Python实现超级玛丽游戏系列教程02玛丽走跑

STAND = 'standing'
WALK = 'walk'
SMALL_ACCEL = .2
SMALL_TURNAROUND = .35

def update(self, keys):
        self.handle_state(keys)
        self.update_position()
        self.animation()
    def update_position(self):
        self.rect.x += self.x_vel
        self.rect.y += self.y_vel
    def handle_state(self, keys):
        if self.state == c.STAND:
            self.standing(keys)
        elif self.state == c.WALK:
            self.walking(keys)
    def animation(self):
        if self.facing_right:
            self.image = self.right_frames[self.frame_index]
        else:
            self.image = self.left_frames[self.frame_index]
    def load_from_sheet(self):
        self.right_frames.append(
            self.get_image(178, 32, 12, 16))  # right
        self.right_frames.append(
            self.get_image(80, 32, 15, 16))  # right walking 1
        self.right_frames.append(
            self.get_image(99, 32, 15, 16))  # right walking 2
        self.right_frames.append(
            self.get_image(114, 32, 15, 16))  # right walking 3
        self.right_frames.append(
            self.get_image(144, 32, 16, 16))  # right jump
        self.right_frames.append(
            self.get_image(130, 32, 14, 16))  # right skid
        # The left image frames are numbered the same as the right
        # frames but are simply reversed.
        for frame in self.right_frames:
            new_image = pg.transform.flip(frame, True, False)
            self.left_frames.append(new_image)

def standing(self, keys):
        self.frame_index = 0
        self.x_vel = 0
        self.y_vel = 0
        if keys[pg.K_LEFT]:
            self.facing_right = False
            self.state = c.WALK
        elif keys[pg.K_RIGHT]:
            self.facing_right = True
            self.state = c.WALK
        else:
            self.state = c.STAND
    def walking(self, keys):
        if self.frame_index == 0:
            self.frame_index += 1
        else:
            if self.frame_index < 3:
                self.frame_index += 1
            else:
                self.frame_index = 1
        if keys[pg.K_LEFT]:
            self.facing_right = False
            self.x_accel = c.SMALL_ACCEL
            #向左速度是负的，如果没达到最小的负的速度，继续向左
            # 比如 -3 > -4，那就继续减小
            if self.x_vel > (self.max_x_vel * -1):
                self.x_vel -= self.x_accel
        elif keys[pg.K_RIGHT]:
            self.facing_right = True
            self.x_accel = c.SMALL_ACCEL
            if self.x_vel < self.max_x_vel:
                self.x_vel += self.x_accel