source: other-projects/playing-in-the-street/summer-2013/trunk/Playing-in-the-Street-WPF/Content/Web/mrdoob-three.js-4862f5f/src/extras/geometries/LatheGeometry.js@ 28897

/**
 * @author astrodud / http://astrodud.isgreat.org/
 * @author zz85 / https://github.com/zz85
 * @author bhouston / http://exocortex.com
 */

// points - to create a closed torus, one must use a set of points 
//    like so: [ a, b, c, d, a ], see first is the same as last.
// segments - the number of circumference segments to create
// phiStart - the starting radian
// phiLength - the radian (0 to 2*PI) range of the lathed section
//    2*pi is a closed lathe, less than 2PI is a portion.
THREE.LatheGeometry = function ( points, segments, phiStart, phiLength ) {

    THREE.Geometry.call( this );

    segments = segments || 12;
    phiStart = phiStart || 0;
    phiLength = phiLength || 2 * Math.PI;

    var inversePointLength = 1.0 / ( points.length - 1 );
    var inverseSegments = 1.0 / segments;

    for ( var i = 0, il = segments; i <= il; i ++ ) {

        var phi = phiStart + i * inverseSegments * phiLength;

        var c = Math.cos( phi ),
            s = Math.sin( phi );

        for ( var j = 0, jl = points.length; j < jl; j ++ ) {

            var pt = points[ j ];

            var vertex = new THREE.Vector3();

            vertex.x = c * pt.x - s * pt.y;
            vertex.y = s * pt.x + c * pt.y;
            vertex.z = pt.z;

            this.vertices.push( vertex );

        }

    }

    var np = points.length;

    for ( var i = 0, il = segments; i < il; i ++ ) {

        for ( var j = 0, jl = points.length - 1; j < jl; j ++ ) {

            var base = j + np * i;
            var a = base;
            var b = base + np;
            var c = base + 1 + np;
            var d = base + 1;

            var u0 = i * inverseSegments;
            var v0 = j * inversePointLength;
            var u1 = u0 + inverseSegments;
            var v1 = v0 + inversePointLength;

            this.faces.push( new THREE.Face3( a, b, d ) );

            this.faceVertexUvs[ 0 ].push( [

                new THREE.Vector2( u0, v0 ),
                new THREE.Vector2( u1, v0 ),
                new THREE.Vector2( u0, v1 )

            ] );

            this.faces.push( new THREE.Face3( b, c, d ) );

            this.faceVertexUvs[ 0 ].push( [

                new THREE.Vector2( u1, v0 ),
                new THREE.Vector2( u1, v1 ),
                new THREE.Vector2( u0, v1 )

            ] );


        }

    }

    this.mergeVertices();
    this.computeCentroids();
    this.computeFaceNormals();
    this.computeVertexNormals();

};

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