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

/**************************************************************
 *  Ellipse curve
 **************************************************************/

THREE.EllipseCurve = function ( aX, aY, xRadius, yRadius, aStartAngle, aEndAngle, aClockwise ) {

    this.aX = aX;
    this.aY = aY;

    this.xRadius = xRadius;
    this.yRadius = yRadius;

    this.aStartAngle = aStartAngle;
    this.aEndAngle = aEndAngle;

    this.aClockwise = aClockwise;

};

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

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

    var angle;
    var deltaAngle = this.aEndAngle - this.aStartAngle;

    if ( deltaAngle < 0 ) deltaAngle += Math.PI * 2;
    if ( deltaAngle > Math.PI * 2 ) deltaAngle -= Math.PI * 2;

    if ( this.aClockwise === true ) {

        angle = this.aEndAngle + ( 1 - t ) * ( Math.PI * 2 - deltaAngle );

    } else {

        angle = this.aStartAngle + t * deltaAngle;

    }

    var tx = this.aX + this.xRadius * Math.cos( angle );
    var ty = this.aY + this.yRadius * Math.sin( angle );

    return new THREE.Vector2( tx, ty );

};