/*  simple.c
 *
 *  Some real simple examples using GLUT.  
 *  Draws a triangle/square defined in display().
 *
 *  Bruce M. Bolden
 *  October 9, 2001
 *
 */

#include <GLUT/glut.h>

   //  prototypes
void DrawColoredTriangle();
void DrawColoredSquare();

void display();


void DrawColoredTriangle()
{
    glBegin( GL_POLYGON );
       glColor3f(1.0, 0.0, 0.0); // Red
       glVertex2f( 0.0, 0.0 );
       glColor3f(0.0, 1.0, 0.0); // Green
       glVertex2f( 0.5, 1.0 );
       glColor3f(0.0, 0.0, 1.0); // Blue
       glVertex2f( 1.0, 0.0 );
    glEnd();
}


void DrawColoredSquare()
{
    glBegin( GL_POLYGON );
       glColor3f(1.0, 0.0, 0.0); // Red
       glVertex2f( -0.5, -0.5 );
       glColor3f(0.0, 1.0, 0.0); // Green
       glVertex2f( -0.5,  0.5 );
       glColor3f(0.0, 0.0, 1.0); // Blue
       glVertex2f(  0.5,  0.5 );
       glColor3f(1.0, 1.0, 0.0); // Yellow
       glVertex2f(  0.5, -0.5 );
    glEnd();
}

void display()
{
    glClear( GL_COLOR_BUFFER_BIT );

    DrawColoredTriangle();

    //DrawColoredSquare();

    glBegin( GL_POLYGON );
       glVertex2f( -0.5, -0.5 );
       glVertex2f( -0.5,  0.5 );
       glVertex2f(  0.5,  0.5 );
       glVertex2f(  0.5, -0.5 );
    glEnd();

    glFlush();
}

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

     glutCreateWindow( "Simple" );
     glutDisplayFunc( display );

     glutMainLoop();
}