Translucent Water Material - Displacement Banding Issue

[anonymous_user_0df12f74]

@The Beej;154271

is probably caused by the fact that transparent materials don’t write to the depth buffer. means that when a closer wave is occluding a further wave, which one ends up on top depends on the order in which the GPU renders them. Fixing is harder than it should be because Unreal doesn’t seem to have a depth only material domain and it doesn’t write custom depth for meshes with transparent materials. So you’ll need to make a few things: an opaque material that does your wave vertex displacement only, and a blueprint that has an extra ocean mesh component placed exactly on top of the original component, and a few extra nodes in your current ocean material. On the extra mesh, you want to use the opaque vertex displacement only material, mark it Render Custom Depth, and not Render in Main Pass. will write your oceans mesh into the custom depth buffer. Now in your normal transparent ocean material, add these nodes to depth test against the custom depth buffer:

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Note that depth test is far from perfect but it should be good enough for what you need.

First of all, thank you for taking the time to create an example for me. Even better is the fact your method worked first try!

I have put together the 2 planes in a BP that I was working on (all parameters are adjustable from the BP) with a trimmed down version of the material, and everything worked as expected. I had to adjust the Custom node’s formula a bit however, as using .999 caused the ocean to disappear at the far end when zoomed out, with the boundary between giving off a lot of noise and flickering. Is there a minimum level you can recommend for value? I have pulled it down to .8 and the goes away without affecting the wave depth test.

The only concern I have with is the performance, I have noticed a fps reduction (basic 2k landscape, GTX 660 ti) from ~80 to ~70 fps, most of that is likely from using 2 planes, but how much performance concern is there for using a SceneTexture, is it similar to using a RenderTarget performance wise?

Thank you very much for your help on , I thought it had something to do with rendering order but did not know how to fix it.

**Edit - One last question, with method when using the Two Sided material setting, everything falls apart, and the banding becomes extreme. Is there a method aside from duplicating the meshes underneath to get around ?