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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:

      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!
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OpenGL Texture Display Issues

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Hi all. Sorry if this is a beginner question, but I have not been able to find any solution to this problem, or indeed anyone else who has had the same problem. I have tried several times to display a texture on a simple polygon using OpenGL, but for some reason, no matter what image library I use, I have problems. The texture does not load, leaving the polygon a default white colour. I have tried with Cocoa image loading, SDL, and GLFW. I'm compiling on a PPC running Mac OS X, and I'm using XCode v2.4. Here is a sample of my OpenGL code:
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include "GL/glfw.h"

#define S_WIDTH 640
#define S_HEIGHT 480

// Bad Global Variables:
//int width, height;													// Window dimensions
double t;																// Time (seconds)
GLuint texture;															// Texture reference

// Function prototypes:
void reSizeGLScene( GLsizei width, GLsizei height );
bool initGL();
bool loadTexture( const char* path );
bool drawGLScene();
void cleanUp();

int main( int argc, char** argv )
	// Initialize variables:
	bool status = true;		// Is the program okay?
	bool done = false;		// Is the program done?
	// Start up GLFW
	// Open up a window
	status = glfwOpenWindow(
		8, 8, 8, 8,
	// Exit if there is an error opening the window
	if ( !status )
		fprintf( stderr, "ERROR OPENING GLFW WINDOW\n" );
		return 1;
	// Set the window title
	glfwSetWindowTitle( "My OpenGL Program" );
	// Enable sticky keys
	glfwEnable( GLFW_STICKY_KEYS );
	loadTexture( "data/test.tga" );
	// Game loop:
	while ( !done )
		reSizeGLScene( S_WIDTH, S_HEIGHT );
		// Call the render function:
		status = drawGLScene();
		// Flip buffers:
		done = glfwGetKey( GLFW_KEY_ESC ) || !glfwGetWindowParam( GLFW_OPENED );
	// Clean up:
/*~~~~~~~~~~~ reSizeGLScene() ~~~~~~~~~~~~*/
/*  - Resize and initialize the GL window
void reSizeGLScene( GLsizei width, GLsizei height )
	// Make sure the height is non-zero
	if ( height < 1 )
		height = 1;
	// Set the viewport:
	glViewport( 0, 0, width, height );
	// Now set up the projection matrix:
	glMatrixMode( GL_PROJECTION );										// Change the matrix mode to projection
	glLoadIdentity();													// Identity Matrix
	gluPerspective( 65.0, (double)width/(double)height, 1.0, 100.0 );	// Set the perspective
	// Set up the modelview matrix:
	glMatrixMode( GL_MODELVIEW );										// Modelview matrix
	glLoadIdentity();													// Identity matrix
/*~~~~~~~~~~~~~~~ initGL() ~~~~~~~~~~~~~~~*/
/*  - Initializes OpenGL
bool initGL()
	glEnable( GL_TEXTURE_2D );											// Enable texture mapping
	glShadeModel( GL_SMOOTH );											// Use the smooth shader model
	glClearColor( 0.0f, 0.0f, 0.0f, 0.0f );								// Set a black background
	glClearDepth( 1.0f );												// Setup the depth buffer
	glEnable( GL_DEPTH_TEST );											// Enable depth testing
	glDepthFunc( GL_LEQUAL );											// The type of depth test to do
	glHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST );				// Really Nice perspective calculations
	return true;														// Return success
/*~~~~~~~~~~~~ loadTexture() ~~~~~~~~~~~~~*/
/*  - Initializes Textures
bool loadTexture( const char* path )
	glGenTextures( 0, &texture );
	glBindTexture( GL_TEXTURE_2D, texture );
	glfwLoadTexture2D( path, 0 );
	return true;
/*~~~~~~~~~~~~ drawGLScene() ~~~~~~~~~~~~~*/
/*  - Main OpenGL draw function
bool drawGLScene()
	// Now let's get the system time
	t = glfwGetTime();

	// Clear colour and depth buffers:
	glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );				// Clear the screen and depth buffer
	glLoadIdentity();													// Reset the ModelView Matrix
	glTranslatef( 0.0f, 0.0f,-6.0f );									// Set the offset
	glEnable( GL_TEXTURE_2D );
	glBindTexture( GL_TEXTURE_2D, texture );							// Select texture
	fprintf( stderr, "Texture id: %d\n", texture );
	glBegin( GL_QUADS );
		glTexCoord2f( 0.0f, 0.0f ); glVertex3f(-2.0f, 2.0f, 0.0f );
		glTexCoord2f( 1.0f, 0.0f ); glVertex3f( 2.0f, 2.0f, 0.0f );
		glTexCoord2f( 1.0f, 1.0f ); glVertex3f( 2.0f,-2.0f, 0.0f );
		glTexCoord2f( 0.0f, 1.0f ); glVertex3f(-2.0f,-2.0f, 0.0f );
	glDisable( GL_TEXTURE_2D );
	return true;														// Return success
/*~~~~~~~~~~~~~~ cleanUp() ~~~~~~~~~~~~~~~*/
/*  - Clean everything up
void cleanUp()
I have already looked at several examples and tutorials. I suspect that the problem is probably in the draw function, but I can't seem to pinpoint the exact problem. While I have no error checking on my image file, it is a 256x256 targa file. It also has the correct filepath. Hopefully I'm not wasting your time with a stupid mistake, and thanks in advance for helping out.

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