如何在pygame中添加敌人？

Question

我正在做一个简单的游戏与pygame，目标是躲开即将到来的敌人。我想要一个平局战斗机的形象随机下来，X翼必须躲避他们，否则你会死。如何在脚本中实现随机捆绑战斗机？在我的代码中，我得到一个错误，说x没有定义。在

import pygame
import time
import random
pygame.init()

display_width = 1280
display_height= 800


pygame.display.set_mode((display_width, display_height), pygame.FULLSCREEN)

gameDisplay= pygame.display.set_mode((display_width,display_height))
pygame.display.set_caption('X-Wing Game')
clock= pygame.time.Clock()

black= (0,0,0)
white= (255,255,255)
red = (255,0,0)
blue_violet = (138,43,226)


xwing_width = 65
xwing_height = 130

tie_width = 80
tie_height =64

#images
xwingImg = pygame.image.load('X-Wing.bmp')
tieImg= pygame.image.load('tiefighter.png')

def things(thingx, thingy, thingw, thingh, color):
    pygame.draw.rect(gameDisplay, color, [thingx, thingy, thingw, thingh])
    gameDisplay.blit(tieImg,(x,y))

def tieImg (x,y):
    pygame.image.load('tieImg')


def xwing (x,y):
    gameDisplay.blit (xwingImg,(x,y))

def text_objects(text, font):
    textSurface = font.render(text, True, red)
    return textSurface, textSurface.get_rect()

def crash ():
    message_display ('Ouch, You Crashed!')

def message_display(text):
    largeText = pygame.font.Font('freesansbold.ttf',25)
    TextSurf, TextRect = text_objects(text, largeText)
    TextRect.center = ((display_width/2), (display_height/2))
    gameDisplay.blit(TextSurf, TextRect)

    pygame.display.update()

    time.sleep(1.3)

    game_loop()


def game_loop():

    x = (display_width * 0.45)
    y = (display_height * .75)

    x_change = 0
    y_change = 0

    thing_startx = random.randrange(0, display_width)
    thing_starty = -600
    thing_speed = 7
    thing_width = 81
    thing_height =65


    gameEXIT = False

    while not gameEXIT:

        for event in pygame.event.get() :
            if event.type == pygame.QUIT:
                pygame.quit()
                quit()

            if event.type == pygame.KEYDOWN:
                if event.key == pygame.K_LEFT:
                    x_change = -5
                if event.key == pygame.K_UP:
                     y_change= -5
                if event.key == pygame.K_DOWN:
                    y_change =5
                elif event.key == pygame.K_RIGHT:
                    x_change = 5


            if event.type == pygame.KEYUP:
                if event.key == pygame.K_LEFT or event.key == pygame.K_RIGHT:
                    x_change=0



        x += x_change
        y += y_change

        gameDisplay.fill(black)

        things(thing_startx, thing_starty, thing_width, thing_height, black )
        thing_starty += thing_speed
        xwing (x,y)

        if x > display_width - xwing_width or x < 0:
             x_change=0
        if y>display_height-xwing_height or y<0:
            y_change=0


        pygame.display.update()
        clock.tick(60)


game_loop()
pygame.quit()
quit()

Answer 1

你可以使用一个列表并将pygame.Rects附加到它上面，它存储了敌人的位置和大小，然后只需将敌人的图像快速地放到矩形位置。对于碰撞检测，循环查看敌方列表并使用Rect.colliderect方法检查player rect是否与敌方rect发生碰撞。在

import sys
import random
import pygame as pg


pg.init()
screen = pg.display.set_mode((640, 480))

XWING_IMG = pg.Surface((25, 38))
XWING_IMG.fill((90, 120, 150))
TIE_IMG = pg.Surface((40, 24))
TIE_IMG.fill((190, 60, 50))
BG_COLOR = pg.Color('gray15')


def main():
    clock = pg.time.Clock()
    # Surfaces/images have a `get_rect` method which 
    # returns a rect with the dimensions of the image.
    player_rect = XWING_IMG.get_rect()
    player_rect.center = (300, 400)
    change_x = 0
    change_y = 0
    enemies = []
    spawn_counter = 30

    done = False

    while not done:
        for event in pg.event.get():
            if event.type == pg.QUIT:
                done = True
            if event.type == pg.KEYDOWN:
                if event.key == pg.K_d:
                    change_x = 5
                if event.key == pg.K_a:
                    change_x = -5
            if event.type == pg.KEYUP:
                if event.key == pg.K_d and change_x > 0:
                    change_x = 0
                if event.key == pg.K_a and change_x < 0:
                    change_x = 0

        # Spawn enemies if counter <= 0 then reset it.
        spawn_counter -= 1
        if spawn_counter <= 0:
            # Append an enemy rect. You can pass the position directly as an argument.
            enemies.append(TIE_IMG.get_rect(topleft=(random.randrange(600), 0)))
            spawn_counter = 30

        # Update player_rect and enemies.
        player_rect.x += change_x
        player_rect.y += change_y
        for enemy_rect in enemies:
            enemy_rect.y += 5
            # Collision detection with pygame.Rect.colliderect.
            if player_rect.colliderect(enemy_rect):
                print('Collision!')

        # Draw everything.
        screen.fill(BG_COLOR)
        for enemy_rect in enemies:
            screen.blit(TIE_IMG, enemy_rect)
        screen.blit(XWING_IMG, player_rect)

        pg.display.flip()
        clock.tick(30)


if __name__ == '__main__':
    main()
    pg.quit()
    sys.exit()

以这种方式用spawn_counter变量计算帧数意味着游戏将依赖于帧速率（对象生成速度取决于帧速率而变慢或变快）。要实现与帧速率无关的生成计时器，可以使用clock.tick或{}返回的时间，如here所述。在