#include <SDL.h>
#include <SDL_OpenGL.h>

void draw() {
    static float angle = 0.0f;
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    //glClear(GL_COLOR_BUFFER_BIT);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glTranslatef(0.0,0.0,-1.0);
    glRotatef(angle,1.0f,0.0f,0.0f);
    angle+=0.3f;
    glBegin(GL_QUADS);
        glColor3f(1.0f,0.0f,0.0f);
        glVertex3f(-0.5f,-0.5f,0.0f);
        glColor3f(0.0f,1.0f,0.0f);
        glVertex3f(-0.5f,0.5f,0.0f);
        glColor3f(0.0f,0.0f,1.0f);
        glVertex3f(0.5f,0.5f,0.0f);
        glColor3f(1.0f,1.0f,0.0f);
        glVertex3f(0.5f,-0.5f,0.0f);
    glEnd();
    glBegin(GL_QUADS);
        glColor3f(1.0f,0.0f,0.0f);
        glVertex3f(-0.5f,-0.5f,1.0f);
        glColor3f(0.0f,1.0f,0.0f);
        glVertex3f(-0.5f,0.5f,1.0f);
        glColor3f(0.0f,0.0f,1.0f);
        glVertex3f(0.5f,0.5f,1.0f);
        glColor3f(1.0f,1.0f,0.0f);
        glVertex3f(0.5f,-0.5f,1.0f);
    glEnd();
}

int main(int argc, char *argv[]) {
    const int xres=640;
    const int yres=480;
    SDL_Event event;
    SDL_Init(SDL_INIT_VIDEO);
    SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 ) ;
    SDL_GL_SetAttribute( SDL_GL_DEPTH_SIZE, 16 );
    SDL_SetVideoMode(xres,yres,0,SDL_OPENGL | SDL_HWSURFACE | SDL_DOUBLEBUF);
    glViewport(0,0,xres,yres);
    glClearColor(0.0f,0.0f,0.0f,0.0f);
    glShadeModel(GL_SMOOTH);
    glClearDepth(1.0);
    glEnable( GL_DEPTH_TEST );
    glDepthFunc( GL_LEQUAL );
    glDepthMask( GL_TRUE );

    glMatrixMode(GL_PROJECTION);
    gluPerspective(70.0,(double)xres/yres,0.0,3.0);
    glMatrixMode(GL_MODELVIEW);

    bool done = false;
    while(!done) {
        draw();
        SDL_GL_SwapBuffers();

        while(SDL_PollEvent(&event)) {
            switch(event.type) {       
                case SDL_KEYDOWN:
                    if(event.key.keysym.sym == SDLK_ESCAPE)
                        done=true;
                    break;
                case SDL_QUIT:
                    done=true;
            }
        }
    }
    SDL_Quit();
    return(0);
}