P3-02 P5-02: integrate Bitbybit OCCT geometry runtime

src/facade/threeViewport.ts

@@ -1,5 +1,5 @@
 import * as THREE from 'three'
-import type { BitBybitViewportAdapter } from './types'
+import type { BitBybitViewportAdapter, MeshAsset } from './types'
 
 /** Internal renderer boundary. React receives only the adapter contract. */
 export class ThreeViewportAdapter implements BitBybitViewportAdapter {
@@ -20,6 +20,7 @@ export class ThreeViewportAdapter implements BitBybitViewportAdapter {
     this.renderer = new THREE.WebGLRenderer({ antialias: true, alpha: false, powerPreference: 'high-performance' })
     this.renderer.setPixelRatio(Math.min(window.devicePixelRatio || 1, 2))
     this.renderer.setSize(host.clientWidth || 1, host.clientHeight || 1, false)
+    this.renderer.domElement.dataset.geometrySource = 'three-fallback'
     host.appendChild(this.renderer.domElement)
     const grid = new THREE.GridHelper(8, 16, 0x31555a, 0x1e3439)
     grid.rotation.x = 0
@@ -35,7 +36,6 @@ export class ThreeViewportAdapter implements BitBybitViewportAdapter {
     this.scene.add(key)
     const render = () => {
       if (!this.renderer || !this.scene || !this.camera) return
-      this.selection && (this.selection.rotation.y += 0.002)
       this.renderer.render(this.scene, this.camera)
       this.frame = requestAnimationFrame(render)
     }
@@ -43,6 +43,32 @@ export class ThreeViewportAdapter implements BitBybitViewportAdapter {
     render()
   }
 
+  setMesh(mesh: MeshAsset | null) {
+    if (!this.selection) return
+    if (!mesh) {
+      this.selection.visible = false
+      if (this.renderer) {
+        this.renderer.domElement.dataset.geometrySource = 'none'
+        delete this.renderer.domElement.dataset.triangleCount
+      }
+      return
+    }
+    const geometry = new THREE.BufferGeometry()
+    geometry.setAttribute('position', new THREE.BufferAttribute(mesh.positions, 3))
+    geometry.setAttribute('normal', new THREE.BufferAttribute(mesh.normals, 3))
+    geometry.setIndex(new THREE.BufferAttribute(mesh.indices, 1))
+    if (!mesh.normals.some((component) => component !== 0)) geometry.computeVertexNormals()
+    geometry.computeBoundingSphere()
+    this.selection.geometry.dispose()
+    this.selection.geometry = geometry
+    this.selection.visible = true
+    this.selection.position.set(0, -mesh.bounds.min[1], 0)
+    if (this.renderer) {
+      this.renderer.domElement.dataset.geometrySource = 'bitbybit-occt'
+      this.renderer.domElement.dataset.triangleCount = String(mesh.indices.length / 3)
+    }
+  }
+
   resize(width: number, height: number, devicePixelRatio = Math.min(window.devicePixelRatio || 1, 2)) {
     if (!this.renderer || !this.camera) return
     this.camera.aspect = Math.max(width, 1) / Math.max(height, 1)