ValueError：表面区域外的次表面矩形

Question

我正在制作一款相机跟随玩家的平台游戏。我试图通过在整个地图上拥有一个大的表面表面并且只对放大的部分进行 blitting 来实现这一点。但是我只获得 30 fps（最小化）和 8 fps（全屏）。

所以我尝试优化它是在 blitting 之前对其进行裁剪，但我得到 ValueError: subsurface rectangle outside surface area

代码

class screen_handler:
    def __init__(self, screen=False, mapSize=[3, 3]):
        if not screen:  # if screen isn't open
            init()  # initialize pygame
            user32 = ctypes.windll.user32  # set user32
            os.environ['SDL_VIDEO_WINDOW_POS'] = "%d,%d" % (user32.GetSystemMetrics(0) / 4, user32.GetSystemMetrics(1) / 4)  # center future screen
            screen = display.set_mode((640, 512),  RESIZABLE)  # create screen

        self.screen = screen  # save screen
        self.blit_surf = Surface((640 * mapSize[0], 512 * mapSize[1]))  # create blit_surf
        self.clock = time.Clock() # create clock
        self.neutralizerZoom = min(self.blit_surf.get_width() / 640, self.blit_surf.get_height() / 512)  # reset zoom

        self.zoom = 2
        self.mousePos = [0, 0]
        self.cameraPos = [0, 0]

        self.fit_to_rect = self.blit_surf.get_rect().fit(self.screen.get_rect())  # fit the surface to the screen
        self.fit_to_rect.size = self.fit_to_rect.width * self.neutralizerZoom * self.zoom, self.fit_to_rect.height * self.neutralizerZoom * self.zoom  # add zoom



    def video_resize(self):
        self.fit_to_rect = self.blit_surf.get_rect().fit(self.screen.get_rect())  # fit the surface to the screen
        self.fit_to_rect.size = self.fit_to_rect.width * self.neutralizerZoom * self.zoom, self.fit_to_rect.height * self.neutralizerZoom * self.zoom  # add zoom

    def update(self):
        scaled = transform.scale(self.blit_surf, (self.fit_to_rect.width, self.fit_to_rect.height))  # scale surface to screen
        self.fit_to_rect.topleft = self.screen.get_rect().top + self.cameraPos[0], self.screen.get_rect().left + self.cameraPos[1]  # center surface & camera pos

        self.mousePos[0] = (mouse.get_pos()[0] / (scaled.get_width() / self.blit_surf.get_width())) - (self.cameraPos[0] / (scaled.get_width() / self.blit_surf.get_width()))  # scale x axis mouse pos
        self.mousePos[1] = (mouse.get_pos()[1] / (scaled.get_height() / self.blit_surf.get_height()))  # scale y axis mouse pos
        scaled = scaled.subsurface(self.fit_to_rect.x, self.fit_to_rect.y, self.fit_to_rect.x + self.fit_to_rect.width, self.fit_to_rect.y + self.fit_to_rect.height)
        self.screen.blit(scaled ,(0, 0))  # blit surface to screen
        #self.screen.blit(scaled, self.fit_to_rect)
        display.flip()  # update screen
        self.clock.tick(60)
        print(self.clock.get_fps())

注意：请告诉我是否有更好/更快的方式来实现相机

Answer 1

这是我的相机移动方式：

WINDOW_WIDTH, WINDOW_HEIGHT = ...
window = pygame.display.set_mode((WINDOW_WIDTH, WINDOW_HEIGHT), RESIZABLE)
screen = pygame.Surface(your_resolution)
...
scroll_x, scroll_y = player_position  # get the scroll
...
screen.blit(image, (x_pos + scroll_x, y_pos + scroll_y))
...
for event in pygame.event.get():
    if event.type == VIDEORESIZE:
        WINDOW_WIDTH, WINDOW_HEIGHT = event.size
...
window.blit(pygame.transform.scale(screen, (WINDOW_WIDTH, WINDOW_HEIGHT)), (0, 0))
pygame.display.update()

每次你想展示一些东西时，你需要将它放到屏幕上而不是窗口上。

如果你想拥有相同的规模，我会推荐以下课程：

class Window:
    def __init__(self, surf, width, height):
        self.screen = pygame.display.set_mode((width, height), RESIZABLE)
        self.surf = surf
        self.orig_w, self.orig_h = surf.get_size()
        self.set_sizes(width, height)

    def set_sizes(self, width, height):
        self.rate = min(width / self.orig_w, height / self.orig_h)
        self.width = int(self.orig_w * self.rate)
        self.x_off = int((width - self.width) / 2)
        self.height = int(self.orig_h * self.rate)
        self.y_off = int((height - self.height) / 2)

    def get_mouse_pos(self):
        mouse_x, mouse_y = pygame.mouse.get_pos()
        return int((mouse_x - self.x_off) / self.rate), int((mouse_y - self.y_off) / self.rate)

    def show(self):
        self.screen.fill((50, 50, 50))
        self.screen.blit(pygame.transform.scale(self.surf, (self.width, self.height)), (self.x_off, self.y_off))
        pygame.display.flip()

编辑：优化

以下代码将替换导致您出现问题的行：
而不是

scaled = scaled.subsurface(...)
self.screen.blit(scaled, (0, 0))

做

self.screen.blit(scaled, (0, 0), self.fit_to_rect)

这更有效，因为它不需要创建次表面，但 blits 直接在屏幕上。 优化提示： 避免每帧都重新创建表面。
您的大表面只需要在加载地图时创建，并且不再需要。如果您正在旋转图像，您可以在程序开始时简单地创建一个旋转图像的列表或字典，并且只需要调用它。规模变化也是如此。

使用img = img.convert()
这是一个非常简单的优化技巧。