Fix aliasing artifact in MultiScaleVolumetricObscurance (AmbientOcclusion) #7489
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| #ifdef MSAA | ||
| float2 TestSamplePair(float frontDepth, float2 invRange, uint base, int offset) | ||
| { | ||
| // "Disocclusion" measures the penetration distance of the depth sample within the sphere. | ||
| // Disocclusion < 0 (full occlusion) -> the sample fell in front of the sphere | ||
| // Disocclusion > 1 (no occlusion) -> the sample fell behind the sphere | ||
| float2 disocclusion1 = DepthSamples[base + offset] * invRange - frontDepth; | ||
| float2 disocclusion2 = DepthSamples[base - offset] * invRange - frontDepth; | ||
| float2 disocclusion1 = DepthSamples[base + offset] * invRange - (frontDepth - zBias); |
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frontDepth is related to invThickness of sphere samples, which isn't what we want. Z bias should be done on the screen sample in Main() before invThisDepth is calculated. Remember, thisIdx in Main() is the index of the screen sample where the sphere samples are centered around.
| /// <summary> | ||
| /// Modifies the z-bias to the depth buffer. This eliminates the banding aliasing artifact for MSVO. | ||
| /// </summary> | ||
| [Range(0f, 0.001f), Tooltip("Modifies the bias to the depth buffer for reducing aliasing artifact.")] |
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Change wording to "Add a bias distance to sampled depth in AO to reduce self-shadowing aliasing artifacts."
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Verified fix with customer repro project. Checked Desktop D3D and Vulkan as well as Android. Did a sanity check on URP PP which didn't exhibit any regresssions. Finally, ran through the xr automated end to end test and manually checked a few random other PP effects. Looks good to me.
| @@ -63,5 +63,6 @@ This mode is optimized for consoles and desktop platforms. It has better graphic | |||
| | Mode | Select the type of **Ambient Occlusion** to use. | | |||
| | Intensity | Adjust the degree of darkness **Ambient Occlusion** produces. | | |||
| | Thickness Modifier | Modify the thickness of occluders. This increases dark areas but can introduce dark halos around objects. | | |||
| | Z Bias | Modifies the z-bias to the depth buffer. This eliminates the banding aliasing artifact for MSVO. | | |||
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Also plz update the wording in the doc .md file.
Added pull request : Unity-Technologies/Graphics#7489
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Hi, I see that this change has been approved for about three months, but hasn't been merged in yet. According to LinkedIn, it seems that the original submitter of the PR was an intern at Unity but currently is no longer at Unity. What are the next steps for this to get merged in? This is an important fix as it seems to be related to this bug which is affecting multiple teams (including us) from shipping our games: https://issuetracker.unity3d.com/issues/horizontal-line-artifacts-when-using-ambient-occlusion-with-multi-scale-volumetric-obscurance Thanks! |
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@sebastienlagarde Can we merge this PR to master soon (for postfx V2)? This fix will help several teams @mrtenda |
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Looks like postprocess test are broken :( . Not related to this PR |
Please read the Contributing guide before making a PR.
Checklist for PR maker
need-backport-*label. After you backport the PR, the label changes tobackported-*.CHANGELOG.mdfile.Purpose of this PR
Fixes for the FogBugz case in Multi Scale Ambient Occlusion where there exists banding and aliasing artifacts when applying the post-processing. This fix adds a configurable parameter Z Bias in the MSVO UI settings and eliminates the banding artifact.
Testing status
Tested manually against FogBugz case on Windows
Comments to reviewers