fix(TerrainBlending): prevent ground artifact shadows

[ParticleTroned]

Issue:
In VR with Terrain Blending, a rectangular ground shadow artifact can appears (not always). The artifact moves with the HMD, is visible in the shadowmask path, and is gone when TB is toggled off. The acrtifact scales with TB’s depth mismatch; lowering the bias removes it while keeping blending stable.

Fix: Decreasing Depth Offset Utility.hlsl to vsout.PositionCS.z += 1.25; I could see no difference in blending on snow, rock etc when using values from 1.5 to 10.

--> I have not tested this extensively in flat! but in principle it should behave the same as VR.

Example: vsout.PositionCS.z += 10;

Example: vsout.PositionCS.z += 5; -> artifact only visible when looking straight down

Example: vsout.PositionCS.z += 1.25; -> artifact not visible anymore in HMD

Summary by CodeRabbit

• Bug Fixes
  • Adjusted depth offset calculations to enhance rendering accuracy in shadow mapping and VR scenarios.

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[coderabbitai]

📝 Walkthrough

Walkthrough

This PR adjusts a depth offset constant in the Utility shader file from 5.0 to 1.25, affecting depth bias calculations when the OFFSET_DEPTH preprocessor directive is defined.

Changes

Cohort / File(s)	Summary
Shader Depth Bias package/Shaders/Utility.hlsl	Reduced depth offset value from 5.0 to 1.25 in the OFFSET_DEPTH conditional code path, adjusting z-position bias for depth calculations.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~5 minutes

Possibly related PRs

• doodlum/skyrim-community-shaders#1771: Modifies the same OFFSET_DEPTH code path in package/Shaders/Utility.hlsl, adjusting depth-bias offset calculations.

Suggested reviewers

• alandtse
• doodlum

Poem

🐰 A whisker-deep adjustment, so small yet precise,
From five-point-oh down to one-point-two-five's nice,
The shadows now shimmer with quantum delight,
As depth takes a softer, more subtle bite! ✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Title check	✅ Passed	The title describes the main change—reducing depth offset to prevent ground artifact shadows in terrain blending—which aligns with the PR's primary objective of fixing VR shadow artifacts.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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[github-actions]

Using provided base ref: e9462c2
Using base ref: e9462c2
Base commit date: 2026-01-30T00:39:41-08:00 (Friday, January 30, 2026 12:39 AM)
No actionable suggestions for changed features.

[github-actions]

✅ A pre-release build is available for this PR:
Download

[alandtse]

Please get some testers to confirm vr and flat. You can just point to the PR pre-release that was built.

[doodlum]

not a real fix