Tutorial: Creating Flappy Bird Game with Kivy in Python

Flappy Bird is a classic game that became extremely popular on mobile platforms, and it’s a great project to tackle when learning game development with Python and Kivy. Kivy is an open-source Python library for developing multitouch applications, allowing you to create interactive applications and games across multiple platforms.

In this tutorial, we will walk through the process of creating a Flappy Bird game using Python and Kivy. By the end of this tutorial, you will have a working Flappy Bird game that you can run on your computer or mobile device.

Step 1: Install Kivy

The first step in creating a Flappy Bird game with Kivy is to install the Kivy library. You can install Kivy using pip by running the following command:

pip install kivy

If you encounter any issues with the installation, you can refer to the official Kivy documentation for troubleshooting tips.

Step 2: Set up your project structure

To create our Flappy Bird game, we will need to set up a project structure with the following files:

• main.py (the main Python script for our game)
• flappy_bird.kv (the Kivy language file for defining the user interface)
• images folder (containing the images for the game)

Create these files and folders in a new directory for your project.

Step 3: Create the game interface using Kivy language

In the flappy_bird.kv file, we will define the user interface for our game using Kivy language. Here is a basic layout for our game interface:

<RootWidget>:
    canvas.before:
        Rectangle:
            pos: self.pos
            size: self.size
            source: 'images/background.jpg'

    Bird:
        pos: 100, root.height / 2
        size_hint: None, None
        size: 50, 50

    Pipe:
        pos: root.width, 0

In this code snippet, we define a RootWidget that contains a background image and two other widgets: Bird and Pipe. The Bird widget will represent the player’s character, and the Pipe widget will represent the obstacles in the game.

Step 4: Implement the game logic in Python

In the main.py file, we will define the game logic for our Flappy Bird game. Here is a basic outline of the Python script:

import kivy
from kivy.app import App
from kivy.uix.widget import Widget
from kivy.properties import NumericProperty
from kivy.clock import Clock

class RootWidget(Widget):
    pass

class Bird(Widget):
    pass

class Pipe(Widget):
    pass

class FlappyBirdApp(App):
    def build(self):
        pass

if __name__ == '__main__':
    FlappyBirdApp().run()

In this code snippet, we import the necessary modules from Kivy, define the RootWidget, Bird, and Pipe classes, and create the FlappyBirdApp class that will serve as the entry point for our game.

Step 5: Add movement to the Bird widget

To make the Bird widget move up and down in response to player input, we need to add some code to the Bird class in the main.py file. Here is an example of how you can implement movement for the Bird widget:

class Bird(Widget):
    velocity = NumericProperty(0)

    def on_touch_down(self, touch):
        self.velocity = 5

    def on_touch_up(self, touch):
        self.velocity = -5

    def update(self):
        self.y += self.velocity

In this code snippet, we define a velocity property for the Bird widget and use the on_touch_down and on_touch_up methods to change the velocity of the Bird when the player presses or releases the screen. We also define an update method that will be called every frame to update the position of the Bird on the screen.

Step 6: Add collision detection

To detect collisions between the Bird and Pipe widgets, we need to add some code to the Pipe class in the main.py file. Here is an example of how you can implement collision detection:

class Pipe(Widget):
    def check_collision(self, bird):
        if self.collide_widget(bird):
            return True
        return False

In this code snippet, we define a check_collision method in the Pipe class that takes a Bird widget as an argument. We use the collide_widget method to check if there is a collision between the Pipe and Bird widgets, returning True if there is a collision and False otherwise.

Step 7: Update the game loop

To update the game loop and handle collision detection, we need to modify the build method in the FlappyBirdApp class in the main.py file. Here is an example of how you can update the game loop:

class FlappyBirdApp(App):
    def build(self):
        root = RootWidget()

        bird = Bird()
        pipe = Pipe()

        root.add_widget(bird)
        root.add_widget(pipe)

        def update(dt):
            bird.update()
            if pipe.check_collision(bird):
                print("Game Over")

        Clock.schedule_interval(update, 1 / 60)

        return root

In this code snippet, we create instances of the Bird and Pipe widgets, add them to the RootWidget, and define an update function that will be called every frame to update the position of the Bird and check for collisions between the Bird and Pipe.

Step 8: Run the game

To run your Flappy Bird game, you can simply execute the main.py file from the command line:

python main.py

Your game should now launch, and you can start playing Flappy Bird by clicking or tapping on the screen to make the Bird move up and avoid colliding with the pipes.

Conclusion

In this tutorial, we have covered the basics of creating a Flappy Bird game with Python and Kivy. While this tutorial provides a simple implementation, there are many ways to customize and enhance your game, such as adding more obstacles, implementing a scoring system, and creating more complex game mechanics.

I hope this tutorial has inspired you to explore game development with Python and Kivy further and create your own unique games. If you have any questions or run into any issues while following this tutorial, don’t hesitate to reach out to the Kivy community for support and guidance. Happy coding!