Latihan Menggerakkan Objek Grafika

#include <GL/glut.h>
#include <windows.h>
GLfloat xangle=0.0, yangle=0.0;
void init (void) {
glClearColor (1.0, 1.0, 1.0, 0.0);
glLineWidth (1.0);
glColor3f (1.0, 0.0, 0.0);
glMatrixMode (GL_PROJECTION);
glLoadIdentity ();
glOrtho (-6,6, -6,6, -6,6);
}
void display (void) {
glClear (GL_COLOR_BUFFER_BIT);
glPushMatrix();
glBegin (GL_LINES);
glVertex2f (-5.5,0.0);
glColor3f(1.0, 0.0, 0.0);
glVertex2f (5.5,0.0);
glEnd ();
glBegin (GL_LINES);
glVertex2f (0.0,-5.5);
glColor3f(1.0, 0.0, 0.0);
glVertex2f (0.0, 5.5);
glEnd ();
glRotatef(xangle, 1.0, 0.0, 0.0);
glBegin (GL_POLYGON);
glColor3f(-1.0, 0.0, 0.0);
glVertex2f (1.0, 1.0);
glColor3f(-1.0, 0.0, 0.0);
glVertex2f (4.0, 1.0);
glColor3f(0.0, 1.0, 0.0);
glVertex2f (1.0, 5.0);
glEnd ();
glPopMatrix();
glutSwapBuffers();
glFlush ();
}
void KeyboardAssign (GLubyte key, GLint x, GLint y) { switch (key) {
case 'g':
xangle +=10.0;
glColor3f (0.0, 0.0, 1.0);
glutPostRedisplay ();
break;
}
}
int main (int argc, char** argv) {
glutInit (&argc, argv);
glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB); glutInitWindowPosition (0, 0); glutInitWindowSize (1500, 1500); glutCreateWindow ("Latihan Menggerakkan Objek"); init();
glutDisplayFunc (display);
glutKeyboardFunc (KeyboardAssign);
glutMainLoop ();
}

Tekan "G"  melihat rotasi