Coding the Pong Recreation from Scratch in Python

is likely one of the earliest and most iconic video games within the historical past of digital leisure. In its basic kind, the sport simulates a desk tennis match with two paddles that transfer vertically throughout the display to hit a bouncing ball. Every of the participant controls a paddle and has to bounce the ball again to the opposite participant, or else they offer some extent to the other participant.

The historical past of the sport is considerably attention-grabbing. The Pong recreation was created and written by Allan Alcom as a take a look at when he was recruited by Atari. This recreation then turned an enormous success, promoting a great deal of machines the world over’s pubs and bars, and it so occurred that the machines would choke with the a great deal of cash folks would put in, in order that finally the bars and pubs’ homeowners needed to name Atari to repair their machines!

On this tutorial, we are going to use Python’s Object Oriented Programming method to code the Pong recreation. That is an intermediate-level Python programming tutorial that requires one to have a preliminary data of Python fundamentals: checklist, …

Understanding the Challenge

There are a selection of how we will code this recreation. We are able to use the easy methodology and do every job step-by-step with the mandatory repetitions, or we will use Python’s Object Oriented Programming method to escapre the repetition and have a neat and arranged code. We’ll choose the second choice as this might make the sport’s program extra systematic and fewer messy!

We’ll use Python’s Turtle module for the visible recreation improvement. The turtle module is a built-in performance that enables one to visulalize code in a straightforward method. It mainly consists of a turtle that’s drawing shapes and contours because it strikes throughout the display in accordance with the coder’s directions. It’s a highly effective device to create beginner-level video games, and get prompt suggestions via a visible display.

The next are the important thing duties that we’ll method in an orderly method:

1. Creating the Recreation Display – that is the display on which the Pong recreation shall be displayed
2. Creating the Paddle & Paddle Class – that is the code that may create a paddle on display, and configure its actions, which we are going to convert to a category as a blueprint to create 2 paddles, one on the left facet and the opposite on the appropriate facet
3. Creating the Ball Class and Objects – persevering with with the OOP method, we are going to create a generic ball class after which create the ball that may transfer throughout the display, we can even outline its related strategies
4. Detecting Collision of Ball with Prime/Backside Wall -this is the piece of code that may detect collision with the higher and decrease partitions, and if collision happens, it can make the ball bounce throughout the y-axis
5. Detecting Collision with Paddle – that is the piece of code that may detect whether or not the ball collides with the paddle. If sure, it can make the ball bounce; else, if the paddles misses the ball, it can give a rating to the other participant and restart the sport with the ball on the centre.
6. Creating the Scoreboard Class and Object – that is the piece of code that features the creation of the Scoreboard class in a separate Python file and the creation of its object in the primary recreation file.

Creating the Recreation Display

The primary job is to create the sport display. This display shall be rectangular in form, as in the actual recreation. We’ll first import the turtle module in or code and use its Display class to create the display object and customise it to have a width of 800px and a top of 600px utilizing the Display class setup() methodology. We’ll set the background coloration to black utilizing the bgcolor() methodology, and identify the display as “Pong Recreation” utilizing the title() methodology. Beneath is the code, the place we’ve created the display object:

from turtle import Turtle, Display

#Establishing the Recreation Display
display = Display()
display.setup(width=800, top=600)
display.bgcolor("black")
display.title("Pong Recreation")


display.exitonclick()

Discover that we’ve written the final line the place we’ve used the display’s exitonclick() methodology in order to make sure the display will stay there till we click on on it.

For those who discover any confusion within the above strategies, be happy to take a look at the official documentation of the Turtle Module from right here.

Following is the output as we run this system:

Creating the Paddle & Paddle Class

The following job is to create a paddle, which is a rectangular-shaped object at each side of the Recreation Display. We’ll create this paddle utilizing the turtle module’s form() operate, and customise it to be white in coloration utilizing the coloration() methodology, and use the shapesize() methodology to customize it to have a width of 20px and a top of 100px. Discover that we’ve handed 5 and 1 because the arguments to the shapesize() methodology. It’s because the shapesize() is just not in pixels, however in reference to a base of 20px. So to get a size of 100px, we are going to cross 5 (as 20px x 5 = 100px). Furthermore, we are going to place it such that initially of the sport it’s in the course of the appropriate facet, that’s, a y coordinate of 0 and an x coordinate of 350 (keep in mind our display is 800px extensive). We’ll use the penup() methodology to take away the turtle’s hint and make it transfer to the specified location utilizing the goto() methodology.

#Creating the Paddle
paddle = Turtle()
paddle.form("sq.")
paddle.coloration("white")
paddle.shapesize(5,1)
paddle.penup()
paddle.goto(350,0)

The next is the output of the above code. We are able to see a paddle created on the Recreation Display on the proper facet, with none turtle hint.

Operating the above code will create the paddle. Nevertheless, we will see that the paddle is first created, after which it goes to its location. To be able to flip off the animation, we are going to add the display’s class tracer() methodology in our code. This can even require us to replace the display manually:

#Retain the Unique Code
display.tracer(0)

display.replace()
display.exitonclick()

Calling the tracer() methodology and passing it a price of 0 will flip off the animation.

As soon as we’ve created the paddle and up to date the display by turning off the animations, subsequent is to configure the paddle actions. To do that, we are going to use display listeners. The display’s class pay attention() methodology permits us to take heed to keyboard occasions, and the onkey() methodology permits us to name an outlined operate at any time when a selected key’s pressed. We’ll thus outline the go_up and go_down capabilities that may make the paddle transfer up and down alongside the y-axis.

    def go_up():
        new_y = paddle.ycor() + 40
        paddle.goto(paddle.xcor(), new_y)

    def go_down():
        new_y = paddle.ycor() - 40
        paddle.goto(paddle.xcor(),new_y)

As might be seen, we’ve outlined the paddle’s up and down motion operate by making it transfer 40px vertically from its unique place. Subsequent, we are going to use the display listeners functionality to permit these capabilities to be referred to as on urgent keyboard keys.

display.pay attention()
display.onkey(paddle.go_up, "Up")
display.onkey(paddle.go_down, "Down")

Now that we’ve created the paddle and configured the mechanism of its motion, allow us to now shift our code to Object Oriented Programming Method. It’s because we are going to want 2 paddles for the sport, and having a generic blueprint that creates paddles immediately will make our job simpler. We’ll refactor our code to create one other paddle simply. We’ll transfer all of the paddle associated code to a different file and create the padlle class in it.

For the reason that paddles we’re creating are in essence turtle objects, we are going to make this paddle class inherit from the Turtle class. So we are going to create a brand new python file in our PyCharm IDE and once more import the turtle module’s Turtle class on this separate Python file. Subsequent, we are going to use the category creation syntax and def __inti__() to outline the Paddle class. As each the left and proper paddles can have totally different positions throughout the sport display, we are going to add the x and y coordinates as attributes to the category.

Now we are going to use the idea of inheritance in OOP and make the Turtle class the tremendous class, and the paddle class will inherit its attributes and strategies. Subsequent, we are going to simply substitute the phrase “paddle” in our former code the place we created the paddle with the “self” key phrase.

from turtle import Turtle, Display

class Paddle(Turtle):
    def __init__(self,x,y):
        # Creating the Paddle Objects
        tremendous().__init__()
        self.form("sq.")
        self.coloration("white")
        self.shapesize(5, 1)
        self.penup()
        self.x = x
        self.y = y
        self.goto(x,y)

    # Configure Paddle Motion
    def go_up(self):
        new_y = self.ycor() + 40
        self.goto(self.xcor(), new_y)

    def go_down(self):
        new_y = self.ycor() - 40
        self.goto(self.xcor(),new_y)

As might be seen above, we’ve additionally outlined the 2 strategies of Paddle class. One is the upward motion and the second is the downward motion that we’ve already outlined earlier. As soon as the Paddle class is outlined, we are going to create the paddle objects and configure the up and down actions of each paddles:

from paddle import Paddle

# Creating Paddle Objects
left_paddle = Paddle(-350, 0)
right_paddle = Paddle(350, 0)

# Configuring Paddles' Motion
display.pay attention()
display.onkey(right_paddle.go_up, "Up")
display.onkey(right_paddle.go_down, "Down")
display.onkey(left_paddle.go_up, "w")
display.onkey(left_paddle.go_down, "s")

Operating the Recreation

To be able to run the sport and replace it utilizing the Display’s replace() methodology, we are going to outline some time loop that may proceed to run till externally stopped, or when the situation of the loop turns to False.

#Recreation is ON:
game_is_on = True
whereas game_is_on:
    display.replace()

Now, once you run the primary file, you will note the sport display and paddles created, and the power of the paddles to maneuver.

Create the Ball Class & Objects

Now persevering with on our OOP method to code this recreation, we are going to create the Ball class because the generic blueprint and create the ball object from it in our predominant Python file. We’ll create the ball as a turtle object, by making the Ball class inherit from the tremendous class Turtle. We’ll use the turtle class’s strategies coloration() and form() to initialize a ball of white coloration in a round form. As earlier than, we are going to use the penup() methodology of turtle to cover the turtle’s hint.

from turtle import Turtle

class Ball(Turtle):

    def __init__(self):
        tremendous().__init__()
        self.coloration("white")
        self.form("circle")
        self.penup()

Now that our ball’s attributes are outlined, we can even create the ball’s strategies of shifting as quickly as the sport begins. The sport will begin with the ball being on the centre of the sport display, and when the display refreshes, will probably be shifting in the appropriate path first. In our predominant whereas loop we are going to name this methodology so the ball will proceed to maneuver all through when the sport is on, that’s, its x and y coordinates will change at each refresh of the sport display.

The best way to make the ball transfer is by altering each its x and y coordinates by a sure quantity, allow us to say 10 in the interim. We’ll outline the transfer() methodology of the ball and code the above state of affairs:

class Ball(Turtle):

    #Retain earlier code
    def transfer(self):
        new_x = self.xcor() + 10
        new_y = self.ycor() + 10
        self.goto(new_x, new_y)

We’ll add this methodology of the ball object to be referred to as inside the sport’s whereas loop:

#Recreation is ON:
game_is_on = True
whereas game_is_on:
    display.replace()
    ball.transfer()

On operating the code, we see that the ball vanishes shortly, and what we’re left with is simply the two paddles.

We are able to resume the animation by commenting out the display.tracer() traces and rerunning the code. We’ll now see the two paddles and the ball being created and moved.

One other technique to visualise that is utilizing the time module and bringing a delay in the primary whereas loop of the sport. This may be carried out as follows (with out commenting out the tracer() operate):

import time

#Retain the Unique Code
#Recreation is ON:
game_is_on = True
whereas game_is_on:
    time.sleep(0.1)
    display.replace()
    ball.transfer()

Now you possibly can see that the ball strikes at a slower tempo and we will catch it with a paddle.

Detecting Collision of Ball with Prime/Backside Wall

Now that our ball is created and operating, we have to design a mechanism to make the ball bounce when it hits the highest and backside partitions, as for the left and proper partitions, the ball must be caught by the left and proper paddles. If the ball is just not caught, it could imply the opposite participant scores some extent.

So, contemplating that our ball is shifting from the centre of the display to the highest proper nook, and it reaches the nook, it must bounce now. In simple phrases, bouncing would merely be a change of path within the y-axis, because the ball would nonetheless be going ahead within the x-axis. We’ll now outline a brand new methodology of the Ball class referred to as bounce() and name it in the primary recreation loop when the ball reaches the boundary:

from turtle import Turtle

class Ball(Turtle):

    def __init__(self):
        tremendous().__init__()
        self.coloration("white")
        self.form("circle")
        self.penup()
        self.x_move = 10
        self.y_move = 10

    def transfer(self):
        new_x = self.xcor() + self.x_move
        new_y = self.ycor() + self.y_move
        self.goto(new_x, new_y)

    def bounce(self):
        self.y_move *= -1

Discover that within the above, we’ve outlined 2 new attributes of the Ball class, the x_move and the y_move, and have made them equal to 10. Then, within the transfer() methodology, we’ve changed the determine of 10 with these attributes. As might be seen, this is useful for our bounce() methodology. Now, at any time when the ball bounces, it can transfer in the wrong way to its earlier y place. This merely implies that if the ball goes up, and collides with the wall, the y_move would change from +10 to -10, and the ball will transfer downwards, because the damaging quantity would imply the ball is shifting down. Consequently, a collision with the underside wall would change this y_move from -10 to +10, and the ball will then transfer upwards.

Now, allow us to add this situation in the primary whereas loop:

whereas game_is_on:
    #Retain Unique Code

    #Detect Collision with Prime and Backside Partitions
    if ball.ycor() > 275 or ball.ycor() < -275:
        ball.bounce_y()

Within the code above, we’ve added the situation of the collision with the partitions to be detected, after which the bounce() methodology to be referred to as. You should use any worth for the boundaries, however via repeated tries, the worth of 275 is nice sufficient!

Detecting Collision with Paddle

Now that we all know the right way to make the ball bounce from the highest and backside partitions, the following step is to detect a collision with the paddle and make the ball bounce from the paddle. We’ll make use of a similiar methodology as earlier than, besides that now we’re speaking concerning the x-axis.

The traditional technique to detect a collision between the ball and the wall is to make use of the space methodology. If the space between the 2 is lower than a specific amount, we will conclude that the two have touched/collided. Nevertheless, know that the distance() operate works by calculating the space between the facilities of the 2 turtle objects. In our case, one is a 20x20px ball, and the opposite is a 20×200 rectangular paddle. The gap between them would differ alongside the size of the paddle. If the ball hits the paddle on its edge, the space() methodology would fail to conclude that each of them have made contact.

We are able to add one other situation which might examine if the ball has gone previous a sure level on the x-axis, over to the appropriate (within the case of the appropriate paddle), and it’s inside a 50px distance from the paddle, then the ball will need to have made contact. We’ll add this situation to the primary whereas loop. As soon as the collision is detected, we can have the ball bounce, however this time within the x-direction. Allow us to redefine our bounce capabilities so we’ve each bounce capabilities, one for the x-axis when colliding with pthe addle, and the opposite on the y-axis when colliding with the wall:

    def bounce_y(self):
        self.y_move *= -1

    def bounce_x(self):
        self.x_move *= -1

whereas game_is_on:
    ...

    # Detect Collision of the Ball with the Proper Paddle
    if ball.distance(right_paddle) < 50 and ball.xcor() > 320:
        ball.bounce_x()

    # Detect Collision of the Ball with the Left Paddle
    elif ball.distance(left_paddle) < 50 and ball.xcor() < -320:
        ball.bounce_x()

Observe, we’ve added a price of 320 after some hit and trial and visualizations of the ball colliding with the paddle.

If one of many paddles misses the ball, then the opposite participant will get some extent, and the sport restarts with the ball within the centre. To be able to examine if the ball is missed by the paddle, we will visualize this by contemplating the ball going past a sure level on the horizontal axis. We all know that the width of the display is 800 and the paddle is at 350 alongside the x-axis, so the paddle really goes from 340 to 360 because it has a width of 20px, so if the ball goes past the 360 x axs, it means the paddles has missed the ball. This might imply we are going to reset the ball to the beginning place on the centre worth (0,0). We’ll outline a reset_position() methodology of the ball that shall be referred to as when the above situation is met. Furthermore, we can even add a function that may reverse the ball’s path, so as a substitute of going to the appropriate, it can go to the left.

Class Ball(Turtle):
    ...
    def reset_position(self):
        self.goto(0, 0)
        self.bounce_x()

The bounce_x() methodology will trigger the ball to reverse path because it did when it could bounce off a paddle. Placing these situations within the recreation’s predominant whereas loop:

whereas game_is_on:
    ...
    # Detect Proper Paddle Lacking the Ball
    if ball.xcor() > 380:
        ball.reset_position()

    # Detect Left Paddle Lacking the Ball
    if ball.xcor() < -380:
        ball.reset_position()

Operating the code above will present us what occurs when a paddle misses the ball; the ball would reverse its path and would go to the opposite padlle. Now all that’s left is to create a scoreboard to retailer and show the rating for every participant.

Creating the Scoreboard

To be able to show and replace the rating for every participant, we are going to outline a scoreboard class in a brand new python file. We’ll create the Scoreboard class inheriting from the turtle class, and can outline the attributes that may assist the turtle object to put in writing. First we are going to initialize the 2 attributes, l_score and r_score and set them to 0 initially of the sport. We’ll outline two strategies, l_point and r_point which shall be referred to as at any time when a participant misses the ball, and can enhance the factors of the opposite consumer. We can even outline a way referred to as update_scoreboard(), and name it when a participant scores an extra level. This methodology, when referred to as will merely replace the scoreboard.

Following is the Scoreboard Class creation:

from turtle import Turtle

class Scoreboard(Turtle):
    def __init__(self):
        tremendous().__init__()
        self.coloration("white")
        self.penup()
        self.hideturtle()
        self.l_score = 0
        self.r_score = 0
        self.update_scoreboard()

    def update_scoreboard(self):
        self.clear()
        self.goto(-100, 200)
        self.write(self.l_score, align="middle", font=("Arial", 40, "regular"))
        self.goto(100, 200)
        self.write(self.r_score, align="middle", font=("Arial", 40, "regular"))

    def l_point(self):
        self.l_score += 1
        self.update_scoreboard()

    def r_point(self):
        self.r_score += 1
        self.update_scoreboard()

The update_scoreboard() methodology creates a turtle that writes the rating of each gamers on the primary display. Discover that we’ve used the Turtle module’s write() operate in right here.

Subsequent we are going to import and create a scoreboard object in the primary file, and we are going to use this object to entry its strategies, satisfying the 2 situations: at any time when a participant’s paddle misses the ball, the opposite participant would get some extent.

from scoreboard import Scoreboard

#Initializing Scoreboard Object
scoreboard = Scoreboard()

whereas game_is_on:
    ...
   # Detect Proper Paddle Lacking the Ball
    if ball.xcor() > 380:
        ball.reset_position()
        scoreboard.l_point()

    # Detect Left Paddle Lacking the Ball
    if ball.xcor() < -380:
        ball.reset_position()
        scoreboard.r_point()

That is the place the sport designing and coding involves its finish. Runing the primary python file will generate the sport display and its elements, with the ball shifting as the sport begins. Now you simply must fins a participant to play this recreation with!

You too can change the velocity of the sport via some modifications within the code (that’s so that you can work out!)

Conclusion

On this article, we’ve developed the basic Pong recreation with the assistance of the Python Turtle module. Now we have used the idea of Object Oriented Programming to create courses, initialize attributes and strategies, and from these courses create objects in the primary recreation file. That is an intermediate-level Python undertaking, and if you happen to stumbled upon some a part of the code, be sure to both consult with the Python official documentation or revise your fundamental ideas, notably OOP on this case.