Space Invaders

# space Invaders
# Set up screen
import turtle
import math
import random

# set up the screen
wn = turtle.Screen()
wn.bgcolor("black")
wn.title("Space Invaders")

# Draw border
border_pen = turtle.Turtle()
border_pen.speed(0)
border_pen.color("white")
border_pen.penup()
border_pen.setposition(-300,-300)
border_pen.pendown()
border_pen.pensize(3)
for side in range(4):
    border_pen.fd(600)
    border_pen.lt(90)
border_pen.hideturtle()

# Create player
player = turtle.Turtle()
player.color("blue")
player.shape("triangle")
player.penup()
player.speed(0)
player.setposition(0,-250)
player.setheading(90)

playerspeed = 15



# choose number of enemies
number_of_enemies = 5
# create an empty list
enemies = []

# add enemies to the list
for i in range(number_of_enemies):
    enemies.append(turtle.Turtle())


for enemy in enemies:
    enemy.color("red")
    enemy.shape("circle")
    enemy.penup()
    enemy.speed(0)
    x = random.randint(-200, 200)
    y = random.randint(100,250)
    enemy.setposition(x, y)

enemyspeed = 2




# Create bullet
bullet = turtle.Turtle()
bullet.color("yellow")
bullet.shape("triangle")
bullet.penup()
bullet.speed(0)
bullet.setheading(90)
bullet.shapesize(0.5, 0.5)
bullet.hideturtle()

bulletspeed = 20

# Define bullet state
# Ready - ready to fire
# Fire - bullet is firing

bulletstate = "ready"




# Control player
def move_left():
    x = player.xcor()
    x -= playerspeed
    if x < -280:
        x = -280
    player.setx(x)

def move_right():
    x = player.xcor()
    x += playerspeed
    if x > 280:
        x = 280
    player.setx(x)

def fire_bullet():
    # Declare bulletstate as a global if it needs to be changed
    global bulletstate
    if bulletstate == "ready":
        bulletstate = "fire"
    # Move bullet to just above the player
    x = player.xcor()
    y = player.ycor() + 10
    bullet.setposition(x, y)
    bullet.showturtle()

def isCollision(t1, t2):
    distance = math.sqrt(math.pow(t1.xcor()-t2.xcor(),2)+math.pow(t1.ycor()-t2.ycor(),2))
    if distance < 15:
        return True
    else:
        return False



# Keyboard Bindings
wn.listen()
wn.onkey(move_left, "Left")
wn.onkey(move_right, "Right")
wn.onkey(fire_bullet, "space")




# Main game loop
while True:

    for enemy in enemies:
        # Move the enemy
        x = enemy.xcor()
        x += enemyspeed
        enemy.setx(x)

        # Move the enemy back and down
        if enemy.xcor() > 280:
            y = enemy.ycor()
            y -= 40
            enemyspeed *= -1
            enemy.sety(y)


        if enemy.xcor() < -280:
            y = enemy.ycor()
            y -= 40
            enemyspeed *= -1
            enemy.sety(y)


        # check for a collision between the bullet and the enemy
        if isCollision(bullet, enemy):
            # Reset the bullet
            bullet.hideturtle()
            bulletstate = "ready"
            bullet.setposition(0, -400)
            # Reset the enemy
            enemy.setposition(-200, 250)

        if isCollision(player, enemy):
            player.hideturtle()
            enemy.hideturtle()

            print("Game Over")
            break







        # Move the bullet
        if bulletstate == "fire":
            y = bullet.ycor()
            y += bulletspeed
            bullet.sety(y)


        # Check to see if the bullet has gone to the top
        if bullet.ycor() > 275:
            bullet.hideturtle()
            bulletstate = "ready"




















turtle.done()
input()