/*
 *  simple.c
 *  This program draws a white rectangle on a black background.
 */


#include <stdlib.h>           
#include <GL/glut.h>              /* glut.h */


void display(void)

{
/* set clear color to black and clear window */

	glClearColor (0.0, 0.0, 0.0, 0.0);
	glClear(GL_COLOR_BUFFER_BIT);

/* set drawing/fill  color to white */

	glColor3f(1.0, 1.0, 1.0);

/* set up standard orthogonal view with clipping */
/* box as cube of side 2 centered at origin */
/* This is default view and these statement could be removed */

	glMatrixMode (GL_PROJECTION);
	glLoadIdentity ();
	glOrtho(-1.0, 1.0, -1.0, 1.0, -1.0, 1.0); 
/* define unit square polygon */

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

/* flush GL buffers */

	glFlush();

}

int main(int argc, char** argv)
{

/* Initialize mode and open a window in upper left corner of screen */
/* Window title is name of program (arg[0]) */

	glutInit(&argc,argv);
	glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB); 
	glutInitWindowSize(500,500);
	glutInitWindowPosition(0,0);
	glutCreateWindow("simple");
	glutDisplayFunc(display);
	glutMainLoop();

}