GLUS for OpenGL, OpenGL ES and OpenVG
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README.md

GLUS - Cross platform and cross graphic library utilities

The cross platform and cross Graphic Library UtilitieS (GLUS) is an open-source C library, which provides a hardware (HW) and operating system (OS) abstraction plus many functions usually needed for graphics programming using OpenGL, OpenGL ES or OpenVG.


Download

Visit OpenGL repository on GitHub for the GLUS library plus many OpenGL 3 and 4 examples source code.
Visit OpenGL ES repository on GitHub for the GLUS library plus OpenGL ES 2.0, 3.0 and 3.1 examples source code.
Visit OpenVG repository on GitHub for the GLUS library plus OpenVG 1.1 examples source code.


Features

  • Same interface on different HW and OS
  • Tested on Windows, Linux, Mac OS X with AMD and NVIDIA GPUs. Also tested on the Raspberry Pi and the i.MX6
  • GLUT like rendering loop plus providing delta/passed time and terminate callback function
  • EGL surface and context parameters used on all platforms for initialization
  • Extension and version checking functions
  • Logging functions
  • Basic FPS profiling function
  • Screenshot and automatic screenshot for movie clip generation functions
  • Dynamic memory wrapper. Optional basic memory manager available
  • GLSL shader loading and program building
  • Image loading (TGA, HDR and PKM) and saving (TGA and HDR)
  • Binary and text file loading and saving
  • Distance functions for Plane, Sphere, Axis-Aligned- and Oriented-Bounding-Box
  • Ray-intersection function for Sphere
  • Basic mathematics functions
  • Matrix and vector mathematics functions
  • Special matrix functions: View, orthogonal and perspective projection, planar reflection, planar shadow with point and directional light
  • Complex number mathematics functions
  • Quaternion mathematics functions
  • Fourier transform mathematics functions
  • Random number functions
  • Perlin noise generation functions for 1D, 2D and 3D images
  • Line based geometry generation functions: Line, Square, Rectangle, Circle
  • Triangle based geometry generation functions: Planes, Disc, Cube, Sphere, Dome, Torus, Cylinder and Cone
  • Wavefront object file (OBJ) loading functions with and without materials
  • Adjacent vertices calculation functions for 3D objects
  • Texture coordinate calculation functions for 3D objects
  • Helper functions, to set up ray trace buffers
  • Converter functions for vectors and images

Compatibility

GLUS is written in ANSI C and uses GLFW and GLEW for desktop OpenGL. For OpenGL ES and OpenVG on embedded systems or desktop simulations, EGL and platform dependent code and libraries are used.


Usage

The following source code shows a minimal OpenGL 3.2 program using GLUS:

/**  
 * Include GLUS. Needed OpenGL, OpenGL ES or OpenVG headers will be included depending on the build profile.  
 */  
#include "GL/glus.h"  

/**  
 * Function for initialization.  
 *  
 * @return GLUS_TRUE when initalization succeeded, otherwise GLUS_FALSE and the application will exit.  
 */  
GLUSboolean init(GLUSvoid)  
{  
    // The background will be just cleared with blue color.  
    glClearColor(0.0f, 0.0f, 1.0f, 0.0f);  

    return GLUS_TRUE;  
}  

/**  
 * Function is called before first update and every time when the window is resized.  
 *  
 * @param width  The width of the window.  
 * @param height The height of the window.  
 */  
GLUSvoid reshape(GLUSint width, GLUSint height)  
{  
    // Set the viewport depending on the width and height of the window.  
    glViewport(0, 0, width, height);  
}  

/**  
 * Function to update and render content. Swapping of the buffers is automatically done.  
 *  
 * @param time The passed / delta time from last frame.  
 *  
 * @return GLUS_TRUE for continuing, GLUS_FALSE to exit the application.  
 */  
GLUSboolean update(GLUSfloat time)  
{  
    // Now, the background is painted blue.  
    glClear(GL_COLOR_BUFFER_BIT);  

    return GLUS_TRUE;  
}  

/**  
 * Function to clean up things.  
 */  
GLUSvoid terminate(GLUSvoid)  
{  
    // No resources have to be freed in this case.  
}  

/**  
 * Main entry point.  
 */  
int main(int argc, char* argv[])  
{  
    // Parameters for the used window surface. See EGL man pages for more info.  
    EGLint eglConfigAttributes[] = {  
        EGL_RED_SIZE, 8,  
        EGL_GREEN_SIZE, 8,  
        EGL_BLUE_SIZE, 8,  
        EGL_DEPTH_SIZE, 0,  
        EGL_STENCIL_SIZE, 0,  
        EGL_RENDERABLE_TYPE, EGL_OPENGL_BIT,  
        EGL_NONE  
    };  

    // Parameters for the used context. See EGL man pages for more info.  
    EGLint eglContextAttributes[] = {  
        EGL_CONTEXT_MAJOR_VERSION, 3,  
        EGL_CONTEXT_MINOR_VERSION, 2,  
        EGL_CONTEXT_OPENGL_FORWARD_COMPATIBLE, EGL_TRUE,  
        EGL_CONTEXT_OPENGL_PROFILE_MASK, EGL_CONTEXT_OPENGL_CORE_PROFILE_BIT,  
        EGL_NONE  
    };  

    glusWindowSetInitFunc(init);  

    glusWindowSetReshapeFunc(reshape);  

    glusWindowSetUpdateFunc(update);  

    glusWindowSetTerminateFunc(terminate);  

    // Create the used window. See GLUS man pages for different parameters.  
    if (!glusWindowCreate("GLUS Example Window", 640, 480, GLUS_FALSE, GLUS_FALSE, eglConfigAttributes, eglContextAttributes))  
    {  
        return -1;  
    }  

    // Enter the update render loop. See below state machine for more information.  
    glusWindowRun();  

    return 0;  
}  

The live time of an application using GLUS is showed in the following state machine:
GLUS state machine

The different parameters on how to initialize and use GLUS can be found in the different examples:

Visit the GLUS man pages for the documentation of each available function.


Copyright

The source code is licensed under the GNU LESSER GENERAL PUBLIC LICENSE. If another licence is needed, please contact the author.