Pygame collidepoint（）无法正常工作

Question

我正在制作一个游戏，其中您砍树并想要砍树，以便您只能砍掉您在游戏中位置（以正方形表示）的50像素半径（每个方向上大约1棵树）内的树。问题是，当我对其进行测试时，我发现它只能工作一次，这意味着您仅需采取行动即可停止半径障碍的工作，并且可以破坏任何树木。有人可以告诉我为什么会这样以及如何解决吗？代码如下：

# I'll only put in the bit that makes the bug
# Tree objects are sorted in a Tree class with a method destroy() to destroy the tree
for tree in trees:
            if pygame.mouse.get_pressed()[0] and tree.trunk.collidepoint(pygame.mouse.get_pos()):
                    mouse_x, mouse_y = pygame.mouse.get_pos()
                    print('clicked tree') # For testing purposes
                    if mouse_x < x + 51 and mouse_y < y + 51:
                        countdown = 3
                        destroy_tree = tree
                    elif mouse_x < x + 51 and mouse_y < y - 51:
                        countdown = 3
                        destroy_tree = tree
                    elif mouse_x < x - 51 and mouse_y < y - 51:
                        countdown = 3
                        destroy_tree = tree
                    elif mouse_x < x - 51 and mouse_y < y + 51:
                        countdown = 3
                        destroy_tree = tree

Answer 1

您必须评估它的坐标处于一个条件的范围内。您实际执行的操作类似于：

if x < value + 50:
   countdown = 3
elif x > value - 50:
   countdown = 3

其中一个条件总是被满足，并且在任何情况下都设置为countdown。

条件必须是：

if x - 51 < mouse_x < x + 51:
    if y - 51 < mouse_y < y + 51:
        countdown = 3
        destroy_tree = tree

此外，可以使用abs()简化算法。例如：

abs()

或者，您可以计算

mouse_x, mouse_y = pygame.mouse.get_pos()
for tree in trees:
    if pygame.mouse.get_pressed()[0] and tree.trunk.collidepoint((mouse_x, mouse_y)):
        print('clicked tree') # For testing purposes

        dx = mouse_x - x
        dy = mouse_y - y
        if abs(dx) <= 50 and abs(dy) <= 50:
            countdown = 3
            destroy_tree = tree

：

Euclidean distance