Create a Python game for the Raspberry Pi

If you’re the proud owner of a Raspberry Pi, the visual Scratch language is a great way to take your first steps in programming. But to unlock more of the power and potential of the hardware, take a look at Python.

Python is the default educational programming language for the Raspberry Pi. It’s used around the world as an introductory language for many platforms, thanks to its uncluttered style and easy-to-understand syntax. It isn’t only for beginners, though: according to the TIOBE Programming Community index, Python is the eighth most popular programming language among professional engineers, ahead of Perl, JavaScript and Visual Basic .NET. It’s also free, so it’s easy to see why so many people choose Python as their first scripting language.

In this feature we’ll introduce the key concepts of Python, and show you how to get started with the language by walking you through a sample game written in Python. Then it’s over to you to create your own masterpiece, which you can submit to our Raspberry Pi coding competition.

Getting to know Python

There are two major versions of Python in use. Python 3 is the future, but Python 2 enjoys wider compatibility with existing resources, and it’s this version that’s currently bundled with Raspberry Pi. For this tutorial, we’ll use Python 2.7, the final stable release in the 2.x series: this means we can use the majority of online examples and pre-written code unchanged. When the time comes, moving up to version 3 will be straightforward.

The first thing you may notice about Python is how neat it looks. Those used to PHP, JavaScript or other modern languages will also spot the absence of curly braces, as conventionally used to enclose sections of code. This is because Python uses indentation to organise code. This is good practice in most languages, because it makes code more readable: in Python it’s mandatory. If you don’t get your spacing right, your code won’t work. While this can be a shift for experienced programmers, it becomes natural quickly and leads to clear, intelligible code by default.

Python also makes a good first language because it represents a simple implementation of object-oriented programming – a concept any aspiring coder must understand – and is relaxed about how variables are created and managed. The net result is a particularly productive programming environment.

Python code is usually run through an interpreter rather than being compiled, but despite this, end results are pretty fast. Python applications can run on all major operating systems, so it’s possible to create a Python game on a Windows PC and have it run on a Mac or Linux box – or, indeed, a Raspberry Pi.

A final great strength of Python is the availability of a wide range of add-on modules that bring extra functionality. One such module is Pygame. As its name suggests, Pygame helps you create games using Python: for example, it greatly improves image handling through its Sprite class, makes it easy to control in-game audio, and even allows your game to work with joysticks. Games such as Call of Duty might be beyond its capabilities, but an Angry Birds clone certainly isn’t.

Native and cross-platform development

If you’re running the recommended Debian Squeeze Linux distribution on your Raspberry Pi, Python and Pygame come preinstalled, so you can start programming right away. You can write Python scripts in a text editor, but we suggest you take advantage of the free Geany integrated development environment (IDE) that’s also installed as part of the operating system. This software offers numerous helpful features for programmers, such as automatic syntax colouring, to make your code simpler to read and debug, and a symbol browser to help keep track of all the classes and variables in your code.

As we’ve mentioned, however, Python works across many platforms, so you can write your code on a Windows PC and then move it across to the Raspberry Pi when you’re finished. To do this, you’ll need to install Python 2.7 on your PC. Even if you’re running 64-bit Windows, choose the regular Windows installer, not the x86-64 one, since the standard Pygame installation is 32-bit only.