• 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 Orthographic matrix not working

This topic is 1879 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

Hi all,

 

I am having trouble creating an orthographic projection in opengl (without using glOrtho).  And before anyone tells me to use glOrtho, lets just pretend I'm using opengl 3.0 as an exercise.  Here is the way I have set up my matrix:

 

projectionMatrix.m00 = 2/WIDTH;
projectionMatrix.m11 = 2/HEIGHT;
projectionMatrix.m22 = -2/(far_plane - near_plane);
projectionMatrix.m32 = -((far_plane + near_plane)/(far_plane - near_plane));
projectionMatrix.m33 = 1;

This is your typical ortho projection matrix, taken straight from the opengl spec def. for glOrtho. 

 

When I set up a frustrum and use a perspective matrix, this works fine, but I can't use my regular screen coordinates properly.  But when I use the glOrtho matrix above, I see nothing but my background color. Anyone know what's going on? Is my matrix wrong?

 

My shader looks like this:

 

 

#version 150 core
uniform mat4 projectionMatrix;
uniform mat4 viewMatrix;
uniform mat4 modelMatrix;


in vec4 in_Position;
in vec4 in_Color;
in vec2 in_TextureCoord;


out vec4 pass_Color;
out vec2 pass_TextureCoord;


void main(void){
    gl_Position = in_Position;
    
    //override gl position with new calculated position
    gl_Position = projectionMatrix * viewMatrix * modelMatrix * in_Position;
    
    pass_Color = in_Color;
    pass_TextureCoord = in_TextureCoord;


}

 

Any help appreciated.

 

Thanks!

 

 

 

Share this post


Link to post
Share on other sites
Advertisement

Try this:

 

void glOrtho(float* out, float left, float right,float bottom, float top,float near, float far)
{
    
    float a = 2.0f / (right - left);
    float b = 2.0f / (top - bottom);
    float c = -2.0f / (far - near);
    
    float tx = - (right + left)/(right - left);
    float ty = - (top + bottom)/(top - bottom);
    float tz = - (far + near)/(far - near);
    
    float ortho[16] = {
        a, 0, 0, 0,
        0, b, 0, 0,
        0, 0, c, 0,
        tx, ty, tz, 1
    };
    
    memcpy(out, ortho, sizeof(float)*16);
}

 

Your vertex program should be fine if it works with your perspective matrix.  Let me know if this fixes your problem, this has been confirmed to work for OpenGL ES 2.0.

 

Shogun.

Share this post


Link to post
Share on other sites

What geometry are you feeding it?

 

A mistake I see sometimes is that people will be drawing, say, a quad: (-1,-1,0) -> (1,1,0) or some other geometry on a very small scale. Which will work fine with a perspective matrix, since you can always move your camera to near enough the object that it appears as large in the viewport as you need it to be. But in a screen-size orthographic projection, that 2x2 size quad will only ever be 2x2 pixels on screen, regardless of where you put your camera. This makes switching from perspective to ortho tricky, in that you have to think about the scale of your objects. If you make your base unit to be a meter for example (ie, 1 unit=1 meter) then you might have a character model that is 2 units tall. In an orthographic projection, this object will only be 2 pixels tall.

 

So if your geometry is small, you either need to scale the geometry or include a scaling factor when constructing your matrix.

Share this post


Link to post
Share on other sites

Well right now all I am trying to do is get a 40 pixel by 40 sprite displayed on the screen.  I have tried messing around with the size of the sprite to no avail.  Once I get home I will take a look at the code and give you some more details about it, but I have a feeling you ar right about the scaling/size/etc.

Share this post


Link to post
Share on other sites

Ok, so I have a sprite with x,y,z (10,10,0)  with w/h 10fx10f

 

I have left as 0 and right as 680

top as as 480, bottom as 0

 

Still I see nothing.

 

Also, I am using lwjgl, in which if you have a matrix4f, I think m23 means 2nd column, 3rd row. 

 

 

 

  

 

              Sprite sprite = new Sprite("assets/texture/redman.png", 50f, 50f, 10f, 10f );
 
projectionMatrix.m00 = 2/WIDTH;
        projectionMatrix.m11 = 2/HEIGHT;
        projectionMatrix.m22 = -2/(far_plane - near_plane);
        projectionMatrix.m30 = -1;
        projectionMatrix.m31 = -1;
        projectionMatrix.m32 = -((far_plane + near_plane)/(far_plane - near_plane));
        projectionMatrix.m33 = 1;

         cameraPos = new Vector3f(0,0,-1); ...

 

 

//Translate camera        
Matrix4f.translate(cameraPos, viewMatrix, viewMatrix);

        //Scale, translate and rotate model
        Matrix4f.scale(modelScale, modelMatrix, modelMatrix);
        Matrix4f.translate(modelPos, modelMatrix, modelMatrix);
        Matrix4f.rotate((float)Math.toRadians(modelAngle.z), new Vector3f(0,0,1), modelMatrix, modelMatrix);
        Matrix4f.rotate((float)Math.toRadians(modelAngle.y), new Vector3f(0,1,0), modelMatrix, modelMatrix);
        Matrix4f.rotate((float)Math.toRadians(modelAngle.x), new Vector3f(1,0,0), modelMatrix, modelMatrix);
 

 

 

..

Edited by sufimaster

Share this post


Link to post
Share on other sites

Have you tried disabling back face culling?

If your sprite doesn't have the correct winding, and back face culling is enabled , then it will not be drawn.

 

Also, in OpenGL the Y coordinate goes from bottom to top, so make sure that you are positioning the sprite inside the view (unlike the projection matrix where point 0.0, 0.0, 0.0, is the center of the screen, on an orthographic projection, it is the left bottom corner).

Although you can change this when you build the matrix.

You can also try a bigger sprite, like with a size of (100, 100).

 

One last note. You should try the function Shogun posted to calculate your matrix. Somehow, and i might be wrong, but it doesn't seem like your matrix is being calculated like it should (again, it may be just me).

 

Don't know if this is your problem, but try it and see.

Edited by __SKYe

Share this post


Link to post
Share on other sites

Ok- so i used Shogun's method, I messed around with the camera position and near and far plane.

 

Now:

near plane is 1f, far plane is 100f (though I dont see why this matters in an ortho projection)

Camera is located at 0,0,-1

 

Sprite is at 0,0,0 dim: 10x10 pixels.

 

I can actually see it on the screen now, but it seems like everything is vanishing at the origin point, as attached:

 

This is supposed to be a quad, but the perspective is all wonky. Any idea what's going on now?

Share this post


Link to post
Share on other sites

How are you sending this to your shader?  Are you multiplying it by your previous projection matrix before doing so?  These are two other areas where things can go wrong, and you haven't provided sufficient info to diagnose.

Share this post


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

  • Advertisement