world42-cbt

name

world42-cbt

description

World42's CBT/OCBT terrain-LOD knowledge and workflow. Per planet a planet runs CDLOD or a Concurrent Binary Tree (never both); the CBT side has grown from a CPU stub into an integrated, validated GPU pool-CBT (OCBT) engine. Use when requests mention Concurrent Binary Trees, OCBT, large_cbt, bisectors, triangle-area/screen-space LOD, the GPU topology engine, or selecting the per-planet terrain algorithm in paths under src/systems/lod/, src/app/setup_lod_and_shadows.ts, src/game_world/stellar_system/, and camera-space contracts.

World42 CBT / OCBT terrain engine

Per planet, a planet runs either CDLOD or CBT — no hybrid blending on a single planet. The CBT path has grown from a CPU stub into an integrated, validated GPU pool-CBT (OCBT) engine. The Claude mirror (.claude/skills/world42-cbt/) carries the full reference set (10–15) and is the authoritative copy.

MVP Goal

Deliver a working scene-level and planet-level choice:

• Planet A can run CDLOD.
• Planet B can run CBT.
• A single planet uses one algorithm at a time.

Guardrails

• Keep coordinate-space boundaries explicit (WorldDouble, render-space, planet-local).
• Preserve current CDLOD behavior for planets configured as CDLOD.
• Keep rollout low-risk with feature flags and defaults.

Workflow

1) Add per-planet algorithm config

Add a field on the planet runtime config:

• lodAlgorithm: 'cdlod' | 'cbt'

Default to cdlod when not provided.

2) Keep CDLOD path untouched

Do not refactor existing CDLOD internals during MVP. Only route planets to existing CDLOD flow when lodAlgorithm='cdlod'.

3) Add minimal CBT path

Implement a basic CBT planet path:

• Classify by projected triangle area.
• Apply a split-first strategy (simplify can come later).
• Keep a conservative per-frame budget.

4) Route by planet in scene setup

In scene setup/orchestration:

• If planet config says cdlod, build the CDLOD tree.
• If planet config says cbt, build the CBT planet pipeline.

No cross-fade, no near/far mix for the same planet.

5) Validate

Run:

./.codex/skills/world42-cbt/scripts/check-cbt-mvp-integration.ps1
npm run pw:validate

Deliverables

• Per-planet LOD algorithm selection (cdlod or cbt).
• Working CBT MVP path for configured planets.
• No regressions for CDLOD planets.
• Implementation notes in references/mvp-implementation-plan.md.

Resources

• Use references/mvp-implementation-plan.md for the end-to-end implementation sequence.
• Use references/08_world42_mapping.md to map CBT concepts to current World42 modules.
• Use references/09_checklist.md as a final review checklist.
• Use scripts/check-cbt-mvp-integration.ps1 to inspect routing and coordinate-space touch points.