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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:

      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!
    • 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 how to properly managing textures?

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In opengl there are texture units with different texture bindings and array textures. this makes me a bit confused what feature I should use if I have lots of textures. it seems that I can only use 4 texture units on my machine. and (1) is there a limit to the number of elements in an array texture object? can I just use many small textures and put them in array textures instead of a large texture atlas? ; or (2) should I bind different textures when using them? ; or (3) have many "uniform sampler2D(array) m_textureN" in my shader and binding to them?

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about (2): which means call "glBindTexture(GL_TEXTURE_2D, texture2d1ID)" in render loop to set different textures..
about (3): have many "uniform sampler2D m_textureN" :
//fragment shader
layout(location = 2) uniform sampler2DArray texarray;
layout(location = 3) uniform sampler2D tex2d1;
layout(location = 4) uniform sampler2D tex2d2;
is setting texture unit the only way to assign those different textures[ike: layout(binding = 2) uniform sampler2D tex2d1]? or I can use location to specify?

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There may be a limit to how many textures you can use an ONCE but I suspect you wouldn't reach that limit through standard use (there is probably a total limit too but I would imagine that is very high as well).


The simplest thing for you to do is to just bind a new texture each time you need a new texture.

glBindTexture(GL_TEXTURE_2D, rock);
glBindTexture(GL_TEXTURE_2D, grass);

I doubt you will hit a limit to how many textures you can use that way and it is the simplest approach.

Next up is if you need to use more than one texture at a time, maybe you are doing a landscapr and need to blend between rock and grass in a shader.

glBindTexture(GL_TEXTURE_2D, rock);
glBindTexture(GL_TEXTURE_2D, grass);
I did a quick check with intelisense and the highest GL_TEXTURE? that showed up for me was 29! That's pretty high but it may be limited by other factors. Still I would think you can use more than enough textures at once for whatever your needs.
layout(location = 2) uniform sampler2DArray texarray;
layout(location = 3) uniform sampler2D tex2d1;
layout(location = 4) uniform sampler2D tex2d2;
You don't NEED to do this, you can treat them as normal uniforms and set their locations from code
uniform sampler2DArray texarray;
uniform sampler2D tex2d1;
uniform sampler2D tex2d2;
location = glGetAttribLocation(shader, tex2d1);
glProgramUniform1i(shader, location, 3);
glBindTexture(GL_TEXTURE_2D, grass);

Just think about how many textures you will need to use at the same time, it probably won't be very high unless you are doing various maps - normal maps, diffuse maps, specular maps etc.

Edited by Nanoha

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According to opengl wiki




Array texture sizes are normally limited to the usual GL_MAX_TEXTURE_SIZE limitation. However, the dimension that represents the number of array levels is limited by GL_MAX_ARRAY_TEXTURE_LAYERS, which is generally much smaller. OpenGL 4.5 requires that the limit be at least 2048, while OpenGL 3.3 requires it be at least 256.


So if youre not using the very latest gl version, you are only guaranteed 256 textures in the array.

NOTE: looking online, most discrete gpu seem to support 2048 (nvidia), 8192 (amd), but intel integrated gpus are closer to the actual minimum.

You can also use multiple array textures for some extra capacity.

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thanks a lot! I think now I've decided how to manage textures in a game engine...

and, another problem is that if I use "glBindTexture(GL_TEXTURE_2D, texture)" every frame or even many times a frame, will there be a overhead that will damage the performance?

my idea about sprite animation is:

use one " uniform sampler2D texture" and one "uniform sampler2DArray texarr" in fragment shader. also a "uniform int curframe" to indicate which frame is on now. In the render function, I traverse every sprite and update the "texture" (with a normap 2d texture loaded before) and the "texarr" (with a normal 2d array texture loaded before) with the info stored in that sprite. It might work... but is it ok? Also, using this method requires dozens of drawing calls (even hundreds of...because for every sprite I have to update a world transform uniform to specify its location).

sorry for the badly organized post

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it seems that I can only use 4 texture units on my machine.


Just to clarify, you can have hundreds of textures loaded/created on the videocard, but you can only use 4 textures at the same time for a single drawcall; for example, if you have four texture units, that means you can only use 4 textures on a single triangle. To additionally confuse things, a "Texture" can actually be an array of multiple textures, and only take one Texture Unit spot.


When drawing a frame, you might do something like this:

//==============================================//Just once when the level resources (or general game resources) is loaded.

TextureID grass = MyTextureRetriever.LoadFromFile("../my/textures/grass.png");
TextureID dirt     = MyTextureRetriever.LoadFromMemory(dirtTextureData);
TextureID mask = MyTextureRetriever.LoadFromTheInternet("");

//On every frame:

//Bind the textures you are going to use.
Bind [grass] to GL_TEXTURE0 //Texture Unit 0
Bind [dirt] to GL_TEXTURE1 //Texture Unit 1
Bind [mask] to GL_TEXTURE2 //Texture Unit 2

//Draw the terrain using those textures.

//Bind other textures.
Bind [crateTexture] to GL_TEXTURE0
Unbind GL_TEXTURE1 and GL_TEXTURE2 //Since we're not using them here

//Draw the objects using those textures.

You can keep hundreds of textures loaded, but you can only have several active at once, so during a single frame of your game, you might switch your active textures hundreds of times (though generally you try to reduce the amount of switching, by drawing all the objects that share the same texture before switching to the next texture and drawing the objects using that one).


You want to use more than one texture if you are doing texture splatting, or bump mapping, or any of hundreds of other techniques. Nowadays games use textures for storing all kinds of data.


IIRC, the minimum number of texture units required to be supported is eight, so I'm not sure where your four is coming from?

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thanks! I am now much more clear about this! And the "four" is a wrong result due to my passing a wrong parameter to glGetIntegerv.. it's actually 32 units..

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