Open GL

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <GL/glut.h>
void mydisplay(){
glClear(GL_COLOR_BUFFER_BIT);
glBegin(GL_POLYGON);
glColor3f(0, 1, 0);
glVertex3f(-0.5, -0.5, 1);
glColor3f(0, 0, 1);
glVertex3f(-0.75, 0, 1);
glColor3f(1, 0, 0);
glVertex3f(-0.5, 0.5, 1);
glColor3f(0, 1, 0);
glVertex3f(0, 0.75, 1);
glColor3f(0, 0, 1);
glVertex3f(0.5, 0.5, -1);
glColor3f(1, 0, 0);
glVertex3f(0.75, 0, -1);
glColor3f(0, 1, 0);
glVertex3f(0.5, -0.5, -1);
glColor3f(0, 0, 1);
glVertex3f(0,-0.75, -1);
glEnd();
glFlush();
}
int main(int argc, char** argv){
glutCreateWindow("simple");
glutDisplayFunc(mydisplay);
glutMainLoop();
}