile]

Jack

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There is one thing I want to HIGHLIGHT. I mean I want to implement a ALPHA- BLENDING-LIKE logical operation. How can I do it Just Like In OPENGL.
Rendering layer after layer has the shortcoming of complexity. First of all, you do not know how many layers there actually are. You need to guarantee that all layers have been rendered. You need to do depth peeling again and again. You need to sample many many samples from the layers in the final combination pass whose efficiency can not be guaranteed.

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As Niko suggested, you'll need to look into the D3DBLEND enumeration. That lists each and every operation you can do in an "alpha blend style".

The fixed function texture cascade can do some clever operations, but ultimately that is only a different way of expressing SM1 pixel shaders.

If you can't find anything in D3DBLEND then you're going to have to go down the complex pixel shader route. Might just be that D3D doesn't expose the same GPU functionality as OpenGL...

hth
Jack

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NicholasYang, can you tell me how it's done in OpenGL? I don't remember such a blending operation in OpenGL (granted, I used it long ago), and it doesn't make sense to me, considering that bitwise operations depend on the number format. So seeing some reference to the operation in OpenGL would be nice. Thanks.

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Quote:
Original post by ET3D
NicholasYang, can you tell me how it's done in OpenGL? I don't remember such a blending operation in OpenGL (granted, I used it long ago), and it doesn't make sense to me, considering that bitwise operations depend on the number format. So seeing some reference to the operation in OpenGL would be nice. Thanks.


It is called logical operation in OpenGL, you can get some discussion from the book <<OpenGL programming Guide>> chapter 10, section 10.2.5. I suppose that for GPU, there is only one architecture of pipeline, only drivers differ for OpenGL and D3D. If I'm right, there must be some method to achieve the same functionality in D3D as in OpenGL

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