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

/**************************************************************
 *  Spline curve
 **************************************************************/

THREE.SplineCurve = function ( points /* array of Vector2 */ ) {

    this.points = (points == undefined) ? [] : points;

};

THREE.SplineCurve.prototype = Object.create( THREE.Curve.prototype );

THREE.SplineCurve.prototype.getPoint = function ( t ) {

    var v = new THREE.Vector2();
    var c = [];
    var points = this.points, point, intPoint, weight;
    point = ( points.length - 1 ) * t;

    intPoint = Math.floor( point );
    weight = point - intPoint;

    c[ 0 ] = intPoint == 0 ? intPoint : intPoint - 1;
    c[ 1 ] = intPoint;
    c[ 2 ] = intPoint  > points.length - 2 ? points.length -1 : intPoint + 1;
    c[ 3 ] = intPoint  > points.length - 3 ? points.length -1 : intPoint + 2;

    v.x = THREE.Curve.Utils.interpolate( points[ c[ 0 ] ].x, points[ c[ 1 ] ].x, points[ c[ 2 ] ].x, points[ c[ 3 ] ].x, weight );
    v.y = THREE.Curve.Utils.interpolate( points[ c[ 0 ] ].y, points[ c[ 1 ] ].y, points[ c[ 2 ] ].y, points[ c[ 3 ] ].y, weight );

    return v;

};