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Won't Fix

Under Consideration for 2022.3.X

Votes

0

Found in

2021.3.21f1

2022.3.18f1

2023.2.0a6

2023.3.0a3

6000.0.0b11

Issue ID

UUM-30368

Regression

No

[URP/HDRP] Decals have artefacts along geometry edges when mipmapped

-

Reproduction steps:

1. Open the user’s attached project "URP Beta.zip"
2. Select Assets > Textures > “Decal.png”
3. Enable “Generate Minimap”
4. Press Apply in the Inspector
5. Observe Scene View

Expected result: Decal is rendered without artefacts
Actual result: Decal is rendered with artefacts

Reproduced with: 2021.3.21f1, 2022.2.11f1, 2023.1.0b8, 2023.2.0a6
Could not test with: 2020.3.46f1 (Due to errors)

Reproducible on: macOS 13.2.1 (Intel), Windows 11 (by user)

Note: Issue reproducible in Editor and Player mode

  1. Resolution Note:

    From the description and screenshots I suspect this is the problem: There's a fundamental issue with projected screen-space decals where texture coordinate derivatives have high values at geometry borders due to the depth discontinuity, which ends up sampling low resolution mips at geometry borders causing the artifact. There's no proper fix for this but I "fixed" (or rather reduced) the issue in HDRP on emissive decals some time ago, with manual LOD calculation and clamping the LOD with depth derivatives (DecalData.hlsl, line ~35). Here's some details about the fundamental issue: https://bartwronski.com/2015/03/12/fixing-screen-space-deferred-decals/

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