# This program draws a spinning triangle
# It demonstrates the use of the glutIdleFunc to animate objects.
# It also uses the "time" package, to make the animation happen
# at a fixed rate, rather than depending on how fast the graphics run.

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

angle = 0
prevTime = time.time()

def draw():
	global angle
	glLoadIdentity()
	glClear(GL_COLOR_BUFFER_BIT)

	glColor3f(0, 0, 1)
	glBegin(GL_TRIANGLES)
	glVertex2f(0.5, 0.0)
	glVertex2f(0.8, 0.0)
	glVertex2f(0.65, 0.5)
	glEnd()

	glTranslatef(0.65, 0.25, 0.0)
	glRotatef(angle, 0, 0, 1)
	glTranslatef(-0.65, -0.25, 0.0)
	glColor3f(0, 1, 0)
	glBegin(GL_TRIANGLES)
	glVertex2f(0.5, 0.0)
	glVertex2f(0.8, 0.0)
	glVertex2f(0.65, 0.5)
	glEnd()

	glFlush()


def keyboard(key, x, y):
	if key == chr(27):
		sys.exit(0)

def update():
	global angle
	global prevTime
	currentTime = time.time()
	deltaTime = currentTime - prevTime
	prevTime = currentTime
	angle = angle + 25 * deltaTime
	glutPostRedisplay()

glutInit([])
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB)
glutInitWindowSize(300, 300)
glutInitWindowPosition(0,0)
glutCreateWindow(sys.argv[0])
glutDisplayFunc(draw)
glutKeyboardFunc(keyboard)
glutIdleFunc(update)
glutMainLoop()