import sys, string
from OpenGL.GL import *
from OpenGL.GLU import *
from OpenGL.GLUT import *


class OBJFace:
	def __init__(self, vertices, obj):
		self.vertices = vertices
		self.obj = obj
	def draw(self):
		glBegin(GL_POLYGON)
		for v in self.vertices:
			glVertex3fv(self.obj.vertices[v-1])
		glEnd()

class OBJUseMtl:
	def __init__(self, mtl):
		self.material = mtl
	def draw(self):
		if self.material.has_key('Kd'):
			glColor3fv(self.material['Kd'])

class OBJFile:
	def __init__(self, filename):
		self.vertices = []
		self.materials = {}
		self.commands = []
		file = open(filename, "r")
		lines = file.readlines()
		for line in lines:
			values = string.split(line)
			if len(values) < 1:
				continue
			if values[0] == 'v':
				x = string.atof(values[1])
				y = string.atof(values[2])
				z = string.atof(values[3])
				self.vertices.append([x,y,z])
			elif values[0] == 'mtllib':
				self.loadMtllib(values[1])
			elif values[0] == 'f':
				face = []
				for v in values[1:]:
					w = string.split(v,'/')
					face.append(string.atoi(w[0]))
				self.commands.append(OBJFace(face,self))
			elif values[0] == 'usemtl':
				if self.materials.has_key(values[1]):
					self.commands.append(OBJUseMtl(self.materials[values[1]]))
				else:
					print 'Warning: %s trying to use unknown material %s' % (filename, values[1])

	def loadMtllib(self, filename):
		for line in open(filename, "r").readlines():
			values = string.split(line)
			if len(values) < 1:
				continue
			if values[0] == 'newmtl':
				mtl = {}
				self.materials[values[1]] = mtl
			elif values[0] == 'Kd':
				r = string.atof(values[1])
				g = string.atof(values[2])
				b = string.atof(values[3])
				mtl['Kd'] = [ r, g, b ]

	def draw(self):
		for c in self.commands:
			c.draw()

viewRotY = 0
viewRotX = 0

cow = OBJFile("cow.obj")

def draw():
    glClear(GL_COLOR_BUFFER_BIT)
    
    glMatrixMode(GL_PROJECTION)
    glLoadIdentity()
    glOrtho(-10, 10, -10, 10, -10, 10)
    glMatrixMode(GL_MODELVIEW)

    glLoadIdentity()
    glRotatef(viewRotX, 1.0, 0.0, 0.0)
    glRotatef(viewRotY, 0.0, 1.0, 0.0)
    
    cow.draw()
    glutSwapBuffers()


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

def specialkey(key,x,y):
    global viewRotX, viewRotY
    if key == GLUT_KEY_LEFT:
        viewRotY = viewRotY + 3
    elif key == GLUT_KEY_RIGHT:
        viewRotY = viewRotY - 3
    elif key == GLUT_KEY_UP:
        viewRotX = viewRotX + 3
    elif key == GLUT_KEY_DOWN:
        viewRotX = viewRotX - 3
    glutPostRedisplay()

glutInit([])
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE)
glutInitWindowSize(400,400)
glutCreateWindow(sys.argv[0])
glutDisplayFunc(draw)
glutKeyboardFunc(keyboard)
glutSpecialFunc(specialkey)
glutMainLoop()