Added computeVertexNormals to BufferGeometry.

src/extras/core/BufferGeometry.js

@@ -152,6 +152,115 @@ THREE.BufferGeometry.prototype = {
 
 		}
 
+	},
+
+	computeVertexNormals: function () {
+
+		var indices = this.vertexIndexArray;
+		var vertices = this.vertexPositionArray;
+
+		if ( vertices && indices ) {
+
+			var i, il;
+			var j, jl;
+
+			var nElements = vertices.length;
+
+			if ( this.vertexNormalArray === undefined ) {
+
+				this.vertexNormalArray = new Float32Array( nElements );
+
+			} else {
+
+				// reset existing normals to zero
+
+				for ( i = 0, il = this.vertexNormalArray.length; i < il; i ++ ) {
+
+					this.vertexNormalArray[ i ] = 0;
+
+				}
+
+			}
+
+			var offsets = this.offsets;
+			var normals = this.vertexNormalArray;
+
+			var vA, vB, vC, x, y, z,
+
+			pA = new THREE.Vector3(),
+			pB = new THREE.Vector3(),
+			pC = new THREE.Vector3(),
+
+			cb = new THREE.Vector3(),
+			ab = new THREE.Vector3();
+
+			for ( j = 0, jl = offsets.length; j < jl; ++ j ) {
+
+				var start = offsets[ j ].start;
+				var count = offsets[ j ].count;
+				var index = offsets[ j ].index;
+
+				for ( i = start, il = start + count; i < il; i += 3 ) {
+
+					vA = index + indices[ i ];
+					vB = index + indices[ i + 1 ];
+					vC = index + indices[ i + 2 ];
+
+					x = vertices[ vA * 3 ];
+					y = vertices[ vA * 3 + 1 ];
+					z = vertices[ vA * 3 + 2 ];
+					pA.set( x, y, z );
+
+					x = vertices[ vB * 3 ];
+					y = vertices[ vB * 3 + 1 ];
+					z = vertices[ vB * 3 + 2 ];
+					pB.set( x, y, z );
+
+					x = vertices[ vC * 3 ];
+					y = vertices[ vC * 3 + 1 ];
+					z = vertices[ vC * 3 + 2 ];
+					pC.set( x, y, z );
+
+					cb.sub( pC, pB );
+					ab.sub( pA, pB );
+					cb.crossSelf( ab );
+
+					normals[ vA * 3 ] 	  += cb.x;
+					normals[ vA * 3 + 1 ] += cb.y;
+					normals[ vA * 3 + 2 ] += cb.z;
+
+					normals[ vB * 3 ] 	  += cb.x;
+					normals[ vB * 3 + 1 ] += cb.y;
+					normals[ vB * 3 + 2 ] += cb.z;
+
+					normals[ vC * 3 ] 	  += cb.x;
+					normals[ vC * 3 + 1 ] += cb.y;
+					normals[ vC * 3 + 2 ] += cb.z;
+
+				}
+
+			}
+
+			// normalize normals
+
+			for ( i = 0, il = normals.length; i < il; i += 3 ) {
+
+				x = normals[ i ];
+				y = normals[ i + 1 ];
+				z = normals[ i + 2 ];
+
+				var n = 1.0 / Math.sqrt( x * x + y * y + z * z );
+
+				normals[ i ] 	 *= n;
+				normals[ i + 1 ] *= n;
+				normals[ i + 2 ] *= n;
+
+			}
+
+			this.normalsNeedUpdate = true;
+
+		}
+
 	}
 
 };