Improve feedback when using Wang tiles

[bjorn]

Feedback from @therahedwig:

When a wang tile transition won't draw because it is missing, could we maybe get some feedback about which one is missing? Like, in the overlay somehow?

Because I am puzzling which one is missing here(it tries to draw grass...)

Maybe @Bdtrotte could comment on the general possibility of this request. I think in general it isn't the case that there is a single Wang ID missing, but maybe this doesn't matter?

[therahedwig]

Well, the status bar tells us there is a wang tile missing in this situation.

[bjorn]

@therahedwig Yes, but there can be multiple options, depending on the neighboring tiles. But I think it could render the colors of the first or last one it tried.

[Bdtrotte]

@bjorn If I remember correctly, that's not quite how it works: it checks all the surrounding tiles to build a desired wangId, then checks if it exists. You'd then have to go back through and change each corner/edge (probably with wild) and see if that exists. This could end up being non trivial, but I'm not sure...

[Bdtrotte]

Pretty scarce for time now, but I'll try to find some time to look at this and the other issues/improvements, and at least pitch in ideas