Sky Environment Parity Implementation Plan

Prompt file imported from akspa0/parp-tools (.codex/prompts/sky-environment-parity-implementation-plan.md). Copyright stays with the author.

Implement the skybox and environment parity slice in gillijimproject_refactor/src/MdxViewer after material and lighting work have established a more trustworthy base scene.

Read First

1. gillijimproject_refactor/memory-bank/activeContext.md
2. gillijimproject_refactor/memory-bank/progress.md
3. gillijimproject_refactor/memory-bank/data-paths.md
4. gillijimproject_refactor/src/MdxViewer/memory-bank/activeContext.md
5. gillijimproject_refactor/src/MdxViewer/Terrain/WorldScene.cs
6. gillijimproject_refactor/src/MdxViewer/Rendering/SkyDomeRenderer.cs
7. gillijimproject_refactor/src/MdxViewer/Rendering/ModelRenderer.cs
8. gillijimproject_refactor/src/MdxViewer/Terrain/LightService.cs

Goal

Make skybox, sky backdrop, and environment context believable enough that PM4 object-variant matching is not biased by the current procedural or heuristic sky behavior.

Why This Slice Exists

• The active viewer already has a minimal skybox-backdrop path and a procedural sky dome.
• Those systems are useful recovery steps, but they are still too heuristic-driven for trustworthy final matching.
• Sky/environment parity should be implemented after material and lighting improvements, otherwise visual changes are hard to attribute correctly.

Scope

• In scope:
  • skybox instance detection and selection rules
  • backdrop render ordering and camera anchoring behavior
  • interaction between skybox assets, procedural sky, and lighting-driven sky colors
  • environment context that visibly changes how objects are perceived at distance
• Out of scope unless direct evidence requires it:
  • unrelated model-material fixes
  • speculative weather systems
  • terrain shader rewrites with no clear sky/environment dependency

Non-Negotiable Constraints

• Do not remove the current minimal sky path unless the replacement is ready in the same change set.
• Do not hardcode map-specific sky hacks and call that parity.
• Keep sky/environment behavior tied to decoded runtime data whenever possible.
• Update memory-bank files in the same change set when the sky/environment contract changes.

Required Implementation Order

1. Inventory the current sky pipeline:
   • skybox model detection
   • skybox instance selection
   • RenderSkyboxBackdrop(...)
   • procedural SkyDomeRenderer
   • lighting-driven sky color overrides
2. Identify where the current path is heuristic or contradictory.
3. Decide which source of truth should win in each case:
   • asset skybox
   • lighting-derived sky colors
   • procedural fallback
4. Implement the smallest coherent parity slice that reduces visible contradiction without destabilizing the rest of the scene.
5. Record what still remains heuristic after the change.

Investigation Checklist

• Confirm how skybox-like models are currently classified.
• Confirm whether multiple sky systems are active at once and which one visually dominates.
• Confirm how lighting data currently influences the sky dome and backdrop.
• Distinguish between:
  • missing sky data
  • present data but wrong precedence
  • correct data with wrong render ordering/state

Validation Rules

• Build the changed viewer solution.
• If you do not run runtime validation on real data, say so explicitly.
• If automated tests are not added or run, say so explicitly.
• Do not call sky/environment parity complete if the scene still relies on unresolved heuristic conflicts.

Deliverables

Return all items:

1. exact sky/environment behavior implemented
2. files changed and why
3. which sky/context conflicts were removed
4. what remains heuristic or incomplete
5. build status
6. automated-test status
7. runtime-validation status
8. memory-bank updates made

First Output

Start with:

1. the current sky/environment path in the viewer
2. the biggest contradiction or heuristic currently affecting scene trustworthiness
3. the smallest coherent slice to land first
4. what files will be changed first