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

Its main part is a simple gl3w_gen.py Python script that downloads the Khronos supported glcorearb.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.

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

#include <stdio.h>
#include <GL/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;
}

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.

gl3w is in the public domain.

Slavomir Kaslev <[email protected]>

Initial implementation

Kelvin McDowell

Mac OS X support

Sjors Gielen

Mac OS X support

Travis Gesslein

Patches regarding glcorearb.h

Rommel160 [github.com/Rommel160]

Code contributions

OpenGL is a registered trademark of SGI.