Question

所以我的代码在背景中有一堆星星可以自动移动，用户可以通过按箭头键设置方向。向上，向下，向左和向右工作都很好，但是，当我测试出“直立”方向时，我无法移动它。

到目前为止我尝试了什么：

while running == True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        elif event.type == pygame.KEYDOWN:
            #cardinal directions
                if event.key ==pygame.K_LEFT:
                    starDirection = "left"

                elif event.key == pygame.K_RIGHT:
                    starDirection = "right"


                elif event.key ==pygame.K_UP:
                    starDirection = "up"


                elif event.key ==pygame.K_DOWN:
                    starDirection ="down"

                elif event.key == pygame.K_UP and event.key == pygame.K_DOWN:
                    starDirection ="upright"




    for a_star in star_list:
        if starDirection == "right":
            a_star.rect.x += 5
            if a_star.rect.x > width:
                a_star.rect.x = 0
                a_star.rect.y = random.randint(0,height)

        elif starDirection == "left":
            a_star.rect.x -=5
            if a_star.rect.x < 0:
                a_star.rect.x = width
                a_star.rect.y = random.randint(0,height)

        elif starDirection == "up":
            a_star.rect.y -= 5
            if a_star.rect.y < 0:
                a_star.rect.x = random.randint(0,width)
                a_star.rect.y = height

        elif starDirection == "down":
            a_star.rect.y += 5
            if a_star.rect.y > height:
                a_star.rect.x = random.randint(0,width)
                a_star.rect.y = 0

        #diagonal directions
        elif starDirection == "upright":
            a_star.rect.y-=5
            a_star.rect.x+=5
            if a_star.rect.y < 0:
                a_star.rect.x = random.randint(0,width)
                a_star.rect.y = height

            elif a_star.rect.x > width:
                a_star.rect.x = 0
                a_star.rect.y = random.randint(0,height)

        elif starDirection == "upleft":

            a_star.rect.y-=5
            a_star.rect.x-=5
            if a_star.rect.y < 0:
                a_star.rect.x = random.randint(0,width)
                a_star.rect.y = height

            elif a_star.rect.x < 0:
                a_star.rect.x = width
                a_star.rect.y = random.randint(0,height)

        elif starDirection == "downright":

            a_star.rect.y += 5
            a_star.rect.x+=5
            if a_star.rect.y > height:
                a_star.rect.x = random.randint(0,width)
                a_star.rect.y = 0

            elif a_star.rect.x > width:
                a_star.rect.x = 0
                a_star.rect.y = random.randint(0,height)



        elif starDirection == "downleft":
            a_star.rect.y += 5
            a_star.rect.x-=5
            if a_star.rect.y > height:
                    a_star.rect.x = random.randint(0,width)
                    a_star.rect.y = 0

            elif a_star.rect.x < 0:
                    a_star.rect.x = width
                    a_star.rect.y = random.randint(0,height)

Answer 1

event.key不可能同时成为两个不同的东西。您需要通过处理KEYDOWN和KEYUP事件来存储关键状态。

最简单的是为每个向上，向下，向左，向右键设置一个布尔变量。在KEYDOWN上设置它们并在KEYUP上清除它们。

然后你可以测试像if leftIsPressed and upIsPressed

这样的东西

Answer 2

不是查找KEYDOWN事件，而只是使用pygame.key.get_pressed()查询所有按下的键。这样，显然很容易看出此刻按下哪些键。

此外，您应该使用移动矢量并在移动星星之前将其标准化。否则，您的星星以5和对角的速度以√(5² + 5²) = 7,07的速度水平/垂直移动。

以下是一个完整的例子：

import pygame import math from random import randint from functools import partial pygame.init() width, height = (800, 600) screen = pygame.display.set_mode((width, height)) clock = pygame.time.Clock() rand_x = lambda: randint(0, width) rand_y = lambda: randint(0, height) def magnitude(v): """returns the lenght of a vector""" return math.sqrt(sum(v[i]*v[i] for i in range(len(v)))) def normalize(v): """normalizes a vector""" vmag = magnitude(v) return [ v[i]/vmag for i in range(len(v)) ] class Star(object): def __init__(self): self.rect = pygame.Rect(rand_x(), rand_y(), 1, 1) self.speed = randint(2, 5) def move(self, vec): if vec == [0, 0]: return # move star by applying its speed # to the normalized movement vector self.rect.move_ip(*[self.speed * a for a in normalize(vec)]) # check if the star needs to appear on the opposite edge if self.rect.x > width: self.rect.x = 0 self.rect.y = rand_y() elif self.rect.x < 0: self.rect.x = width self.rect.y = rand_y() if self.rect.y > height: self.rect.y = 0 self.rect.x = rand_x() elif self.rect.y < 0: self.rect.y = height self.rect.x = rand_x() def draw(self, surface): pygame.draw.circle(surface, pygame.Color('white'), self.rect.center, 2) def main(): # create a bunch of stars stars = [Star() for _ in xrange(100)] # a map of possible movements move = {pygame.K_UP: (0, -1), pygame.K_DOWN: (0, 1), pygame.K_LEFT: (-1, 0), pygame.K_RIGHT: (1, 0)} quit = False while not quit: # draw everything screen.fill(pygame.Color('black')) for star in stars: star.draw(screen) pygame.display.flip() # check for pressed keys keys = pygame.key.get_pressed() # create a movement vector by adding all vectors # whose key (according to 'move') is pressed vec = map(sum, zip(*[v for (k, v) in move.iteritems() if keys[k]])) or [0, 0] # move all stars for star in stars: star.move(vec) # check for exit quit = pygame.event.get(pygame.QUIT) pygame.event.poll() # limit FPS clock.tick(60) if __name__ == '__main__': main()

Pygame不会为对角输入选择两个键

2 个答案: