Python – Spaceship 讲解
11月 9th, 2014,由 frank撰写
1. 引用相关的module
import simplegui import math import random
2. 全局参量
WIDTH = 800 # 画布的宽 HEIGHT = 600 # 画布的高 score = 0 # 初始分数0 lives = 3 # 3条命 time = 0.5 # 时间为0.5 FRICTION = 0.95 #摩擦系数
3.元素类
class ImageInfo: # 设置ImageInfo类,所有图片都放进去初始化,方便调用 def __init__(self, center, size, radius = 0, lifespan = None, animated = False): # 对应关系:对象本身;图像中心;图像大小;半径 self.center = center self.size = size self.radius = radius if lifespan: self.lifespan = lifespan else: self.lifespan = float('inf') self.animated = animated def get_center(self): return self.center def get_size(self): return self.size def get_radius(self): return self.radius def get_lifespan(self): return self.lifespan def get_animated(self): return self.animated
4. 飞船类
class Ship: def __init__(self, pos, vel, angle, image, info): self.pos = [pos[0],pos[1]] self.vel = [vel[0],vel[1]] self.thrust = False self.angle = angle self.angle_vel = 0 self.image = image self.image_center = info.get_center() self.image_size = info.get_size() self.radius = info.get_radius() def draw(self,canvas): if self.thrust: self.image_center[0]=135 else: self.image_center[0]=45 canvas.draw_image(self.image, self.image_center, self.image_size, self.pos, self.image_size,self.angle) def update(self): self.pos[0] += self.vel[0] self.pos[1] += self.vel[1] #飞船的现有坐标加上速度,使其坐标移动 self.angle += self.angle_vel forward = angle_to_vector(self.angle) if self.thrust: self.vel[0] += forward[0] self.vel[1] += forward[1] #如果是加速的,那么如上所示 self.vel[0] *= FRICTION self.vel[1] *= FRICTION #如果没有加速,那么加上摩擦系数 self.pos[0] %= WIDTH self.pos[1] %= HEIGHT def set_angle_vel(self, angle_vel): self.angle_vel += angle_vel def set_thrust(self, thrust): self.thrust = thrust if self.thrust: ship_thrust_sound.play() else: ship_thrust_sound.rewind() def shoot(self): global a_missile foward=angle_to_vector(self.angle) tmppos=[self.pos[0]+45*foward[0],self.pos[1]+45*foward[1]] tmpvel=[self.vel[0]+foward[0]*3,self.vel[1]+foward[1]*3] a_missile = Sprite(tmppos, tmpvel, 0, 0, missile_image, missile_info, missile_sound) missile_sound.play()
5. Sprite类
class Sprite: def __init__(self, pos, vel, ang, ang_vel, image, info, sound = None): self.pos = [pos[0],pos[1]] self.vel = [vel[0],vel[1]] self.angle = ang self.angle_vel = ang_vel self.image = image self.image_center = info.get_center() self.image_size = info.get_size() self.radius = info.get_radius() self.lifespan = info.get_lifespan() self.animated = info.get_animated() self.age = 0 if sound: sound.rewind() sound.play() def draw(self, canvas): canvas.draw_image(self.image, self.image_center, self.image_size, self.pos, self.image_size,self.angle) def update(self): self.pos[0]+=self.vel[0] self.pos[0]%=WIDTH self.pos[1]+=self.vel[1] self.pos[1]%=HEIGHT self.angle+=self.angle_vel
6. 辅助函数
def angle_to_vector(ang): return [math.cos(ang), math.sin(ang)] def dist(p,q): return math.sqrt((p[0] - q[0]) ** 2+(p[1] - q[1]) ** 2) def draw(canvas): global time # animiate background time += 1 wtime = (time / 4) % WIDTH #定义两个星云,以匀速向右移动,一个是从全屏开始,另一个是从最右边开始 #例如速度是1-10,当到10后,第一张图已经画完了,刚出画布的右边,这时回到1重画; #而此时第二张图也画完了,刚好铺满画布 center = debris_info.get_center() size = debris_info.get_size() #上面是定义背景的中心点和大小 canvas.draw_image(nebula_image, nebula_info.get_center(), nebula_info.get_size(), [WIDTH/2, HEIGHT/2], [WIDTH, HEIGHT]) #调用星云背景,并平铺到画布中 canvas.draw_image(debris_image, center, size, (wtime-WIDTH/2, HEIGHT/2), (WIDTH, HEIGHT)) canvas.draw_image(debris_image, center, size, (wtime+WIDTH/2, HEIGHT/2), (WIDTH, HEIGHT)) canvas.draw_text('lives:'+str(lives), (50, 50), 24, "Red") canvas.draw_text('score:'+str(score), (50, 100), 24, "Red") # draw ship and sprites my_ship.draw(canvas) a_rock.draw(canvas) a_missile.draw(canvas) # update ship and sprites my_ship.update() a_rock.update() a_missile.update() def rock_spawner(): global a_rock a_rock = Sprite([random.random()*WIDTH, random.random()*HEIGHT], [random.random(), random.random()], random.random()*2*math.pi, random.random()*0.1, asteroid_image, asteroid_info) def keydown(key): if key==simplegui.KEY_MAP['left']: my_ship.angle_vel=-0.1 elif key==simplegui.KEY_MAP['right']: my_ship.angle_vel=0.1 elif key==simplegui.KEY_MAP['up']: my_ship.thrust=True elif key==simplegui.KEY_MAP['space']: my_ship.shoot() def keyup(key): if key==simplegui.KEY_MAP['left']: my_ship.angle_vel=0 elif key==simplegui.KEY_MAP['right']: my_ship.angle_vel=0 elif key==simplegui.KEY_MAP['up']: my_ship.thrust=False
7. 主程序
# 创建一个框,名为"Asteroids",设置宽高,全局变量已设 frame = simplegui.create_frame("Asteroids", WIDTH, HEIGHT) # 初始化元素 # 元素1:尘埃的图像和初始数值 debris_info = ImageInfo([320, 240], [640, 480]) debris_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/debris2_blue.png") # 元素2:星云的图像和初始数值 nebula_info = ImageInfo([400, 300], [800, 600]) nebula_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/nebula_blue.f2014.png") # 元素3:开始图像和初始数值 splash_info = ImageInfo([200, 150], [400, 300]) splash_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/splash.png") # 元素4:飞船图像和初始数值 ship_info = ImageInfo([45, 45], [90, 90], 35) ship_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/double_ship.png") # 元素5:导弹的图像和初始数值 missile_info = ImageInfo([5,5], [10, 10], 3, 50) missile_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/shot2.png") # 元素6:小行星图像和初始数值 asteroid_info = ImageInfo([45, 45], [90, 90], 40) asteroid_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/asteroid_blue.png") # 元素7:爆炸动画和初始数值 explosion_info = ImageInfo([64, 64], [128, 128], 17, 24, True) explosion_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/explosion_alpha.png") # 元素8:声音和初始数值 soundtrack = simplegui.load_sound("http://commondatastorage.googleapis.com/codeskulptor-assets/sounddogs/soundtrack.mp3") missile_sound = simplegui.load_sound("http://commondatastorage.googleapis.com/codeskulptor-assets/sounddogs/missile.mp3") missile_sound.set_volume(.5) ship_thrust_sound = simplegui.load_sound("http://commondatastorage.googleapis.com/codeskulptor-assets/sounddogs/thrust.mp3") explosion_sound = simplegui.load_sound("http://commondatastorage.googleapis.com/codeskulptor-assets/sounddogs/explosion.mp3") # 初始化飞船的对象和两个Sprite类的对象,注意后面非数值参数都是ImageInfo的对象 my_ship = Ship([WIDTH/2, HEIGHT/2], [0, 0], 0, ship_image, ship_info) a_rock = Sprite([WIDTH/3, HEIGHT/ 3], [1, 1], 0, 0, asteroid_image, asteroid_info) a_missile = Sprite([2*WIDTH/3, 2*HEIGHT/3], [-1,1], 0, 0, missile_image, missile_info, missile_sound) # register handlers frame.set_draw_handler(draw) frame.set_keydown_handler(keydown) frame.set_keyup_handler(keyup) timer = simplegui.create_timer(1000.0, rock_spawner) # get things rolling timer.start() frame.start()本文出自 Frank's Blog