python判断按键是否按下_Pygame检测是否按下了一个键？

使用pygame.key.get_pressed()来检查某个键是否被按下更容易，因为您不需要自己通过事件跟踪这些键的状态。在

我通常会创建一个字典，将键映射到它们应该移动对象的方向。在

这样，很容易查询pygame.key.get_pressed()的结果。在

你可以使用一些简单的矢量数学来规范化运动方向，这样你就可以以与只沿x或y轴相同的速度对角移动。在

另外，使用Rect来存储对象的位置也更容易，因为pygame提供了很多有用的函数来处理Rect类。在import pygame, math

from pygame.locals import *

# some simple functions for vetor math

# note that the next pygame release will ship with a vector math module included!

def magnitude(v):

return math.sqrt(sum(v[i]*v[i] for i in range(len(v))))

def add(u, v):

return [ u[i]+v[i] for i in range(len(u)) ]

def normalize(v):

vmag = magnitude(v)

return [ v[i]/vmag for i in range(len(v)) ]

pygame.init()

screen = pygame.display.set_mode((1440,900))

screen_r = screen.get_rect()

pygame.display.update()

black=(0,0,0)

white=(255,255,255)

background = pygame.image.load("G:/starfield.jpg")##loads the background

# here we define which button moves to which direction

move_map = {pygame.K_w: ( 0, -1),

pygame.K_s: ( 0, 1),

pygame.K_a: (-1, 0),

pygame.K_d: ( 1, 0)}

banshee = pygame.image.load("G:/banshee.png")

# create a Rect from the Surface to store the position of the object

# we can pass the initial starting position by providing the kwargs top and left

# another useful feature is that when we create the Rect directly from the

# Surface, we also have its size stored in the Rect

banshee_r = banshee.get_rect(top=50, left=50)

speed = 5

gameexit = False

while not gameexit:

# exit the game when the window closes

for event in pygame.event.get():

if event.type == pygame.QUIT:

gameexit = True

# if it touches the sides of the window, end the game

# note how easy this part becomes if you use the Rect class

if not screen_r.contains(banshee_r):

gameexit = True

# get all pressed keys

pressed = pygame.key.get_pressed()

# get all directions the ship should move

move = [move_map[key] for key in move_map if pressed[key]]

# add all directions together to get the final direction

reduced = reduce(add, move, (0, 0))

if reduced != (0, 0):

# normalize the target direction and apply a speed

# this ensures that the same speed is used when moving diagonally

# and along the x or y axis. Also, this makes it easy to

# change the speed later on.

move_vector = [c * speed for c in normalize(reduced)]

# move the banshee

# Another useful pygame functions for Rects

banshee_r.move_ip(*move_vector)

screen.blit(background,(0,0))

# we can use banshee_r directly for drawing

screen.blit(banshee, banshee_r)

pygame.display.update()