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    • 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
    • By Fadey Duh
      Good evening everyone!

      I was wondering if there is something equivalent of  GL_NV_blend_equation_advanced for AMD?
      Basically I'm trying to find more compatible version of it.

      Thank you!
    • By Jens Eckervogt
      Hello guys, 
       
      Please tell me! 
      How do I know? Why does wavefront not show for me?
      I already checked I have non errors yet.
      using OpenTK; using System.Collections.Generic; using System.IO; using System.Text; namespace Tutorial_08.net.sourceskyboxer { public class WaveFrontLoader { private static List<Vector3> inPositions; private static List<Vector2> inTexcoords; private static List<Vector3> inNormals; private static List<float> positions; private static List<float> texcoords; private static List<int> indices; public static RawModel LoadObjModel(string filename, Loader loader) { inPositions = new List<Vector3>(); inTexcoords = new List<Vector2>(); inNormals = new List<Vector3>(); positions = new List<float>(); texcoords = new List<float>(); indices = new List<int>(); int nextIdx = 0; using (var reader = new StreamReader(File.Open("Contents/" + filename + ".obj", FileMode.Open), Encoding.UTF8)) { string line = reader.ReadLine(); int i = reader.Read(); while (true) { string[] currentLine = line.Split(); if (currentLine[0] == "v") { Vector3 pos = new Vector3(float.Parse(currentLine[1]), float.Parse(currentLine[2]), float.Parse(currentLine[3])); inPositions.Add(pos); if (currentLine[1] == "t") { Vector2 tex = new Vector2(float.Parse(currentLine[1]), float.Parse(currentLine[2])); inTexcoords.Add(tex); } if (currentLine[1] == "n") { Vector3 nom = new Vector3(float.Parse(currentLine[1]), float.Parse(currentLine[2]), float.Parse(currentLine[3])); inNormals.Add(nom); } } if (currentLine[0] == "f") { Vector3 pos = inPositions[0]; positions.Add(pos.X); positions.Add(pos.Y); positions.Add(pos.Z); Vector2 tc = inTexcoords[0]; texcoords.Add(tc.X); texcoords.Add(tc.Y); indices.Add(nextIdx); ++nextIdx; } reader.Close(); return loader.loadToVAO(positions.ToArray(), texcoords.ToArray(), indices.ToArray()); } } } } } And It have tried other method but it can't show for me.  I am mad now. Because any OpenTK developers won't help me.
      Please help me how do I fix.

      And my download (mega.nz) should it is original but I tried no success...
      - Add blend source and png file here I have tried tried,.....  
       
      PS: Why is our community not active? I wait very longer. Stop to lie me!
      Thanks !
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OpenGL OpenGL Check if VBO Upload is Complete

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I've learnt that the upload of VBOs is asynchronous.

 

How can I check that my VBO is uploaded?

 

I'd like to do this in order not to try to draw it before the upload is complete, as this halts the program (and a lag spike is felt).

 

Edit: I've read up on fence syncing but supposing that I have my fence, how do I check for whether it's been used by the GPU without using glWaitSync? I'd like to check and get a boolean response, as opposed to waiting.

Edited by Lolums

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Because the OpenGL spec doesn't recognize the transfer as asynchronous, per se, there's no way to check. The only option is to force it to wait by issuing a dummy draw call. There are a variety of other things that can also be deferred and lead to hitching in-game, and so it's standard practice to issue dummy draw calls for these things. Getting rid of all this is one of the big improvements in the new APIs (DX12/Vulkan).

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Because the OpenGL spec doesn't recognize the transfer as asynchronous, per se, there's no way to check. The only option is to force it to wait by issuing a dummy draw call. There are a variety of other things that can also be deferred and lead to hitching in-game, and so it's standard practice to issue dummy draw calls for these things. Getting rid of all this is one of the big improvements in the new APIs (DX12/Vulkan).

 

Ah, I see! In that case, I may just set a time-out and only try to render after half a second or something; this won't be noticeable. Problem with DX12 is that one can't support Linux,  which for me is a crime if one can avoid it. Vulkan looks promising. Thanks for letting me know though.

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Because the OpenGL spec doesn't recognize the transfer as asynchronous, per se, there's no way to check. The only option is to force it to wait by issuing a dummy draw call. There are a variety of other things that can also be deferred and lead to hitching in-game, and so it's standard practice to issue dummy draw calls for these things. Getting rid of all this is one of the big improvements in the new APIs (DX12/Vulkan).

 

Ah, I see! In that case, I may just set a time-out and only try to render after half a second or something; this won't be noticeable. Problem with DX12 is that one can't support Linux,  which for me is a crime if one can avoid it. Vulkan looks promising. Thanks for letting me know though.

 

It's not necessarily on a timer. Sometimes the driver simply can't be bothered to finish the upload until you actually issue a draw call.

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All GL commands are asynchronous, but act like they're immediate. Drawing commands are async too, so if you update a VBO and then draw, both those commands go into the same queue and are processed by the GPU one after the other.

If you want it to he truely async where the GPU is doing two things at once, you need to create another GL context and share the VBO between both contexts. This gives you a second queue that's independent of your main queue, and then you can use fences to track the progress of this secondary queue.
This is tricky though -- multiple contexts can ruin performance, because GPUs only ever have one hardware queue. However, if you only ever use this second queue for buffer updates, some drivers will detect that usage pattern and create a DMA command queue instead of a graphics command queue, which can simultaneously run alongside the main context.

This is getting into very advanced and vendor-specific territory though, so if you're looking for a solution, some more details on your exact situation and problem would help --- in the common situation of small buffer updates, you just update the buffer, then draw immediately after, and let the driver do it's thing.

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Going with what Hodgman said. If you are NOT using multiple context from multiple threads then your concerns are unfounded.


All GL commands are asynchronous, but act like they're immediate. Drawing commands are async too, so if you update a VBO and then draw, both those commands go into the same queue and are processed by the GPU one after the other.


Meaning that if you update the VBO then call draw, the result will appear to be sequential/serialized..they WILL happen in the order submitted.

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Meaning that if you update the VBO then call draw, the result will appear to be sequential/serialized..they WILL happen in the order submitted.

We're not talking about logical ordering or things appearing serialized. There's a ton of operations in GL that are deferred internally, which in turn will cause runtime hitches when the driver decides to actually commit operations. Buffer uploads, texture uploads, and especially shader (re)compiles are the prime suspects here. This is not an imaginary problem for anyone who has actually shipped a game on a GL pipeline.

 

Issuing a dummy draw call - and potentially a fence or glFlush/glFinish/SwapBuffers - is the only way to combat this problem of runtime hitches. 

Edited by Promit

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Thank you! I've literally learnt so much from your responses. This made me think about where the problem actually lies, since I was not mapping any buffers or performing any sort of expensive GPU downloads. After running my profiler in "Telemetry" mode for the first time, I've discovered (within two minutes) that actually, the garbage collector usage correlates perfectly with lag spikes and I happen to be wasting a lot of memory in a certain place.

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apitest shows how to issue a fence and wait for it. The first time it checks if the fence has been signaled. The second time it tries again but flushing the queue since the driver may not have processed the copy yet (thus the GPU hasn't even started the copy, or whatever you're waiting for. If we don't flush, we'll be waiting forever. aka deadlock)
 
Of course if you want to just check if the copy has finished, and if not finished then do something else: you just need to do the 'wait' like the first time (i.e. without flushing), but using waiting period of zero (so that you don't wait, and get a boolean-like response like OP wants). We do this in Ogre to check for async transfer's status.

So can you use a fence to test for the actual status of a BufferSubData call uploading to server? And that works consistently across platforms without issuing a draw call against that buffer? After all the driver must do a full copy of the buffer to somewhere in-core at the point of call, but what the rube goldberg machine does after that is anyone's guess.

 

 


Calling glDraw* family of functions won't stall because it's also asynchronous. I can't think of a scenario where the API will stall because an upload isn't complete yet.

It'll stall if it gets caught in a situation where it can't continue dispatching frames without finishing a pending operation. I don't remember seeing this happen with buffer uploads, but I've seen it many, many times with shader recompiles. Whether this is because shader recompiles are a long goddamn process, or they have to happen in the main thread, or it just runs up against the limit of buffered frames, or some combination thereof, I'm not sure. It seems conceivable that a large upload followed by lots of dispatched frames could conceivably trigger the same effect.

Edited by Promit

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