Center on origin?

[mattdm]

It appears that the current code puts the corner of the splat map — that is, the entire terrain — at global 0,0,0. I think it would make sense, instead, to center on 0,0.

Or, perhaps alignment could be configurable? But I think centered-on-origin makes sense generally.

I am not so sure about height — I can see arguments for heightmap 0 = 0, but also heightmap 50% — or some arbitrary level. So that, I think, should be a parameter.

Thoughts?