IPP-Project 8

RiceRocks (Asteroids)

For our last mini-project, we will complete the implementation of RiceRocks, an updated version of Asteroids, that we began last week. You may start with either your code or the program template which includes a full implementation of Spaceship and will be released immediately after the deadline for the Spaceship mini-project (by making the preceding link live). If you start with your own code, you should add the splash screen image that you dismiss with a mouse click before starting this mini-project. We strongly recommend using Chrome for this mini-project since Chrome’s superior performance will become apparent when your program attempts to draw dozens of sprites.

Mini-project development process

At the end of this project, your game will have multiple rocks and multiple missiles. You will lose a life if your ship collides with a rock and you will score points if your missile collides with a rock. You will keep track of the score and lives remaining and end the game at the proper time. You may optionally add animated explosions when there is a collision.

Phase one - Multiple Rocks

For this phase, you will keep a set of rocks and spawn new rocks into this set. This requires the following steps:

Remove a_rock and replace it with rock_group. Initialize the rock group to an empty set. Modify your rock spawner to create a new rock (an instance of a Sprite object) and add it to rock_group.
Modify your rock spawner to limit the total number of rocks in the game at any one time. We suggest you limit it to 12. With too many rocks the game becomes less fun and the animation slows down significantly.
Create a helper function process_sprite_group. This function should take a set and a canvas and call the update and draw methods for each sprite in the group.
Call the process_sprite_group function on rock_group in the draw handler.

Phase two - Collisions

For this phase, you will detect collisions between the ship and a rock. Upon a collision, the rock should be destroyed and the player should lose a life. To implement ship-rock collisions, you need to do the following:

Add a collide method to the Sprite class. This should take an other_object as an argument and return True if there is a collision or False otherwise. For now, this other object will always be your ship, but we want to be able to use this collide method to detect collisions with missiles later, as well. Collisions can be detected using the radius of the two objects. This requires you to implement methods get_position and get_radius on both the Sprite and Ship classes.
Implement a group_collide helper function. This function should take a set group and a sprite other_object and check for collisions between other_object and elements of the group. If there is a collision, the colliding object should be removed from the group. To avoid removing an object from a set that you are iterating over (which can cause you a serious debugging headache), iterate over a copy of the set created via set(group). This function should return True or False depending on whether there was a collision. Be sure to use the collide method from part 1 on the sprites in the group to accomplish this task.
In the draw handler, use the group_collide helper to determine if the ship hit any of the rocks. If so, decrease the number of lives by one. Note that you could have negative lives at this point. Don’t worry about that yet.

At this point, you should have a game of “dodge ’em”. You can fly around trying to avoid the rocks!

Phase three - Missiles

For this phase, you will keep a set of missiles and spawn new missiles into this set when firing using the space bar. This requires the following steps:

Remove a_missile and replace it with missile_group. Initialize the missile group to an empty set. Modify your shoot method of my_ship to create a new missile (an instance of the Sprite class) and add it to the missile_group. If you use our code, the firing sound should play automatically each time a missile is spawned.
In the draw handler, use your helper function process_sprite_group to process missile_group. While you can now shoot multiple missiles, you will notice that they stick around forever. To fix this, we need to modify the Sprite class and the process_sprite_group function.
In the update method of the Sprite class, increment the age of the sprite every time update is called. If the age is greater than or equal to the lifespan of the sprite, then we want to remove it. So, return False (meaning we want to keep it) if the age is less than the lifespan and True (meaning we want to remove it) otherwise.
Modify process_sprite_group to check the return value of update for sprites. If it returns True, remove the sprite from the group. Again, you will want to iterate over a copy of the sprite group in process_sprite_group to avoid deleting from the same set over which you are iterating.

Phase four - Collisions Revisited

Now, we want to destroy rocks when they are hit by a missile. We can’t quite use group_collide, because we want to check for collisions between two groups. All we need to do is add one more helper function:

Implement a final helper function group_group_collide that takes two groups of objects as input. group_group_collide should iterate through the elements of a copy of the first group using a for-loop and then call group_collide with each of these elements on the second group. group_group_collide should return the number of elements in the first group that collide with the second group as well as delete these elements in the first group. You may find the discard method for sets to be helpful here.
Call group_group_collide in the draw handler to detect missile/rock collisions. Increment the score by the number of missile collisions.

Phase five - Finish it off

You now have a mostly working version of RiceRocks!!! Let’s add a few final touches.

Add code to the draw handler such that, if the number of lives becomes 0, the game is reset and the splash screen appears. In particular, set the flag started to False, destroy all rocks and prevent any more rocks for spawning until the game is restarted.
When the game starts/restarts, make sure the lives and the score are properly initialized. Start spawning rocks. Play/restart the background music loaded in the variable soundtrack in the program template.
When you spawn rocks, you want to make sure they are some distance away from the ship. Otherwise, you can die when a rock spawns on top of you, which isn’t much fun. One simple way to achieve this effect to ignore a rock spawn event if the spawned rock is too close to the ship.
Experiment with varying the velocity of rocks based on the score to make game play more difficult as the game progresses.
Tweak any constants that you have to make the game play the way you want.

Congratulations! You have completed the assignment. Enjoy playing your game!!!

Bonus

The following will not be graded. Feel free to try this, but do not break any of the other game functionality. We strongly recommend that you save your work before doing this and keep track of it, so you can submit a working version of the first five phases if you end up breaking your game trying to add more features.

One thing that is missing in your game is explosions when things collide. We have provided a tiled explosion image that you can use to create animated explosions. To get things working, you will need to do a few things:

In the draw method of the Sprite class, check if self.animated is True. If so, then choose the correct tile in the image based on the age. The image is tiled horizontally. If self.animated is False, it should continue to draw the sprite as before.
Create an explosion_group global variable and initialize it to an empty set.
In group_collide, if there is a collision, create a new explosion (an instance of the Sprite class)and add it to the explosion_group. Make sure that each explosion plays the explosion sound.
In the draw handler, use process_sprite_group to process explosion_group.

You should now have explosions working!

Grading Rubric - 13 pts total (scaled to 100 pts)

1 pt - The program spawns multiple rocks.
1 pt - The program correctly determines whether the ship collides with a rock.
1 pt - The program removes a rock when the ship collides with a rock.
1 pt - The number of lives decreases by one when the ship collides with a rock.
1 pt - The program spawns multiple missiles.
1 pt - The program plays the firing sound when each missile is spawned.
1 pt - The program removes a missile that does not collide with a rock after some fixed time period.
1 pt - The program correctly determines whether a missile and a rock collide.
1 pt - The program removes missiles and rocks that collide.
1 pt - The score is updated appropriately after missile/rock collisions.
1 pt - When the lives go to zero, the splash screen reappears and all rocks are removed.
1 pt - When the splash screen is clicked, the lives are reset to 3, score is reset to zero and the background music restarts.
1 pt - The game spawns rocks only when the splash screen is not visible and a game is in progress.

Submission

# implementation of Spaceship - program template for RiceRocks
import simplegui
import math
import random

# globals for user interface
WIDTH = 800
HEIGHT = 600
score = 0
lives = 3
time = 0
started = False
rocks = 12


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 - 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("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/debris2_blue.png")

# nebula images - nebula_brown.png, nebula_blue.png
nebula_info = ImageInfo([400, 300], [800, 600])
nebula_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/nebula_blue.f2014.png")

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

# ship image
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 - shot1.png, shot2.png, shot3.png
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 - asteroid_blue.png, asteroid_brown.png, asteroid_blend.png
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 - 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("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/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("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
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)
        # 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 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):
        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)
        
    def get_position(self):
        return self.pos
    
    def get_radius(self):
        return self.radius
    
    
# 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):
        canvas.draw_image(self.image, self.image_center, self.image_size,
                          self.pos, self.image_size, self.angle)
        if self.animated:
            self.image_center = [64 + 128 * self.age, 64]
            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 age
        self.age += 1
        if self.age >= self.lifespan:
            return True
        else:
            return False
    
    def get_position(self):
        return self.pos
    
    def get_radius(self):
        return self.radius
    
    def collide(self, other_object):
        if (dist(self.get_position(), other_object.get_position()) < (self.get_radius() + other_object.get_radius())):
            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)
        
# mouseclick handlers that reset UI and conditions whether splash image is drawn
def click(pos):
    global started, rocks, lives, score
    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
        rocks = 12
        lives = 3
        score = 0
        soundtrack.rewind()
        soundtrack.play()

def draw(canvas):
    global time, started, lives, score, rocks, rock_group
    
    # animiate 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))

    # 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)
    process_sprite_group(rock_group, canvas)
    process_sprite_group(explosion_group, canvas)
    process_sprite_group(missile_group, canvas)
    
    # update ship and sprites
    my_ship.update()

    # determine collisions
    if group_collide(rock_group, my_ship):
        lives -= 1
        if lives <= 0:
            started = False
    score += group_group_collide(missile_group, rock_group)
            
    # 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())
        rocks = 0
        rock_group = set([])
        soundtrack.pause()

# timer handler that spawns a rock    
def rock_spawner():
    global rock_group, rocks
    if len(rock_group) < rocks:
        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 a_rock.collide(my_ship):
            rock_spawner()
        else:
            rock_group.add(a_rock)

# take a set and canvas and call the update and draw methods for each sprite in the group
def process_sprite_group(sprite_group, canvas):
    for sprite in set(sprite_group):
        sprite.draw(canvas)
        if sprite.update():
            sprite_group.remove(sprite)
            
# take a set group and a sprite other_object and check for collisions between other_object and elements of the group
def group_collide(group, other_object):
    for sprite in set(group):
        if sprite.collide(other_object):
            an_explosion = Sprite(sprite.get_position(), [0, 0], 0, 0, explosion_image, explosion_info, explosion_sound)
            explosion_group.add(an_explosion)
            group.remove(sprite)
            return True
    return False
            
# return the number of elements in the first group that collide with the second group as well as delete these elements in the first group
def group_group_collide(first_group, second_group):
    collide_count = 0
    for element in set(first_group):
        if group_collide(second_group, element):
            collide_count += 1
            first_group.discard(element)
    return collide_count
           
# initialize stuff
frame = simplegui.create_frame("Asteroids", WIDTH, HEIGHT)
frame.add_label('How to control the ship?')
frame.add_label('- UP ARROW to accelerate')
frame.add_label('- LEFT ARROW to rotate counter clockwise')
frame.add_label('- RIGHT ARROW to rotate clockwise')
frame.add_label('- SPACE to spawn a missile')

# initialize ship and two sprites
my_ship = Ship([WIDTH / 2, HEIGHT / 2], [0, 0], 0, ship_image, ship_info)
rock_group = set([])
# a_rock = Sprite([WIDTH / 3, HEIGHT / 3], [1, 1], 0, .1, asteroid_image, asteroid_info)
missile_group = set([])
# a_missile = Sprite([2 * WIDTH / 3, 2 * HEIGHT / 3], [-1,1], 0, 0, missile_image, missile_info, missile_sound)
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)

timer = simplegui.create_timer(1000.0, rock_spawner)

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