/**
 * @author mrdoob / http://mrdoob.com/
 */

THREE.SphereGeometry = function ( radius, widthSegments, heightSegments, phiStart, phiLength, thetaStart, thetaLength ) {

	THREE.Geometry.call( this );

	radius = radius || 50;

	phiStart = phiStart !== undefined ? phiStart : 0;
	phiLength = phiLength !== undefined ? phiLength : Math.PI * 2;

	thetaStart = thetaStart !== undefined ? thetaStart : 0;
	thetaLength = thetaLength !== undefined ? thetaLength : Math.PI;

	var segmentsX = Math.max( 3, Math.floor( widthSegments ) || 8 );
	var segmentsY = Math.max( 2, Math.floor( heightSegments ) || 6 );

	var x, y, vertices = [], uvs = [];

	for ( y = 0; y <= segmentsY; y ++ ) {

		var verticesRow = [];
		var uvsRow = [];

		for ( x = 0; x <= segmentsX; x ++ ) {

			var u = x / segmentsX;
			var v = y / segmentsY;

			var vertex = new THREE.Vector3();
			vertex.x = - radius * Math.cos( phiStart + u * phiLength ) * Math.sin( thetaStart + v * thetaLength );
			vertex.y = radius * Math.cos( thetaStart + v * thetaLength );
			vertex.z = radius * Math.sin( phiStart + u * phiLength ) * Math.sin( thetaStart + v * thetaLength );

			this.vertices.push( vertex );

			verticesRow.push( this.vertices.length - 1 );
			uvsRow.push( new THREE.UV( u, 1 - v ) );

		}

		vertices.push( verticesRow );
		uvs.push( uvsRow );

	}

	for ( y = 0; y < segmentsY; y ++ ) {

		for ( x = 0; x < segmentsX; x ++ ) {

			var v1 = vertices[ y ][ x + 1 ];
			var v2 = vertices[ y ][ x ];
			var v3 = vertices[ y + 1 ][ x ];
			var v4 = vertices[ y + 1 ][ x + 1 ];

			var n1 = this.vertices[ v1 ].clone().normalize();
			var n2 = this.vertices[ v2 ].clone().normalize();
			var n3 = this.vertices[ v3 ].clone().normalize();
			var n4 = this.vertices[ v4 ].clone().normalize();

			var uv1 = uvs[ y ][ x + 1 ].clone();
			var uv2 = uvs[ y ][ x ].clone();
			var uv3 = uvs[ y + 1 ][ x ].clone();
			var uv4 = uvs[ y + 1 ][ x + 1 ].clone();

			if ( Math.abs( this.vertices[ v1 ].y ) == radius ) {

				this.faces.push( new THREE.Face3( v1, v3, v4, [ n1, n3, n4 ] ) );
				this.faceVertexUvs[ 0 ].push( [ uv1, uv3, uv4 ] );

			} else if ( Math.abs( this.vertices[ v3 ].y ) ==  radius ) {

				this.faces.push( new THREE.Face3( v1, v2, v3, [ n1, n2, n3 ] ) );
				this.faceVertexUvs[ 0 ].push( [ uv1, uv2, uv3 ] );

			} else {

				this.faces.push( new THREE.Face4( v1, v2, v3, v4, [ n1, n2, n3, n4 ] ) );
				this.faceVertexUvs[ 0 ].push( [ uv1, uv2, uv3, uv4 ] );

			}

		}

	}

	this.computeCentroids();
	this.computeFaceNormals();

	this.boundingSphere = { radius: radius };

};

THREE.SphereGeometry.prototype = Object.create( THREE.Geometry.prototype );
