# This program draws a moving "car" with rotating wheel.s
# It demonstrates the use of the glPushMatrix and glPopMatrix to
# create a hierarchy of transformations.

import sys
import math
import time
from OpenGL.GLUT import *
from OpenGL.GL import *
from OpenGL.GLU import *

angle = 0
prevTime = time.time()

points = [  [-1, -1, -1] , [1, -1, -1],
			[1, -1, -1], [1, 1, -1],
			[1, 1, -1], [-1, 1, -1],
			[-1, 1, -1], [-1, -1, -1],
		    [-1, -1, 1] , [1, -1, 1],
			[1, -1, 1], [1, 1, 1],
			[1, 1, 1], [-1, 1, 1],
			[-1, 1, 1], [-1, -1, 1],
		    [-1, -1, -1] , [-1, -1, 1],
			[1, -1, -1], [1, -1, 1],
			[1, 1, -1], [1, 1, 1],
			[-1, 1, -1], [-1, 1, 1]
		]

def draw():
	global angle
	glLoadIdentity()
	glTranslatef(0, 0, -7)
	glClear(GL_COLOR_BUFFER_BIT)
	glRotatef(angle, 0, 1, 0)
	glTranslatef(-2, 0, 0)
	glBegin(GL_LINES)
	for p in points:
		glVertex3fv(p)
	glEnd()
	glTranslatef(4, 0, 0)
	glBegin(GL_LINES)
	for p in points:
		glVertex3fv(p)
	glEnd()
	glutSwapBuffers()


spin = 0

def keyboard(key, x, y):
	global spin, prevTime
	if key == chr(27):
		sys.exit(0)
	elif key == ' ':
		spin = not spin
		prevTime = time.time()

def update():
	global angle, prevTime
	if spin:
		currentTime = time.time()
		deltaTime = currentTime - prevTime
#		prevTime = currentTime
#		angle = angle + 30 * deltaTime
		angle = math.sin(deltaTime) * 20
		glutPostRedisplay()

glutInit([])
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB)
glutInitWindowSize(400, 400)
glutInitWindowPosition(0,0)
glutCreateWindow(sys.argv[0])
glMatrixMode(GL_PROJECTION)
glLoadIdentity()
gluPerspective(70, 1, 0.1, 100)
glMatrixMode(GL_MODELVIEW)
glutDisplayFunc(draw)
glutKeyboardFunc(keyboard)
glutIdleFunc(update)
glutMainLoop()