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• ### Similar Content

• 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

• 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!

• Hello guys,

How do I know? Why does wavefront not show for me?
I already checked I have non errors yet.

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 !

# OpenGL Opengl scaling using ortho projection not working correctly

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## Recommended Posts

Hi there. I was trying to write a sprite renderer using opentk and C#. Everything was working fine till I've noticed zooming out using ortho projection changes sprites colors. I've created a small example of what I'm doing.

First of all as I use linear texture filtering I add half texel to top and left vertices texture coordinates, and subtract half texel from right and bottom vertices texture coordinates. As this ends to make mapped area of the texture one pixel smaller I subtract 0.5 from bottom and right vertices positions, and add 0.5 to left and top vertices positions.

float x = 0;
?float y = 64;
float w = 400;
?float h = 16;

VertexPositionTexColor[] vertices = new VertexPositionTexColor[] {
new VertexPositionTexColor(){Position = new Vector2(x + 0.5f, y + 0.5f),TexCoord = new Vector2(22.5f / bmp.Width,0.5f/bmp.Height) // added 0.5f to uv to map center of the texel. did the same thing for position
,Color =new Vector4(1f,1f,1f,1f)},
new VertexPositionTexColor(){Position = new Vector2(x + w - 0.5f, y + 0.5f),TexCoord = new Vector2(22.5f / bmp.Width,0.5f/bmp.Height) // subtracted u by 0.5f and added 0.5f to v to map center of the texel. did the same thing for position
,Color =new Vector4(1f,1f,1f,1f)},
new VertexPositionTexColor(){Position = new Vector2(x + w - 0.5f, y + h - 0.5f),TexCoord = new Vector2(22.5f / bmp.Width,15.5f/bmp.Height) // subtracted uv by 0.5f to map center of the texel. did the same thing for position
,Color =new Vector4(1f,1f,1f,1f)},
new VertexPositionTexColor(){Position = new Vector2(x + 0.5f, y + h - 0.5f),TexCoord = new Vector2(22.5f / bmp.Width,15.5f/bmp.Height) // subtracted v by 0.5f and added 0.5f to u to map center of the texel. did the same thing for position
,Color =new Vector4(1f,1f,1f,1f)},
};

The texture is setup as below and I'm using an atlas.

GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMinFilter, (int)TextureMinFilter.Linear);
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMagFilter, (int)TextureMagFilter.Linear);
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapS, (int)TextureWrapMode.ClampToEdge);
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapT, (int)TextureWrapMode.ClampToEdge);


Is this approach correct?

Now I setup my viewport and projection matrix

float viewPortWorldX = 400;
float viewPortWorldY = 300;

.
.
.
.

Matrix4 ortho = Matrix4.CreateOrthographicOffCenter(0, viewPortWorldX,
viewPortWorldY, 0, -1, 1);

GL.Viewport(0, 0, 400, 300);
GL.UniformMatrix4(GL.GetUniformLocation(program, "projection"), false,
ref ortho);

The above code works fine because my ortho projection and viewport are the same size. Except one thing. The line is one pixel shorter than 400 while I've set w to 400. It is not surprising because I've subtracted 0.5 pixel from the right side.

The strange things start when I change ortho projection configuration.

float viewPortWorldX = 800;
float viewPortWorldY = 600;

.
.
.
.

Matrix4 ortho = Matrix4.CreateOrthographicOffCenter(0, viewPortWorldX,
viewPortWorldY, 0, -1, 1);

GL.Viewport(0, 0, 400, 300);
GL.UniformMatrix4(GL.GetUniformLocation(program, "projection"), false,
ref ortho);


The line color has changed! the middle of it was white but now it is blue!

if I change position of the line from 64 to 65 or any other odd number the result will be correct!

I've attached the visual studio 2013 project to this post:

[attachment=33274:OpenTKTest.zip]

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The color change may happen due to the linear filtering, because by using linear filtering, you're averaging between the 4 closest texels, and, since most of the texture is blueish, the resulting color will also be blueish.

The odd line position thing, may also be somehow related to this (though I can't properly explain it).

Have you tried setting the minification filtering to nearest instead of linear, to see if the results improve? You could keep the magnification filter linear, so that, if you zoom in, the result will be linearly filtered.

Anyway, I'm not sure this is the case, but I hope it helps.

Edited by __SKYe

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The color change may happen due to the linear filtering, because by using linear filtering, you're averaging between the 4 closest texels, and, since most of the texture is blueish, the resulting color will also be blueish.

The odd line position thing, may also be somehow related to this (though I can't properly explain it).

Have you tried setting the minification filtering to nearest instead of linear, to see if the results improve? You could keep the magnification filter linear, so that, if you zoom in, the result will be linearly filtered.

Anyway, I'm not sure this is the case, but I hope it helps.

Yes this solves the problem. But makes another problem in some viewport sizes the line is thicker. It seems that there is no real solution to this problem. Even if I solve this problem there is another problem. When zooming in or out at some viewport sizes the alignment of objects breaks. some objects may overlap. I tested this situation in gamemaker 8 and it has the alignment problem.

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Yes this solves the problem. But makes another problem in some viewport sizes the line is thicker. It seems that there is no real solution to this problem

Yeah, but you can't really help that, if you view such a small graphic zoomed out, stuff like this will happen.

Have you tried mipmaps? You might get a better result with them.

Even if I solve this problem there is another problem. When zooming in or out at some viewport sizes the alignment of objects breaks. some objects may overlap. I tested this situation in gamemaker 8 and it has the alignment problem.

This, I can't really help, except you could enforce sizes for the viewport zooming, instead of allowing arbitrary zooming amounts.

What I mean is, allow zooming, but in 50% increments (or something along those lines), so that you can ensure it doesn't break the alignment.

Obviously, depending on what you're trying to do, this may not be possible (or wanted), but it's a thought.

Anyway, good luck.

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Thanks. I just wanted to know if there is an out of the box way to solve this. I think using some fixed viewport sizes is a good way. I already force the aspect ration to be the same in all view sizes. I should choose some viewport sizes and use them.

I should take a look at mipmaps too.

Thank you