asteroids.py

# Implementation of Asteroids in Python
#
# Please use Google Chrome. Sound may not be available on Firefox and other browsers
#
# Controls
# left and right arrow keys to rotate
# forward key to thrust
# spacebar to shoot
#
#
# Have fun =)
#
# http://www.codeskulptor.org/#user38_ygFa6LSRap_16.py


import simplegui
import math
import random

# globals for user interface
WIDTH = 800
HEIGHT = 600
score = 0
lives = 3
time = 0
started = False
expl_time = 0


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

# Base resource urls
IMG_RESOURCE_URL = "https://raw.githubusercontent.com/RyanOM/python_asteroids/gh-pages/imgs/{}"
SOUND_RESOURCE_URL = "https://raw.githubusercontent.com/RyanOM/python_asteroids/gh-pages/sounds/{}"
    
# 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
debris_info = ImageInfo([320, 240], [640, 480])
debris_image = simplegui.load_image(IMG_RESOURCE_URL.format("debris2_blue.png"))

# nebula images - nebula_brown.png, nebula_blue.png
nebula_info = ImageInfo([400, 300], [800, 600])
nebula_image = simplegui.load_image(IMG_RESOURCE_URL.format("nebula_blue.f2014.png"))

# splash image
splash_info = ImageInfo([200, 150], [400, 300])
splash_image = simplegui.load_image(IMG_RESOURCE_URL.format("splash.png"))

# ship image
ship_info = ImageInfo([45, 45], [90, 90], 35)
ship_image = simplegui.load_image(IMG_RESOURCE_URL.format("double_ship.png"))

# missile image - shot1.png, shot2.png, shot3.png
missile_info = ImageInfo([5,5], [10, 10], 3, 50)
missile_image = simplegui.load_image(IMG_RESOURCE_URL.format("shot2.png"))

# asteroid images - asteroid_blue.png, asteroid_brown.png, asteroid_blend.png
asteroid_info = ImageInfo([45, 45], [90, 90], 40)
asteroid_image = simplegui.load_image(IMG_RESOURCE_URL.format("asteroid_blue.png"))

# animated explosion - explosion_orange.png, explosion_blue.png, explosion_blue2.png, explosion_alpha.png
explosion_info = ImageInfo([64, 64], [128, 128], 17, 24, True)
explosion_image = simplegui.load_image(IMG_RESOURCE_URL.format("explosion_alpha.png"))

# sound assets purchased from sounddogs.com, please do not redistribute
# .ogg versions of sounds are also available, just replace .mp3 by .ogg
soundtrack = simplegui.load_sound(SOUND_RESOURCE_URL.format("soundtrack.mp3"))
missile_sound = simplegui.load_sound(SOUND_RESOURCE_URL.format("missile.mp3"))
missile_sound.set_volume(.5)
ship_thrust_sound = simplegui.load_sound(SOUND_RESOURCE_URL.format("thrust.mp3"))
explosion_sound = simplegui.load_sound(SOUND_RESOURCE_URL.format("explosion.mp3"))
scream_sound = simplegui.load_sound("https://github.com/RyanOM/python_asteroids/blob/gh-pages/sounds/void_scream.mp3?raw=true")


# helper functions to handle transformations
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
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)

    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 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 missile_group
        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
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):
        global expl_time
        if self.animated:
            explosion_index = expl_time % 24
            canvas.draw_image(self.image, [self.image_center[0] + explosion_index * self.image_size[0], 
                                           self.image_center[1]], self.image_size, self.pos, self.image_size)
            expl_time += 1
        else:
            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
        
        # lifespan
        self.age += 1
        if self.age >= self.lifespan:
            return True
        else:
            return False

    def collide(self, other_object):
        if self.radius + other_object.radius > dist(self.pos, other_object.pos):
            return True
        else:
            return False
  
        
# key handlers to control ship   
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()
        

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)
        

# mouse click handlers that reset UI and conditions whether splash image is drawn
def click(pos):
    global started
    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
        reset()


def draw(canvas):
    global time, started, lives, score, soundtrack
    
    # animate background
    time += 1
    wtime = (time / 4) % WIDTH
    center = debris_info.get_center()
    size = debris_info.get_size()
    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, size, (wtime - WIDTH / 2, HEIGHT / 2), (WIDTH, HEIGHT))
    canvas.draw_image(debris_image, center, size, (wtime + WIDTH / 2, HEIGHT / 2), (WIDTH, HEIGHT))

    if lives <= 0:
        started = False
        soundtrack.pause()
        scream_sound.play()
        
    if started:
        # draw ship and sprites
        my_ship.draw(canvas)
        process_sprite_group(rock_group, canvas)
        process_sprite_group(missile_group, canvas)
        process_sprite_group(explosion_group, canvas)
        
        # update ship and sprites
        my_ship.update() 
   
    # 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 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())
        
    # remove life for collisions
    if group_collide(rock_group, my_ship):
        lives -= 1
        
    # missile/rock collisions score
    score += 10*group_group_collide(missile_group, rock_group)


# timer handler that spawns a rock
def rock_spawner():
    global rock_group, my_ship, score
    rock_pos = [random.randrange(0, WIDTH), random.randrange(0, HEIGHT)]
    speedup = score//80
    # Rock velocity
    rock_vel = [
        float(random.randrange(1, 5+speedup))/10*random.choice([-1, 1]),
        float(random.randrange(1, 5+speedup))/10*random.choice([-1, 1]),
    ]
    # Rock angle velocity
    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:
        # make safe distance before spawn
        if dist(a_rock.pos, my_ship.pos) > a_rock.radius + my_ship.radius + 15:
            rock_group.add(a_rock)


# Drawing sprites in set
def process_sprite_group(myset, mycanvas): 
    iterate = myset.copy()
    for sprite in iterate:
        sprite.draw(mycanvas)
        sprite.update()
        if sprite.update():
            myset.remove(sprite)


def group_collide(group, other_object):
    iterate = group.copy()
    for sprite in iterate:
        if sprite.collide(other_object):
            group.remove(sprite)
            explosion_group.add(Sprite(sprite.pos, sprite.vel, 0, 0, explosion_image, explosion_info, explosion_sound))
            sprite.animated = True
            return True
        

def group_group_collide(mgroup, rgroup):
    hits = 0
    iterate = mgroup.copy()
    for missile in iterate:
        if group_collide(rgroup, missile):
            hits += 1
            mgroup.remove(missile)
    return hits


def reset():
    global explosion_group, lives, rock_group, my_ship, missile_group, score, soundtrack
    lives = 3
    my_ship = Ship([WIDTH / 2, HEIGHT / 2], [0, 0], 0, ship_image, ship_info)
    rock_group = set([])
    missile_group = set([])
    explosion_group = set([])
    score = 0
    soundtrack.rewind()
    soundtrack.play()


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

# initialize ship and two sprites
my_ship = Ship([WIDTH / 2, HEIGHT / 2], [0, 0], 0, ship_image, ship_info)
rock_group = set([])
missile_group = set([])
explosion_group = set([])


# register handlers
frame.set_keyup_handler(keyup)
frame.set_keydown_handler(keydown)
frame.set_mouseclick_handler(click)
frame.set_draw_handler(draw)
frame.add_label('### Controls ###')
frame.add_label('')
frame.add_label('Left and right arrow keys to move')
frame.add_label('Forward key to thrust')
frame.add_label('Spacebar to fire')
frame.add_label('')
frame.add_label('Please use Google Chrome. Sound may not be available on Firefox and other browsers')

timer = simplegui.create_timer(1000.0, rock_spawner)

# get things rolling
timer.start()
frame.start()