Piotr Pluta – portfolio & blog

Every, even most simple game requires some architecture specification. Inspired by Google I/O talk by Chris Pruett, I made up following game application foundations for Android game:

Architecture is based on three threads: main thread created with every Android application, rendering thread and simulation thread. Simulation should keep watch on timer, update game word, calculate physics, AI, etc. Rendering thread draws a frame as frequent as possible, and it’s independent from simulation. If very long draw call is encountered, the simulation wouldn’t have to wait for it to finish and would continue to update itself, ensuring smoother synchronization with rendering.

Rendering thread must be set up with instance of renderer class implementing IRenderer interface. This way renderers can be easily attached to application. I hope we wouldn’t be forced to use anything beside simple Canvas renderer, although if heavier optimization is required, switching to some fancier renderer which uses OpenGL ES to draw textured squares shouldn’t be a problem.

I have already made some prototypes with flying plane, scrolling background and simple enemies. Game runs fine until garbage collector kicks in, and when it does, everything freezes for about 200-400 miliseconds(!). It happens very often, successfully ruining all gameplay. Of course, that prototype was written very casually, but it appears that almost all memory would have to be allocated before actual gameplay to stop garbage collection during it.

As I am digging deeper into Android development, I decided to share some thoughts about it here.

1. Mobile games / Game development

For my point of view (developer and gamer) it is the most interesting part of Android market. I would really wish that more complex games would show up: point and click adventure, RPG or just some shooter with nice controls and graphics. Although I have to admit, many casual games are beautifully polished and they are just pleasure to play (Buka or Jewellust/Devilry Huntress).

I have already spent some time with SDK, and I am aware that writing complex, graphically demanding game is challenging on Android platform. First of all, main there is Java as main programming language. The old programming joke:

“Knock, knock”
“- who’s there?”
…very long pause…
“- Java”

may be funny, but when you write a game on such limited hardware, you suddenly bump into bottlenecks not encountered on other platforms. Excellent talk about Android game development can be found here:
Google I/O 2009 – Writing Real-Time Games for Android. It’s author, Chris Pruett, presents efficent game framework and different rendering methods (Canvas, OpenGL), which I adapted to use with my own project. On the other hand, Mystique is a 3D first person adventure game which overcame platform restrictions. I certainly hope that more games like Mystique would appear on Android market.

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I’m the fresh and happy owner of G1 Android phone. I have chosen it instead of Apple IPhone, because Android is open platform and I have read many dissatisfied IPhone developers complaints about Apple distribution model and objective C language unnecessary complexity. Android advertises it’s SDK as fast and easy, so I had to verify it immediately after unpacking and fully charging my phone. SDK comes with Eclipse plugin, which aids refactoring, debugging, provides class and method stubs etc. Installing it, setting enviroment and connecting your phone is piece of cake. After writing “hello world” application and running it on my phone , I noticed a possibility of using OpenGL ES 1.0 (fixed pipeline). I’m not really familiar with OpenGL API, but I managed to find some code samples showing how to create vertex-colored cube (standard example – not fun to watch anymore). After adding simple touch interface, I’m able to rotate my cube using index finger.

The whole process – setting everything up, going through hello world and adding controls to simple OpenGL ES demo took me around an hour. It is indeed very easy to start developing on Android. I would like to create something more sophisticated now – maybe a game with touch interface. Android store is not overwhelmed by games like Apple store, creating even simple, free game could be nice thing for community.

Result may be not very impressive , but anyway – here’s the screenshot:

If you would like to read more, a nice artice which compares Android and IPhone development can be found here:

Android vs IPhone Development: a comparison

PS. Android also has ASE – Android scripting enviroment that allows you to write simple Python or Lua scripts directly on your phone (preferably by using attached keyboard). Scripts can be used to make phone calls, send messages, poll location from GPS, use text-to-speech module and many more. There is even a guy who wrote automatic garage door opener using ASE – you can read about it on his blog: brad’s life .