81 lines
2.7 KiB
Plaintext
81 lines
2.7 KiB
Plaintext
---
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description: Scene registry pattern — mapping node IDs to live THREE.Object3D instances
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globs: packages/core/src/hooks/scene-registry/**,packages/viewer/**
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alwaysApply: false
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---
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# Scene Registry
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The scene registry is a global, mutable map that links node IDs to their live `THREE.Object3D` instances. It avoids tree traversal and lets systems and selection managers do O(1) lookups.
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**Source**: @packages/core/src/hooks/scene-registry/scene-registry.ts
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## Structure
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```ts
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export const sceneRegistry = {
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nodes: new Map<string, THREE.Object3D>(), // id → Object3D
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byType: {
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wall: new Set<string>(),
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slab: new Set<string>(),
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item: new Set<string>(),
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// … one Set per node type
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},
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}
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```
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`nodes` is the primary lookup. `byType` lets systems iterate all objects of one type without scanning the whole map.
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## Registering in a Renderer
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Every renderer must call `useRegistry` with a `ref` to its root mesh or group. Registration is synchronous (`useLayoutEffect`) so it's available before the first paint.
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```tsx
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import { useRegistry } from '@pascal-app/core'
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export function WallRenderer({ node }: { node: WallNode }) {
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const ref = useRef<Mesh>(null!)
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useRegistry(node.id, 'wall', ref) // ← required in every renderer
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return <mesh ref={ref} … />
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}
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```
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The hook handles both registration on mount and cleanup on unmount automatically.
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## Looking Up Objects
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Anywhere outside the renderer — in systems, selection managers, export logic:
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```ts
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// Single lookup
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const obj = sceneRegistry.nodes.get(nodeId)
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if (obj) { /* use obj */ }
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// Iterate all walls
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for (const id of sceneRegistry.byType.wall) {
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const obj = sceneRegistry.nodes.get(id)
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}
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```
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## Rules
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- **One registration per node ID.** If a renderer spawns multiple meshes, register the outermost group (the one that represents the node).
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- **Never hold a stale reference.** Always read from `sceneRegistry.nodes.get(id)` at the time you need it — don't cache the result across frames.
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- **Don't mutate the registry manually.** Only `useRegistry` should add/remove entries. Systems and selection managers are read-only consumers.
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- **Core systems must not use the registry.** They work with plain node data. Only viewer systems and selection managers may do Three.js object lookups.
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## Outliner Sync
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The `outliner` in `useViewer` holds live `Object3D[]` arrays used by the post-processing outline pass. Selection managers sync them imperatively for performance (array mutation rather than new allocations):
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```ts
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outliner.selectedObjects.length = 0
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for (const id of selection.selectedIds) {
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const obj = sceneRegistry.nodes.get(id)
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if (obj) outliner.selectedObjects.push(obj)
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}
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```
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See @packages/viewer/src/components/viewer/selection-manager.tsx for the full sync pattern.
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