• 10
• 9
• 12
• 14
• 14
• ### 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 Lighting: Object Space vs Eye Space

This topic is 4341 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

## Recommended Posts

I'm playing about with lighting through Cg. I have setup a basic lighting algorithm which calculates diffuse,specular, global ambient etc. I also have some nice looking distance attenuation going on. It is using the same basic model as OpenGL. I am lighting all my objects in their local object-space and it's been working great... until they move. Then I found that the lighting still think they're in their original location and they end being completely unlit. Not a good thing. How can I solve this?? Is this a limit with lighting in object space? Do I need to perform my lighting in eye-space instead?? Sre there any tutorials on lighting in eye space?? How do you do this because I am unable to get the same visual effect like I had in my object-space calculations. The lighting keeps flying off everytime I rotate the camera and it only lights the scenery properly when I'm looking directly down the negative Z axis. Looking down the positive Z axis causes the scene to go pitch black. This may be linked to the light flying off when the camera is rotated. Anyone got any advice?? :) Cheers, Steve

##### Share on other sites
just multiply with current modelview ?!

##### Share on other sites
Like Eitsch said, you need to either transform the lights into object space, or transform the objects into view space. Obviously, your lighting calculations should be the same in either space, so I'm curious as to what's wrong with your view space lighting calculations. Perhaps you can paste the relevant snippet of your lighting calculation?

##### Share on other sites
hi, i have the same problem (http://www.gamedev.net/community/forums/topic.asp?topic_id=395799 == wrong explanation ;-( ).

The mathematical solution is simple and easy, but i have trouble with implementation.

Math:

Let l be the light position. Now do some transformation's with our object A. The resulting matrix is R. So the origin o = (0, 0, 0) for object A has coordinates Ro. Simple math. So the new light coordinates for A in A's space are l' = l - Ro. Isn't it so?

Implementation:

Here is the problem:

//the transformation
glTranslatef(10, 10, 10);
glRotatef(rotate, 0,0,1);

//computing the new coordinates of the light
GLfloat m[16];
glGetFloatv(GL_MODELVIEW_MATRIX, &(m[0]));

float r = rotate*(3.14159265/180);

float l[3];
l[0] = light.position[0] - m[12];
l[1] = light.position[1] - m[13];
l[2] = light.position[2] - m[14];

cgGLSetParameter3fv(cgGetNamedParameter(*vertexProgram, "lightVec"), l);

End of problem.

The problem is, the result is completly wrong. If i compute it by hand it is correct, but in games i would not be able to compute it by hand on the fly ;-D.

The problem is that the computation of Ro is wrong. I dont know how to aquire the R matrix. Well with the modelview matrix it does not work. One solution is to keep track of the transformation's done. So we would need another matrix multiplycation. But that is weird. I want to know how to get the R matrix from openGL.

Can anybody help?

XorMultiPleXus

##### Share on other sites
Well, there's a few solutions that should work. You can specify your light in view space and transform it to object space with the inverse modelview matrix. If you're specifying your light in world space, you can pass in R_inverse (given that R is he matrix that transforms from object to world space); just compute R_inverse in your application and pass it in as an uniform and transform your light by it in your vertex program.

Quote:
 The problem is that the computation of Ro is wrong. I dont know how to aquire the R matrix. Well with the modelview matrix it does not work. One solution is to keep track of the transformation's done. So we would need another matrix multiplycation. But that is weird. I want to know how to get the R matrix from openGL.

Unfortunately, there is no way to retrieve the model matrix from the modelview matrix unless you're carrying around an extra copy of the (inverse) view matrix.

##### Share on other sites
Here is the code that I'm using. Mhamlin: If you look at the code you will see the lines which perform the modelview inverse calculations. They are commented out cos of the problems I've been having. I think I may have to send the camera view vector to the cg function as well as the eye position. Maybe??

Output VertexShader(Input IN, Lighting LIGHT,                    Surfaces MATERIAL,                    uniform float4 eyePosition,                    uniform float3x3 modelView,                    uniform float4x4 modelViewInverse,                    uniform float3x3 modelViewInvTrans,                    uniform float4x4 modelViewProj){	Output OUT;	// Here we convert the output vertex from object-space to clip-space	OUT.position = mul(modelViewProj, IN.position);	// Set the material ambient property to 100% by default (temporary??)	MATERIAL.Ka = (1.0, 1.0, 1.0);	// *** NEW EYE-SPACE TRANSFORMATIONS ***	float3 P = IN.position.xyz;	float3 N = IN.normal.xyz;	// Convert the vertex position from object-space to eye-space/*	float3 P = mul(modelView, IN.position.xyz);	normalize(P);	// Convert the vertex normal using the inverse transpose of the modelview matrix	float3 N = mul(modelViewInvTrans, IN.normal);	normalize(N);*/		// Multiply the light position by the inverse modelview matrix//	float3 L = mul(modelViewInverse, LIGHT.position - P);	float3 L = normalize(LIGHT.position.xyz - P);	// *** NEW EYE-SPACE TRANSFORMATIONS ***	// Calculate the attenuation	float attenuation = Attenuation(P, LIGHT);	// Compute the emmisive term	float3 emmisive = MATERIAL.Ke;	// Compute the ambient term	float3 ambient = MATERIAL.Ka * LIGHT.ambient.xyz;	// Compute the diffuse term	float diffuseLight = max(dot(N, L), 0);	float3 diffuse = MATERIAL.Kd * LIGHT.colour.xyz * diffuseLight * attenuation;	// Compute the specular term	float3 V = eyePosition.xyz;	float3 H = normalize(L + V);	float specularLight = pow(max(dot(N, H), 0), MATERIAL.shininess);	if(diffuseLight <= 0) specularLight = 0;	float3 specular = MATERIAL.Ks * LIGHT.colour.xyz * specularLight * attenuation;	// Compute the final vertex colour	float3 lighting = (emmisive + ambient + diffuse + specular);	// Pass the texture in Texture Unit 0 to the fragment program	OUT.texCoord = IN.texCoord;	// Pass the current colour to the fragment program	OUT.colour.xyz = IN.colour.xyz * lighting;	OUT.colour.w = IN.colour.w;		return OUT;}

##### Share on other sites
I just quickly look over the code, so I apologize in advance if I misunderstood anything.

float3 P = mul(modelView, IN.position.xyz);normalize(P);

Firstly, I'm guessing the Cg compiler rejects this bit? Firstly, you can't multiply a 3-vector by a 4x4 matrix, you need to just pass in IN.position. Secondly, you shouldn't normalize the result. P is not a vector, it's a point--normalizing it will change its translation, which is disastrous.

float3 L = mul(modelViewInverse, LIGHT.position - P);

So you're specifying your light position in object space? By the time you are performing the vector subtraction, P is in view space and LIGHT.position is (presumably) still in object space. You need to transform the light into view space, then calculate the vector from P to the light.

The view space transformation should probably look more like this:
float3 view_space_vertex = mul(modelView, IN.position).xyz;float3 view_space_normal = normalize(mul(modelViewInvTrans, IN.normal).xyz);float3 view_space_light = mul(modelView, LIGHT.position).xyz; /* Assuming LIGHT.position is the light's position in object space. */float3 vertex_to_light = normalize(view_space_light - view_space_vertex);...