• Advertisement
  • Popular Tags

  • Popular Now

  • Advertisement
  • Similar Content

    • 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. 
      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
  • Advertisement
  • Advertisement
Sign in to follow this  

OpenGL [OpenGL 3.3+] Newbie phong shading issues

This topic is 2033 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Hello, I would like to find a solution for the problem which is haunting me lately.

I am starting to use OpenGL3.3+ and shaders(I've been using immediate mode for 2D rendering most of the time, and Irrlicht 3D rendering engine.), so I am practically new at those. After some time fiddling with the new syntax and shaders, I've finally came to the lighting stage and tried to implement phong lighting, everything seemed okay at first, but then I realised it's screwed. After a day and a half of trying to fix it, intense googling for the same problem, I couldn't find a solution. My problem is simple:
Light is orientating with camera even if it's in a static place(like 0,0,100) so if it's lighting the back of the model, the front is lit, and even more strangely, when I go away from the dark side, it lights up..

Here's a screenshot:
lightz.png
(Light is in front of the model, while the back is being lit brightly as I am far away.)

Here's my phong shader, I've taken it from Anton's OpenGL4 wiki and added texturing support:

phong.fs
#version 400

in vec4 vpeye; // fragment position in eye coords
in vec4 vneye; // surface normal in eye coords
in vec2 UV; // UV coordinates
uniform vec4 lightPosition; // light position in eye coords
uniform vec4 Ka; // ambient coefficient
uniform vec4 Kd; // diffuse coefficient
uniform vec4 Ks; // specular coefficient
uniform float Ns; // specular exponent
uniform vec4 Ld; // diffuse light colour
// Values that stay constant for the whole mesh.
uniform sampler2D myTextureSampler;

layout (location = 0) out vec4 fragmentColour;

void main() {
vec4 n_eye = normalize(vneye); // normalise just to be on the safe side
vec4 s_eye = normalize(lightPosition - vpeye); // get direction from surface fragment to light
vec4 v_eye = normalize(-vpeye); // get direction from surface fragment to camera
vec4 h_eye = normalize(v_eye + s_eye); // Blinn's half-way vector
//vec4 r_eye = reflect(-s_eye, vneye); // Phong's full reflection (could use instead of h)

vec4 Ia = vec4(0.1,0.1,0.1,1) * Ka; // ambient light has a hard-coded colour here, but we could load an La value
vec4 Id = Ld * Kd * max(dot(s_eye, n_eye), 0.0); // max() is a safety catch to make sure we never get negative colours
vec4 Is = vec4(1,1,1,1) * Ks * pow(max(dot(h_eye, v_eye), 0), Ns); // my ambient light colour is hard coded white, but could load Ls

fragmentColour = texture( myTextureSampler, UV ).rgba *(Ia + Id + Is);
}


phong.vs
#version 400
layout (location = 0) in vec3 vertexPosition;
layout(location = 1) in vec2 vertexUV;
layout (location = 2) in vec3 vertexNormal;

uniform mat4 modelViewMatrix;
uniform mat4 projectionMatrix;
uniform mat3 normalMatrix;

// Output data ; will be interpolated for each fragment.
out vec2 UV;
out vec4 vpeye;
out vec4 vneye;

void main() {
vpeye = modelViewMatrix * vec4(vertexPosition, 1.0);
vneye = vec4(normalMatrix * vertexNormal, 0);
UV = vertexUV;
gl_Position = projectionMatrix * modelViewMatrix * vec4(vertexPosition, 1.0);
}


Also, I think this might be related to my matrices. I load the model with assimp so the normals are correct. The other matrices are set like this:

The ModelView matrix:
glm::mat4 ModelView=cam->getView()*Model;
glUniformMatrix4fv(MVMat,1,GL_FALSE,&ModelView[0][0]);


The NormalMatrix:
//The "normal matrix" is an inverse*transpose of the model*view matrix
glm::mat4 normat=glm::inverse(glm::transpose(ModelView));
glUniformMatrix3fv(NMat,1,GL_FALSE,&glm::mat3(normat)[0][0]);


How I calculate the view matrix:
// Camera matrix
_view = glm::lookAt(
_pos, // Camera is here
_pos+direction, // and looks here : at the same position, plus "direction"
up // Head is up (set to 0,-1,0 to look upside-down)
);


Hope you can help a poor noobley out and explain some things. smile.png

Share this post


Link to post
Share on other sites
Advertisement
I think I have managed to pretty much fix it by converting light's position to eyespace(?) by multiplying modelView matrix by light position in the vertex shader and then outputting it to fragment shader. Now it looks properly, like it's supposed to, but I still want some clarification why is it so. :)

Here's the output now:
behind.png
(The light's behind.)

infront.png
(The light's in front.)

Share this post


Link to post
Share on other sites
If your light's position is in object space, and your mesh is in eye space, then imagine that you have a light that is in a position away from the camera that is equal to it's position, and moves with the camera when the camera moves.

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement