Coding the Pong Game from Scratch in Python

is likely one of the earliest and most iconic video games within the historical past of digital leisure. In its traditional type, 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 provide a degree to the alternative participant.

The historical past of the sport is considerably fascinating. The Pong sport was created and written by Allan Alcom as a take a look at when he was recruited by Atari. This sport then grew to become 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 individuals would put in, in order that ultimately the bars and pubs’ house owners needed to name Atari to repair their machines!

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

Understanding the Venture

There are a selection of how we are able to code this sport. We will use the simple methodology and do every process step-by-step with the mandatory repetitions, or we are able to use Python’s Object Oriented Programming strategy to escapre the repetition and have a neat and arranged code. We are going to choose the second possibility as this could make the sport’s program extra systematic and fewer messy!

We are going to use Python’s Turtle module for the visible sport growth. The turtle module is a built-in performance that enables one to visulalize code in a simple method. It mainly consists of a turtle that’s drawing shapes and contours because it strikes throughout the display based on the coder’s directions. It’s a highly effective instrument to create beginner-level video games, and get immediate suggestions by a visible display.

The next are the important thing duties that we are going to strategy in an orderly method:

1. Creating the Sport Display – that is the display on which the Pong sport might be displayed
2. Creating the Paddle & Paddle Class – that is the code that can 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 strategy, we are going to create a generic ball class after which create the ball that can transfer throughout the display, we will even outline its related strategies
4. Detecting Collision of Ball with Prime/Backside Wall -this is the piece of code that can detect collision with the higher and decrease partitions, and if collision happens, it’s going to make the ball bounce throughout the y-axis
5. Detecting Collision with Paddle – that is the piece of code that can detect whether or not the ball collides with the paddle. If sure, it’s going to make the ball bounce; else, if the paddles misses the ball, it’s going to give a rating to the alternative 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 sport file.

Creating the Sport Display

The primary process is to create the sport display. This display might be rectangular in form, as in the actual sport. We are going to 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 peak of 600px utilizing the Display class setup() methodology. We are going to set the background shade to black utilizing the bgcolor() methodology, and identify the display as “Pong Sport” utilizing the title() methodology. Under is the code, the place we’ve got created the display object:

from turtle import Turtle, Display

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


display.exitonclick()

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

When you discover any confusion within the above strategies, be happy to take a look at the official documentation of the Turtle Module from here.

Following is the output as we run this system:

Creating the Paddle & Paddle Class

The subsequent process is to create a paddle, which is a rectangular-shaped object at each side of the Sport Display. We are going to create this paddle utilizing the turtle module’s form() operate, and customise it to be white in shade utilizing the shade() methodology, and use the shapesize() methodology to customize it to have a width of 20px and a peak of 100px. Discover that we’ve got handed 5 and 1 because the arguments to the shapesize() methodology. It is because the shapesize() will not be in pixels, however in reference to a base of 20px. So to get a size of 100px, we are going to go 5 (as 20px x 5 = 100px). Furthermore, we are going to place it such that firstly 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 (bear in mind our display is 800px broad). We are going to 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.shade("white")
paddle.shapesize(5,1)
paddle.penup()
paddle.goto(350,0)

The next is the output of the above code. We will see a paddle created on the Sport Display on the proper facet, with none turtle hint.

Operating the above code will create the paddle. Nonetheless, we are able to 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 will 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 got 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 specific key’s pressed. We are going to thus outline the go_up and go_down capabilities that can 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 got 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 got created the paddle and configured the mechanism of its motion, allow us to now shift our code to Object Oriented Programming Strategy. It is because we are going to want 2 paddles for the sport, and having a generic blueprint that creates paddles immediately will make our process simpler. We are going to refactor our code to create one other paddle simply. We are going to 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 could have completely 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 exchange 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.shade("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 got additionally outlined the 2 strategies of Paddle class. One is the upward motion and the second is the downward motion that we’ve got 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 Sport

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 can proceed to run till externally stopped, or when the situation of the loop turns to False.

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

Now, while you run the primary file, you will notice the sport display and paddles created, and the flexibility of the paddles to maneuver.

Create the Ball Class & Objects

Now persevering with on our OOP strategy to code this sport, we are going to create the Ball class because the generic blueprint and create the ball object from it in our important Python file. We are going to create the ball as a turtle object, by making the Ball class inherit from the tremendous class Turtle. We are going to use the turtle class’s strategies shade() and form() to initialize a ball of white shade 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.shade("white")
        self.form("circle")
        self.penup()

Now that our ball’s attributes are outlined, we will even create the ball’s strategies of transferring 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, it will likely be transferring in the appropriate route first. In our important 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 way in which 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 are going to 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 are going to add this methodology of the ball object to be referred to as inside the sport’s whereas loop:

#Sport 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 will resume the animation by commenting out the display.tracer() traces and rerunning the code. We are going to now see the two paddles and the ball being created and moved.

One other method 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
#Sport 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 are able to 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 needs to be caught by the left and proper paddles. If the ball will not be caught, it will imply the opposite participant scores a degree.

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

from turtle import Turtle

class Ball(Turtle):

    def __init__(self):
        tremendous().__init__()
        self.shade("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 got 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 got 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’s going to transfer in the other way to its earlier y place. This merely signifies 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 unfavourable quantity would imply the ball is transferring 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 got 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 by 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 are going to make use of a similiar methodology as earlier than, besides that now we’re speaking in regards to the x-axis.

The traditional method 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 certain quantity, we are able to conclude that the two have touched/collided. Nonetheless, 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 fluctuate 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 will add one other situation which might test 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 should have made contact. We are going to add this situation to the primary whereas loop. As soon as the collision is detected, we could have the ball bounce, however this time within the x-direction. Allow us to redefine our bounce capabilities so we’ve got 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()

Notice, we’ve got 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 a degree, and the sport restarts with the ball within the centre. To be able to test if the ball is missed by the paddle, we are able to 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 truly 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 is able to imply we are going to reset the ball to the beginning place on the centre worth (0,0). We are going to outline a reset_position() methodology of the ball that might be referred to as when the above situation is met. Furthermore, we will even add a characteristic that can reverse the ball’s route, so as a substitute of going to the appropriate, it’s going to 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 route because it did when it will bounce off a paddle. Placing these situations within the sport’s important 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 route 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 are going to create the Scoreboard class inheriting from the turtle class, and can outline the attributes that can assist the turtle object to jot down. First we are going to initialize the 2 attributes, l_score and r_score and set them to 0 firstly of the sport. We are going to outline two strategies, l_point and r_point which might be referred to as at any time when a participant misses the ball, and can enhance the factors of the opposite consumer. We will 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.shade("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="heart", font=("Arial", 40, "regular"))
        self.goto(100, 200)
        self.write(self.r_score, align="heart", 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 got 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 a degree.

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 parts, with the ball transferring as the sport begins. Now you simply must fins a participant to play this sport with!

You can too change the velocity of the sport by some adjustments within the code (that’s so that you can determine!)

Conclusion

On this article, we’ve got developed the traditional Pong sport with the assistance of the Python Turtle module. We have now used the idea of Object Oriented Programming to create lessons, initialize attributes and strategies, and from these lessons create objects in the primary sport file. That is an intermediate-level Python mission, and if you happen to stumbled upon some a part of the code, make sure that to both check with the Python official documentation or revise your fundamental ideas, significantly OOP on this case.