Melakukan Rotasi di OpenGL

Rotasi.cpp

#include <windows.h> 
#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 
#include <stdarg.h> 
#include <GL\glut.h> 
#include <math.h> 

void rotasi() {
	glBegin(GL_POLYGON); //membuat persegi  
	glVertex2f(0.0,0.0);  
	glVertex2f(0.0, 50.0);  
	glVertex2f(200.0, 50.0);  
	glVertex2f(200.0, 0.0);  
	glEnd();   
} 

void render3() {
	glColor3f(0.0, 1.0, 0.0); //memberi warna hijau objek rotasi  
	rotasi();  
	glRotatef(-90, 0, 0, 1); //rotasi objek berdasar sudut,x,y,z  
	glColor3f(1.0, 0.0, 0.0);  // warna merah
	rotasi(); 
	glFlush();   
} 

// uncomment this section to run
int main(int argc, char** argv) {
	glutInit(&argc, argv);  
	glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);  
	glutInitWindowSize(480, 480);  
	glutInitWindowPosition(0, 0);  
	glutCreateWindow("Rotasi Objek");  //Judul Window
	gluOrtho2D(-320.0, 320.0, -320.0, 320.0);  
	glutDisplayFunc(render3);  
	glutMainLoop();  
	return 0;
}