three.js/examples/primitives/Sphere.js

/**
 * @author mr.doob / http://mrdoob.com/
 * based on http://papervision3d.googlecode.com/svn/trunk/as3/trunk/src/org/papervision3d/objects/primitives/Sphere.as
 */

var Sphere = function ( radius, segments_width, segments_height ) {

	THREE.Geometry.call( this );

	var gridX = segments_width || 8,
	gridY = segments_height || 6;

	var i, j;
	var iHor = Math.max( 3, gridX );
	var iVer = Math.max( 2, gridY );
	var aVtc = [];

	for ( j = 0; j < ( iVer + 1 ) ; j++ ) {

		var fRad1 = j / iVer;
		var fZ = radius * Math.cos( fRad1 * Math.PI );
		var fRds = radius * Math.sin( fRad1 * Math.PI );
		var aRow = [];
		var oVtx = 0;

		for ( i = 0; i < iHor; i++ ) {

			var fRad2 = 2 * i / iHor;
			var fX = fRds * Math.sin( fRad2 * Math.PI );
			var fY = fRds * Math.cos( fRad2 * Math.PI );

			if ( !( ( j == 0 || j == iVer ) && i > 0 ) ) {

				oVtx = this.vertices.push( new THREE.Vertex( new THREE.Vector3( fY, fZ, fX ) ) ) - 1;

			}

			aRow.push( oVtx );

		}

		aVtc.push( aRow );

	}

	var iVerNum = aVtc.length;

	for ( j = 0; j < iVerNum; j++ ) {

		var iHorNum = aVtc[ j ].length;

		if ( j > 0 ) {

			for ( i = 0; i < iHorNum; i++ ) {

				var bEnd = i == ( iHorNum - 1 );
				var aP1 = aVtc[ j ][ bEnd ? 0 : i + 1 ];
				var aP2 = aVtc[ j ][ ( bEnd ? iHorNum - 1 : i ) ];
				var aP3 = aVtc[ j - 1 ][ ( bEnd ? iHorNum - 1 : i ) ];
				var aP4 = aVtc[ j - 1 ][ bEnd ? 0 : i + 1 ];

				var fJ0 = j / ( iVerNum - 1 );
				var fJ1 = ( j - 1 ) / ( iVerNum - 1 );
				var fI0 = ( i + 1 ) / iHorNum;
				var fI1 = i / iHorNum;

				var aP1uv = new THREE.UV( 1 - fI0, fJ0 );
				var aP2uv = new THREE.UV( 1 - fI1, fJ0 );
				var aP3uv = new THREE.UV( 1 - fI1, fJ1 );
				var aP4uv = new THREE.UV( 1 - fI0, fJ1 );

				if ( j < ( aVtc.length - 1 ) ) {

					this.faces.push( new THREE.Face3( aP1, aP2, aP3 ) );
					this.uvs.push( [ aP1uv, aP2uv, aP3uv ] );

				}

				if ( j > 1 ) {

					this.faces.push( new THREE.Face3( aP1, aP3, aP4 ) );
					this.uvs.push( [ aP1uv, aP3uv, aP4uv ] );

				}

			}
		}
	}
}

Sphere.prototype = new THREE.Geometry();
Sphere.prototype.constructor = Sphere;