python - 如何通过碰撞检测阻止玩家 Sprite 穿过方 block ？

Question

我试图阻止玩家穿过方 block 。我希望它们能够降落在方 block 上，但如果方 block 的另一侧发生碰撞，它们会弹开

我之前尝试过更改玩家击中方 block 时重置的距离

运行每一帧以检查是否存在碰撞:

hits = pygame.sprite.spritecollide(player, walls, False)
if hits:
    player.checkCollisionWall(hits)

玩家等级

import pygame, time, Settings
from pygame.locals import *
vec = pygame.math.Vector2

pygame.init()

class player(pygame.sprite.Sprite):
    ACCEL = 0.5 # Acceleration
    GFRICTION = vec(-0.2, 0) # Ground Friction
    AFRICTION = vec(-0.2, 0) # Air Friction
    GRAVITY = 0.8 # must be greater than 0.6
    JUMP_HEIGHT = 10
    START_X = 25 
    START_Y = 600
    WIDTH = 10
    HEIGHT = 10
    START_POS = vec(START_X + WIDTH/2, START_Y + HEIGHT) # point at bottom middle
    def __init__(self):
        pygame.sprite.Sprite.__init__(self)
        self.Pos = self.START_POS
        self.image = pygame.surface.Surface((self.WIDTH, self.HEIGHT))
        self.image.fill((0, 255, 0))
        self.rect = self.image.get_rect()
        self.rect.center = (self.Pos.x, self.Pos.y)
        self.vel = vec(0,0) # set velocity as a vector
        self.acc = vec(0,0) # set acceleration as a vector
        self.inJump = False
        self.tryingToJump = False
    def update(self):
        self.tryingToJump = False
        self.acc = vec(0, self.GRAVITY)
        self.move()
    def draw(self):
        # draw the rectangle
        self.Pos += self.vel + 0.5 *self.acc
        self.rect.center = self.Pos
    def move(self):
        # identify which keys are pressed
        pressed_keys = pygame.key.get_pressed()
        if pressed_keys[K_LEFT]:
            self.changeX("left")
        elif pressed_keys[K_RIGHT]:
            self.changeX("right")
        if pressed_keys[K_UP]:
            self.jump()
        # check player is on screen and place player where it should be if neccessary
        if self.Pos.y > Settings.WINDOW_HEIGHT:
            self.Pos.x = self.START_POS.x
            self.Pos.y = self.START_POS.y
        if self.Pos.x < 0:
            self.vel.x = 2
        if self.Pos.x > Settings.WINDOW_WIDTH:
            self.vel.x = -2
        # apply friction 
        if self.inJump: #in the air
            self.acc.x += self.vel.x * self.AFRICTION.x
        else: #touching the ground
            self.acc.x += self.vel.x * self.GFRICTION.x
        # move the player
        self.vel += self.acc
    def changeX(self, direction):
        # move left or right
        if direction == "right":
            self.acc.x = self.ACCEL
        elif direction == "left":
            self.acc.x = -self.ACCEL
    def jump(self):
        # jump only if standing on a platform
        if self.inJump == False:
            self.tryingToJump = True
            self.inJump = True
            self.vel.y -= self.JUMP_HEIGHT
    def checkCollisionWall(self, hits):
        self.lowestWall = self.highestWall = hits[0]
        for i in hits:
            if i.rect.bottom > self.lowestWall.rect.bottom:
                self.lowestWall = i # find the lowest wall that the player is touching
            if i.rect.top < self.highestWall.rect.top:
                self.highestWall = i # find the highest wall that the player is touching
        if self.vel.y > 0: # check if a block is below
            print("below")
            self.rect.bottom = self.lowestWall.rect.top
            self.acc.y = self.vel.y = 0 # set acceleration and velocity to 0 on the y axis
            self.inJump = False
        if self.vel.y < 0: # check if a block is above
            if not self.tryingToJump: # if the block isn't trying to jump (I have this in otherwise player doesn't jump)
                print("above")
                self.rect.top = self.highestWall.rect.bottom
                self.acc.y = self.vel.y = 0 # set acceleration and velocity to 0 on the y axis
        if self.highestWall.rect.top < self.lowestWall.rect.top and self.rect.bottom == self.lowestWall.rect.top: # I have this line in too make sure that the player does not snap to the side of the block it is in when it moves side to side
            if self.vel.x > 0:
                print("right")
                self.rect.right = self.highestWall.rect.left
                self.acc.x = self.vel.x = -self.ACCEL # set acceleration and velocity to -0.5 on the x axis
            if self.vel.x < 0:
                print("left")
                self.rect.left = self.highestWall.rect.right
                self.acc.x = self.vel.x = self.ACCEL # set acceleration and velocity to 0.5 on the x axis

当我尝试这个时，玩家会很好地落在方 block 上，但是当他们触摸方 block 的底部时，玩家会捕捉到方 block 的顶部，而不是从方 block 上弹开。当玩家在移动到方 block 时跳跃时，玩家会跳到较高方 block 的顶部。

Answer 1

根据我(不太丰富)的经验，当没有针对每个维度单独测试玩家运动时，可能会出现此类问题。

我建议您:

1. 单独的 x 和 y 移动和碰撞测试，以便您可以沿 x 移动玩家，测试碰撞并根据需要修复 x 位置，然后对 y 重复该过程。

2. 编辑 checkCollisionWall 方法，使其采用单个 block ，而不是 block 列表。如果将 x 和 y 运动分开，玩家最多会与一个方 block 发生碰撞。因此无需寻找最低的墙壁和最高的墙壁。您的代码会更简单。

在这里我建议您进行一些编辑。 move 已分为 move_x 和 move_y。 checkCollisionWall 到 checkCollision_x 和 checkCollision_y。
我还编辑了 update 方法:现在它执行第 1 点中描述的整个过程，因此调用 update 也会检查碰撞。

def update(self):
    self.tryingToJump = False
    self.acc = vec(0, self.GRAVITY)

    self.move_x()
    hits = pygame.sprite.spritecollide(player, walls, False)
    for bhit in hits:
        player.checkCollision_x(bhit)

    self.move_y()
    hits = pygame.sprite.spritecollide(player, walls, False)
    for bhit in hits:
        player.checkCollision_y(bhit)

def move_x(self):
    # identify which keys are pressed
    pressed_keys = pygame.key.get_pressed()
    if pressed_keys[K_LEFT]:
        self.changeX("left")
    elif pressed_keys[K_RIGHT]:
        self.changeX("right")
    # check player is on screen and place player where it should be if neccessary
    if self.Pos.x < 0:
        self.vel.x = 2
    if self.Pos.x > Settings.WINDOW_WIDTH:
        self.vel.x = -2
    # apply friction 
    if self.inJump: #in the air
        self.acc.x += self.vel.x * self.AFRICTION.x
    else: #touching the ground
        self.acc.x += self.vel.x * self.GFRICTION.x
    # move the player
    self.vel.x += self.acc.x

def move_y(self):
    # identify which keys are pressed
    pressed_keys = pygame.key.get_pressed()
    if pressed_keys[K_UP]:
        self.jump()
    # check player is on screen and place player where it should be if neccessary
    if self.Pos.y > Settings.WINDOW_HEIGHT:
        self.Pos.x = self.START_POS.x
        self.Pos.y = self.START_POS.y
    # move the player
    self.vel.y += self.acc.y


def checkCollision_x(self, coll_block):
    if self.vel.x > 0:
        print("right")
        self.rect.right = coll_block.rect.left
        self.acc.x = self.vel.x = -self.ACCEL # set acceleration and velocity to -0.5 on the x axis
    elif self.vel.x < 0:
        print("left")
        self.rect.left = coll_block.rect.right
        self.acc.x = self.vel.x = self.ACCEL # set acceleration and velocity to 0.5 on the x axis


def checkCollision_y(self, coll_block):
    if self.vel.y > 0: # check if a block is below
        print("below")
        self.rect.bottom = coll_block.rect.top
        self.acc.y = self.vel.y = 0 # set acceleration and velocity to 0 on the y axis
        self.inJump = False
    elif self.vel.y < 0: # check if a block is above
        if not self.tryingToJump: # if the block isn't trying to jump (I have this in otherwise player doesn't jump)
            print("above")
            self.rect.top = coll_block.rect.bottom
            self.acc.y = self.vel.y = 0 # set acceleration and velocity to 0 on the y axis

这段代码当然没有经过测试，但即使不能解决您的问题，我认为应该让您走上正确的方向。