/**
 * @author kile / http://kile.stravaganza.org/
 * @author mr.doob / http://mrdoob.com/
 */

THREE.Geometry = function () {

	this.vertices = [];
	this.faces = [];
	this.uvs = [];

	this.computeNormals = function () {

		var v, f, vA, vB, vC, cb, ab, normal;

		for( v = 0; v < this.vertices.length; v++ ) {

			this.vertices[v].normal.set(0,0,0);

		}

		for( f = 0; f < this.faces.length; f++ ) {

			vA = this.vertices[ this.faces[f].a ];
			vB = this.vertices[ this.faces[f].b ];
			vC = this.vertices[ this.faces[f].c ];

			cb = new THREE.Vector3();
			ab = new THREE.Vector3();
			normal = new THREE.Vector3();

			cb.sub(vC.position,vB.position);
			ab.sub(vA.position,vB.position);
			cb.cross(ab);

			if ( !cb.isZero() ) {

				cb.normalize();

			}

			this.faces[f].normal = cb;

			vA.normal.addSelf( normal );
			vB.normal.addSelf( normal );
			vC.normal.addSelf( normal );

			if ( this.faces[f] instanceof THREE.Face4 ) {

				this.vertices[ this.faces[f].d ].normal.addSelf( normal );

			}

		}

	};

};