just the initGL function

main.cpp

void Main::initGL() {
    /* Request opengl 3.2 context.
     * SDL doesn't have the ability to choose which profile at this time of writing,
     * but it should default to the core profile */
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 1);
 
    /* Turn on double buffering with a 24bit Z buffer.
     * You may need to change this to 16 or 32 for your system */
    SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
    SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 32);

    glViewport(0.0, 0.0, SCREEN_WIDTH, SCREEN_HEIGHT);
    glOrtho( 0.0, SCREEN_WIDTH, SCREEN_HEIGHT, 0.0, 1.0, -1.0 );

    glContext = SDL_GL_CreateContext(this->window);
    SDL_GL_SetSwapInterval(0);

    glMatrixMode( GL_PROJECTION );
    glLoadIdentity();
    glMatrixMode( GL_MODELVIEW );
    glLoadIdentity();

    //Initialize clear color
    glClearColor( 0.f, 0.f, 0.f, 1.f );

    //Enable texturing
    glEnable( GL_TEXTURE_2D );
    glEnable(GL_TEXTURE_RECTANGLE_ARB);

    //Check for error
    GLenum error = glGetError();
    if(error != GL_NO_ERROR) {
        printf("Error initializing OpenGL!\n");
    }
}