+ self._health = 500
+
+ def pygame_pos(self, surface):
+ """Convert to pygame coordinates and offset position so
+ our position is the centre of the image."""
+ # The odd sign combination is because of the pymunk / pygame
+ # transform, but we do it this way to exploit Vec2d math magic
+ return pymunk.pygame_util.to_pygame(self.position + (-16, 16), surface)