Yeah, I design the walls/floor layer first.
The cut and paste that it to make another layer and then add the other stuff.
It works pretty well, but the layer idea is not my own, I saw it on the net somewhere.
My ultimate goal...make a highly configurable game, maps, objects, details, etc all from one simple text file.
I may create a "layer editor" at some point that creates that TXT file for you...but that's not fun for me right now
Seriously, a simple level layer 1 would look like this
W=Wall F=Floor
WWWWWWWWWW
WFFFFFWFFFFFFFFW
WFFFFFWFFFFFFFFW
WFFFFFFFFFFFFFFFW
WWWWWWWWWW
Then I'll cut paste and remove an F and add a detail "B" bush "T" Tree or whatever.
Same with the other layers, they all start out as a cut/paste of layer 1.
All that layer data is stored in a 3 Dimensional Array called MapData()
So it's easy to take my X,Y Character's map position, and index into the array and to the various layers in that array.