BufferGeometry: Use dedicated `BufferAttribute` API in `computeTangents()`. (#27825)

src/core/BufferGeometry.js

@@ -487,24 +487,21 @@ class BufferGeometry extends EventDispatcher {
 
 		}
 
-		const indices = index.array;
-		const positions = attributes.position.array;
-		const normals = attributes.normal.array;
-		const uvs = attributes.uv.array;
-
-		const nVertices = positions.length / 3;
+		const positionAttribute = attributes.position;
+		const normalAttribute = attributes.normal;
+		const uvAttribute = attributes.uv;
 
 		if ( this.hasAttribute( 'tangent' ) === false ) {
 
-			this.setAttribute( 'tangent', new BufferAttribute( new Float32Array( 4 * nVertices ), 4 ) );
+			this.setAttribute( 'tangent', new BufferAttribute( new Float32Array( 4 * positionAttribute.count ), 4 ) );
 
 		}
 
-		const tangents = this.getAttribute( 'tangent' ).array;
+		const tangentAttribute = this.getAttribute( 'tangent' );
 
 		const tan1 = [], tan2 = [];
 
-		for ( let i = 0; i < nVertices; i ++ ) {
+		for ( let i = 0; i < positionAttribute.count; i ++ ) {
 
 			tan1[ i ] = new Vector3();
 			tan2[ i ] = new Vector3();
@@ -524,13 +521,13 @@ class BufferGeometry extends EventDispatcher {
 
 		function handleTriangle( a, b, c ) {
 
-			vA.fromArray( positions, a * 3 );
-			vB.fromArray( positions, b * 3 );
-			vC.fromArray( positions, c * 3 );
+			vA.fromBufferAttribute( positionAttribute, a );
+			vB.fromBufferAttribute( positionAttribute, b );
+			vC.fromBufferAttribute( positionAttribute, c );
 
-			uvA.fromArray( uvs, a * 2 );
-			uvB.fromArray( uvs, b * 2 );
-			uvC.fromArray( uvs, c * 2 );
+			uvA.fromBufferAttribute( uvAttribute, a );
+			uvB.fromBufferAttribute( uvAttribute, b );
+			uvC.fromBufferAttribute( uvAttribute, c );
 
 			vB.sub( vA );
 			vC.sub( vA );
@@ -563,7 +560,7 @@ class BufferGeometry extends EventDispatcher {
 
 			groups = [ {
 				start: 0,
-				count: indices.length
+				count: index.count
 			} ];
 
 		}
@@ -578,9 +575,9 @@ class BufferGeometry extends EventDispatcher {
 			for ( let j = start, jl = start + count; j < jl; j += 3 ) {
 
 				handleTriangle(
-					indices[ j + 0 ],
-					indices[ j + 1 ],
-					indices[ j + 2 ]
+					index.getX( j + 0 ),
+					index.getX( j + 1 ),
+					index.getX( j + 2 )
 				);
 
 			}
@@ -592,7 +589,7 @@ class BufferGeometry extends EventDispatcher {
 
 		function handleVertex( v ) {
 
-			n.fromArray( normals, v * 3 );
+			n.fromBufferAttribute( normalAttribute, v );
 			n2.copy( n );
 
 			const t = tan1[ v ];
@@ -608,10 +605,7 @@ class BufferGeometry extends EventDispatcher {
 			const test = tmp2.dot( tan2[ v ] );
 			const w = ( test < 0.0 ) ? - 1.0 : 1.0;
 
-			tangents[ v * 4 ] = tmp.x;
-			tangents[ v * 4 + 1 ] = tmp.y;
-			tangents[ v * 4 + 2 ] = tmp.z;
-			tangents[ v * 4 + 3 ] = w;
+			tangentAttribute.setXYZW( v, tmp.x, tmp.y, tmp.z, w );
 
 		}
 
@@ -624,9 +618,9 @@ class BufferGeometry extends EventDispatcher {
 
 			for ( let j = start, jl = start + count; j < jl; j += 3 ) {
 
-				handleVertex( indices[ j + 0 ] );
-				handleVertex( indices[ j + 1 ] );
-				handleVertex( indices[ j + 2 ] );
+				handleVertex( index.getX( j + 0 ) );
+				handleVertex( index.getX( j + 1 ) );
+				handleVertex( index.getX( j + 2 ) );
 
 			}