animated_sprite.py 文件源码

def apply_physics(self, tile_map):
        """Gravity in this case"""
        # The dy should be controlled by 'gravity' only for now - jumps will impart an
        # Initial up velocity (done in the keyhandler), then gravity acts here on update.
        # Without some sort of gravity approximation, sprites would move at the same speed
        # while in the air and seem very light, like they're walking on the moon in low gravity
        # only worse.  Not a problem for a top-down 2D game :)

        # If not on the ground floor, just assume we're falling (for now this will be true)
        if self.rect.bottom < tile_map.player_bounds_rect.bottom and self.falling == False:
            self.falling = True
            self.falling_frames = 1

        if self.falling:
            # As long as the sprite is continually falling, the 'speed' increases each
            # frame by the acceleration until some terminal speed
            if self.dy < self.settings.terminal_velocity:
                self.dy += self.settings.gravity
            self.rect.centery += self.dy
            self.falling_frames += 1