name: world42-shader-terrain-lab description: Evolve and debug World42 terrain and atmosphere shaders safely, including GLSL uniform contracts, Babylon ShaderMaterial bindings, shadow integration, and LOD/UV debug modes. Use when changing files under src/assets/shaders/, src/game_objects/planets/rocky_planet/terrains_shader.ts, atmospheric postprocess code, or when visual artifacts appear in terrain lighting, shadows, or debug LOD rendering.

World42 Shader Terrain Lab

Work from contract to effect: keep GLSL declarations, TS uniform/sampler lists, and runtime set* bindings in sync before tuning visual output.

Workflow

1) Audit shader bindings

Run:

./.codex/skills/world42-shader-terrain-lab/scripts/audit-shader-bindings.ps1

Use it to detect:

• Uniforms declared in GLSL but not declared in TS material/postprocess lists
• Uniforms declared but never set
• Runtime set* calls on names not declared in GLSL
• Sampler mismatches

2) Apply shader changes in lockstep

When adding/removing a uniform or sampler:

• Update GLSL declaration.
• Update TS uniforms/samplers arrays.
• Update runtime set* calls and default values.

Do this for both terrain shader and atmosphere postprocess paths.

3) Verify space assumptions

• Terrain shader local geometry logic remains planet-local (vPosition, uPatchCenter).
• Shadow projection inputs stay render-space (vWorldPosRender + lightMatrix).
• Lighting direction passed from chunk forge stays normalized and local as expected.

4) Validate visual debug modes

• Toggle ChunkTree.debugLODEnabled path and confirm debugLOD branch.
• Keep debugUV branch available for UV diagnostics.
• Recheck shadows after changing normal or world-position paths.

Use references/shader-uniform-contracts.md and references/shader-debug-playbook.md.

Resources

• Script: scripts/audit-shader-bindings.ps1
• Reference: references/shader-uniform-contracts.md
• Reference: references/shader-debug-playbook.md