/*
 * simple2.c -- Angel, OpenGL: A Primer, p. 23
 * line-loop variant: p. 26
 */

#include <glut.h>

void display() {
 glClear(GL_COLOR_BUFFER_BIT);
 glBegin(GL_LINE_LOOP);
  glVertex2f(-0.5,-0.5);
  glVertex2f(-0.5,0.5);
  glVertex2f(0.5,0.5);
  glVertex2f(0.5,-0.5);
 glEnd();
 glFlush();
 }

void init() {
 glClearColor(0.0,0.0,0.0,0.0);
 glColor3f(1.0,1.0,1.0);
 glMatrixMode(GL_PROJECTION);
 glLoadIdentity();
 gluOrtho2D(-1.0,1.0,-1.0,1.0);
 }

int main(int argc,char *argv[]) {
 glutInit(&argc,argv);
 glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
 glutInitWindowSize(500,500);
 glutInitWindowPosition(0,0);
 glutCreateWindow("simple");
 glutDisplayFunc(display);
 init();
 glutMainLoop();
 }