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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 Frustum Planes Extraction: I just don't get it

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I'm starting to feel like I'm the first person to ever really try to extract the frustum planes from the view and projection matrices... This can't possibly be true so there must be something very fundamental that I'm missing..... right? First of all it seems like just about every article on this subject is for OpenGL and the few which are for DirectX are conflicting... if you look at these two DirectX examples, they have a similar idea... but they are also very different at the same time plane extraction How do I get the viewing frustum? I just don't know what to make of it... I've tried the code in both articles and I just can't seem to get it to work at all... I'm actually having trouble understanding how any of these algorithms CAN work... in all the articles I read (including the OpenGL ones), all of the information about the D component of the planes is extracted from the bottom row of the matrix... in all of the tests I've run, my View*Projection matrix has all zeros in that last row... which means that no matter what I do, all of the D's are zero here's an example matrix I got:
[1.73205	0		0		0	]
[0		1.001		1		0	]
[-1.73205	-0.1001		0		1.29904	]
[0		0		0		0	]
And here's the code I use to make the matrices:
	D3DXMATRIX matWorld;
	d3dDevice->SetTransform(D3DTS_WORLD, &matWorld);

	//D3DXMATRIX matView;
	D3DXVECTOR3 vEye( 0.0f, 0.0f, 0.0f );
	D3DXVECTOR3 vAt( 0.0f, 0.0f, 1.0f );
	D3DXVECTOR3 vUp( 0.0f, 1.0f, 0.0f );
	D3DXMatrixLookAtLH( &matView, &vEye, &vAt, &vUp);
	d3dDevice->SetTransform( D3DTS_VIEW, &matView );

	D3DXMATRIX matProj;
	D3DXMatrixPerspectiveFovLH( &matProj, D3DX_PI/3, 4/(float)3, 0.1f, 100.0f );
	d3dDevice->SetTransform( D3DTS_PROJECTION, &matProj );

What in the heck am I forgetting?... maybe I'm not supposed to multiply the matrices in the order that I do (View * Projection)? maybe this algorithm doesn't return the planes in world space... but that still doesn't explain why the D's are always zero

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Yes, the equations for DirectX and OpenGL are different, owing to the fact that one is right-handed and one is not. I believe a simple transposition of the matrices will correct the differences.

Even with the OpenGL/DX thing cleared up, I remember it took me a bit of work to get the correct matrices in and the right clip planes out. Keep trying and you'll get it.

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The plan extraction article (http://www2.ravensoft.com/users/ggribb/plane%20extraction.pdf) is definetly correct.

The View * Projection is also correct.

It looks like you are calculating the view and proj matrices correctly.

And the paper you linked does return the frutum in world space.

Maybe you're messing up somewhere else. If you would like me to send you a frustum class just PM me and Ill send you one so that you can compare and see if you catch anything.

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I finally figured out what I was doing wrong!

I was using the D3DXMATRIX structure (SDK 8.0) and to get at the elements of the matrices I was using its overloaded () operator

from the sdk

// access grants
FLOAT& operator () ( UINT Row, UINT Col );
FLOAT operator () ( UINT Row, UINT Col ) const;

by "access grants" I assumed they meant they would grant me access to the elements... but I can't really figure out what they do

here is a View*Projection matrix:

[-1.81066 0 0 0 ]
[0 2.41421 0 0 ]
[0 0 -1.002 -1]
[0 -2.41421 -0.1002 0 ]

And here is that same matrix through the eyes of the () operator:

[2.41421 0 0 0 ]
[0 -1.002 -1 0 ]
[-2.41421 -0.1002 0 1.81066 ]
[0 0 0 0 ]

I'm wondering if this is a bug that has long been fixed by newer versions or if this has some legitimate purpose...

Anyhow... Thanks for your responses guys... much appreciated

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This is three weeks old (sorry, almost necro :-) but the reason you got that bug was that you used indices from 1 through 4; the () operator wants values from 0 through 3. You can tell this is the case, because the upper-left 3x3 matrix you got out is the same as the lower-right 3x3 of the input matrix.

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I have also never quite understood the way the frustum planes are exracted from the view and projection matrices. I propose a simpler approach. Maybe this is already a well know one, but I have not seen any tutorial using it). I figured this one out myself and it is so much simpler.

Here is the technique,

you already know the nearZ, farZ and fov (horizontal)and aspect (width / height) of your view volume.

From this information, using simple trignometry , we can compute the camera space coordinates of the 8 corners of the frustum. Compute these once every time you update any FOV related settings and store them.

Then each frame, transform each of these points to world spcae, using your world transform matrix. Once in world space, use these points to compute the 6 planes! (computing a plane from 3 points is easy enough)

I am attaching the code to do this. It is not compilable as is, (as it uses other classes as well and is a work in progress) but will serve to explain the concept!


[Edited by - AQ on September 25, 2004 10:40:29 AM]

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I used the frustum tut from ravensoft as a result of reading this thread a few weeks ago. I replaced the frustum plane comp i was using with that one and I am very happy with the results. I highly recommend that tutorial to everyone.

AQ your concept sounds very interesting. when I clicked on the link the code sample doesn;t show how you build your planes. would be interesting to see that. I think that's pretty cool that you have developed your own view frustum technique.

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Another approach is to treat the frustum planes as 2D rays, like consider from top view i.e. the XZ plane (if your camera is at origin and facing along the positive x-axis):

the left plane is equivalent to a ray:

(cos (fov/2), 0, sin(fov/2))

then any point u want to test as inside or outside the frustum:

point -= camera; //translate to frustum space
//unrotate point if necessary

dPl = dot(leftPlane, xAxis);
dPt = dot(point, xAxis);

if (dPl < dPt) //point is "below" the left plane ray
if (dot (leftPlane, point) > 0)
//point is within left/right planes

Then you can do an && with testing on the XY plane for top and bottom planes (left view).
This way requires testing of only 2 planes (left and top) and deal with rays rather than planes (which i find easier anyway), and for near and far clip you can just test if (near < point.x < far). Also this way you dont have to worry about transforming the frustum to world space, it is easier and faster to untransform the point/volume being tested to frustum-relative space. Atleast, I found it to be so.

The only snag is it screens out coplanar points, but you can do a quick prelim test for that easily (dot(plane, point) == 1).
Can anyone spot any problems?

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