python - Pygame 中鼠标的对象移动不准确

Question

我正在尝试制作该游戏的近似副本:

https://yppedia.puzzlepirates.com/Carpentry

它使用五联骨牌，即由 5 个方 block 组成的物体。我有一个 Piece 类，它将每个 block 存储在列表中。当我单击一个 block 来移动它时，我还会移动共享同一父 block 对象的所有其他 block ，因此我可以用鼠标拖动整个 block 。

我遇到的问题是，当我单击其中一个 block 时，该 block 会远离我的光标。拖动效果很好，但我希望它能够更精确地跟随光标。

我正在使用鼠标类，因此我可以实现鼠标单击和 block 之间的简单碰撞，但我认为这是我的问题的原因。

编辑:我可能可以通过对每个 block 的 x 和 y 位置进行硬编码更改来解决此问题，但理想情况下我更喜欢更模块化的解决方案，因为我认为我误解了鼠标位置在 pygame 中的工作原理。

import pygame
import sys
import collections
import random

pygame.init()
FPS = 25
fpsClock = pygame.time.Clock()

# -----------SCREEN----------------#
WIN_WIDTH = 680  # width of window
WIN_HEIGHT = 500  # height of window
DISPLAY = (WIN_WIDTH, WIN_HEIGHT)  # variable for screen display
DEPTH = 32  # standard
FLAGS = 0  # standard
screen = pygame.display.set_mode(DISPLAY, FLAGS, DEPTH)
pygame.display.set_caption('Carpentry')
# ---------------------------------#

# ---------------colours-----------#
WOOD = (182, 155, 76)
RED = (255, 0, 0)
BLACK = (0, 0, 0)
# ---------------------------------#

blocks = pygame.sprite.Group()
pieces = []

class Block(pygame.sprite.Sprite):
    def __init__(self, x, y, parent):
        super().__init__()
        self.image = pygame.Surface([15, 15])
        self.colour = WOOD
        self.parent = parent
        self.image.fill(self.colour)
        self.rect = self.image.get_rect()
        self.rect.x = x
        self.rect.y = y
        self.original_x = x
        self.original_y = y
        self.drag = False

class Mouse(pygame.sprite.Sprite):
    def __init__(self):
        super().__init__()
        self.image = pygame.Surface([15, 15])
        self.colour = RED
        self.image.fill(self.colour)
        self.rect = self.image.get_rect()
        self.rect.x = pygame.mouse.get_pos()[0]
        self.rect.y = pygame.mouse.get_pos()[1]

    def update_mouse(self):
        self.rect.x = pygame.mouse.get_pos()[0]
        self.rect.y = pygame.mouse.get_pos()[1]

class Piece:
    def __init__(self):
        self.blocks = []
        self.c = 0

    def insert(self, template):
        for direction in template:
            self.blocks.append([])
            x = 0
            y = 0
            for line in direction:
                for character in line:
                    if character == "O":
                        my_block = Block(x, y, self)
                        self.blocks[self.c].append(my_block)
                        blocks.add(my_block)

                    x += 15
                y += 15
                x = 0
            self.c += 1

J_TEMPLATE = [['..O..',
               '..O..',
               '..O..',
               '.OO..',
               '.....']]
templates = {}

my_piece = Piece()
my_piece.insert(J_TEMPLATE)
pieces.append(my_piece)

mouse = Mouse()
while True:
    screen.fill(BLACK)

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()
        elif event.type == pygame.MOUSEBUTTONDOWN:
            if event.button == 1:
                bool = pygame.sprite.spritecollide(mouse, blocks, False)
                if len(bool) > 0:
                    target = bool[0]
                    target.drag = True
                    for block in blocks:
                        if block.parent == target.parent: #if blocks are part of the same piece
                            block.drag = True
                else:
                    for block in blocks:
                        block.drag = False
    mouse.update_mouse()
    for block in blocks:
        if block.drag == True:
            block.rect.x = mouse.rect.x + block.original_x
            block.rect.y = mouse.rect.y + block.original_y

    blocks.draw(screen)
    pygame.display.update()
    fpsClock.tick(FPS)

Answer 1

我会这样做:如果单击了一个 block ，则将其父 block 分配给一个变量并计算 block 的偏移量，如下所示:block.offset = block.rect.topleft - Vec(事件.pos)。在文件顶部，您需要导入 from pygame.math import Vector2 as Vec。现在，您可以检查 pygame.MOUSEMOTION 事件并将 block 移动到新的 event.pos + block.offset。不再需要 Mouse 类。

selected = None

while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()
        elif event.type == pygame.MOUSEBUTTONDOWN:
            if event.button == 1:
                if selected:  # If a piece was selected ...
                    selected = None  # Deselect it.
                else:
                    # Find a colliding block.
                    collided_sprites = [block for block in blocks
                                        if block.rect.collidepoint(event.pos)]
                    if collided_sprites:  # If we clicked a block ...
                        # Select the parent of the block.
                        selected = collided_sprites[0].parent
                        # Calculate the offsets for the blocks.
                        for block in selected.blocks[0]:
                            block.offset = block.rect.topleft - Vec(event.pos)
        elif event.type == pygame.MOUSEMOTION:
            if selected:
                # Update the block positions by adding their offsets to the mouse pos.
                for block in selected.blocks[0]:
                    block.rect.topleft = event.pos + block.offset

    screen.fill(BLACK)
    blocks.draw(screen)
    pygame.display.update()
    fpsClock.tick(25)