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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. 
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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
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OpenGL OpenGL - Render Plane equation

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Hi guys, i'm trying to figure out how to render a plane. My internal plane representation consists of a normal, and distance from origin

Vector3 Normal;
float Distance;

Given this, i've tried the following to render the plane:

GL.PushMatrix();

GL.Translate(Normal.X * Distance, Normal.Y * Distance, Normal.Z * Distance);
GL.Rotate(Normal.Y * 360f, 0f, 1f, 0f);
GL.Rotate(Normal.X * 360f, 1f, 0f, 0f);
GL.Rotate(Normal.Z * 360f, 0f, 0f, 1f);

GL.Begin(PrimitiveType.Quads);
    GL.Vertex3(-1, 1, 0);
    GL.Vertex3(-1, -1, 0);
    GL.Vertex3(1, -1, 0);
    GL.Vertex3(1, 1, 0);
GL.End();

GL.PopMatrix();

While this seems to work, i have doubts that it will with all angles... (Reason being the rotation order).

 

So, my question, is there a better way to derive a plane to be rendered?

 

I'm using C# and OpenTK to render this.

Please don't comment that i should be using more modern OpenGL, that is not constructive to the question i'm asking.

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Your doubts are valid, but the reason is wrong. The vertices are placed onto the local x/y plane, hence the normal is along the direction of the local z axis. Putting (0,0,1) into your rotation code and considering that rotation by 360° is identical to rotation by 0°, you correctly see the front of your plane. However, just using normals along x (1,0,0) or y (0,1,0) or so with your rotation code still give you the same vertices, since all transformations are the same. Changing the order of rotation does not make any difference then.

 

Actually, using a normal and a distance lets several degrees of freedom in an open state. Rendering a plane with vertices need those degree of freedom to be fixed. What I mean is that you need a definition of

a) an origin of the plane, so that there is a point with local co-ordinates (0,0,0), 

b) an orientation angle around the normal (think of the rolling angle of a camera; the normal gives you just 2 of the 3 angles).

 

You solved a) by using the point

   origin := (0,0,0) + distance * normal

 

You solve b) by just picking an angle, i.e. so that rolling is zero.

 

So with these fixes you have a position and an orientation as a direction and "no rolling". Let's express "no rolling" as

   up_vector := (0,1,0)
And instead of a pure direction, let's use it as difference vector from the origin to a tip point

   center_point := origin + normal * 1

 

Now (with the origin and the center point and the up vector), what we have here are the ingredients for the gluLookAt function! Although being described as a function to compute a view matrix, the function actually just builds a transformation matrix with a translation and rotations so that the z axis points in a specific direction.

 

The math behind the gluLookAt function isn't complicated and leaving OpenGL's matrix stack behind is ever a Good Thing TM, but I assume you may be happy with the sketched solution. Otherwise feel free to ask :)

Edited by haegarr

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I think this is what you are describing:

Vector3 forward = new Vector3(Normal.X, Normal.Y, Normal.Z);
Vector3 up = new Vector3(0f, 1f, 0f);
Vector3 right = Vector3.Cross(forward, up);
up = Vector3.Cross(right, forward);

Matrix4 rot = new Matrix4(right.X, up.X, -forward.X, 0.0f,
    right.Y, up.Y, -forward.Y, 0.0f,
    right.Z, up.Z, -forward.Z, 0.0f,
    0.0f, 0.0f, 0.0f, 1.0f);
Matrix4 trans = Matrix4.Translate(Normal * Distance);

Matrix4 result = rot * trans;

GL.PushMatrix();
GL.LoadMatrix(result.OpenGL);

GL.Begin(PrimitiveType.Quads);
GL.Vertex3(-1, 1, 0);
GL.Vertex3(-1, -1, 0);
GL.Vertex3(1, -1, 0);
GL.Vertex3(1, 1, 0);
GL.End();

GL.Begin(PrimitiveType.Points);
GL.Color3(1f, 1f, 0f);
GL.Vertex3(0f, 0f, 0f);
GL.Color3(1f, 0f, 1f);
GL.Vertex3(Normal.X * Distance, Normal.Y * Distance, Normal.Z * Distance);
GL.End();

GL.PopMatrix();

This however does not seem to work either. I can't even get the reference points rendering once i load the matrix generated above :(

 

Am i missing a step in this?

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I don't know how your framework linearizes matrices, so this code snippet
   Matrix4 rot = new Matrix4(...) 

may or may not be correct.

 

But there is a noticeable difference in transformation computation between your 1st and your 2nd post. In the 1st post you compute

    Mi+1 := Mi * T * R

with M being the transformation matrix on the stack, T being the translation and R the rotation. The snippet in your 2nd post computes

    Mi+1 := I * R * T

instead, where I is the identity matrix. Notice that (a) the matrix being formerly on the top of the stack is now ignored, and that (b) the order of translation and rotation is exchanged.

 

Hence try to change this line

   Matrix4 result = rot * trans;

into 

   Matrix4 result = trans * rot;

 
Further, if the former stack matrix should play a role, instead of 
   GL.LoadMatrix(result.OpenGL);
use
   GL.MultMatrix(result.OpenGL);

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Wow, GREAT CATCH! Rookie mistake on my part! You where correct in both cases, first i multiplied the matrix instead of loading; and the multiplication order did need to be reversed also. The matrix constructor was correct. Thank you so much for the help, it works flawlesly now!

 

For anyone who might be interested, my final code ended up being:

// Debug Normal
GL.Color3(1f, 1f, 0f);
GL.Begin(PrimitiveType.Lines);
GL.Vertex3(0f, 0f, 0f);
GL.Vertex3(Normal.X * 500, Normal.Y * 500, Normal.Y * 500);
GL.End();

GL.Color3(1f, 1f, 1f);
Vector3 forward = new Vector3(Normal.X, Normal.Y, Normal.Z);
Vector3 up = new Vector3(0f, 1f, 0f);
Vector3 right = Vector3.Cross(forward, up);
up = Vector3.Cross(right, forward);

Matrix4 rot = new Matrix4(right.X, up.X, -forward.X, 0.0f,
    right.Y, up.Y, -forward.Y, 0.0f,
    right.Z, up.Z, -forward.Z, 0.0f,
    0.0f, 0.0f, 0.0f, 1.0f);
Matrix4 trans = Matrix4.Translate(Normal * Distance);

Matrix4 result = trans * rot;

GL.PushMatrix();
GL.MultMatrix(result.OpenGL);

// Draw Plane
GL.Begin(PrimitiveType.Quads);
GL.Vertex3(-1, -1, 0);
GL.Vertex3(-1, 1, 0);
GL.Vertex3(1, 1, 0);
GL.Vertex3(1, -1, 0);
GL.End();

// Debug Points
GL.Begin(PrimitiveType.Points);
GL.Color3(1f, 1f, 0f);
GL.Vertex3(0f, 0f, 0f);
GL.Color3(1f, 0f, 1f);
GL.Vertex3(Normal.X * Distance, Normal.Y * Distance, Normal.Z * Distance);
GL.End();

GL.PopMatrix();

Tough my math lib is a bit wonky, you might need to adjust.

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