Star Dust (tutorial 5)

#Star Dust
import turtle
import os
import math

#Set up the screen
wn = turtle.Screen()
wn.tracer(0)
wn.bgcolor("black") #space
wn.title("Star Dust")

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

#Create the player turtle
player = turtle.Turtle()
player.color("silver") #turtle color
player.shape("triangle") #turtle shape
player.penup()
player.speed(0) #max speed
player.setposition(0, -250) #1st position
player.setheading(90) #90 = up

playerspeed = 15 #best speed option

#Create the enemy
enemy = turtle.Turtle()
enemy.color("red")
enemy.shape("circle")
enemy.penup() #no drawing on screen
enemy.speed(0)
enemy.setposition(-200, 250) #starting pos. not a necessity

enemyspeed = 0.35

#Create the turtle's bullet
bullet = turtle.Turtle()
bullet.color("yellow")
bullet.shape("square")
bullet.penup()
bullet.speed(0)
bullet.setheading(90) #bullet's heading
bullet.shapesize(0.25, 0.25) #dimensions of the bullet
bullet.hideturtle() #hides bullet when game is started

bulletspeed = 1.5

#Define bullet state(s)
#ready - ready to fire
#fire - bullet is firing
bulletstate = "ready" #bullet state when game is started

#Move the player turtle left and right
def move_left(): #left function
    x = player.xcor() #x = turtle x
    x -= playerspeed #negative movement
    if x < - 285:
        x = - 285
    player.setx(x) #sets x to x(turtle)

def move_right(): #right function
    x = player.xcor()
    x += playerspeed #positive movement
    if x > 285:
        x = 285
    player.setx(x)

def fire_bullet():
    #Declare bullet state as a global
    global bulletstate
    if bulletstate == "ready":
        bulletstate = "fire"
        #Move the bullet just above the player upon start
        x = player.xcor()
        y = player.ycor()   +10 #10 pixels above turtle
        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: #15 or any
        return True
    else:
        return False

#Create keyboard bindings
turtle.listen() #listen for keyword actions
turtle.onkey(move_left, "Left")
turtle.onkey(move_right, "Right")
turtle.onkey(fire_bullet, "space")

#Main game loop
while True:
    wn.update()
    #Move the enemy
    x = enemy.xcor() #cor. position of enemy(starting)
    x += enemyspeed #enemy moves alone with this speed
    enemy.setx(x) #set enemy as that x

    #Move the enemy back and down
    if enemy.xcor() > 285:
        y = enemy.ycor()
        y -= 70 #when enemy hits boundary, drop down 40px
        enemyspeed *=-1 #when touching boundary, turn negative to reverse
        enemy.sety(y) #set y pos. to y(enemy)

    if enemy.xcor() < - 285:
        y = enemy.ycor()
        y -= 70
        enemyspeed *= -1
        enemy.sety(y)

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

    #Check to see if bullet hit boundary
    if bullet.ycor() > 282.5:
        bullet.hideturtle() #hides bullet if it crosses boundary
        bullet.sety(-240)
        bulletstate = "ready" #when it does, it switches to 'ready' state

    if isCollision(bullet, enemy):
        #Reset the bullet
        bullet.hideturtle() #if hit enemy, hide bullet
        bulletstate = "ready" #when enemy hit, ready another bullet
        bullet.setposition(-600, -600) #move bullet offscreen(bc. hidden bullet still impacts)
        #Reset the enemy
        enemy.setposition(-200, 250) #when killed, spawn another on this cor.

    if isCollision(player, enemy):
        player.hideturtle()
        enemy.hideturtle()
        print("GAME OVER")
        break #breaks the main loop(ends the game)





turtle.mainloop()