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