To give the effect of moving the perspective viewpoint in OpenGL, use a transformation at the beginning of the frame, which affects all objects.
For example, to move the camera 10 units from the origin
in the +Z direction, translate the world by -10 in Z:
def draw():
glMatrixMode(GL_PROJECTION)
glLoadIdentity()
gluPerspective(fovy, 1, 0.1, 100)
glMatrixMode(GL_MODELVIEW)
glLoadIdentity()
glTranslatef(0, 0, -10)
drawObjects()