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    • 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
    • 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!
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OpenGL Dynamic Environment Cubemap

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Hello guys,
 
Im implementing cubemap reflections of the environment, which basically consists of rendering a cubemap in the position of the camera for all 6 directions in each frame (which i know is correct):
 
Screen+Shot%202016-06-29%20at%2019.41.33
 
The issue that i'm having is when the viewing camera angle crosses an inclination threshold: (on the top pic we have a correct reflection, but on the bottom pic you start to see the top cubemap texture showing on the bottom of the cube and if you go up further you start to see the bottom texture of the cubemap on the top of the cube too)
 
correct.png incorrect.png
 
The actual test scene (with the car reflecting everything, and notice the road appearing in the boot instead of the sky)
 
fullscene.png
 
Here's the relevant glsl shader code:
 
vec3 viewDir  = normalize(-FragPos);
if (Specular.b > 0.0)
{
        vec3 R = reflect(viewDir, Normal);
        vec4 R_World = inverseView * vec4(R, 0.0);
        
        // we have to flip the x axis because of RenderMan specification, i.e. legacy opengl
        R_World.x = -R_World.x;

        vec3 reflectionColor = texture(cubemap, R_World.xyz).rgb;
        Diffuse.rgb = (Specular.b * reflectionColor) + ((1.0 - Specular.b) * Diffuse.rgb);
}

 

where the viewDir and Normal are in camera view space

 

Any extra info you need just ask. Thanks in advance.

Edited by André

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I've had issues before either in the rendering or the reflection vector.  I suggest using a sphere to debug.

 

In my current shader, I have to flip the x-axis of the reflection vector: texCube(envMap, vec3(refVec.x*-1, refVec.y, refVec.z) ). Pretty sure that is just an issue with my current code as I dont recall doing that before.  But I've had issues where I had to convert the vector from GL to DX coordinates because the cube map is stored in directX coordinates most likely. So try flipping y and z, and/or negating one of those after flipping.

 

aside from that, you could also be potentially rendering to the wrong cube face on accident or using the wrong view matrix to render to the face.

 

 

vec4 R_World = inverseView * vec4(R, 0.0);

 

You could also using an interpolate/varying of the world eye/camera and get rid of the matrix multiply in the pixel shader.

Edited by dpadam450

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I've had issues before either in the rendering or the reflection vector.  I suggest using a sphere to debug.

 

In my current shader, I have to flip the x-axis of the reflection vector: texCube(envMap, vec3(refVec.x*-1, refVec.y, refVec.z) ). Pretty sure that is just an issue with my current code as I dont recall doing that before.  But I've had issues where I had to convert the vector from GL to DX coordinates because the cube map is stored in directX coordinates most likely. So try flipping y and z, and/or negating one of those after flipping.

 

aside from that, you could also be potentially rendering to the wrong cube face on accident or using the wrong view matrix to render to the face.

 

 

vec4 R_World = inverseView * vec4(R, 0.0);

 

You could also using an interpolate/varying of the world eye/camera and get rid of the matrix multiply in the pixel shader.

 

Yea, i'm already flipping the x-axis because of the way that opengl reads textures. The weird thing is that it works fairly well until you get in a higher position than the reflective object. As for the matrix multiplication, that FragPos one of the outputs of a geometry pass and it is used for other things that are expecting it to be in viewspace (like SSAO) so i think that is going to have to stay, at least for now.

 

Well i have to say that the sphere debug was an excellent sugestion, there's definitely something wrong in here, even when the camera is not looking from above:

 

Screen+Shot%202016-06-29%20at%2023.44.38

Screen+Shot%202016-06-29%20at%2023.45.02

 

Looks like the top and bottom textures are switched. Will continue to debug based on your suggestions, thanks.

 

EDIT:

Yup, just switched the order of the cameras and sure enough:

 

Screen_Shot_2016_06_29_at_23_56_30.png

 

Now the problem is that my cube map looks switched in the OpenGL Profiler, so the error was not really in the cubemap generation but in the reading, will investigate. Thanks again

Edited by André

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Cool. The thing I was suggesting about that matrix multiply is that I have 4 varying vectors, normal/view vec in both world space and camera space. I compute those both in the vertex shader and interpolate the values. As opposed to just have noraml/viewvec in camera space and then doing a matrix multiply inversion later. The matrix multiply in the pixel shader should be more expensive than what I'm suggesting. Probably won't change your framerate but it saves some cycles.

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Cool. The thing I was suggesting about that matrix multiply is that I have 4 varying vectors, normal/view vec in both world space and camera space. I compute those both in the vertex shader and interpolate the values. As opposed to just have noraml/viewvec in camera space and then doing a matrix multiply inversion later. The matrix multiply in the pixel shader should be more expensive than what I'm suggesting. Probably won't change your framerate but it saves some cycles.

 

Yes i know what you mean, but as i mentioned, i am using deferred rendering, which would imply i would have to create another texture to store the position values in world space in the geometry pass, and then in the lighting pass (the one where i also calculate the reflectons) i would have to perform texture lookups to access the positions, which is also expensive.

I will try that in the future for sure though.

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