import sys, math
from pyglet.gl import *

window = pyglet.window.Window()
glEnable(GL_DEPTH_TEST)
glEnable(GL_LIGHTING)
glEnable(GL_LIGHT0)

cameraDist = 15
cameraXrot = 0
cameraYrot = 0

@window.event
def on_draw():
    global cameraDist, cameraXrot, cameraYrot
    glClearColor(0, 0.3, 0.5, 0)
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
    glMatrixMode(GL_PROJECTION)
    glLoadIdentity()
    gluPerspective(60, 1, 0.1, 1000)
    glMatrixMode(GL_MODELVIEW)
    glLoadIdentity()
    glTranslatef(0, 0, -cameraDist)
    glRotatef(-cameraXrot, 1, 0, 0)
    glRotatef(-cameraYrot, 0, 1, 0)

    glLightfv(GL_LIGHT0, GL_POSITION, (GLfloat*4)(*[-1, 0, 1, 0]))
    glMaterialfv(GL_FRONT, GL_DIFFUSE, (GLfloat*4)(*[1, 0.7, 0, 1]))
    glMaterialfv(GL_FRONT, GL_SPECULAR, (GLfloat*4)(*[1, 1, 1, 1]))
    glMaterialf(GL_FRONT, GL_SHININESS, 80)
    glShadeModel(GL_FLAT)
    drawRing()


def drawRing():
    glBegin(GL_TRIANGLE_STRIP)
    for theta in range(0,370,10):
        x = 5 * math.sin(theta * math.pi/180.0)
        z = 5 * math.cos(theta * math.pi/180.0)
        nx = math.sin(theta*math.pi/180.0)
        nz = math.cos(theta*math.pi/180.0)
        glNormal3f(nx, 0, nz)
        glVertex3f(x, -1, z)
        glVertex3f(x, 1, z)
    glEnd()


@window.event
def on_key_press(key, modifiers):
    global cameraDist
    global cameraXrot, cameraYrot
    if key == pyglet.window.key.PERIOD:
        cameraDist = cameraDist - 1
    elif key == pyglet.window.key.COMMA:
        cameraDist = cameraDist + 1
    elif key == pyglet.window.key.LEFT:
        cameraYrot = cameraYrot - 3
    elif key == pyglet.window.key.RIGHT:
        cameraYrot = cameraYrot + 3
    elif key == pyglet.window.key.UP:
        cameraXrot = cameraXrot - 3
    elif key == pyglet.window.key.DOWN:
        cameraXrot = cameraXrot + 3


pyglet.app.run()