fix: fix grass not animating

[doodlum]

Summary by CodeRabbit

• New Features

  • Grass now reacts to wind, adding dynamic movement in both standard and VR modes for improved visual realism.

• Chores

  • Project version updated to 1.4.4.
  • Internal shader cache version updated; shaders may recompile once on first run after the update.

[coderabbitai]

Caution

Review failed

The pull request is closed.

Walkthrough

Project version bumped to 1.4.4 in CMake. Grass vertex shader now applies wind displacement to current and previous positions across lighting and VR/non‑VR paths. Shader cache version incremented to 0.0.0.40.

Changes

Cohort / File(s)	Summary
Versioning updates CMakeLists.txt, src/ShaderCache.h	Increment project VERSION 1.4.3 → 1.4.4; update SHADER_CACHE_VERSION {0,0,0,39} → {0,0,0,40}.
Grass shader wind integration package/Shaders/RunGrass.hlsl	Add CalculateWindDisplacement calls to compute windDisplacement and previousWindDisplacement; apply to msPosition and previousMsPosition (GRASS_LIGHTING and non-GRASS_LIGHTING, VR and non‑VR paths) before projection and previous-world assignments.

Sequence Diagram(s)

sequenceDiagram
  autonumber
  participant VS as Vertex Shader\n(package/Shaders/RunGrass.hlsl)
  participant Wind as Wind calc (CalculateWindDisplacement)
  participant Pipe as GPU Pipeline

  Note over VS: Per-vertex processing (current & previous frame)

  VS->>Wind: CalculateWindDisplacement(WindTimer)
  Wind-->>VS: windDisplacement

  VS->>Wind: CalculateWindDisplacement(PreviousWindTimer)
  Wind-->>VS: previousWindDisplacement

  Note over VS: Apply displacements to msPosition & previousMsPosition\n(before projection / previous-world assignment)

  VS->>Pipe: Emit transformed position + previous position (for projection/motion vectors)

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Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• chore: bump to 1.3.4 #1358 — similar CMake VERSION bump in CMakeLists.txt.
• chore: bump to 1.3.3 #1354 — another project version bump touching CMakeLists.txt.

Suggested reviewers

• jiayev

Poem

I twitch my ears at version’s chime,
1.4.4 hops into time.
Grass leans into a windy song,
frames remember where they belong.
Cache ticks up — a quick little score. 🐇🌿

Pre-merge checks and finishing touches

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title Check	✅ Passed	The title succinctly conveys that this pull request addresses the grass animation issue by fixing the lack of wind displacement and clearly reflects the primary intent without extraneous details.
Docstring Coverage	✅ Passed	No functions found in the changes. Docstring coverage check skipped.

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Reviewing files that changed from the base of the PR and between 6f45554 and 9efc94c.

📒 Files selected for processing (1)

• package/Shaders/RunGrass.hlsl (4 hunks)

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[github-actions]

Using provided base ref: 337da72
Using base ref: 337da72
Base commit date: 2025-10-06T15:54:04+01:00 (Monday, October 06, 2025 03:54 PM)
No actionable suggestions for changed features.

[coderabbitai]

Actionable comments posted: 1

📜 Review details

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 337da72 and 6f45554.

📒 Files selected for processing (3)

• CMakeLists.txt (1 hunks)
• package/Shaders/RunGrass.hlsl (4 hunks)
• src/ShaderCache.h (1 hunks)

🧰 Additional context used

📓 Path-based instructions (2)

**/*.{cpp,cxx,cc,c,h,hpp,hxx,hlsl,hlsli,fx,fxh,py}

📄 CodeRabbit inference engine (.github/copilot-instructions.md)

Do not include TODO/FIXME placeholders; provide complete, working solutions

Files:

• package/Shaders/RunGrass.hlsl
• src/ShaderCache.h

src/**/*.{cpp,cxx,cc,h,hpp,hxx}

📄 CodeRabbit inference engine (.github/copilot-instructions.md)

src/**/*.{cpp,cxx,cc,h,hpp,hxx}: Ensure SE/AE/VR runtime compatibility; use runtime detection patterns (e.g., REL::RelocateMember())
Include robust error handling and resource management with graceful degradation in the plugin code

Files:

• src/ShaderCache.h

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• GitHub Check: Build plugin and addons
• GitHub Check: Validate shader compilation (VR, .github/configs/shader-validation-vr.yaml)
• GitHub Check: Validate shader compilation (Flatrim, .github/configs/shader-validation.yaml)

🔇 Additional comments (5)

src/ShaderCache.h (1)

6-6: LGTM! Shader cache version bump is appropriate.

The shader cache version increment aligns with the grass shader modifications in this PR, ensuring that cached shaders are properly invalidated and recompiled.

CMakeLists.txt (1)

5-5: LGTM! Project version bump is appropriate.

The patch version increment from 1.4.3 to 1.4.4 correctly reflects a bug fix release addressing grass animation issues.

package/Shaders/RunGrass.hlsl (3)

144-157: LGTM! Wind displacement calculation is well-structured.

The function correctly computes procedural wind displacement using trigonometric functions, per-instance variation, and vertex color alpha for wind intensity. The approach is sound for creating natural-looking grass animation.

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200-201: LGTM! Current position wind displacement is correctly implemented.

The wind displacement for the current frame is properly calculated using WindTimer and applied to msPosition after collision displacement, ensuring correct rendering order.

Also applies to: 209-209

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274-275: LGTM! Non-GRASS_LIGHTING path wind displacement is correctly implemented.

The wind displacement logic is properly implemented with:

• Correct timer usage for current (WindTimer) and previous (PreviousWindTimer) frames
• Proper application of windDisplacement to current position
• Proper application of previousWindDisplacement to previous position

This ensures accurate motion vectors and temporal effects.

Also applies to: 283-283, 331-331

[github-actions]

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