Depth offset

Hi there. So I'm trying to set up a psudo-3d level where each layer would have a set height in the game. Basically something like this: http://ogrebattlesaga.wikia.com/wiki/Scabellum?file=Scabellum_Map.gif. Right now I'm using layer offsets but it feels really clunky to have to math out the exact pixel offsets each time I add a new layer. I feel like there should definitely be a better way to do this.

I'm thinking each layer could have a depth property and then the map would have a depth offset to automatically determine offsets based on that depth. For example with a depth offset of x=0,y=8 a layer with depth 0 would be at x=0,y=0; depth 1: x=0,y=8; depth 2: x=0,y=16 etc..

With this I could set the default depth offset for the map and for each layer I would only have to assign a single depth value.

The issue names no files, tests, or entry points. Start by tracing how maps and layers currently store and apply layer offsets, then determine where map and layer depth properties would belong. Done means depth values automatically produce the requested offsets without manual pixel calculations.

Written by the indexing model from the issue text.