Add paint hover previews to viewer

packages/viewer/src/systems/roof/roof-materials.ts

@@ -8,6 +8,17 @@ import { createMaterial, createMaterialFromPresetRef } from '../../lib/materials
 
 export type RoofMaterialArray = [THREE.Material, THREE.Material, THREE.Material, THREE.Material]
 
+const roofMaterialArrayCache = new Map<string, RoofMaterialArray>()
+
+function getSurfaceMaterialSignature(
+  spec: ReturnType<typeof getEffectiveRoofSurfaceMaterial>,
+): string {
+  return JSON.stringify({
+    material: spec.material ?? null,
+    materialPreset: spec.materialPreset ?? null,
+  })
+}
+
 function createResolvedMaterial(
   material: RoofNode['material'] | RoofSegmentNode['material'] | undefined,
   materialPreset: string | undefined,
@@ -27,6 +38,14 @@ export function getRoofMaterialArray(node: RoofNode): RoofMaterialArray | null {
   const top = getEffectiveRoofSurfaceMaterial(node, 'top')
   const edge = getEffectiveRoofSurfaceMaterial(node, 'edge')
   const wall = getEffectiveRoofSurfaceMaterial(node, 'wall')
+  const cacheKey = JSON.stringify({
+    top: getSurfaceMaterialSignature(top),
+    edge: getSurfaceMaterialSignature(edge),
+    wall: getSurfaceMaterialSignature(wall),
+  })
+
+  const cached = roofMaterialArrayCache.get(cacheKey)
+  if (cached) return cached
 
   const topMaterial = createResolvedMaterial(top.material, top.materialPreset)
   const edgeMaterial = createResolvedMaterial(edge.material, edge.materialPreset)
@@ -36,11 +55,13 @@ export function getRoofMaterialArray(node: RoofNode): RoofMaterialArray | null {
     return null
   }
 
-  return [
+  const materialArray: RoofMaterialArray = [
     edgeMaterial ?? wallMaterial ?? topMaterial ?? new THREE.MeshStandardMaterial(),
     wallMaterial ?? edgeMaterial ?? topMaterial ?? new THREE.MeshStandardMaterial(),
     wallMaterial ?? edgeMaterial ?? topMaterial ?? new THREE.MeshStandardMaterial(),
     topMaterial ?? wallMaterial ?? edgeMaterial ?? new THREE.MeshStandardMaterial(),
   ]
-}
 
+  roofMaterialArrayCache.set(cacheKey, materialArray)
+  return materialArray
+}