initial commit

node_modules/three/examples/js/BufferGeometryUtils.js

@@ -0,0 +1,187 @@
+/**
+ * @author mrdoob / http://mrdoob.com/
+ */
+
+THREE.BufferGeometryUtils = {
+
+	computeTangents: function ( geometry ) {
+
+		var index = geometry.index;
+		var attributes = geometry.attributes;
+
+		// based on http://www.terathon.com/code/tangent.html
+		// (per vertex tangents)
+
+		if ( index === null ||
+			 attributes.position === undefined ||
+			 attributes.normal === undefined ||
+			 attributes.uv === undefined ) {
+
+			console.warn( 'THREE.BufferGeometry: Missing required attributes (index, position, normal or uv) in BufferGeometry.computeTangents()' );
+			return;
+
+		}
+
+		var indices = index.array;
+		var positions = attributes.position.array;
+		var normals = attributes.normal.array;
+		var uvs = attributes.uv.array;
+
+		var nVertices = positions.length / 3;
+
+		if ( attributes.tangent === undefined ) {
+
+			geometry.addAttribute( 'tangent', new THREE.BufferAttribute( new Float32Array( 4 * nVertices ), 4 ) );
+
+		}
+
+		var tangents = attributes.tangent.array;
+
+		var tan1 = [], tan2 = [];
+
+		for ( var k = 0; k < nVertices; k ++ ) {
+
+			tan1[ k ] = new THREE.Vector3();
+			tan2[ k ] = new THREE.Vector3();
+
+		}
+
+		var vA = new THREE.Vector3(),
+			vB = new THREE.Vector3(),
+			vC = new THREE.Vector3(),
+
+			uvA = new THREE.Vector2(),
+			uvB = new THREE.Vector2(),
+			uvC = new THREE.Vector2(),
+
+			sdir = new THREE.Vector3(),
+			tdir = new THREE.Vector3();
+
+		function handleTriangle( a, b, c ) {
+
+			vA.fromArray( positions, a * 3 );
+			vB.fromArray( positions, b * 3 );
+			vC.fromArray( positions, c * 3 );
+
+			uvA.fromArray( uvs, a * 2 );
+			uvB.fromArray( uvs, b * 2 );
+			uvC.fromArray( uvs, c * 2 );
+
+			var x1 = vB.x - vA.x;
+			var x2 = vC.x - vA.x;
+
+			var y1 = vB.y - vA.y;
+			var y2 = vC.y - vA.y;
+
+			var z1 = vB.z - vA.z;
+			var z2 = vC.z - vA.z;
+
+			var s1 = uvB.x - uvA.x;
+			var s2 = uvC.x - uvA.x;
+
+			var t1 = uvB.y - uvA.y;
+			var t2 = uvC.y - uvA.y;
+
+			var r = 1.0 / ( s1 * t2 - s2 * t1 );
+
+			sdir.set(
+				( t2 * x1 - t1 * x2 ) * r,
+				( t2 * y1 - t1 * y2 ) * r,
+				( t2 * z1 - t1 * z2 ) * r
+			);
+
+			tdir.set(
+				( s1 * x2 - s2 * x1 ) * r,
+				( s1 * y2 - s2 * y1 ) * r,
+				( s1 * z2 - s2 * z1 ) * r
+			);
+
+			tan1[ a ].add( sdir );
+			tan1[ b ].add( sdir );
+			tan1[ c ].add( sdir );
+
+			tan2[ a ].add( tdir );
+			tan2[ b ].add( tdir );
+			tan2[ c ].add( tdir );
+
+		}
+
+		var groups = geometry.groups;
+
+		if ( groups.length === 0 ) {
+
+			groups = [ {
+				start: 0,
+				count: indices.length
+			} ];
+
+		}
+
+		for ( var j = 0, jl = groups.length; j < jl; ++ j ) {
+
+			var group = groups[ j ];
+
+			var start = group.start;
+			var count = group.count;
+
+			for ( var i = start, il = start + count; i < il; i += 3 ) {
+
+				handleTriangle(
+					indices[ i + 0 ],
+					indices[ i + 1 ],
+					indices[ i + 2 ]
+				);
+
+			}
+
+		}
+
+		var tmp = new THREE.Vector3(), tmp2 = new THREE.Vector3();
+		var n = new THREE.Vector3(), n2 = new THREE.Vector3();
+		var w, t, test;
+
+		function handleVertex( v ) {
+
+			n.fromArray( normals, v * 3 );
+			n2.copy( n );
+
+			t = tan1[ v ];
+
+			// Gram-Schmidt orthogonalize
+
+			tmp.copy( t );
+			tmp.sub( n.multiplyScalar( n.dot( t ) ) ).normalize();
+
+			// Calculate handedness
+
+			tmp2.crossVectors( n2, t );
+			test = tmp2.dot( tan2[ v ] );
+			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;
+
+		}
+
+		for ( var j = 0, jl = groups.length; j < jl; ++ j ) {
+
+			var group = groups[ j ];
+
+			var start = group.start;
+			var count = group.count;
+
+			for ( var i = start, il = start + count; i < il; i += 3 ) {
+
+				handleVertex( indices[ i + 0 ] );
+				handleVertex( indices[ i + 1 ] );
+				handleVertex( indices[ i + 2 ] );
+
+			}
+
+		}
+
+	}
+
+};