PyGame：碰撞檢測與塊

Question

在平台游戲中，我正在生成地形，但沒有碰撞。 這是我嘗試用來檢查碰撞的代碼：

def player_move(self):

    self.player.rect.x += self.player.velX
    self.check_collision(self.player, self.player.velX, 0)
    self.player.rect.y += self.player.velY
    self.check_collision(self.player, 0, self.player.velY)

def check_collision(self, sprite, x_vel, y_vel):
    # for every tile in Background.levelStructure, check for collision
    for block in self.moon.get_surrounding_blocks(sprite):
        if block is not None:
            if pygame.sprite.collide_rect(sprite, block):
                # we've collided! now we must move the collided sprite a step back
                if x_vel < 0:
                    sprite.rect.x = block.rect.x + block.rect.w

                if x_vel > 0:
                    sprite.rect.x = block.rect.x - sprite.rect.w

                if y_vel < 0:
                    sprite.rect.y = block.rect.y + block.rect.h

然后，如果有幫助的話，我也有用於生成關卡的代碼：

import pygame, random

# Level
class Block(pygame.sprite.Sprite):
    def __init__(self, x, y):
        pygame.sprite.Sprite.__init__(self)

        self.image = pygame.image.load('data/images/block.png')

        self.rect = self.image.get_rect()
        self.rect.x = x
        self.rect.y = y

    def render(self, surface):
        surface.blit(self.image, self.rect)



class Background():

    def __init__(self):
        self.bg_image = pygame.image.load('data/images/background.jpg')


        # create a 2-dimensional array (etc. tile[x][y]) for holding the level structure
        self.levelStructure = [[None for i in range(50)] for i in range(50)]

        # generate level on initialization
        self.generateLevel()

    def generateLevel(self):
        # fill self.levelStructure with tiles
        for x in range(20):
            for y in range(9):
                if y < 11:
                    # make top space for the player to be
                    continue

                tempBlock = Block(x*40, y*40)

                # add block to both and self.levelStructure
                self.levelStructure[x][y] = tempBlock

        # generate some random terrain
        for x in range(25):
            # get a random height
            height = random.randint(2, 5)

            for y in range(height):
                y += 15
                tempBlock = Block(x*40, (y-height)*40)
                self.levelStructure[x][y-height] = tempBlock

    def get_surrounding_blocks(self, sprite):
        # calculate the grid position of the sprite
        sprite_x = sprite.rect.x // 40
        sprite_y = sprite.rect.y // 40

        # generate a list of surrounding sprites
        blocks = []
        for x in range(-2, 2+1):
            for y in range(-2, 2+1):
                blocks.append(self.levelStructure[sprite_x + x][sprite_y + y])

        return blocks

    def render(self, surface):
        surface.blit(self.bg_image, (0, 0))

        # also draw the blocks we created
        for x in range(22):
            for y in range(15):
                block = self.levelStructure[x][y]

                # check if there is a block, or if the grid is empty
                if block is not None:
                    block.render(surface)

任何幫助將不勝感激，謝謝。

Answer 1

有幾個問題。

首先，您永遠不要告訴速度改變...您可能希望速度停止或在碰到障礙物時反轉。

其次，您要遍歷所有塊兩次，一次用於檢查X軸，一次用於Y。對於大型或復雜的地圖，這會使它慢兩倍。

我也建議不要在這種情況下使用collide_rect函數來測試碰撞，除非您非常確定速度不能高於塊（或精靈）的總大小。 如果您以每幀71px的速度移動，但塊的大小為20px，而播放器的寬度僅為50px，則可以直接跳過一個塊而完全不碰它！

要特別注意的一件事是，先移動對象，然后檢查碰撞。 這可能會引起問題，因為您隨后必須將其移回以前的位置。

我建議您將結構更改為：

def player_move(self):

    # create some local vars for ease of reading...
    x = self.player.rect.x
    x_next = x + self.player.velX

    y = self.player.rect.y
    y_next = y + self.player.vely

    w = self.player.rect.w
    h = self.player.rect.h

    # has a collision happened?
    hitX = False
    hitY = False

    for block in self.moon.get_surrounding_blocks(self.player):

        # empty blocks are 'None' in this map system...
        if not block:
            continue

        if self.player.velX > 0:  # moving right
            if x + w < block.x and x_next + w >= block.x:
                # collision!
                x_next =  block.x - w
                hitX = True
        elif self.player.velX < 0: # moving left
            if x > block.x + block.w and x_next > block.x + block.w:
                # collision!
                x_next = block.x + block.w
                hitX = True

         if self.player.velY...... # do the same for Y axis...

    # now update rect to have the new collision fixed positions:

    self.player.rect.x = x_next
    self.player.rect.y = y_next

    # and if there was a collision, fix the velocity.

    if hitX:
        self.velX = 0  # or 0 - velX to bounce instead of stop
    if hitY:
        self.velY = 0  # or 0 - velY to bounce instead of stop

希望這有助於朝正確的方向發展...

另一個想法是，幾年前當我編寫平台引擎時，我記得我在某個階段遇到了一些問題，播放器對象碰到了塊，然后停止，然后又重新開始。 最后，它是代碼中某處的一個錯誤。 可能值得添加一堆調試打印（最好使用'logging'包...），然后放慢幀速率，這樣您就可以確切地看到發生了什么。

祝好運！ 編寫游戲很有趣，但有時也會很令人沮喪。