BatchedMesh: Make data copying more robust, handle interleaved attributes

examples/jsm/objects/BatchedMesh.js

@@ -10,8 +10,8 @@ import {
 } from 'three';
 
 const ID_ATTR_NAME = '_batch_id_';
-const _identityMatrix = new Matrix4();
-const _zeroScaleMatrix = new Matrix4().set(
+const _identityMatrix = /* @__PURE__ */ new Matrix4();
+const _zeroScaleMatrix = /* @__PURE__ */ new Matrix4().set(
 	0, 0, 0, 0,
 	0, 0, 0, 0,
 	0, 0, 0, 0,
@@ -64,6 +64,36 @@ const batchingVertex = /* glsl */`
 // @TODO: SkinnedMesh support?
 // @TODO: Future work if needed. Move into the core. Can be optimized more with WEBGL_multi_draw.
 
+// copies data from attribute "src" into "target" starting at "targetOffset"
+function copyAttributeData( src, target, targetOffset = 0 ) {
+
+	const itemSize = target.itemSize;
+	if ( src.isInterleavedBufferAttribute || src.array.constructor !== target.array.constructor ) {
+
+		// use the component getters and setters if the array data cannot
+		// be copied directly
+		const vertexCount = src.count;
+		for ( let i = 0; i < vertexCount; i ++ ) {
+
+			for ( let c = 0; c < itemSize; c ++ ) {
+
+				target.setComponent( i + targetOffset, c, src.getComponent( i, c ) );
+
+			}
+
+		}
+
+	} else {
+
+		// faster copy approach using typed array set function
+		target.array.set( src.array, targetOffset * itemSize );
+
+	}
+
+	target.needsUpdate = true;
+
+}
+
 class BatchedMesh extends Mesh {
 
 	constructor( maxGeometryCount, maxVertexCount, maxIndexCount = maxVertexCount * 2, material ) {
@@ -332,9 +362,7 @@ class BatchedMesh extends Mesh {
 
 			const srcAttribute = geometry.getAttribute( attributeName );
 			const dstAttribute = batchGeometry.getAttribute( attributeName );
-
-			dstAttribute.array.set( srcAttribute.array, vertexCount * dstAttribute.itemSize );
-			dstAttribute.needsUpdate = true;
+			copyAttributeData( srcAttribute, dstAttribute, vertexCount );
 
 		}