用户输入：Bomb Catcher游戏
本章介绍使用键盘和鼠标获得用户输入。包括如下主题：
学习pygame事件
学习实时循环
学习键盘和鼠标事件
学习轮询键盘和鼠标的状态
编写Bomb Catcher游戏
1本章所涉及pygame事件
QUIT
KEYDOWN
KEYUP
MOUSEMOTION
MOUSEBUTTONUP
MOUSEBUTTONDOWN
1.1实时事件循环
while True:
for event in pygame.event.get():
if event.type==QUIT:
sys.exit()
在循环中不断地对事件队列中的特定事件进行相应的处理。
1.2键盘事件
KEYUP KEYDOWN
1.3鼠标事件
MOUSEBUTTONDOWN MOUSEBUTTONUP MOUSEMOTION
具体属性见《pygame几个重要模块》
2设备轮询
pygame中的事件系统并非我们可以用来检测用户输入的唯一方法。我们可以轮询输入设备，看看用户是否与我们的
程序交互。
2.1轮询键盘
在pygame中，使用pygame.key.get_pressed()来轮询键盘接口。该方法返回布尔值的一个列表，对应于键盘
上的按键，每个键一个标志。使用相同的键常量值来索引布尔值数组。一次轮询所有的键的好处是不必遍历事件
系统就可以检测多个键的按下。
以下示例检测escape键。
keys=pygame.key.get_pressed()
if keys[K_ESCAPE]:
sys.exit()
2.2轮询鼠标
pygame.mouse.get_pos()
pygame.mouse.get_rel()
pygame.mouse.get_pressed()
具体使用参考《pygame几个重要模块》
import sys,pygame
from pygame.locals import *
pygame.init()
def print_text(font,x,y,text,color=(255,255,255)):
imgtext=font.render(text,True,color)
screen.blit(imgtext,(x,y))
#main program begins
screen=pygame.display.set_mode((600,500))
pygame.display.set_caption("Mouse Demo")
font1=pygame.font.Font(None,24)
white=255,255,255
mouse_x=mouse_y=0
move_x=move_y=0
mouse_down=mouse_up=0
mouse_down_x=mouse_down_y=0
mouse_up_x=mouse_up_y=0
#repeating loop
while True:
for event in pygame.event.get():
if event.type==QUIT:
sys.exit()
elif event.type==MOUSEMOTION:
mouse_x,mouse_y=event.pos
move_x,move_y=event.rel
elif event.type==MOUSEBUTTONDOWN:
mouse_down=event.button
mouse_down_x,mouse_down_y=event.pos
elif event.type==MOUSEBUTTONUP:
mouse_up=event.button
mouse_up_x,mouse_up_y=event.pos
keys=pygame.key.get_pressed()
if keys[K_ESCAPE]:
sys.exit()
screen.fill((0,100,0))
print_text(font1,0,0,"Mouse Events")
print_text(font1,0,20,"Mouse position: "+str(mouse_x)+","+str(mouse_y))
print_text(font1,0,40,"Mouse relative: "+str(move_x)+","+str(move_y))
print_text(font1,0,60,"Mouse button down: "+str(mouse_down)+" at "+str(mouse_down_x)+","+str(mouse_down_y))
print_text(font1,0,80,"Mouse button up: "+str(mouse_up)+" at "+str(mouse_up_x)+","+str(mouse_up_y))
print_text(font1,0,160,"Mouse Polling")
x,y=pygame.mouse.get_pos()
print_text(font1,0,180,"Mouse Position: "+str(x)+str(y))
b1,b2,b3=pygame.mouse.get_pressed()
print_text(font1,0,200,"Mouse buttons: "+str(b1)+","+str(b2)+","+str(b3))
pygame.display.update()
3游戏简介
bomb Catcher游戏综合了鼠标输入、一些基本图形绘制和少量冲突检测逻辑。
炸弹是不断重复地从屏幕顶端落下的黄色圆圈。
当炸弹到达屏幕底部的时候，玩家未接住炸弹就会丢掉一条生命。
当炸弹撞击到挡板，算作玩家接住炸弹，另一个炸弹还会继续落下。
import sys,random,time,pygame
from pygame.locals import *
pygame.init()
def print_text(font,x,y,text,color=(255,255,255)):
imgtext=font.render(text,True,color)
screen.blit(imgtext,(x,y))
screen=pygame.display.set_mode((600,500))
pygame.display.set_caption("Bomb Catching Game")
font1=pygame.font.Font(None,24)
pygame.mouse.set_visible(False)
white=255,255,255
red=220,50,50
yellow=230,230,50
black=0,0,0
lives=3
score=0
game_over=True
mouse_x=mouse_y=0
pos_x=300
pos_y=460
bomb_x=random.randint(0,500)
bomb_y=-50
vel_y=3
#repeating loop
while True:
for event in pygame.event.get():
if event.type==QUIT:
sys.exit()
elif event.type==MOUSEMOTION:
mouse_x,mouse_y=event.pos
move_x,move_y=event.rel
elif event.type==MOUSEBUTTONUP:
if game_over:
game_over=False
lives=3
score=0
keys=pygame.key.get_pressed()
if keys[K_ESCAPE]:
sys.exit()
screen.fill((0,0,100))
if game_over:
print_text(font1,100,200,"")
else:
#move the bomb
bomb_y+=vel_y
#has player missed the bomb?
if bomb_y>500:
bomb_x=random.randint(0,500)
bomb_y=-50
lives-=1
if lives==0:
game_over=True
#see if player has caught the bomb
elif bomb_y>pos_y:
if bomb_x>pos_x and bomb_x
score+=10
bomb_x=random.randint(0,500)
bomb_y=-50
#draw the bomb
pygame.draw.circle(screen,black,(bomb_x-4,int(bomb_y)-4),30,0)
pygame.draw.circle(screen,yellow,(bomb_x,int(bomb_y)),30,0)
#set basket position
pos_x=mouse_x
if pos_x<0:
pos_x=0
elif pos_x>480:
pos_x=500
#draw basket
pygame.draw.rect(screen,black,(pos_x-4,pos_y-4,120,40),0)
pygame.draw.rect(screen,red,(pos_x,pos_y,120,40),0)
#print # of lives
print_text(font1,0,0,"Lives: "+str(lives))
#print score
print_text(font1,500,0,"Score: "+str(score))
pygame.display.update()
可以改进的地方很多，比如说难度的提升，炸弹的显示效果等等。
现在我会改进这个程序，但是并不能独立写出这个程序来。
