Camera Movement

For general camera movement:

• keep track of camera position & orientation
• apply inverse transformation to the world

def draw():
    global cameraX, cameraY, cameraZ
    global cameraHeading

    glLoadIdentity()
    glRotatef(-cameraHeading, 0, 1, 0)
    glTranslatef(-cameraX, -cameraY, -cameraZ)

    drawObjects()