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

v = ((0,0,1),
     (0, .942809, -0.333333),
     (-.816497, -.471405, -.333333),
     (.816497,  -.471405, -.333333))

mode  = 0

def triangle(a,b,c):
    glVertexPointerf( [a,b,c] )
    if mode == 1:
        # take the average of the vertices, use that for the whole triangle
        n = normal(add(add(a,b),c))
        glNormalPointerf( [n,n,n] )
    else:
        glNormalPointerf( [a,b,c] )
    glDrawArrays( [GL_LINE_LOOP, GL_TRIANGLES, GL_TRIANGLES][mode], 0, 3 )


def normal(p):
    import math
    d = math.sqrt(p[0]*p[0]+p[1]*p[1]+p[2]*p[2])
    return (p[0] / d, p[1] / d, p[2] / d)

    
def divide_triangle(a,b,c,m):
    if m > 0:
        v1 = normal(add(a,b))
        v2 = normal(add(a,c))
        v3 = normal(add(b,c))
        divide_triangle(a, v1, v2, m-1)
        divide_triangle(c, v2, v3, m-1)
        divide_triangle(b, v3, v1, m-1)
        divide_triangle(v1, v3, v2, m-1)
    else:
        triangle(a,b,c)

def add(a,b):
    return (a[0]+b[0],a[1]+b[1],a[2]+b[2])


def tetrahedron(m):
    divide_triangle(v[0], v[1], v[2], m)
    divide_triangle(v[3], v[2], v[1], m)
    divide_triangle(v[0], v[3], v[1], m)
    divide_triangle(v[0], v[2], v[3], m)


dl = 0
def display():
    global dl
    if not dl:
        dl = 1
        glNewList(1, GL_COMPILE)
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
        glLoadIdentity()
        global mode
        mode = 0
        tetrahedron(n)
        mode = 1
        glTranslate(-2,0,0)
        tetrahedron(n)
        mode = 2
        glTranslate(4,0,0)
        tetrahedron(n)
        glEndList()
        print 'list'
    print 'disp'
    glCallList(1)
    glFlush()

def reshape(w,h):
    print w, h
    glViewport(0,0,w,h)
    glMatrixMode(GL_PROJECTION)
    glLoadIdentity()
    if w <= h:    x,y = 2, 2*float(h)/w
    else:         x,y = 2*float(w)/h, 2
    glOrtho(-x,x,-y,y,-10,10)
    glMatrixMode(GL_MODELVIEW)

def init():
    glLight(GL_LIGHT0, GL_AMBIENT, (1,1,1,1))
    glLight(GL_LIGHT0, GL_DIFFUSE, (1,1,1,1))
    glLight(GL_LIGHT0, GL_SPECULAR, (1,1,1,1))

    glMaterial(GL_FRONT, GL_AMBIENT, (0,0,0,1))
    glMaterial(GL_FRONT, GL_DIFFUSE, (1,0,0,1))
    glMaterial(GL_FRONT, GL_SPECULAR, (0,1,0,1))
    glMaterial(GL_FRONT, GL_SHININESS, 100)
    
    glEnable(GL_LIGHTING)
    glEnable(GL_LIGHT0)
    glEnable(GL_DEPTH_TEST)
    glShadeModel(GL_SMOOTH)
    glClearColor(0,0,0,1)
    glColor3(0,0,0)
    glEnableClientState( GL_VERTEX_ARRAY )
    glEnableClientState( GL_NORMAL_ARRAY )

if __name__ == '__main__':

    import sys, string
    try:
        n = string.atoi(sys.argv[1])
    except:
        n = 4

    glutInit([])
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB)
    glutInitWindowSize(500,300)
    glutInitWindowPosition(300,100)
    glutCreateWindow('Sphere')
    glutReshapeFunc (reshape)
    glutDisplayFunc (display)
    init()
    glutMainLoop()