Python Game Programming Tutorial: Space Invaders 6

Only one enemy? Let's add more!

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#Python #Tutorial #Beginner

[andrespalusalu]

wow this really helps with my school assignment. i get so much good information here and i even understand now how the for cycles work, thanks!

[defmake_a_sound]

we can fix the bullet bug by including "if bullet.ycor() > 275:" to "if bulletstate == 'fire':" using tab

[programmingduntless]

Thanks for the tutorial, now I can add clones in my python games

[playertew]

My code isn't working:
The error that pops up is
TypeError: unsupported overhand type(s) for +=: 'float' and 'method'
(Line 125 - x += enemy.speed)

Here is the code:
#Space Invaders - Part 1
# Add multiple enemies
# Setup screen
import turtle
import os
import math
import random

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

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

#Create the player turtle
player= turtle.Turtle()
player.color("blue")
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 of enemies
enemies = []

#Add enemies to the list
for i in range(number_of_enemies):


for enemy in enemies:
#Create the enemy
enemy = turtle.Turtle()
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)

enemy.speed = 2




#Create the player's bullet
bullet = turtle.Turtle()
bullet.color("white")
bullet.shape("triangle")
bullet.penup()
bullet.speed(0)
bullet.setheading(90)
bullet.shapesize(0.5, 0.5)
bullet.hideturtle()

bullet.speed = 20

#Define bullet state
#ready - ready to fire
# fire - bullet is firing
bulletstate = "ready"

#Move the player left and right
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 bullet state as a global if it needs changed
global bulletstate
if bulletstate == "ready":
bulletstate = "fire"
# Move the bullet 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


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

#Main game loop
while True:

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

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

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

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

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

#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

delay = turtle.done()

[shaharyarahmed]

It looks as if your copying from somewhere, good job by the way! This helped me alot!

[sahidansari]

Hi, a question again, can't I make the enemies a bit tougher and make them take a hit or two before resetting them. I have been thinking about it for two days, but haven't got any idea how to do it. So I thought maybe you could help if you got the time.

[MonocledTree]

Hello! So i have a problem, for some reason whenever i start the game my weapons bullet also starts moving with them and makes a line can u help me?

[theobenadict]

when i get to the point where there are 5 enemies moving on the screen none of them move, could you help me with this if you have time???

[natehinchliffe]

Thanks for this, great tutorial, but do you know how i could make the enemies form rows like the classic Space Invaders? Thanks in advance.

[raz]

i have get problem in enemy Collision if i shooting the enemy only one is in Collision help me

[TheJacklwilliams]

I like it so far. I've learned a lot. However, what's kinda driving me nuts is it's klugey? Sometimes the bullet doesn't leave the muzzle, the enemies slow down, speed up, hang up.... Am I missing something?

[Onaneehsyu]

I am fairly new to your channel and I wanted to ask is (I don't know if it will be corrected in later videos) everytime 1 enemy reaches the limit xcor all of them moves down even if they haven't reached it. Is there a way we can check individually if the enemy truly reached the limit xcor before going down?

[vodzzzer]

Hey liking the videos! I was experimenting a little with the code and wanted to try and make each enemy move independently. So that it doesn't move/change direction on the y-axis and x-axis unless it hits the wall. How would I go about this?

[cekop]

hey um bro um so in this episode i wrote everything and for some reason
the enemies just phase through the border and i cant hit them all
like what code do i need to fix or what?

[amanrohilla]

I am making the game step by step but when i apply the for loop for movement of multiple enemies they don't move. And even collision check is not working for them. Please help

[lolind]

Quick question:

How do you "move" the lines a tab when you've selected them?

For example when you did that with this:
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)

[j-vahalla-b]

hey man i just wanted to tell that this series is so good@ but he problem i encountered here is that my enemies are not moving once i kept the for loop. please help me!

[kshitijakubal]

I am getting this error and none of my enemies are moving, The code is same
Error -

Exception has occurred: _tkinter.TclError
invalid command name ".!canvas"
File "D:\python games\<string>", line 1, in coords
File "D:\python games\bot.py", line 127, in <module>
enemy.setx(x)


The above error is in following part of code -
#Main Game Loop
while True:

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

[ryancameron]

Hi Christian, I tried adding more enemies to the game. I'm having a problem with my enemies lagging when they move, is there anyway I can move them all at once instead of one at a time?

[SantoshKumar-teuh]

hey thank you for the tutorial but i have an error that in 5:11 my enemies don't move!
here is my code
#Space invaders
#Import Packages
#set up screen
import turtle
import os
import math
import random

#Setup Screen
wn = turtle.Screen()
wn.bgcolor("black")
wn.title("Space Invaders! V3")

#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

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



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

#add enemies to the list gradually
for i in range(number_of_enemies):
#Enemy


for enemy in enemies:
enemy = turtle.Turtle()
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)

#Enemy Movement
#Enemy Speed
enemyspeed = 2

#Create Player Bullets
#cloning
#from turtle module

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()

#speed of the bullet
bulletspeed = 20

#deine bullet state
#ready - ready to fire/shoot
#fire - bullet in firing format
bulletstate = "ready"


#player Movements
#left and right

playerspeed = 15

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

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

def fire_bullet():
#declare bulletstate as a global var value
global bulletstate
if bulletstate == "ready":
bulletstate = "fire"
#move bullet above player
x = player.xcor()
y = player.ycor() +10
bullet.setposition(x, y)
bullet.showturtle()

def ifCollision (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 binding
turtle.listen()
turtle.onkey(move_left, "Left")
turtle.onkey(move_right, "Right")
turtle.onkey(fire_bullet, "space")


#main game loop
while True:
for enemy in enemies:
#move the enemy
x = enemy.xcor()
x += enemyspeed
enemy.setx(x)

#enemy boundary check
#move 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)

#Moving The Bullet
if bulletstate == "fire":
y = bullet.ycor()
y += bulletspeed
bullet.sety(y)


#Bullet YCOR Check
if bullet.ycor() > 275:
bullet.hideturtle()
bulletstate = "ready"

#Checking For Collison og bullet and enemy
if ifCollision(bullet, enemy):
#reset the bullet
bullet.hideturtle()
bulletstate = "ready"
bullet.setposition(0, -400)
#reset the enemy
enemy.setposition(-200, 250)

if ifCollision(player, enemy):
player.hideturtle()
enemy.hideturtle()
print("Game Over")
break


delay = input("press enter to finish")