ZDoom

Just like 3D Models have a ZOffset property, Voxels also need one. It's not like we are gonna open Slab6 to modify a Voxel every time we want to change the offsets, so shifting the ofsets via a property would be a good idea.

This needs some input how to implement in the refactored software renderer. The rest should be simple.

If we are talking about adding a value to the Z position of the voxel, then I think this is done in RenderVoxel::Project (r_voxel.cpp) by adding something to the 'pos' variable before it is stored in the vis object.

There's a line in there already saying this: "pos.Z -= thing->Floorclip". I'm assuming this is just another line added right after that.

Is this offset in world space or model space? If it needs to be in model space, then voxels already got a Pivot member. Implementing it in model space is probably a question of finding the places where Pivot is accessed in that file and add the new offset to the variable it copies Pivot.Z to.

It needs to be added to the pivot, but I do not want to touch this before the merge so it got moved to 'on hold'.