Pygame - 实体移动限制 - 碰撞检测
好的，我有一个实体，它在两个位置之间来回移动，这两个位置现在是像素坐标，如下所示：
if self.rect.left == 96:
self.right_dis = False
if self.rect.right == 480:
self.right_dis = True
if not self.right_dis:
self.xVel = 2
if self.right_dis:
self.xVel = -2
我想问的是，有没有办法让它在一个平台上移动，直到到达平台的尽头，然后再转身？这样它就可以在平台上来回移动，而不需要我去指定具体的像素位置？下面是我的其他代码和一个视频：
import pygame
from pygame import *
WIN_WIDTH = 1120 - 320
WIN_HEIGHT = 960 - 320
HALF_WIDTH = int(WIN_WIDTH / 2)
HALF_HEIGHT = int(WIN_HEIGHT / 2)
DISPLAY = (WIN_WIDTH, WIN_HEIGHT)
DEPTH = 0
FLAGS = 0
CAMERA_SLACK = 30
def main():
global level
pygame.init()
screen = pygame.display.set_mode(DISPLAY, FLAGS, DEPTH)
pygame.display.set_caption("ABCDEFGHIJKLMNOPQRSTUVWXYZ")
timer = pygame.time.Clock()
level = 0
bg = Surface((32,32))
bg.convert()
bg.fill(Color("#0094FF"))
up = left = right = False
entities = pygame.sprite.Group()
player = Player(32, 32)
enemy = Enemy(32,32)
platforms = []
x = 0
y = 0
if level == 0:
level = [
" ",
" ",
" ",
" ",
" ",
" ",
" ",
" ",
" ",
" ",
" ",
" ",
" ",
" ",
" ",
" E ",
" PPPPPPPPPPPPPPPP",
" PPPPPPPPPPPPPPPP",
" PPPPPPPPPPPPPPPP",
" PPPPP PPPPPPPPPPPPPPPP",
" PPPPPPPPPPPPPPPP",
" PPPP P",
" PPPP P",
" PPPP PPPPPPP",
" PPPPPPPPPP PPPPPPP",
" PPPP PPPPPPP",
" PPPP PPPP PPPPPPP",
" PPPP PPPPPPP",
" PPPP PPPPPPP",
" PPPP PPPPPPP",
"PPPPP PPPP PPPPPPP",
"PPP PPPP PPPPPPP",
"PPP PPPP PPPPPPP",
"PPP PPPP PPPPPPP",
"PPP PPPPP PPPP PPPPPPP",
"PPP PPPP",
"PPP PPPP",
"PPP PPPP",
"PPP PPPPPPPPPPPPPPPPPP",
"PPP PPPPPPPPPPPPPPPPPP",
"PPPPPPPPPPPPPPP PPPPPPPPPPPPPPPPPP",
"PPPPPPPPPPPPPPP PPPPPPPPPPPPPPPPPP",
"PPPPPPPPPPPPPPP PPPPPPPPPPPPPPPPPP",
"PPPPPPPPPPPPPPP PPPPPPPPPPPPPPPPPP",
"PPPPPPPPPPPPPPP PPPPPPPPPPPPPPPPPP",]
#background = pygame.image.load("Untitled.png")
total_level_width = len(level[0]) * 32
total_level_height = len(level) * 32
# build the level
for row in level:
for col in row:
if col == "P":
p = Platform(x, y)
platforms.append(p)
entities.add(p)
if col == "E":
e = ExitBlock(x, y)
platforms.append(e)
entities.add(e)
x += 32
y += 32
x = 0
camera = Camera(complex_camera, total_level_width, total_level_height)
entities.add(player)
entities.add(enemy)
while 1:
timer.tick(60)
for e in pygame.event.get():
if e.type == QUIT: raise SystemExit, "QUIT"
if e.type == KEYDOWN and e.key == K_ESCAPE:
raise SystemExit, "ESCAPE"
if e.type == KEYDOWN and e.key == K_UP:
up = True
if e.type == KEYDOWN and e.key == K_LEFT:
left = True
if e.type == KEYDOWN and e.key == K_RIGHT:
right = True
if e.type == KEYUP and e.key == K_UP:
up = False
if e.type == KEYUP and e.key == K_LEFT:
left = False
if e.type == KEYUP and e.key == K_RIGHT:
right = False
# draw background
for y in range(20):
for x in range(25):
screen.blit(bg, (x * 32, y * 32))
# draw background
#screen.blit(background, camera.apply((0,0)))
#draw entities
for e in entities:
screen.blit(e.image, camera.apply(e))
# update player, update camera, and refresh
player.update(up, left, right, platforms)
enemy.update(platforms)
camera.update(player)
pygame.display.flip()
class Camera(object):
def __init__(self, camera_func, width, height):
self.camera_func = camera_func
self.state = Rect(0, 0, width, height)
def apply(self, target):
try:
return target.rect.move(self.state.topleft)
except AttributeError:
return map(sum, zip(target, self.state.topleft))
def update(self, target):
self.state = self.camera_func(self.state, target.rect)
def complex_camera(camera, target_rect):
l, t, _, _ = target_rect
_, _, w, h = camera
l, t, _, _ = -l + HALF_WIDTH, -t +HALF_HEIGHT, w, h
l = min(0, l) # stop scrolling left
l = max(-(camera.width - WIN_WIDTH), l) # stop scrolling right
t = max(-(camera.height-WIN_HEIGHT), t) # stop scrolling bottom
return Rect(l, t, w, h)
class Entity(pygame.sprite.Sprite):
def __init__(self):
pygame.sprite.Sprite.__init__(self)
class Player(Entity):
def __init__(self, x, y):
Entity.__init__(self)
self.xvel = 0
self.yvel = 0
self.onGround = False
self.image = Surface((32,32))
self.image.fill(Color("#0000FF"))
self.image.convert()
self.rect = Rect(200, 1200, 32, 32)
def update(self, up, left, right, platforms):
if self.rect.top > 1440 or self.rect.top < 0:
main()
if self.rect.left > 1408 or self.rect.right < 0:
main()
if up:
if self.onGround:
self.yvel = 0
self.yvel -= 10 # only jump if on the ground
if left:
self.xvel = -10
if right:
self.xvel = 10
if not self.onGround:
self.yvel += 0.3 # only accelerate with gravity if in the air
if self.yvel > 80: self.yvel = 80 # max falling speed
if not(left or right):
self.xvel = 0
self.rect.left += self.xvel # increment in x direction
self.collide(self.xvel, 0, platforms) # do x-axis collisions
self.rect.top += self.yvel # increment in y direction
self.onGround = False; # assuming we're in the air
self.collide(0, self.yvel, platforms) # do y-axis collisions
def collide(self, xvel, yvel, platforms):
for p in platforms:
if pygame.sprite.collide_rect(self, p):
if isinstance(p, ExitBlock):
pygame.event.post(pygame.event.Event(QUIT))
if xvel > 0: self.rect.right = p.rect.left
if xvel < 0: self.rect.left = p.rect.right
if yvel > 0:
self.rect.bottom = p.rect.top
self.onGround = True
if yvel < 0:
self.rect.top = p.rect.bottom
class Enemy(Entity):
def __init__(self, x, y):
Entity.__init__(self)
self.yVel = 0
self.xVel = 0
self.image = Surface((32,32))
self.image.fill(Color("#00FF00"))
self.image.convert()
self.rect = Rect(300, 1200, 32, 32)
self.onGround = False
self.right_dis = False
def update(self, platforms):
if not self.onGround:
self.yVel += 0.3
if self.rect.left == 96:
self.right_dis = False
if self.rect.right == 480:
self.right_dis = True
if not self.right_dis:
self.xVel = 2
if self.right_dis:
self.xVel = -2
self.rect.left += self.xVel # increment in x direction
self.collide(self.xVel, 0, platforms) # do x-axis collisions
self.rect.top += self.yVel # increment in y direction
self.onGround = False; # assuming we're in the air
self.collide(0, self.yVel, platforms) # do y-axis collisions
def collide(self, xVel, yVel, platforms):
for p in platforms:
if pygame.sprite.collide_rect(self, p):
if xVel > 0: self.rect.right = p.rect.left
if xVel < 0: self.rect.left = p.rect.right
if yVel > 0:
self.rect.bottom = p.rect.top
self.onGround = True
if yVel < 0:
self.rect.top = p.rect.bottom
class Platform(Entity):
def __init__(self, x, y):
Entity.__init__(self)
#self.image = Surface([32, 32], pygame.SRCALPHA, 32) #makes blocks invisible for much better artwork
self.image = Surface((32,32)) #makes blocks visible for building levels
self.image.convert()
self.rect = Rect(x, y, 32, 32)
def update(self):
pass
class ExitBlock(Platform):
def __init__(self, x, y):
Platform.__init__(self, x, y)
self.image = pygame.image.load("end.png")
if __name__ == "__main__":
main()
1 个回答
1
首先，获取你这个Entity的Rect（矩形区域）。
如果它是向右移动的，就取Rect的bottomright（右下角）这个点，把它向右移动一个像素，再向下移动一个像素，然后检查这个点是否和一个Platform（平台）碰撞。如果没有碰撞，那就说明它到达了平台的边缘。
如果它是向左移动的，那你只需要取bottomleft（左下角）这个点，然后把它向左移动一个像素，再向下移动一个像素。
有一个简单的方法可以“移动”一个点（如果它是Tuple（元组）或List（列表）），可以使用map-sum-zip这个技巧：
>>> point = (8,10)
>>> to_move = (1,1)
>>> map(sum, zip(point, to_move))
[9, 11]
>>> to_move = (-1,1)
>>> map(sum, zip(point, to_move))
[7, 11]
>>>
顺便说一下，这里有一个完整的例子（注意注释）：
class Enemy(Entity):
def __init__(self, x, y):
Entity.__init__(self)
self.yVel = 0
self.xVel = 2 # start moving immediately
self.image = Surface((32,32))
self.image.fill(Color("#00FF00"))
self.image.convert()
self.rect = Rect(300, 1200, 32, 32)
self.onGround = False
def update(self, platforms):
if not self.onGround:
self.yVel += 0.3
# no need for right_dis to be a member of the class,
# since we know we are moving right if self.xVel > 0
right_dis = self.xVel > 0
# create a point at our left (or right) feet
# to check if we reached the end of the platform
m = (1, 1) if right_dis else (-1, 1)
p = self.rect.bottomright if right_dis else self.rect.bottomleft
fp = map(sum, zip(m, p))
# if there's no platform in front of us, change the direction
collide = any(p for p in platforms if p.rect.collidepoint(fp))
if not collide:
self.xVel *= -1
self.rect.left += self.xVel # increment in x direction
self.collide(self.xVel, 0, platforms) # do x-axis collisions
self.rect.top += self.yVel # increment in y direction
self.onGround = False; # assuming we're in the air
self.collide(0, self.yVel, platforms) # do y-axis collisions
def collide(self, xVel, yVel, platforms):
for p in platforms:
if pygame.sprite.collide_rect(self, p):
if xVel > 0:
self.rect.right = p.rect.left
self.xVel *= -1 # hit wall, so change direction
if xVel < 0:
self.rect.left = p.rect.right
self.xVel *= -1 # hit wall, so change direction
if yVel > 0:
self.rect.bottom = p.rect.top
self.onGround = True
if yVel < 0:
self.rect.top = p.rect.bottom