Any way to render overlapping transparent triangles "correctly"?

Unity Engine
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1

Hello Community,

am working on some realtime generated mesh deformations and it turns very tricky to acheive that triangles never overlap.
Unfortunately I also need the mesh to be rendered transparent which using the standard shader results in effects like this where the gray is not uniform but has “stripes”:

9741661--1393639--Screenshot 2024-03-31 231149.png
9741661--1393639--Screenshot 2024-03-31 231149.png701×484 156 KB

Is there a way to prevent this via shader? A way to render transparent but just ignore when rendering part of another triangle at the same location (of the same mesh)?

From my limited knowledge on how a shader is actually applied (the gpu is actually never aware of what it has already rendered, right?) the answer is probably no but thought to ask if there’s some genius trick!

Or is there an algorithm available to resolve those overlaps on a mesh level?

Huge thanks in advance :slight_smile:

P.s. using Built-In RP for now.

2

You could probably solve it using one of the various techniques for creating transparent objects that don’t overlap with themselves.

The most basic would be one that does a depth primer pass and then a second pass that draws the object as normal but with depth-testing enabled. There’s also a way to do it with stencils but iirc that’s more to do with avoiding additive blending from multiple different transparent objects. Been a while since I’ve had to do any of this so I’m pretty hazy on the details. For the first technique I think you can just set up a pass that has zwrite enabled and the colormask set to 0 and then do the second pass as normal but with ztesting enabled.