在這個(gè)系列中，將制作一個(gè)雷霆戰(zhàn)機(jī)游戲。

GIF.gif

敵人精靈

首先定義Mob（小怪物）類型：

class Mob(pygame.sprite.Sprite):
    def __init__(self):
        pygame.sprite.Sprite.__init__(self)
        self.image = pygame.Surface((30, 40))
        self.image.fill(RED)
        self.rect = self.image.get_rect()
        self.rect.x = random.randrange(WIDTH - self.rect.width)
        self.rect.y = random.randrange(-100, -40)
        self.speedy = random.randrange(1, 8)

這里的關(guān)鍵是為小怪物初始化一個(gè)好的位置。選擇一個(gè)高于頂部的值（y <0）和一個(gè)介于左右兩邊之間的x的隨機(jī)值。

在update函數(shù)中，更新精靈y軸的坐標(biāo)，向下移動(dòng)精靈；精靈離開底部時(shí)，通過將精靈移回頂部上方的隨機(jī)位置來制造下一個(gè)精靈。

def update(self):
        self.rect.y += self.speedy
        if self.rect.top > HEIGHT + 10:
            self.rect.x = random.randrange(WIDTH - self.rect.width)
            self.rect.y = random.randrange(-100, -40)
            self.speedy = random.randrange(1, 8)

一群敵機(jī)

使用for語句，循環(huán)創(chuàng)建一些怪物，并將它們添加到精靈組中：

player = Player()
all_sprites.add(player)
for i in range(8):
    m = Mob()
    all_sprites.add(m)
    mobs.add(m)

現(xiàn)在應(yīng)該有一群怪物涌入屏幕，如下所示：

這很棒，但讓小怪直接向下移動(dòng)有點(diǎn)無聊。讓在x方向上添加一點(diǎn)運(yùn)動(dòng)：

class Mob(pygame.sprite.Sprite):
    def __init__(self):
        pygame.sprite.Sprite.__init__(self)
        self.image = pygame.Surface((30, 40))
        self.image.fill(RED)
        self.rect = self.image.get_rect()
        self.rect.x = random.randrange(WIDTH - self.rect.width)
        self.rect.y = random.randrange(-100, -40)
        self.speedy = random.randrange(1, 8)
        self.speedx = random.randrange(-3, 3)

    def update(self):
        self.rect.x += self.speedx
        self.rect.y += self.speedy
        if self.rect.top > HEIGHT + 10 or self.rect.left < -25 or self.rect.right > WIDTH + 20:
            self.rect.x = random.randrange(WIDTH - self.rect.width)
            self.rect.y = random.randrange(-100, -40)
            self.speedy = random.randrange(1, 8)

請(qǐng)注意，更改了怪物移出屏幕的判斷語句。對(duì)角線移動(dòng)的怪物可能會(huì)在它離開底部之前就離開側(cè)面。

if self.rect.top > HEIGHT + 10 or self.rect.left < -25 or self.rect.right > WIDTH + 20:

你的游戲現(xiàn)在應(yīng)該是這樣的：

image

# Shmup game - part 2
# Video link: https://www.youtube.com/watch?v=-5GNbL33hz0
# Enemy sprites
import pygame
import random

WIDTH = 480
HEIGHT = 600
FPS = 60

# define colors
WHITE = (255, 255, 255)
BLACK = (0, 0, 0)
RED = (255, 0, 0)
GREEN = (0, 255, 0)
BLUE = (0, 0, 255)
YELLOW = (255, 255, 0)

# initialize pygame and create window
pygame.init()
pygame.mixer.init()
screen = pygame.display.set_mode((WIDTH, HEIGHT))
pygame.display.set_caption("Shmup!")
clock = pygame.time.Clock()

class Player(pygame.sprite.Sprite):
    def __init__(self):
        pygame.sprite.Sprite.__init__(self)
        self.image = pygame.Surface((50, 40))
        self.image.fill(GREEN)
        self.rect = self.image.get_rect()
        self.rect.centerx = WIDTH / 2
        self.rect.bottom = HEIGHT - 10
        self.speedx = 0

    def update(self):
        self.speedx = 0
        keystate = pygame.key.get_pressed()
        if keystate[pygame.K_LEFT]:
            self.speedx = -8
        if keystate[pygame.K_RIGHT]:
            self.speedx = 8
        self.rect.x += self.speedx
        if self.rect.right > WIDTH:
            self.rect.right = WIDTH
        if self.rect.left < 0:
            self.rect.left = 0

class Mob(pygame.sprite.Sprite):
    def __init__(self):
        pygame.sprite.Sprite.__init__(self)
        self.image = pygame.Surface((30, 40))
        self.image.fill(RED)
        self.rect = self.image.get_rect()
        self.rect.x = random.randrange(WIDTH - self.rect.width)
        self.rect.y = random.randrange(-100, -40)
        self.speedy = random.randrange(1, 8)
        self.speedx = random.randrange(-3, 3)

    def update(self):
        self.rect.x += self.speedx
        self.rect.y += self.speedy
        if self.rect.top > HEIGHT + 10 or self.rect.left < -25 or self.rect.right > WIDTH + 20:
            self.rect.x = random.randrange(WIDTH - self.rect.width)
            self.rect.y = random.randrange(-100, -40)
            self.speedy = random.randrange(1, 8)

all_sprites = pygame.sprite.Group()
mobs = pygame.sprite.Group()
player = Player()
all_sprites.add(player)
for i in range(8):
    m = Mob()
    all_sprites.add(m)
    mobs.add(m)

# Game loop
running = True
while running:
    # keep loop running at the right speed
    clock.tick(FPS)
    # Process input (events)
    for event in pygame.event.get():
        # check for closing window
        if event.type == pygame.QUIT:
            running = False

    # Update
    all_sprites.update()

    # Draw / render
    screen.fill(BLACK)
    all_sprites.draw(screen)
    # *after* drawing everything, flip the display
    pygame.display.flip()

pygame.quit()

在下一課中，將學(xué)習(xí)如何檢測(cè)兩個(gè)精靈何時(shí)碰到對(duì)方（碰撞）并讓玩家回?fù)艄治铩?/p>