Python Demo & Code: Game Asteroids

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[ Click on to play the game~：) ]

implementation of Spaceship - program template for RiceRocks

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import simplegui
import math
import random

globals for user interface

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WIDTH = 800
HEIGHT = 600
score = 0
lives = 3
time = 0.5
started = False
rock_group = set() 
rock_remove = set()
missile_group = set()
missile_remove = set()
explosion_group = set()
explosion_remove = set()
class ImageInfo:
def init(self, center, size, radius = 0, lifespan = None, animated = False):
    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

art assets created by Kim Lathrop, may be freely re-used in non-commercial projects, please credit Kim

Debris Images

debris images - debris1_brown.png, debris2_brown.png, debris3_brown.png, debris4_brown.png

debris1_blue.png, debris2_blue.png, debris3_blue.png, debris4_blue.png, debris_blend.png

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debris_info = ImageInfo([320, 240], [640, 480])
debris_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/debris2_blue.png")

nebula images - nebula_brown.png, nebula_blue.png

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nebula_info = ImageInfo([400, 300], [800, 600])
nebula_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/nebula_blue.png")

splash image

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splash_info = ImageInfo([200, 150], [400, 300])
splash_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/splash.png")

ship image

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ship_info = ImageInfo([45, 45], [90, 90], 35)
ship_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/double_ship.png")

missile image

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missile_info = ImageInfo([5,5], [10, 10], 3, 50)
missile_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/shot2.png")

asteroid images

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asteroid_info = ImageInfo([45, 45], [90, 90], 40)
asteroid_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/asteroid_blue.png")

animated explosion

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EXPLOSION_CENTER = [64, 64]
EXPLOSION_SIZE = [100, 100]
EXPLOSION_DIM = [17, 1]
explosion_info = ImageInfo([64, 64], [128, 128], 17, 500, True)
explosion_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/explosion_alpha.png")

sound assets purchased from sounddogs.com

.ogg versions of sounds are also available, just replace .mp3 by .ogg

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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")

helper functions to handle transformations

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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)

Ship class

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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:
        canvas.draw_image(self.image, [self.image_center[0] + self.image_size[0], self.image_center[1]] , self.image_size,
                          self.pos, self.image_size, self.angle)
    else:
        canvas.draw_image(self.image, self.image_center, self.image_size,
                          self.pos, self.image_size, self.angle)
    # canvas.draw_circle(self.pos, self.radius, 1, "White", "White")
def update(self):
    # update angle
    self.angle += self.angle_vel
    
    # update position
    self.pos[0] = (self.pos[0] + self.vel[0]) % WIDTH
    self.pos[1] = (self.pos[1] + self.vel[1]) % HEIGHT
    # update velocity
    if self.thrust:
        acc = angle_to_vector(self.angle)
        self.vel[0] += acc[0] * .1
        self.vel[1] += acc[1] * .1
        
    self.vel[0] *= .99
    self.vel[1] *= .99
    
def collide(self,obj2):
    global rock_remove, lives
    distance = dist(self.pos,obj2.pos)
    if distance < (self.radius+obj2.radius):
        rock_remove.add(obj2)
        lives -=1
        return True
    
def set_thrust(self, on):
    self.thrust = on
    if on:
        ship_thrust_sound.rewind()
        ship_thrust_sound.play()
    else:
        ship_thrust_sound.pause()
   
def increment_angle_vel(self):
    self.angle_vel += .05
    
def decrement_angle_vel(self):
    self.angle_vel -= .05
    
def shoot(self):
    global a_missile
    forward = angle_to_vector(self.angle)
    missile_pos = [self.pos[0] + self.radius * forward[0], self.pos[1] + self.radius * forward[1]]
    missile_vel = [self.vel[0] + 6 * forward[0], self.vel[1] + 6 * forward[1]]
    a_missile = Sprite(missile_pos, missile_vel, self.angle, 0, missile_image, missile_info, missile_sound)
    missile_group.add(a_missile)

​

Sprite class

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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 collide(self,obj2):
    distance = dist(self.pos,obj2.pos)
    if distance < (self.radius+obj2.radius):
        return True   
    
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):
    # update angle
    self.angle += self.angle_vel
    
    # update position
    self.pos[0] = (self.pos[0] + self.vel[0]) % WIDTH
    self.pos[1] = (self.pos[1] + self.vel[1]) % HEIGHT
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def group_Collide(obj1,group2):
global score
for obj2 in group2:
    if obj1.collide(obj2):
        score +=1
        missile_group.pop(obj1)
        rock_remove.add(obj2)
        explosion_group.add(obj2)

key handlers to control ship

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def keydown(key):
if key == simplegui.KEY_MAP['left']:
    my_ship.decrement_angle_vel()
elif key == simplegui.KEY_MAP['right']:
    my_ship.increment_angle_vel()
elif key == simplegui.KEY_MAP['up']:
    my_ship.set_thrust(True)
elif key == simplegui.KEY_MAP['space']:
    my_ship.shoot()
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def keyup(key):
if key == simplegui.KEY_MAP['left']:
    my_ship.increment_angle_vel()
elif key == simplegui.KEY_MAP['right']:
    my_ship.decrement_angle_vel()
elif key == simplegui.KEY_MAP['up']:
    my_ship.set_thrust(False)

mouseclick handlers that reset UI and conditions whether splash image is drawn

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def click(pos):
global started,score
score = 0
center = [WIDTH / 2, HEIGHT / 2]
size = splash_info.get_size()
inwidth = (center[0] - size[0] / 2) < pos[0] < (center[0] + size[0] / 2)
inheight = (center[1] - size[1] / 2) < pos[1] < (center[1] + size[1] / 2)
if (not started) and inwidth and inheight:
    started = True
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def draw(canvas):
global time, started, lives, score
# animiate background
time += 1
center = debris_info.get_center()
size = debris_info.get_size()
wtime = (time / 8) % center[0]
canvas.draw_image(nebula_image, nebula_info.get_center(), nebula_info.get_size(), [WIDTH / 2, HEIGHT / 2], [WIDTH, HEIGHT])
canvas.draw_image(debris_image, [center[0] - wtime, center[1]], [size[0] - 2 * wtime, size[1]], 
                            [WIDTH / 2 + 1.25 * wtime, HEIGHT / 2], [WIDTH - 2.5 * wtime, HEIGHT])
canvas.draw_image(debris_image, [size[0] - wtime, center[1]], [2 * wtime, size[1]], 
                            [1.25 * wtime, HEIGHT / 2], [2.5 * wtime, HEIGHT])
  
for item in explosion_group:
    explosion_index = [time % EXPLOSION_DIM[0], (time // EXPLOSION_DIM[0]) % EXPLOSION_DIM[1]]
    canvas.draw_image(explosion_image,[EXPLOSION_CENTER[0] + explosion_index[0] * EXPLOSION_SIZE[0],EXPLOSION_CENTER[1] + explosion_index[1] * EXPLOSION_SIZE[1]],EXPLOSION_SIZE, item.pos, EXPLOSION_SIZE)
    explosion_remove.add(item)        
explosion_group.difference_update(explosion_remove)
# draw UI
canvas.draw_text("Lives", [50, 50], 22, "White")
canvas.draw_text("Score", [680, 50], 22, "White")
canvas.draw_text(str(lives), [50, 80], 22, "White")
canvas.draw_text(str(score), [680, 80], 22, "White")
# draw ship and sprites
my_ship.draw(canvas)
for rock in rock_group:
    rock.draw(canvas)
    if my_ship.collide(rock):
        explosion_group.add(my_ship)
    
for missile in missile_group:
    group_Collide(missile,rock_group)
    missile.draw(canvas)
    
if len(rock_remove)>0:
    rock_group.difference_update(rock_remove)
    rock_remove.difference_update(rock_remove)
# update ship and sprites
my_ship.update()
for rock in rock_group:
    rock.update()
for missile in missile_group:
    missile.lifespan +=1
    if missile.lifespan > missile_info.lifespan*2:
        missile_remove.add(missile)
    missile.update()  
    
if len(missile_remove)>0:
    missile_group.difference_update(missile_remove)
    missile_remove.difference_update(missile_remove)    
# draw splash screen if not started
if not started:
    canvas.draw_image(splash_image, splash_info.get_center(), 
                      splash_info.get_size(), [WIDTH / 2, HEIGHT / 2], 
                      splash_info.get_size())
# restart game   
if lives == 0 or started == False:
    started = False
    lives = 3
    rock_group.difference_update(rock_group)

timer handler that spawns a rock

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def rock_spawner():
global a_rock, rock_group
rock_pos = [random.randrange(0, WIDTH), random.randrange(0, HEIGHT)]
rock_vel = [random.random() * .6 - .3, random.random() * .6 - .3]
rock_avel = random.random() * .2 - .1
a_rock = Sprite(rock_pos, rock_vel, 0, rock_avel, asteroid_image, asteroid_info)
if len(rock_group) < 12:
    rock_group.add(a_rock)

initialize stuff

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frame = simplegui.create_frame("Asteroids", WIDTH, HEIGHT)

initialize ship and two sprites

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my_ship = Ship([WIDTH / 2, HEIGHT / 2], [0, 0], 0, ship_image, ship_info)
a_rock = Sprite([WIDTH / 3, HEIGHT / 3], [1, 1], 0, .1, 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

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frame.set_keyup_handler(keyup)
frame.set_keydown_handler(keydown)
frame.set_mouseclick_handler(click)
frame.set_draw_handler(draw)
timer = simplegui.create_timer(1000.0, rock_spawner)

get things rolling

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timer.start()
frame.start()