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Won't Fix
Won't Fix in 6000.0.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
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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/
Resolution Note (6000.0.X):
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/