Depth priming breaks depth write

Unity Engine
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1

I’m trying to make an object render behind everything else regardless of its distance from the camera. It should only display over the skybox.

This should be possible by disabling depth write/z write on the material, which I was able to do with a custom shader graph based shader.

However, I found this only works if I disable depth priming in the URP renderer settings. It seems depth priming ignores depth write disabling and the depth test condition, and possibly also the render queue.

Unity editor version 2022.3.15f1.

2

Hi, have you tried changing the surface type to “Transparent” in your custom shader graph? Transparent objects won’t be affected by depth priming.

Depth priming (also called depth pre-pass) disables depth write and forces the depth test to “Equal” to reduce overdraw of opaque objects.

3

I am still trying to figure out how to make something render behind everything else but still on top of the skybox. Ideally I could also render it after everything else, in order to avoid overdraw.

This basically means I have to figure out how to draw something only if the z buffer is unset at that pixel (also not sure what unset would be in this case).

I also don’t understand why Unity engineers don’t grey out settings that end up being overridden when some other feature is enabled. I see this being overlooked quite often :frowning: