def mouse_translate(self, x, y, dx, dy):
glPushMatrix()
glLoadIdentity()
glTranslatef(0, 0, -self._dist)
z = model_to_screen(0, 0, 0)[2]
d = vec_subs(screen_to_model(x, y, z), screen_to_model(x-dx, y-dy, z))
glPopMatrix()
self._x += d[0]
self._y += d[1]
def mouse_translate(self, x, y, dx, dy):
glPushMatrix()
glLoadIdentity()
glTranslatef(0,0,-self._dist)
z = model_to_screen(0,0,0)[2]
d = vec_subs(screen_to_model(x,y,z), screen_to_model(x-dx,y-dy,z))
glPopMatrix()
self._x += d[0]
self._y += d[1]