这一节学习碰撞检测，先看原理图：
2个矩形如果发生碰撞(即：图形有重叠区域)，按上图的判断条件就能检测出来，如果是圆形，则稍微变通一下，用半径检测。如果是其它不规则图形，大多数游戏中，并不要求精确检测，可以在外层套一个矩形，大致用上图的原理检测。
可以封装一个函数：
def collision_check(a, b):
temp1 = (b.x <= a.x + a.width <= b.x + b.width)
temp2 = (b.y <= a.y + a.height <= b.y + b.height)
return temp1 and temp2
要注意的是：矩形A，B碰撞时，有可能是A撞B，也有可能是B撞A，所以使用上面的函数时，最好写好 if collision_check(a,b) or collision_check(b,a):
为了方便观察，我们在上节的3个类文件（即：Player、Enemy、Bullet)里，略做修改，手动在外层套一个矩形（hit_box)
import pygame # 主角
class Player(object): def __init__(self, x, y, width, height, img_base_path):
self.x = x
self.y = y
self.width = width
self.height = height
self.speed = 5
self.left = False
self.right = True
self.isJump = False
self.walkCount = 0
self.t = 10
self.speed = 5
self.char = pygame.image.load(img_base_path + 'standing.png')
self.walkRight = [pygame.image.load(img_base_path + 'actor/R1.png'),
pygame.image.load(img_base_path + 'actor/R2.png'),
pygame.image.load(img_base_path + 'actor/R3.png'),
pygame.image.load(img_base_path + 'actor/R4.png'),
pygame.image.load(img_base_path + 'actor/R5.png'),
pygame.image.load(img_base_path + 'actor/R6.png'),
pygame.image.load(img_base_path + 'actor/R7.png'),
pygame.image.load(img_base_path + 'actor/R8.png'),
pygame.image.load(img_base_path + 'actor/R9.png')] self.walkLeft = [pygame.image.load(img_base_path + 'actor/L1.png'),
pygame.image.load(img_base_path + 'actor/L2.png'),
pygame.image.load(img_base_path + 'actor/L3.png'),
pygame.image.load(img_base_path + 'actor/L4.png'),
pygame.image.load(img_base_path + 'actor/L5.png'),
pygame.image.load(img_base_path + 'actor/L6.png'),
pygame.image.load(img_base_path + 'actor/L7.png'),
pygame.image.load(img_base_path + 'actor/L8.png'),
pygame.image.load(img_base_path + 'actor/L9.png')]
self.hit_box = (self.x + 17, self.y + 11, 29, 52) def draw(self, win):
if self.walkCount >= 9:
self.walkCount = 0 if self.left:
win.blit(self.walkLeft[self.walkCount % 9], (self.x, self.y))
self.walkCount += 1
elif self.right:
win.blit(self.walkRight[self.walkCount % 9], (self.x, self.y))
self.walkCount += 1
else:
win.blit(self.char, (self.x, self.y))
# 碰撞检测框
self.hit_box = (self.x + 17, self.y + 11, 29, 52)
pygame.draw.rect(win, (255, 0, 0), self.hit_box, 2)
Enemy类：
import pygame
class Enemy(object):
def __init__(self, x, y, width, height, end, img_base_path):
self.x = x
self.y = y
self.width = width
self.height = height
self.path = [x, end]
self.walkCount = 0
self.vel = 3
self.walkRight = [pygame.image.load(img_base_path + 'enemy/R1E.png'),
pygame.image.load(img_base_path + 'enemy/R2E.png'),
pygame.image.load(img_base_path + 'enemy/R3E.png'),
pygame.image.load(img_base_path + 'enemy/R4E.png'),
pygame.image.load(img_base_path + 'enemy/R5E.png'),
pygame.image.load(img_base_path + 'enemy/R6E.png'),
pygame.image.load(img_base_path + 'enemy/R7E.png'),
pygame.image.load(img_base_path + 'enemy/R8E.png'),
pygame.image.load(img_base_path + 'enemy/R9E.png'),
pygame.image.load(img_base_path + 'enemy/R10E.png'),
pygame.image.load(img_base_path + 'enemy/R11E.png')]
self.walkLeft = [pygame.image.load(img_base_path + 'enemy/L1E.png'),
pygame.image.load(img_base_path + 'enemy/L2E.png'),
pygame.image.load(img_base_path + 'enemy/L3E.png'),
pygame.image.load(img_base_path + 'enemy/L4E.png'),
pygame.image.load(img_base_path + 'enemy/L5E.png'),
pygame.image.load(img_base_path + 'enemy/L6E.png'),
pygame.image.load(img_base_path + 'enemy/L7E.png'),
pygame.image.load(img_base_path + 'enemy/L8E.png'),
pygame.image.load(img_base_path + 'enemy/L9E.png'),
pygame.image.load(img_base_path + 'enemy/L10E.png'),
pygame.image.load(img_base_path + 'enemy/L11E.png')]
self.hit_box = (self.x + 17, self.y + 2, 31, 57)
def draw(self, win):
self.move()
if self.walkCount >= 11:
self.walkCount = 0
if self.vel > 0:
win.blit(self.walkRight[self.walkCount % 11], (self.x, self.y))
self.walkCount += 1
else:
win.blit(self.walkLeft[self.walkCount % 11], (self.x, self.y))
self.walkCount += 1
# 碰撞检测框
self.hit_box = (self.x + 17, self.y + 2, 31, 57)
pygame.draw.rect(win, (255, 0, 0), self.hit_box, 2)
def move(self):
if self.vel > 0:
if self.x < self.path[1] + self.vel:
self.x += self.vel
else:
self.vel = self.vel * -1
self.x += self.vel
self.walkCount = 0
else:
if self.x > self.path[0] - self.vel:
self.x += self.vel
else:
self.vel = self.vel * -1
self.x += self.vel
self.walkCount = 0
以及子弹类：
import pygame # 子弹类
class Bullet(object): def __init__(self, x, y, direction, img_base_path):
self.x = x
self.y = y
self.direction = direction
self.vel = 8 * direction
self.width = 24
self.height = 6
self.bullet_right = pygame.image.load(img_base_path + 'r_bullet.png')
self.bullet_left = pygame.image.load(img_base_path + 'l_bullet.png')
self.hit_box = (self.x + 17, self.y + 11, 24, 6) def draw(self, win):
# 根据人物行进的方向，切换不同的子弹图片
if self.direction == -1:
win.blit(self.bullet_left, (self.x - 35, self.y))
# 碰撞检测框
self.hit_box = (self.x - 38, self.y + 1, 24, 6)
else:
win.blit(self.bullet_right, (self.x + 10, self.y))
# 碰撞检测框
self.hit_box = (self.x + 10, self.y + 1, 24, 6)
pygame.draw.rect(win, (255, 0, 0), self.hit_box, 2)
这样处理后，运动起来的样子如下：
最后主文件中，加入碰撞检测代码：
import os
from bullet import *
from player import *
from enemy import * WIN_WIDTH, WIN_HEIGHT = 500, 500
pygame.init()
win = pygame.display.set_mode((WIN_WIDTH, WIN_HEIGHT))
pygame.display.set_caption("first game")
img_base_path = os.getcwd() + '/img/'
bg = pygame.image.load(img_base_path + 'bg.jpg') clock = pygame.time.Clock() def redraw_game_window():
win.blit(bg, (0, 0))
# 显示击中后的得分
text = font.render('Score: ' + str(score), 1, (0, 0, 0))
win.blit(text, (370, 10))
man.draw(win)
enemy.draw(win)
for bullet in bullets:
bullet.draw(win)
pygame.display.update() def collision_check(a, b):
temp1 = (b.x <= a.x + a.width <= b.x + b.width)
temp2 = (b.y <= a.y + a.height <= b.y + b.height)
return temp1 and temp2 # main
font = pygame.font.SysFont('comicsans', 30, True)
man = Player(200, 410, 64, 64, img_base_path)
enemy = Enemy(100, 414, 64, 64, 400, img_base_path)
run = True
score = 0
bullets = []
while run:
clock.tick(27) for event in pygame.event.get():
if event.type == pygame.QUIT:
run = False for b in bullets:
# 碰撞检测
if collision_check(b, enemy) or collision_check(enemy, b):
score += 1
bullets.pop(bullets.index(b)) if WIN_WIDTH > b.x > 0:
b.x += b.vel
else:
bullets.pop(bullets.index(b)) keys = pygame.key.get_pressed() if keys[pygame.K_SPACE]:
if man.left:
direction = -1
else:
direction = 1 if len(bullets) < 5:
bullets.append(Bullet(man.x + man.width // 2, man.y + man.height // 2, direction, img_base_path)) if keys[pygame.K_LEFT] and man.x > 0:
man.x -= man.speed
man.left = True
man.right = False
elif keys[pygame.K_RIGHT] and man.x < win.get_size()[0] - man.width:
man.x += man.speed
man.left = False
man.right = True
else:
man.walkCount = 0 if not man.isJump:
if keys[pygame.K_UP]:
man.isJump = True
man.walkCount = 0
else:
if man.t >= -10:
a = 1
if man.t < 0:
a = -1
man.y -= 0.5 * a * (man.t ** 2) man.t -= 1
else:
man.isJump = False
man.t = 10 redraw_game_window() pygame.quit()