This is an entry for the Kivy game design competition (Jan 31st 2011).

It is hugely inspired by Achtung Die Kurve, the classic 1990s game that I had played as a kid, and Tron - the movie with its futuristic graphics. I have named this app as Kron, short for Kivy + Tron :)

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By no means is this piece of software a finished piece. I was pretty crunched for time when I decided to enter the game design competition, so I couldn't honour many Python idioms when coding this up. Forget Python idioms, to get stuff working at times I chose to overrule many basic OOP concepts as I had recently learnt them up and didn't have the luxury of implementing them out due to lack of time.

At people who have been directed to this project to learn about Kivy,the framework, I suggest you wait for a couple of weeks by when I shall refactor this code to make it easy to understand and maintain. Kivy is quite beautifully designed and I wouldn't want you to be scared by this code :P

Some specific details about the code:

• The entire app was squarely aimed at Tablets with multitouch played in a landscape format. It plays just fine on a PC, but you will miss the horizontally aligned 'winner screens' that I have designed for best use on a tablet.

• The screen resolution I have used throughout this project is 1280 X 736. (736 is used instead of 800 to give way for the menubar in most Operating Systems).I tried very hard to implement it using the 'auto' resolution mode in Kivy Config, but it simply wouldn't work. So I had to hardcode the most common tablet res into the app.

• I have used kivy.core.audio for playing a catchy track during the game. While this runs smoothly on my Ubuntu machine, the App force closed on an android tablet. So if you are trying this on Android, do comment out the sections by searching for "audio android" in main.py

• I had a nice time figuring out the algorithm to detect collisions in what appears to be a simple game at first sight. I went from an

  • O(n^2) implementation ( I was checking each point on snake1 with each point on snake2)

  • to an O(n) implementation which was horribly innacurate(It used to check for occupied areas around a bounding box near each snake's head)

  • To finally maintain a central boolean array of occupied places. This is so simple and efficient and remains so, even when I add more snakes into the game.I should probably admit that Stack Overflow nudged me in this direction. Also python must have a O(log n) complexity look up a particular index of a 1D array. So,my algo has the same complexity. :)

    I would never have had this flexibility and agility in core logic in any other language than Python.

• The right and left turns in the game are with respect to the current direction of snake. It takes some time to get used to this, especially when the snake is going reverse.

• I wish I made more use of the .kv file and the instant updation that it offers.

The road ahead/My To-do:

More game features:

• Smooth turns instead of right angled turns. : This can be implemented this instant with a suitable value in Vector.rotate method, but I found that the gameplay suffered due to some some restrictions in the button press events.I need to read more into Button state and how to account for it from the Kivy Docs)
• Add options in the main menu to increase or decrease the difficulty. : This is accomplished by faster and slower velocities of the snakes respectively)
• Add more spice to the game canvas by introducing speed-up collectibles, snake length-reducers and other usual arcade game items :)
• Support 4 players : This can also be implemented in just a couple of hours as the collision detection mechanism remains the same. Just 2 new objects need to be created.
• Graphics need a major overhaul. : This will take time as I need to read about them first.

Better code :

• Implement basic polymorphism in some critical parts of the code : For e.g currently there are 2 methods move1 and move2 for each snake :|

• Like I mentioned before, I need to use the .kv paradigm more. A lot of time and callbacks can be saved

• Implement auto resolution : Try as much as I did, I couldn't get the size_hint and pos_hint working. Need to ask the kivy_support group for help.

Other stuff :

• Contribute to Kivy! : There was no way in the world that I could have coded up a fully functional app(albeit without audio), which runs on all major platforms, and is written in the most awesome language there is : Python, without Kivy. 'nuff said. :)
• Publish in the android market
• Write a blog post detailing all your 'aha!' moments and what you thought was missing from the (pretty comprehensive) documentation. : e.g : Using FloatLayout as the start screen and the root widget was a definite Aha! moment. I struggled around for hours trying how to invoke different screens and then I stumbled across FloatLayout in one of the test apps.
• Research up a proper software licence for this project.

Credits

• The music track is Daft Punk's "Derezzed". (Great music!)
• Most of the images I have used in the game are from free wallpapers released around the movie Tron.