[kitlangton]

What it does. Adds per-light indirect lightmaps (128×128×4 rgb9e5ufloat texture array) and a 4×2×4 3D L1 spherical-harmonics probe grid (packages/kit/gpu/gi/lightmap.ts) baked with headless Blender 5.2 Cycles (scripts/bake-room.py), plus a canopy sky-openness baker (bakeCanopyOpenness) for forests. No game turns it on by default; to see it, open the Lab world preset Baked indirect GI (Cycles) (?preset=baked-gi).

How it works.

1. extractBakeSceneSpec exports the room's packed mesh and physical SceneLight fixtures to scripts/house-bake-scene.json with a SHA-256 input hash (00d64d3e69a5aa26..., verified by assertBakedLightmapFresh).
2. scripts/bake-room.py imports those triangles and emitters into headless Blender 5.2.2 LTS, unwraps UV2 islands with bpy.ops.uv.lightmap_pack(PREF_BOX_DIV=64, PREF_MARGIN_DIV=0.10), and bakes 3-bounce indirect diffuse light (384 samples, use_adaptive_sampling = False, island-clamped despiking and 4-pass separable binomial smoothing) at unit reference power (energy = 4π · P for spot/point, π · P for cosine AREA panels, multiplied by ENGINE_LIGHT_GAIN = 5.0 in WGSL with zero fudge factor; 0.04% vs closed-form analyticSpotFloorBounce).
3. At runtime, evaluateBakedLightWeights scales each light layer and probe strictly linearly by (livePower / bakedPower) * giIntensity (returning 0 immediately when a LiveBounceSource such as screenBounceSource is off). Static lightmapped surfaces sample only the UV2 lightmap array; dynamic objects (MAT.actor) sample only the trilinear L1 SH probe volume.

Risk. Kit, Lab world, scripts and docs only. bakedRoom and the :baked renderer variant in packages/kit/lab/world/world.ts are gated on giMode === "baked". Verified by hashing the compiled scene shaders of every game and every non-baked-gi Lab preset plus the Lab world's static mesh bytes against origin/main (b566ecf0):

Target	origin/main (b566ecf0)	kit-lightmaps	Status
kit: sceneShader(true, false) (Brawl / Blackout / Getaway / Carrier)	3a519e694b51a728	3a519e694b51a728	Identical
kit: sceneShader(false, false) (Renderer baseline)	9d6b6514cf214e3c	9d6b6514cf214e3c	Identical
kit: sceneShader(true, true) (Renderer motion)	89cf8b6c89a1492b	89cf8b6c89a1492b	Identical
kit: makeSceneShader({}, false, false)	5a939988fe356741	5a939988fe356741	Identical
game: Outbreak town scene (shaders.scene)	0aaef9e108110742	0aaef9e108110742	Identical
game: Outbreak vignette scene (vignetteShaders.scene)	bf78443910bd56de	bf78443910bd56de	Identical
game: BARBARA forest scene (forestHooks + treeVertex + cutoutDepth)	9a0de263cba56c04	9a0de263cba56c04	Identical
game: BARBARA batch scene (batchHooks)	7a37736025481bf2	7a37736025481bf2	Identical
game: BARBARA moonlit lake scene (forestLakeHooks)	c44ddc6f1ea747f0	c44ddc6f1ea747f0	Identical
game: Lot scene (makeSceneShader(lotHooks))	984e98afc28efce0	984e98afc28efce0	Identical
game: Nightshift scene (makeSceneShader(nightshiftHooks))	81e9fe6d870dc599	81e9fe6d870dc599	Identical
game: Archers custom scene (archersSceneShader)	60e2061ffe1189d1	60e2061ffe1189d1	Identical
lab preset: day / night-today (Today scene shader)	3a519e694b51a728	3a519e694b51a728	Identical
lab preset: night-physical / spot-shadows / screen-bench (Physical scene shader)	46074b9e088af2b9	46074b9e088af2b9	Identical
lab preset: finished-props (Physical + finish scene shader)	b5ee1abc4c3cdfc0	b5ee1abc4c3cdfc0	Identical
lab preset: finished-props (Today + finish scene shader)	e831946f2283ec5f	e831946f2283ec5f	Identical
lab: WORLD_POST shader	319648dfaf929515	319648dfaf929515	Identical
lab: default world (day) level.chunks[0].data (541,296 B)	0299f39c500ff018	0299f39c500ff018	Identical
lab: screen-bench level.chunks[0].data (616,608 B)	c7eba7a1afd1b8c7	c7eba7a1afd1b8c7	Identical
lab: finished-props level.chunks[0].data (809,280 B)	f51eca92c8f718a1	f51eca92c8f718a1	Identical

Proof. All stills captured at the reframed BAKED_GI_CAMERA (target: [-4.72, 1.42, -11.15], yaw: -0.52, pitch: -0.01, dist: 4.35, 960×600) with fixed exposure (grade = [1.0, 0, 0, 1.45], shadowLift = 0, lensBloom = 0.25, skyLight = 0.015, giIntensity = 1.0, giProbes = 1.0). Paired GPU cost: 1.989 ms Today vs 2.015 ms Baked GI (+0.026 ms, budget ≤ 0.30 ms; 257.5 KiB GPU memory).

1. Lamp ON — Today (left) vs Cycles Baked GI (right), v2 reframed camera & 384-sample blotch-free ceiling:

2. Lamp OFF — Today (left) vs Cycles Baked GI (right), zero residual bounce:

3. CRT Colour Change — Cyan (left) vs Warm Red (right), live runtime re-tint via screenBounceSource:

Condition & Region (960×600 crop)	Today Before (R, G, B)	Today Luma (/255)	Baked GI After (R, G, B)	Baked GI Luma (/255)	Delta Luma
Lamp ON — Ceiling above lamp (420..740, 12..95)	(2.20, 2.40, 2.91)	2.39	(99.66, 43.59, 24.07)	54.10	+51.71
Lamp ON — Back wall near lamp (360..530, 150..275)	(2.83, 3.14, 3.93)	3.13	(62.91, 23.73, 13.60)	31.33	+28.20
Lamp ON — Dark left corner (15..140, 20..130)	(2.51, 2.76, 3.42)	2.76	(35.75, 12.07, 7.54)	16.78	+14.02 (0.31× ceiling)
Lamp ON — Bookcase & dynamic actor (40..320, 240..485)	(10.13, 9.98, 12.32)	10.18	(23.04, 12.65, 13.19)	14.90	+4.72 (+12.91 R)
Lamp ON — Rug pool under lamp (560..840, 480..588)	(213.21, 194.54, 171.74)	196.86	(214.65, 195.28, 172.25)	197.74	+0.88
Lamp OFF — Full frame (0..960, 0..600)	(5.65, 5.42, 6.21)	5.53	(5.65, 5.42, 6.21)	5.53	0.00
Lamp OFF — Ceiling above lamp (420..740, 12..95)	(2.20, 2.40, 2.91)	2.39	(2.20, 2.40, 2.91)	2.39	0.00
CRT Cyan — Back wall (360..530, 150..275)	(2.83, 3.14, 3.93)	3.13	(8.48, 23.88, 28.71)	20.96	+17.83 (B: +24.78)
CRT Red — Back wall (360..530, 150..275)	(2.83, 3.14, 3.93)	3.13	(43.80, 9.99, 7.10)	16.97	+13.84 (R: +40.97)

• bun test packages/kit/gpu/gi/lightmap.test.ts packages/kit/lab/world/world.test.ts packages/kit/architecture-map.test.ts (HiveMind mini): 30 pass
• bun run --cwd packages/kit typecheck && bun run --cwd games/lab typecheck && bun run check:scripts (HiveMind mini): clean
• hivemind run --kind browser --browser-approval "Kit requested baked-gi v2 framing & ceiling rebake proof" --worker mini -- bun run verify:smoke --game lab: build + smoke ok (5.0s)
• LIGHTMAP_PROOF_DIR=/Users/kit/code/home/artifacts/kit-lightmaps-2026-10-23 deno run --unstable-webgpu --sloppy-imports --allow-env --allow-read --allow-write scripts/lightmap-gpu-proof.ts: 0 WebGPU errors, todayBaselineMaxByteDiff = 0, all assertions pass