gl3w: Simple OpenGL 3/4 core profile loading

Introduction

gl3w is the easiest way to get your hands on the functionality offered by the OpenGL 3/4 core profile specification.

Its main part is a simple gl3w_gen.py Python 2.6 script that downloads the Khronos supported gl3.h header and generates gl3w.h and gl3w.c from it. Those files can then be added and linked (statically or dynamically) into your project.

Example

Here is a simple example of using gl3w with glut. Note that GL3/gl3w.h must be included before any other OpenGL related headers:

#include <stdio.h>
#include <GL3/gl3w.h>
#include <GL/glut.h>

// ...

int main(int argc, char **argv)
{
        glutInit(&argc, argv);
        glutInitDisplayMode(GLUT_RGBA | GLUT_DEPTH | GLUT_DOUBLE);
        glutInitWindowSize(width, height);
        glutCreateWindow("cookie");

        glutReshapeFunc(reshape);
        glutDisplayFunc(display);
        glutKeyboardFunc(keyboard);
        glutSpecialFunc(special);
        glutMouseFunc(mouse);
        glutMotionFunc(motion);

        if (gl3wInit()) {
                fprintf(stderr, "failed to initialize OpenGL\n");
                return -1;
        }
        if (!gl3wIsSupported(3, 2)) {
                fprintf(stderr, "OpenGL 3.2 not supported\n");
                return -1;
        }
        printf("OpenGL %s, GLSL %s\n", glGetString(GL_VERSION),
               glGetString(GL_SHADING_LANGUAGE_VERSION));

        // ...

        glutMainLoop();
        return 0;
}

API Reference

The gl3w API consists of just three functions:

int gl3wInit(void)

Initializes the library. Should be called once after an OpenGL context has been created. Returns 0 when gl3w was initialized successfully, -1 if there was an error.

int gl3wIsSupported(int major, int minor)

Returns 1 when OpenGL core profile version major.minor is available, and 0 otherwise.

void *gl3wGetProcAddress(const char *proc)

Returns the address of an OpenGL extension function. Generally, you won't need to use it since gl3w loads all the functions defined in the OpenGL core profile on initialization. It allows you to load OpenGL extensions outside of the core profile.

License

gl3w is in the public domain.

Credits

Slavomir Kaslev <slavomir.kaslev@gmail.com>: Initial implementation
Kelvin McDowell: Mac OS X support
Sjors Gielen: Mac OS X support
Rommel160 [github.com/Rommel160]: Code contributions

Copyright

OpenGL is a registered trademark of SGI.