Thursday, March 09, 2006

apt.dat - a fundamental shift

Long time no post - it's been a busy few weeks, helping friends with projects and traveling. There have been some lively discussions on the scenery list though!

I've been tossing around the idea for a fundamental change in the way the apt.dat format handles metadata. It's subtle but I think it has some far-reaching implications.

Right now the apt.dat format is pretty high level. Let's use taxiways as an example: a taxiway has a light code that indicates whether the taxiway has blue edge lights. This has two effects:
1. The information about whether the taxiway has lights is preserved.
2. You can't put blue edge lights down without a taxiway.

I am exploring the idea of entirely separating edge-lights/lines* from taxiways. This would mean that:
1. We'd have no idea about whether the taxiway has lights. There may happen to be lights nearby, but we can't be sure of where they come from and
2. We can put lights anywhere.

The shift is fundamental because it is reducing the amount of high level data and increasing file size in return for gaining flexibility with a simple system.

Anyway, email me if you have thoughts on for thought.

* The exception will be runways. We will be supporting all existing data in the apt.dat format - nothing's geting dropped, and there isn't a real replacement for runways. Generally runways will still be built by saying "this is a runway and these are it's many properties" and letting the sim do the rest.


Joshwa said...

oh taxilines please!!!

CATTilley said...

I agree. Taxilines are a necessity. I wouldn't mind seeing taxiway signs as well. Beggers can't be choosers, but there's gotta be a way to do this in an efficient manner. I have a question about memory. If i buy a 64 bit cpu and operating system, does that fix the 1gb file size limitation? I've got 2gb of ram with my current 32 bit windows system, but as the xplane executable gets larger than 1gb x-plane notifies me of the limitation. Just curious

Benjamin Supnik said...

Sorry, 64 bit OS doesn't raise x-plane's virtual memory limit; you'll need a 64 bit executable for that, which we do not yet provide.