1、运动速率
上节中，实现了一辆汽车在马路上由下到上行驶，并使用了pygame.time.delay(200)来进行时间延迟。看了很多参考材料，基本每个材料都会谈到不同配置机器下运动速率的问题，有的是通过设定频率解决，有的是通过设定速度解决，自己本身水平有限，看了几篇，觉得还是《Beginning Game Development with Python and Pygame》这里面提到一个方法比较好。代码如下，代码里更改的地方主要是main里的代码，其中利用clock=pygame.time.Clock()来定义时钟，speed=250.0定义了速度，每秒250像素，time_passed=clock.tick()为上次运行时间单位是毫秒，time_passed_seconds=time_passed/1000.0将单位改为秒，distance_moved=time_passed_seconds*speed时间乘以速度得到移动距离，这样就能保证更加流畅。
import pygame,sys
def lineleft():
plotpoints=[]
for x in range(0,640):
y=-5*x+1000
plotpoints.append([x,y])
pygame.draw.lines(screen,[0,0,0],False,plotpoints,5)
pygame.display.flip()
def lineright():
plotpoints=[]
for x in range(0,640):
y=5*x-2000
plotpoints.append([x,y])
pygame.draw.lines(screen,[0,0,0],False,plotpoints,5)
pygame.display.flip()
def linemiddle():
plotpoints=[]
x=300
for y in range(0,480,20):
plotpoints.append([x,y])
if len(plotpoints)==2:
pygame.draw.lines(screen,[0,0,0],False,plotpoints,5)
plotpoints=[]
pygame.display.flip()
def loadcar(yloc):
my_car=pygame.image.load('ok1.jpg')
locationxy=[310,yloc]
screen.blit(my_car,locationxy)
pygame.display.flip()
if __name__=='__main__':
pygame.init()
screen=pygame.display.set_caption('hello world!')
screen=pygame.display.set_mode([640,480])
screen.fill([255,255,255])
lineleft()
lineright()
linemiddle()
clock=pygame.time.Clock()
looper=480
speed=250.0
while True:
for event in pygame.event.get():
if event.type==pygame.QUIT:
sys.exit()
pygame.draw.rect(screen,[255,255,255],[310,(looper+132),83,132],0)
time_passed=clock.tick()
time_passed_seconds=time_passed/1000.0
distance_moved=time_passed_seconds*speed
looper-=distance_moved
if looper<-480:
looper=480
loadcar(looper)
</div>
2、事件
我理解的就是用来解决键盘、鼠标、遥控器等输入后做出什么反映的。例如上面的例子，可以通过按上方向键里向上来使得小车向上移动，按下向下，使得小车向下移动。当小车从下面倒出时，会从上面再出现，当小车从上面驶出时，会从下面再出现。代码如下。event.type == pygame.KEYDOWN用来定义事件类型，if event.key==pygame.K_UP这里是指当按下向上箭头时，车前进。if event.key==pygame.K_DOWN则相反，指按下向下箭头，车后退。
import pygame,sys
def lineleft():
plotpoints=[]
for x in range(0,640):
y=-5*x+1000
plotpoints.append([x,y])
pygame.draw.lines(screen,[0,0,0],False,plotpoints,5)
pygame.display.flip()
def lineright():
plotpoints=[]
for x in range(0,640):
y=5*x-2000
plotpoints.append([x,y])
pygame.draw.lines(screen,[0,0,0],False,plotpoints,5)
pygame.display.flip()
def linemiddle():
plotpoints=[]
x=300
for y in range(0,480,20):
plotpoints.append([x,y])
if len(plotpoints)==2:
pygame.draw.lines(screen,[0,0,0],False,plotpoints,5)
plotpoints=[]
pygame.display.flip()
def loadcar(yloc):
my_car=pygame.image.load('ok1.jpg')
locationxy=[310,yloc]
screen.blit(my_car,locationxy)
pygame.display.flip()
if __name__=='__main__':
pygame.init()
screen=pygame.display.set_caption('hello world!')
screen=pygame.display.set_mode([640,480])
screen.fill([255,255,255])
lineleft()
lineright()
linemiddle()
looper=480
while True:
for event in pygame.event.get():
if event.type==pygame.QUIT:
sys.exit()
elif event.type == pygame.KEYDOWN:
if event.key==pygame.K_UP:
looper=looper-50
if looper<-480:
looper=480
&n