#include <stdio.h>
#include <stdlib.h>
#include <GL/glut.h>
#include <unistd.h>

int frame_count = 0;

static void draw( void )
{
    static float red = 1.0f;
    static float green = 0.0f;
    static float blue = 0.0f;

    glClearColor( red, green, blue, 1.0f );
    glClear( GL_COLOR_BUFFER_BIT );
    glColor4f( red * 0.5f, green * 0.5f, blue * 0.5f, 1.0f );
    glRectf( -0.75f, -0.75f, 0.75f, 0.75f );
    glFinish();

    blue = green;
    green = red;
    red = 0.0f;

    sleep( 1 );

    glutSwapBuffers();

    sleep( 1 );

    if( frame_count != 4 )
    {
        ++frame_count;
        glutPostRedisplay();
        sleep( 1 );
    }
    else
    {
        exit(0);
    }
}

int main( int argc, char *argv[] )
{
    glutInit( &argc, argv );

    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
    glutCreateWindow( "Flasher" );
    glutFullScreen();
    glutDisplayFunc( draw );

    glutMainLoop();
    return 0;
}