/******************************************************
*  MESA/OpenGL program simple1.c
*  draws a filled rectangle in several shades of red
*******************************************************/

#include <GL/gl.h>
#include <stdlib.h>
#include "glaux.h"

int main (int argc, char** argv)
{
      float i;

        auxInitDisplayMode (AUX_SINGLE | AUX_RGB);  /* kind of window */
        auxInitPosition (0, 0, 500, 500);  /* x,y,w,h of window on screen */
        auxInitWindow (argv[0]);  /* open the window */

        glClearColor (0.0, 0.0, 0.0, 0.0); /* bkg color window is to have */
        glClear(GL_COLOR_BUFFER_BIT);  /* clear the window to that color */
        glOrtho (-1,1,-1,1,-1,1);  /* orthographic proj., viewing volume */
        for (i=0.2; i<=1.0; i+=0.2)  /* 5 shades of red */
          {
          glColor3f(i, 0.0, 0.0);  /* drawing color */
          glBegin(GL_POLYGON);     /* define the rectangle */
                glVertex2f(-0.5, -0.5);
                glVertex2f(-0.5, 0.5);
                glVertex2f(0.5, 0.5);
                glVertex2f(0.5, -0.5);
          glEnd();
          glFlush();  /* force execution--send commands over network */
          sleep (2);  /* wait a while */
          }
}


/***********************************************************************

COMPILING/LINKING the MESA/OpenGL application--

   Enter the correct commands
   Or Set up a script file containing the correct commands

csun_simple1 -- contains the command to compile/link the file simple1.c
                on bingsuns at SUNY-B.

usage--  from UNIX prompt:  source csun_simple


Contents of the file csun_simple1

gcc -I/opt/local/Mesa/v1.2.5/include -I/usr/openwin/include simple1.c \
-L/opt/local/Mesa/v1.2.5/lib -lMesaaux -lMesatk -lMesaGLU -lMesaGL -lm \
-lX11 -o simple1


DISPLAY environment variable must be set right for program to run.

*************************************************************************/