canon model game coding using python language

"""Cannon, hitting targets with projectiles.

Exercises

1. Keep score by counting target hits.

2. Vary the effect of gravity.

3. Apply gravity to the targets.

4. Change the speed of the ball.

"""

from random import randrange

from turtle import *

from base import vector

ball = vector(-200, -200)

speed = vector(0, 0)

targets = []

def tap(x, y):

    "Respond to screen tap."

    if not inside(ball):

        ball.x = -199

        ball.y = -199

        speed.x = (x + 200) / 25

        speed.y = (y + 200) / 25

def inside(xy):

    "Return True if xy within screen."

    return -200 < xy.x < 200 and -200 < xy.y < 200

def draw():

    "Draw ball and targets."

    clear()

    for target in targets:

        goto(target.x, target.y)

        dot(20, 'blue')

    if inside(ball):

        goto(ball.x, ball.y)

        dot(8, 'red')

    update()

def move():

    "Move ball and targets."

    if randrange(40) == 0:

        y = randrange(-150, 150)

        target = vector(200, y)

        targets.append(target)

    for target in targets:

        target.x -= 0.5

    if inside(ball):

        speed.y -= 1

        ball.move(speed)

    dupe = targets.copy()

    targets.clear()

    for target in dupe:

        if abs(target - ball) > 13:

            targets.append(target)

    draw()

    for target in targets:

        if not inside(target):

            return

    ontimer(move, 50)

setup(420, 420, 370, 0)

hideturtle()

up()

tracer(False)

onscreenclick(tap)

move()

done()