在《Pygame中Sprite实现逃亡游戏3》中实现了玩家跳跃飞火的效果，接下来通过精灵类的碰撞检测来判断飞火是否击中玩家、飞火是否击中飞龙以及飞龙是否抓住玩家。
1 飞火是否击中玩家的判断
判断飞火是否击中玩家的代码如图1所示。
图1 判断飞火是否击中玩家的代码
第137行代码使用精灵类的collide_rect()方法判断飞火是否击中玩家，该方法的参数arrow表示飞火，参数player表示玩家，当飞火击中玩家时，collide_rect()方法返回True，第138代码在屏幕的右侧重置飞火，第139行代码将玩家的横坐标向左移动（玩家被飞火击中后要退后）。
相关链接1 reset_arrow()方法以及player.X属性请参考《Pygame中Sprite实现逃亡游戏2》
注意1 判断飞火是否击中玩家、飞火是否击中飞龙以及飞龙是否抓住玩家的代码均在while True循环中。
2 飞火是否击中飞龙的判断
判断飞火是否击中飞龙的代码如图2所示。
图2 判断飞火是否击中飞龙的代码
从图2中可知，当飞火是否击中飞龙后，需要重置飞火并且将飞龙的横坐标向左移动。
3 飞龙是否抓住玩家
判断飞龙是否抓住玩家的代码如图3所示。
图3 判断飞龙是否抓住玩家的代码
从图3中可以看出，当飞龙抓住玩家，此时游戏结束，game_over标志设置为True。
4 程序运行效果
程序运行效果如图4所示。
图4 程序运行效果
5 完整代码
import pygame
import os
import time
import random
from pygame.locals import *class MySprite(pygame.sprite.Sprite):def __init__(self, target):pygame.sprite.Sprite.__init__(self) #extend the base Sprite classself.master_image = Noneself.frame = 0self.old_frame = -1self.frame_width = 1self.frame_height = 1self.first_frame = 0self.last_frame = 0self.columns = 1self.last_time = 0#X propertydef _getx(self):return self.rect.xdef _setx(self,value):self.rect.x = valueX = property(_getx,_setx)#Y propertydef _gety(self):return self.rect.ydef _sety(self,value):self.rect.y = valueY = property(_gety,_sety)#position propertydef _getpos(self):return self.rect.topleftdef _setpos(self,pos):self.rect.topleft = posposition = property(_getpos,_setpos)def load(self, filename, width, height, columns):self.master_image = pygame.image.load(filename).convert_alpha()self.frame_width = widthself.frame_height = heightself.rect = Rect(0,0,width,height)self.columns = columns#try to auto-calculate total framesrect = self.master_image.get_rect()self.last_frame = (rect.width // width) * (rect.height // height) - 1def update(self, current_time, rate=30):#update animation frame numberif current_time > self.last_time + rate:self.frame += 1if self.frame > self.last_frame:self.frame = self.first_frameself.last_time = current_time#build current frame only if it changedif self.frame != self.old_frame:frame_x = (self.frame % self.columns) * self.frame_widthframe_y = (self.frame // self.columns) * self.frame_heightrect = Rect(frame_x, frame_y, self.frame_width, self.frame_height)self.image = self.master_image.subsurface(rect)self.old_frame = self.framedef __str__(self):return str(self.frame) + "," + str(self.first_frame) + \"," + str(self.last_frame) + "," + str(self.frame_width) + \"," + str(self.frame_height) + "," + str(self.columns) + \"," + str(self.rect)def reset_arrow():y = random.randint(250,350)arrow.position = 800,ypygame.init()
screen = pygame.display.set_mode((800,600))
pygame.display.set_caption('Escape The Dragon Game')
font = pygame.font.Font('1.ttf', 18)
framerate = pygame.time.Clock()group = pygame.sprite.Group()
player = MySprite(screen)
player.load('caveman.png', 50, 64, 8)
player.first_frame = 1
player.last_frame = 7
player.position = 400, 303
group.add(player)bg = pygame.image.load('background.png').convert_alpha()#create the dragon sprite
dragon = MySprite(screen)
dragon.load("dragon.png", 260, 150, 3)
dragon.position = 100, 230
group.add(dragon)#create the arrow sprite
arrow = MySprite(screen)
arrow.load("flame.png", 40, 16, 1)
arrow.position = 800,320
group.add(arrow)game_over = False
arrow_vel = 8.0
player_jumping = False
jump_vel = 0.0
player_start_y = player.Y
while True:framerate.tick(30)ticks = pygame.time.get_ticks()for event in pygame.event.get():if event.type == QUIT:pygame.quit()os.sys.exit()keys = pygame.key.get_pressed()if keys[K_ESCAPE]:pygame.quit()os.sys.exit()elif keys[K_SPACE]:if not player_jumping:player_jumping = Truejump_vel = -8.0#update the arrowif not game_over:arrow.X -= arrow_velif arrow.X < 0:reset_arrow()if player_jumping:player.Y += jump_veljump_vel += 0.5if player.Y > player_start_y:player.Y = player_start_yplayer_jumping = Falsejump_vel = 0.0if pygame.sprite.collide_rect(arrow, player):reset_arrow()player.X -= 10if pygame.sprite.collide_rect(arrow, dragon):reset_arrow()dragon.X -= 10if pygame.sprite.collide_rect(player, dragon):game_over = Truescreen.blit(bg, (0,0))group.update(ticks, 50)group.draw(screen)pygame.display.update()
