OpenGL tutorial 11

//http://www.youtube.com/user/thecplusplusguy
//Thanks for the typed in code to Tapit85
//other files are the same
#include "functions.h"

float angle = 0.0;

int cube;
void init()
{
    glClearColor(.5,.5,.5,1.);  //background color and alpha
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(45,640.0/480.0,1.0,500.0);
    glMatrixMode(GL_MODELVIEW);
    glEnable(GL_DEPTH_TEST);
    cube = loadObject("test.obj");
    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);
    glEnable(GL_BLEND);
    // (A*S)+(B*D)
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    float col[] = {1.,1.,1.,1.};
    glLightfv(GL_LIGHT0, GL_DIFFUSE, col);
}

void display()
{
    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
    glLoadIdentity();
    float pos[] = {-1.0, 1.0, -2.0, 1.0};
    glLightfv(GL_LIGHT0, GL_POSITION, pos);
    glDisable(GL_LIGHTING);
    glBegin(GL_QUADS);
    // draw transparent objects from far to near!
    // first draw transparent objects then nontransparent objects
        glColor4f(0.,0.,1.,1.); // also possible with materials (for lighting)
        glVertex3f(-2.,2.,-10.);
        glVertex3f(-2.,-2.,-10.);
        glVertex3f(2.,-2.,-10.);
        glVertex3f(2.,2.,-10.);

        glColor4f(1.,0.,0.,.5);
        glVertex3f(-1.,3.,-9.);
        glVertex3f(-1.,-3.,-9.);
        glVertex3f(3.,-3.,-9.);
        glVertex3f(3.,3.,-9.);
    glEnd();
}

int main(int argc, char** argv)
{
    SDL_Init(SDL_INIT_EVERYTHING);
    SDL_Surface *screen;
//  screen = SDL_SetVideoMode(1024, 768, 32, SDL_SWSURFACE|SDL_OPENGL|SDL_FULLSCREEN);
    screen = SDL_SetVideoMode(640, 480, 8, SDL_SWSURFACE|SDL_OPENGL);
    bool running = true;
    const int FPS = 30;
    Uint32 start;
    SDL_Event event;
    init();
    while(running) {
        start = SDL_GetTicks();
        while(SDL_PollEvent(&event)) {
            switch(event.type) {
                case SDL_QUIT:
                    running = false;
                    break;
                case SDL_KEYDOWN:
                    switch(event.key.keysym.sym)
                    {
                        case SDLK_ESCAPE:
                            running = false;
                            break;
                    }
                    break;
            }
        }

        display();
        SDL_GL_SwapBuffers();
        angle += 0.5;
        if(angle > 360)
            angle -= 360;
        if(1000/FPS > SDL_GetTicks()-start)
            SDL_Delay(1000/FPS-(SDL_GetTicks()-start));
    }
    SDL_Quit();
    return 0;
}