重构13岁小孩写的游戏(上）
这个游戏中文名网上写的是《兔子和獾》，启动游戏，BGM 响起，左边是城堡，獾会不断生成，从右边冲向左边，如果冲到城堡位置，血条的血会减少；兔子可以按下鼠标左键不断射箭，鼠标可以更改射箭方向，射中獾，獾就会消失，WASD可以上下左右移动，坚持到1.30没有gameover就算胜利，否则失败。
该游戏作者写了一个教程，步骤非常清晰，教你一步步添加游戏角色，音效，增加各种功能，跟着步骤就能够自己实现最终的游戏。
网址：
https://www.raywenderlich.com/2795-beginning-game-programming-for-teens-with-python
# 1 - Import library
import pygame
from pygame.locals import *
import math
import random
# 2 - Initialize the game
pygame.init()
width, height = 640, 480
screen=pygame.display.set_mode((width, height))
keys = [False, False, False, False]
playerpos=[100,100]
acc=[0,0]
arrows=[]
badtimer=100
badtimer1=0
badguys=[[640,100]]
healthvalue=194
pygame.mixer.init()
# 3 - Load image
player = pygame.image.load("resources/images/dude.png")
grass = pygame.image.load("resources/images/grass.png")
castle = pygame.image.load("resources/images/castle.png")
arrow = pygame.image.load("resources/images/bullet.png")
badguyimg1 = pygame.image.load("resources/images/badguy.png")
badguyimg=badguyimg1
healthbar = pygame.image.load("resources/images/healthbar.png")
health = pygame.image.load("resources/images/health.png")
gameover = pygame.image.load("resources/images/gameover.png")
youwin = pygame.image.load("resources/images/youwin.png")
# 3.1 - Load audio
hit = pygame.mixer.Sound("resources/audio/explode.wav")
enemy = pygame.mixer.Sound("resources/audio/enemy.wav")
shoot = pygame.mixer.Sound("resources/audio/shoot.wav")
hit.set_volume(0.05)
enemy.set_volume(0.05)
shoot.set_volume(0.05)
pygame.mixer.music.load('resources/audio/moonlight.wav')
pygame.mixer.music.play(-1, 0.0)
pygame.mixer.music.set_volume(0.25)
# 4 - keep looping through
running = 1
exitcode = 0
while running:
badtimer-=1
# 5 - clear the screen before drawing it again
screen.fill(0)
# 6 - draw the player on the screen at X:100, Y:100
for x in range(int(width/grass.get_width())+1):
for y in range(int(height/grass.get_height()+1)):
screen.blit(grass,(x*100,y*100))
screen.blit(castle,(0,30))
screen.blit(castle,(0,135))
screen.blit(castle,(0,240))
screen.blit(castle,(0,345 ))
# 6.1 - Set player position and rotation
position = pygame.mouse.get_pos()
angle = math.atan2(position[1]-(playerpos[1]+32),position[0]-(playerpos[0]+26))
playerrot = pygame.transform.rotate(player, 360-angle*57.29)
playerpos1 = (playerpos[0]-playerrot.get_rect().width/2, playerpos[1]-playerrot.get_rect().height/2)
screen.blit(playerrot, playerpos1)
# 6.2 - Draw arrows
for bullet in arrows:
index=0
velx=math.cos(bullet[0])*10
vely=math.sin(bullet[0])*10
bullet[1]+=velx
bullet[2]+=vely
if bullet[1]<-64 or bullet[1]>640 or bullet[2]<-64 or bullet[2]>480:
arrows.pop(index)#返回arrows中index位置的值，并把它从arrows中删除
index+=1
for projectile in arrows:
arrow1 = pygame.transform.rotate(arrow, 360-projectile[0]*57.29)
screen.blit(arrow1, (projectile[1], projectile[2]))
# 6.3 - Draw badgers
if badtimer==0:
badguys.append([640, random.randint(50,430)])#将所有敌人放在这个列表中
badtimer=100-(badtimer1*2)#能让敌人出现的越来越快，然后不变
if badtimer1>=35:
badtimer1=35
else:
badtimer1+=5
index=0
for badguy in badguys:
if badguy[0]<-64:
badguys.pop(index)
badguy[0]-=7
# 6.3.1 - Attack castle
badrect=pygame.Rect(badguyimg.get_rect())
badrect.top=badguy[1]
badrect.left=badguy[0]
if badrect.left<64:
hit.play()
healthvalue -= random.randint(5,20)
badguys.pop(index)
#6.3.2 - Check for collisions
index1=0
for bullet in arrows:
bullrect=pygame.Rect(arrow.get_rect())
bullrect.left=bullet[1]
bullrect.top=bullet[2]
if badrect.colliderect(bullrect):
enemy.play()
acc[0]+=1
badguys.pop(index)
arrows.pop(index1)
index1+=1
# 6.3.3 - Next bad guy
index+=1
for badguy in badguys:
screen.blit(badguyimg, badguy)
# 6.4 - Draw clock
font = pygame.font.Font(None, 24)
survivedtext = font.render(str(int((90000-pygame.time.get_ticks())/60000))+":"+str(int((90000-pygame.time.get_ticks())/1000%60)).zfill(2), True, (0,0,0))
textRect = survivedtext.get_rect()
textRect.topright=[635,5]
screen.blit(survivedtext, textRect)
# 6.5 - Draw health bar
screen.blit(healthbar, (5,5))
for health1 in range(healthvalue):
screen.blit(health, (health1+8,8))
# 7 - update the screen
pygame.display.flip()
# 8 - loop through the events
for event in pygame.event.get():
# check if the event is the X button
if event.type==pygame.QUIT:
# if it is quit the game
pygame.quit()
exit(0)
if event.type == pygame.KEYDOWN:
if event.key==K_w:
keys[0]=True
elif event.key==K_a:
keys[1]=True
elif event.key==K_s:
keys[2]=True
elif event.key==K_d:
keys[3]=True
if event.type == pygame.KEYUP:
if event.key==pygame.K_w:
keys[0]=False
elif event.key==pygame.K_a:
keys[1]=False
elif event.key==pygame.K_s:
keys[2]=False
elif event.key==pygame.K_d:
keys[3]=False
if event.type==pygame.MOUSEBUTTONDOWN:
shoot.play()
position=pygame.mouse.get_pos()
acc[1]+=1
arrows.append([math.atan2(position[1]-(playerpos1[1]+32),position[0]-(playerpos1[0]+26)),playerpos1[0]+32,playerpos1[1]+32])
# 9 - Move player
if keys[0]:
playerpos[1]-=5
elif keys[2]:
playerpos[1]+=5
if keys[1]:
playerpos[0]-=5
elif keys[3]:
playerpos[0]+=5
#10 - Win/Lose check
if pygame.time.get_ticks()>=90000:
running=0
exitcode=1
if healthvalue<=0:
running=0
exitcode=0
if acc[1]!=0:
accuracy=acc[0]*1.0/acc[1]*100
else:
accuracy=0
# 11 - Win/lose display
if exitcode==0:
pygame.font.init()
font = pygame.font.Font(None, 24)
text = font.render("Accuracy: "+str(accuracy)+"%", True, (255,0,0))
textRect = text.get_rect()
textRect.centerx = screen.get_rect().centerx
textRect.centery = screen.get_rect().centery+24
screen.blit(gameover, (0,0))
screen.blit(text, textRect)
else:
pygame.font.init()
font = pygame.font.Font(None, 24)
text = font.render("Accuracy: "+str(int(accuracy))+"%", True, (0,255,0))
textRect = text.get_rect()
textRect.centerx = screen.get_rect().centerx
textRect.centery = screen.get_rect().centery+24
screen.blit(youwin, (0,0))
screen.blit(text, textRect)
while 1:
for event in pygame.event.get():
if event.type == pygame.QUIT:
pygame.quit()
exit(0)
pygame.display.flip()虽然跟着教程一步一步可以实现最终的效果，但是很多人想要自己独立去实现一遍，发现还是有很大难度的，因为中间的代码逻辑全部都关联在一起，容易理不清。如果想为游戏增加一些新玩法，不知道从哪里下手，一动代码就乱了。
之所以会出现这种情况，是因为作者采用的是面向过程的，步骤很清晰，可以看明白，自己实现比较难。如果采用面向对象的方法，增加功能就会比较简单了。
其实绝大数游戏都是采用面向对象的，这样比较容易维护和扩展功能。而写面向对象的程序，最重要的就是抽象，尽量将每个角色的属性和方法独立出来。
比如定义这里的兔子类：
在类里面实现兔子的各种方法，这里暂时先实现其移动以及旋转功能。
# 兔子
class Dude(Sprite):
def __init__(self, image):
super().__init__(image)
self.center_x = SCREEN_WIDTH//4
self.center_y = SCREEN_HEIGHT//2
# 移动
def move(self, direction,speed):
if direction == 1:
self.change_y = speed
elif direction == 0:
self.change_x = speed
# 旋转功能
def rotate(self, mouse_x, mouse_y):
y_distance = mouse_y-self.center_y-26
x_distance = mouse_x - self.center_x-32
radians = math.atan2(y_distance, x_distance)
angle = math.degrees(radians)
self.angle = angle主游戏类：
里面实现绘制背景，绘制城堡，绘制兔子，案件检测，鼠标检测。
class MyGame(Window):
def __init__(self, width, height, title):
super().__init__(width, height, title)
set_background_color(color.SKY_BLUE)
#加载背景图片
self.bg = Sprite("resources/images/grass.png")
self.castle = Sprite("resources/images/castle.png")
# 实例化对象
self.dude = Dude("resources/images/dude.png")
# 绘制背景
def draw_bg(self):
for x in range(640//self.bg.width+1):
for y in range(480//self.bg.height+1):
self.bg.center_x = self.bg.width//2+x*self.bg.width
self.bg.center_y = self.bg.height//2+y*self.bg.height
self.bg.draw()
# 绘制城堡
def draw_castle(self):
castle_pos = [(55, 85), (55, 190), (55, 295), (55, 400)]
for pos in castle_pos:
self.castle.center_x = pos[0]
self.castle.center_y = pos[1]
self.castle.draw()
# 渲染显示
def on_draw(self):
start_render()
self.draw_bg()
self.draw_castle()
self.dude.draw()
# 更新
def on_update(self, delta_time):
self.dude.update()
# 按键按下检测
def on_key_press(self, symbol, key_modifiers):
if symbol == key.LEFT:
self.dude.move(0, -1)
if symbol == key.RIGHT:
self.dude.move(0, 1)
if symbol == key.UP:
self.dude.move(1, 1)
if symbol == key.DOWN:
self.dude.move(1,-1)
# 按键释放检测
def on_key_release(self, symbol, key_modifiers):
if symbol == key.LEFT:
self.dude.move(0, 0)
if symbol == key.RIGHT:
self.dude.move(0, 0)
if symbol == key.UP:
self.dude.move(1, 0)
if symbol == key.DOWN:
self.dude.move(1, 0)
# 鼠标移动检测
def on_mouse_motion(self, x, y, delta_x, delta_y):
self.dude.rotate(x,y)完整代码：
from arcade import *
from arcade import key, color
import math
SCREEN_WIDTH = 640
SCREEN_HEIGHT = 480
SCREEN_TITLE = "Dude&Badguy"
# 兔子
class Dude(Sprite):
def __init__(self, image):
super().__init__(image)
self.center_x = SCREEN_WIDTH//4
self.center_y = SCREEN_HEIGHT//2
# 移动
def move(self, direction,speed):
if direction == 1:
self.change_y = speed
elif direction == 0:
self.change_x = speed
# 旋转功能
def rotate(self, mouse_x, mouse_y):
y_distance = mouse_y-self.center_y-26
x_distance = mouse_x - self.center_x-32
radians = math.atan2(y_distance, x_distance)
angle = math.degrees(radians)
self.angle = angle
class MyGame(Window):
def __init__(self, width, height, title):
super().__init__(width, height, title)
set_background_color(color.SKY_BLUE)
#加载背景图片
self.bg = Sprite("resources/images/grass.png")
self.castle = Sprite("resources/images/castle.png")
# 实例化对象
self.dude = Dude("resources/images/dude.png")
# 绘制背景
def draw_bg(self):
for x in range(640//self.bg.width+1):
for y in range(480//self.bg.height+1):
self.bg.center_x = self.bg.width//2+x*self.bg.width
self.bg.center_y = self.bg.height//2+y*self.bg.height
self.bg.draw()
# 绘制城堡
def draw_castle(self):
castle_pos = [(55, 85), (55, 190), (55, 295), (55, 400)]
for pos in castle_pos:
self.castle.center_x = pos[0]
self.castle.center_y = pos[1]
self.castle.draw()
# 渲染显示
def on_draw(self):
start_render()
self.draw_bg()
self.draw_castle()
self.dude.draw()
# 更新
def on_update(self, delta_time):
self.dude.update()
# 按键按下检测
def on_key_press(self, symbol, key_modifiers):
if symbol == key.LEFT:
self.dude.move(0, -1)
if symbol == key.RIGHT:
self.dude.move(0, 1)
if symbol == key.UP:
self.dude.move(1, 1)
if symbol == key.DOWN:
self.dude.move(1,-1)
# 按键释放检测
def on_key_release(self, symbol, key_modifiers):
if symbol == key.LEFT:
self.dude.move(0, 0)
if symbol == key.RIGHT:
self.dude.move(0, 0)
if symbol == key.UP:
self.dude.move(1, 0)
if symbol == key.DOWN:
self.dude.move(1, 0)
# 鼠标移动检测
def on_mouse_motion(self, x, y, delta_x, delta_y):
self.dude.rotate(x,y)
if __name__ == "__main__":
window = MyGame(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
run()
这样游戏的界面，以及兔子的移动，旋转功能都实现了，剩余的射击，獾的前进，箭与獾的碰撞检测，獾与城堡的碰撞检测，血条实现，限时功能，开始结束界面，背景音乐，关卡设计等在之后的文章再写啦。
(全文完)
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原始发表：2021-03-31，如有侵权请联系 cloudcommunity@tencent.com 删除
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