Architecture Redux

I’ve mentioned the game’s architecture before, but understanding it helps answer some common questions, so I thought I’d draw a picture.

The game has three main divisions. In the original version, different developers were more or less responsible for each.

The user interface (the 50 or so screens and dialogs) were created for the Windows and Macintoshes of the day (that day being somewhere between 1997, when we started the project, and 1999, when it was released). We used mTropolis, a powerful multimedia development system that was discontinued over a year before the game came out.

The interactive scenes (and news) were coded in OSL (the Opal Scripting Language, or the Opal Scene Language).

The game engine, written in C++, executed the OSL code, ran the economic model (tracking cows and the effects of treasures on them), and was responsible for saving the game. It was cross-platform, running equally well on Mac OS and Windows.

When we created a new version for iOS, the basic game code and the scenes didn’t need radical change. Both were enhanced (for example, the game had more advice and supported 7 new treasures, and there were 28 new scenes) but existing code continued to work. By contrast, none of the user interface code could be used. Not that it would have mattered much, the small touch screen needed a new user interface anyway. This was a very substantial effort, and it ended up being partly duplicated for iPad and again for the 4 inch display.

There are numbers in the diagram because they suggest why the iOS version is distinct from anything else. Saved games assume a specific number of scenes and treasures. Adding more would mean substantial reworking of the C++ code. But this code had to work with mTropolis, so it’s tied to 1998 era systems. The hardware and compilers I used back then are long gone.

So that’s why the GOG Windows version can’t be updated.

Some have asked about a new Windows or Mac version, or an Android version. Since mTropolis no longer exists and UIKit is iOS-specific, any version for any other platform will require reworking the user interface (possibly with some redesign, definitely a brand new implementation). Think of it was rewriting a third of the game.

The first iOS release took about 20 calendar months. Since the C++ code didn’t need significant updating, the user interface could thus be said to be about half the code needed for that project.

Actually, there was some new C++ code, because we wanted to add Game Center achievements. Most of this would work on Mac OS X, but not on other platforms.

So unlike the original version, where it was trivial to build for both Mac and Windows, there’s a daunting amount of work to bring the game to another platform.

What we’ve done instead is reflected in those numbers: reworking the 50 screens for iPad (and soon the iPhone 5). And adding new treasures and new scenes in an update we hope to release this month.