python - 将碰撞检测添加到 pygame 中的平台

Question

我正在开发一款小型平台游戏，您可以在其中放置方 block 来打造关卡，然后进行游戏。

我有重力、跳跃和左右移动..但我不确定如何让玩家在左右移动时与墙壁发生碰撞。

我希望它的工作方式是这样的-

如果键[K_LEFT]:

如果左边没有挡住:

向左移动

我将如何去做(相对于这个来源):

import pygame,random
from pygame.locals import *
import itertools
pygame.init()
screen=pygame.display.set_mode((640,480))
class Block(object):
    sprite = pygame.image.load("texture\\dirt.png").convert_alpha()
    def __init__(self, x, y):
        self.rect = self.sprite.get_rect(centery=y, centerx=x)

class Player(object):
    sprite = pygame.image.load("texture\\playr.png").convert()
    sprite.set_colorkey((0,255,0))
    def __init__(self, x, y):
        self.rect = self.sprite.get_rect(centery=y, centerx=x)

blocklist = []
player = []
colliding = False

while True:
    screen.fill((25,30,90))
    mse = pygame.mouse.get_pos()
    key=pygame.key.get_pressed()

    if key[K_LEFT]:
        p.rect.left-=1
    if key[K_RIGHT]:
        p.rect.left+=1
    if key[K_UP]:
        p.rect.top-=10

    for event in pygame.event.get():
        if event.type == QUIT: exit()

        if key[K_LSHIFT]:
            if event.type==MOUSEMOTION:
                if not any(block.rect.collidepoint(mse) for block in blocklist):
                    x=(int(mse[0]) / 32)*32
                    y=(int(mse[1]) / 32)*32
                    blocklist.append(Block(x+16,y+16))
        else:
            if event.type == pygame.MOUSEBUTTONUP:
                if event.button == 1:
                    to_remove = [b for b in blocklist if b.rect.collidepoint(mse)]
                    for b in to_remove:
                        blocklist.remove(b)

                    if not to_remove:
                        x=(int(mse[0]) / 32)*32
                        y=(int(mse[1]) / 32)*32
                        blocklist.append(Block(x+16,y+16))

                elif event.button == 3:
                    x=(int(mse[0]) / 32)*32
                    y=(int(mse[1]) / 32)*32
                    player=[]
                    player.append(Player(x+16,y+16))

    for b in blocklist:
        screen.blit(b.sprite, b.rect)
    for p in player:
        if any(p.rect.colliderect(block) for block in blocklist):
            #collide
            pass
        else:
            p.rect.top += 1
        screen.blit(p.sprite, p.rect)
    pygame.display.flip()

Answer 1

一个常见的方法是将水平和垂直碰撞处理分成两个独立的步骤。

如果您这样做并跟踪玩家的速度，就很容易知道碰撞发生在哪一侧。

首先，让我们给玩家一些属性来跟踪他的速度:

class Player(object):
    ...
    def __init__(self, x, y):
        self.rect = self.sprite.get_rect(centery=y, centerx=x)
        # indicates that we are standing on the ground
        # and thus are "allowed" to jump
        self.on_ground = True 
        self.xvel = 0
        self.yvel = 0
        self.jump_speed = 10
        self.move_speed = 8

现在我们需要一种方法来实际检查碰撞。如前所述，为了让事情变得简单，我们使用我们的 xvel 和 yvel 来知道我们是否与左侧或右侧等发生碰撞。这进入了 Player 类:

def collide(self, xvel, yvel, blocks):
    # all blocks that we collide with
    for block in [blocks[i] for i in self.rect.collidelistall(blocks)]:

        # if xvel is > 0, we know our right side bumped 
        # into the left side of a block etc.
        if xvel > 0: self.rect.right = block.rect.left
        if xvel < 0: self.rect.left = block.rect.right

        # if yvel > 0, we are falling, so if a collision happpens 
        # we know we hit the ground (remember, we seperated checking for
        # horizontal and vertical collision, so if yvel != 0, xvel is 0)
        if yvel > 0:
            self.rect.bottom = block.rect.top
            self.on_ground = True
            self.yvel = 0
        # if yvel < 0 and a collision occurs, we bumped our head
        # on a block above us
        if yvel < 0: self.rect.top = block.rect.bottom

接下来，我们将移动处理移至 Player 类。因此，让我们创建一个跟踪输入的对象。在这里，我使用 namedtuple ，因为为什么不呢。

from collections import namedtuple
...
max_gravity = 100
Move = namedtuple('Move', ['up', 'left', 'right'])
while True:
    screen.fill((25,30,90))
    mse = pygame.mouse.get_pos()
    key = pygame.key.get_pressed()

    for event in pygame.event.get():
       ...

    move = Move(key[K_UP], key[K_LEFT], key[K_RIGHT])
    for p in player:
        p.update(move, blocklist)
        screen.blit(p.sprite, p.rect)

我们将blocklist 传递给Player 的update 方法，这样我们就可以检查碰撞。使用 move 对象，我们现在知道玩家应该移动到哪里，所以让我们实现 Player.update:

def update(self, move, blocks):

    # check if we can jump 
    if move.up and self.on_ground: 
        self.yvel -= self.jump_speed

    # simple left/right movement
    if move.left: self.xvel = -self.move_speed
    if move.right: self.xvel = self.move_speed

    # if in the air, fall down
    if not self.on_ground:
        self.yvel += 0.3
        # but not too fast
        if self.yvel > max_gravity: self.yvel = max_gravity

    # if no left/right movement, x speed is 0, of course
    if not (move.left or move.right):
        self.xvel = 0

    # move horizontal, and check for horizontal collisions
    self.rect.left += self.xvel
    self.collide(self.xvel, 0, blocks)

    # move vertically, and check for vertical collisions
    self.rect.top += self.yvel
    self.on_ground = False;
    self.collide(0, self.yvel, blocks)

唯一剩下的就是使用 Clock限制帧率让游戏以恒定速度运行。就是这样。

完整代码如下:

import pygame,random
from pygame.locals import *
from collections import namedtuple

pygame.init()
clock=pygame.time.Clock()
screen=pygame.display.set_mode((640,480))

max_gravity = 100

class Block(object):
    sprite = pygame.image.load("dirt.png").convert_alpha()
    def __init__(self, x, y):
        self.rect = self.sprite.get_rect(centery=y, centerx=x)

class Player(object):
    sprite = pygame.image.load("dirt.png").convert()
    sprite.set_colorkey((0,255,0))
    def __init__(self, x, y):
        self.rect = self.sprite.get_rect(centery=y, centerx=x)
        # indicates that we are standing on the ground
        # and thus are "allowed" to jump
        self.on_ground = True
        self.xvel = 0
        self.yvel = 0
        self.jump_speed = 10
        self.move_speed = 8

    def update(self, move, blocks):

        # check if we can jump 
        if move.up and self.on_ground: 
            self.yvel -= self.jump_speed

        # simple left/right movement
        if move.left: self.xvel = -self.move_speed
        if move.right: self.xvel = self.move_speed

        # if in the air, fall down
        if not self.on_ground:
            self.yvel += 0.3
            # but not too fast
            if self.yvel > max_gravity: self.yvel = max_gravity

        # if no left/right movement, x speed is 0, of course
        if not (move.left or move.right):
            self.xvel = 0

        # move horizontal, and check for horizontal collisions
        self.rect.left += self.xvel
        self.collide(self.xvel, 0, blocks)

        # move vertically, and check for vertical collisions
        self.rect.top += self.yvel
        self.on_ground = False;
        self.collide(0, self.yvel, blocks)

    def collide(self, xvel, yvel, blocks):
        # all blocks that we collide with
        for block in [blocks[i] for i in self.rect.collidelistall(blocks)]:

            # if xvel is > 0, we know our right side bumped 
            # into the left side of a block etc.
            if xvel > 0: self.rect.right = block.rect.left
            if xvel < 0: self.rect.left = block.rect.right

            # if yvel > 0, we are falling, so if a collision happpens 
            # we know we hit the ground (remember, we seperated checking for
            # horizontal and vertical collision, so if yvel != 0, xvel is 0)
            if yvel > 0:
                self.rect.bottom = block.rect.top
                self.on_ground = True
                self.yvel = 0
            # if yvel < 0 and a collision occurs, we bumped our head
            # on a block above us
            if yvel < 0: self.rect.top = block.rect.bottom

blocklist = []
player = []
colliding = False
Move = namedtuple('Move', ['up', 'left', 'right'])
while True:
    screen.fill((25,30,90))
    mse = pygame.mouse.get_pos()
    key = pygame.key.get_pressed()

    for event in pygame.event.get():
        if event.type == QUIT: exit()

        if key[K_LSHIFT]:
            if event.type==MOUSEMOTION:
                if not any(block.rect.collidepoint(mse) for block in blocklist):
                    x=(int(mse[0]) / 32)*32
                    y=(int(mse[1]) / 32)*32
                    blocklist.append(Block(x+16,y+16))
        else:
            if event.type == pygame.MOUSEBUTTONUP:
                if event.button == 1:
                    to_remove = [b for b in blocklist if b.rect.collidepoint(mse)]
                    for b in to_remove:
                        blocklist.remove(b)

                    if not to_remove:
                        x=(int(mse[0]) / 32)*32
                        y=(int(mse[1]) / 32)*32
                        blocklist.append(Block(x+16,y+16))

                elif event.button == 3:
                    x=(int(mse[0]) / 32)*32
                    y=(int(mse[1]) / 32)*32
                    player=[]
                    player.append(Player(x+16,y+16))

    move = Move(key[K_UP], key[K_LEFT], key[K_RIGHT])

    for b in blocklist:
        screen.blit(b.sprite, b.rect)
    for p in player:
        p.update(move, blocklist)
        screen.blit(p.sprite, p.rect)
    clock.tick(60)
    pygame.display.flip()

请注意，我更改了图像名称，因此我只需要一个图像文件来测试它。另外，我不知道为什么要将玩家保留在列表中，但这是我们游戏的精彩动画: