Exult Forum

The file numbering of the --buildmap option is now in sync with the U7IFIXnn and U7IREGnn (thanks Wjp). This way you can quickly match them, for example with the charts at http://exult.info/studio.php#ifix_iregs .
Previously the file numbering went from top to bottom and left to right and only numbered to hex b (0,1,2,3...9,a,b) instead of up to f.
Now it numbers left to right and top to bottom.
This will break all automatic stitching of the map files to a complete map.
I hope I'm not hurting anyone too much with that

Does this mean 16x16 worlds are now possible?

No
The buildmap option only screenshots the 144 terrains as pcx graphic files

PCX? Did 1993 call us back?

What's the purpose of the --buildmap option?

It allows full resolution screenshots of the 144 terrains which you can stitch together as one big file (each terrain has 2048x2048 pixels so that makes one very bigfile). This can be done by batch processing with some graphic programs.
For example the big screenshot of my Castleton mod was done via buildmap (you need to use --mapnum as well). Much easier than doing the screenshots in game and then stitching it together.

And yes pcx is an ancient, almost forgotten format
No one has upgraded our backend to allow for png screenshots yet

Old file formats like pcx and tga are very simple which makes writing an export function exceedingly easy. You don't even need any external code really. Pretty much just write the header and then the image data.

Even though PNG has it's own standard library, libpng, because it exposes completely functionality of the file format, doing simple things like just writing an image, can be a bit more complicated than you'd think. Also the fact that another library dependency would need to be added to exult can be a slight hold back. Typically we've avoided requiring much else other than sdl.