为什么这艘船向右移动但向左，上下移动（不优化的方式）？

Question

class Ship():

    def __init__(self, ai_setting, screen):
        self.screen = screen
        self.ai_setting = ai_setting
        self.image = pygame.image.load("images/ship.bmp")
        self.image = pygame.transform.scale(self.image, (200, 200))

        self.image_rect = self.image.get_rect()
        self.screen_rect = self.screen.get_rect()

        self.image_rect.bottom = self.screen_rect.bottom
        self.image_rect.centerx = self.screen_rect.centerx

        self.center_xaxis =float( self.image_rect.centerx)
        #move_flags
        self.moving_right = False
        self.moving_left = False
        self.moving_up = False
        self.moving_down = False


    def update(self):
        if self.moving_right:
            self.center_xaxis += self.ai_setting.ship_speed_factor
        if self.moving_left:
            self.image_rect.centerx -= 10
        if self.moving_up:
            self.image_rect.centery -=10
        if self.moving_down:
            self.image_rect.centery +=10

    def blitme(self):
        self.screen.blit(self.image, self.image_rect)

我尝试打印self.center_xaxis和self.image_rect.centerx的值 但是self.center_xaxis并不相同。

我需要self.center的值来通过我在我制作的设置文件中控制的因素进行更改。 game_function文件根据按键将更改的移动标志处理为true或返回false。

Answer 1

您可能想以浮点精度移动对象。因为 pygame.Rect 应该代表一个屏幕上的区域，pygame.Rect对象只能存储积分数据。参见 pygame.Rect ：

rect对象的坐标都是整数。 [...]

如果要以浮点精度存储对象位置，则必须将对象的位置分别存储在单独的变量属性中，并同步pygame.Rect.Rect对象。 round> rounh 坐标并将其分配给矩形的位置：

 class Ship():

    def __init__(self, ai_setting, screen):
        # [...]

        self.center_xaxis = self.image_rect.centerx
        self.center_yaxis = self.image_rect.centery

    def update(self):
        if self.moving_right:
            self.center_xaxis += self.ai_setting.ship_speed_factor
        if self.moving_left:
            self.center_xaxis -= self.ai_setting.ship_speed_factor
        if self.moving_up:
            self.center_yaxis -=10
        if self.moving_down:
            self.center_yaxis +=10

        self.image_rect.centerx = round(self.center_xaxis)
        self.image_rect.centery = round(self.center_yaxis)

    def blitme(self):
        self.screen.blit(self.image, self.image_rect)