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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 Make Light Fade As it Moves Away

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Ok, I'm tired and fixing to go to sleep after I post this; So, I'm reading the OpenGL RedBook and one of the exercises wants me to make the light fade as it gets further away. Ok, with the code it kind of does, but the specular remains no matter how far away it is. I'm still new to this so I don't understand what all goes on with most of the properties: This is just some sample code, no need to read through it if you don't want. I just need the idea of how to accomplish this goal.
// LIGHTING VARIABLES
float light_x = 20.0f;

				// LIGHT0
float mat_ambient[] = { 0.2f, 0.2f, 0.2f, 1.0f };
float mat_diffuse[] = { 1.0f, 1.0f, 0.0f, 1.0f };
float mat_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };
float mat_shininess[] = { 50.0f };
float light_position[] = { 20.0f, 2.0f, 10.0f, 0.0f };
				// LIGHT1
float light1_ambient[] = { 0.2f, 0.2f, 0.2f, 1.0 };
float light1_diffuse[] = { 0.0f, 0.0, 1.0, 1.0 };
float light1_specular[] = { 1.0, 1.0, 1.0, 1.0 };
float light1_position[] = { -20.0, 2.0, 10.0, 0.0 };
float spot_direction[] = { -1.0, -1.0, 1.0 };

void hLighting()
{
	glLightModelfv( GL_LIGHT_MODEL_AMBIENT, mat_ambient );
	glLightModelf( GL_LIGHT_MODEL_LOCAL_VIEWER, 1.0f );

	glMaterialfv( GL_FRONT, GL_SPECULAR, mat_specular );
	glMaterialfv( GL_FRONT, GL_SHININESS, mat_shininess );

	glLightfv( GL_LIGHT0, GL_AMBIENT, mat_ambient );
	glLightfv( GL_LIGHT0, GL_DIFFUSE, mat_diffuse );
	glLightfv( GL_LIGHT0, GL_SPECULAR, mat_diffuse );
	glLightfv( GL_LIGHT0, GL_SHININESS, mat_shininess );
	glLightfv( GL_LIGHT0, GL_POSITION, light_position );

	// LIGHT 1
	glLightfv( GL_LIGHT1, GL_AMBIENT, light1_ambient );
	glLightfv( GL_LIGHT1, GL_DIFFUSE, light1_diffuse );
	glLightfv( GL_LIGHT1, GL_SPECULAR, light1_specular );
	glLightfv( GL_LIGHT1, GL_POSITION, light1_position );

	//glLightf( GL_LIGHT1, GL_CONSTANT_ATTENUATION, 2.0 );
	//glLightf( GL_LIGHT1, GL_LINEAR_ATTENUATION, 1.0f );
	//glLightf( GL_LIGHT1, GL_QUADRATIC_ATTENUATION, 0.2 );
	
	//glLightf( GL_LIGHT1, GL_SPOT_CUTOFF, 45.0f );
	//glLightfv( GL_LIGHT1, GL_SPOT_DIRECTION, spot_direction );
	//glLightf(GL_LIGHT1, GL_SPOT_EXPONENT, 2.0f);
	
	glEnable(GL_LIGHTING);
	glEnable(GL_NORMALIZE);
	//glEnable(GL_COLOR_MATERIAL);
	//glEnable(GL_LIGHT0);
	glEnable(GL_LIGHT1);

}

float angle = 0.0f;

void hDisplay()
{
	ShowCursor(false);

	glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();

	fpCamera->Render();

	glPushMatrix();
		//glRotatef(angle*5, 0.0f, 1.0f, 0.0f);
		light_position[0] = light_x;
		light1_position[0] = light_x;

		glPushMatrix();
			glTranslatef( light_position[0], light_position[1], light_position[2] );
			glutSolidCube(0.5);
		glPopMatrix();

		glPushMatrix();
			glTranslatef( light1_position[0], light1_position[1], light1_position[2] );
			glutSolidSphere(0.5, 5, 5);
		glPopMatrix();

		glLightfv(GL_LIGHT0, GL_POSITION, light_position );
		glLightfv(GL_LIGHT1, GL_POSITION, light1_position );
	glPopMatrix();

	glutSolidTorus(2, 8, 30, 30);

	// Draw Grids
	glPushMatrix();
		DrawGrid();
		glTranslatef(0.0f, 100.0f, 0.0f);
		DrawGrid();
	glPopMatrix();


glFlush();
}


[Edited by - openglJunkie on December 27, 2008 1:09:45 PM]

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Well you should not comment out setting the attenuation properties, as these define how light behaves as you move away from it.

Your lights properties will be multiplied by an attenuation factor to compute the influence on a surface.
This attenuation factor is
1 / (constantAttenuation plus distance * linearAttenuation plus distance^2 * quadricAttenuation)

(dunno why it eats up my "plus" operator)

That means you'll probably want to set these properties (for simple fading perhaps just linear attenuation) to values different from zero.

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the w component of the lightposition alters its 'sort'
from msdn reference;

If the w component of the position is 0, the light is treated as a directional source. Diffuse and specular lighting calculations take the light's direction, but not its actual position, into account, and attenuation is disabled. Otherwise, diffuse and specular lighting calculations are based on the actual location of the light in eye coordinates, and attenuation is enabled. The initial position is (0, 0, 1, 0); thus, the initial light source is directional, parallel to, and in the direction of the -z axis.


iow, setting it to 0 will illuminate regardless distance, 1 will take distance into account.


I believe this is the effect youre looking for


edit: this is specific to opengl native lighting only, of course. Otherwise, simply alter your own light equation to fit the need.

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