Decals mapped to custom geometry?

[Nick]

The issue with this approach is that it doesn’t work with normal maps at all.

I actually tried this solution much earlier and posted results in this thread showing the issue

@Z-enzyme;326232

I’m doing more less same thing but with no overlapping faces and masked textures - that’s because masked is very expensive for mobile. Let me explain:
I’m using something called Mesh Trim. It’s not adding another layer of faces on top of other faces with alpha channel. The parts that should have this “decal” effect are actually a part of the mesh.

Then I’m using 2 UV channels to map both, I don’t bother with the 1st one much:

But the second - here comes the trimming magic:

This way I can create nice trims for mobile devices as well - one mask based material is much cheaper then alpha material, and you don’t get Z-pass artifacts on low end devices.

But that’s just a different kind of story, as it serves a bit other purposes.