<!-- NEW3 — TEST 3 · THE RIVER'S JOURNEY · part 168 -->
ngle + t * deltaAngle;
		let x = this.aX + this.xRadius * Math.cos( angle );
		let y = this.aY + this.yRadius * Math.sin( angle );

		if ( this.aRotation !== 0 ) {

			const cos = Math.cos( this.aRotation );
			const sin = Math.sin( this.aRotation );

			const tx = x - this.aX;
			const ty = y - this.aY;

			// Rotate the point about the center of the ellipse.
			x = tx * cos - ty * sin + this.aX;
			y = tx * sin + ty * cos + this.aY;

		}

		return point.set( x, y );

	}

	copy( source ) {

		super.copy( source );

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

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

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

		this.aClockwise = source.aClockwise;

		this.aRotation = source.aRotation;

		return this;

	}

	toJSON() {

		const data = super.toJSON();

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

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

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

		data.aClockwise = this.aClockwise;

		data.aRotation = this.aRotation;

		return data;

	}

	fromJSON( json ) {

		super.fromJSON( json );

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

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

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

		this.aClockwise = json.aClockwise;

		this.aRotation = json.aRotation;

		return this;

	}

}

/**
 * A curve representing an arc.
 *
 * @augments EllipseCurve
 */
class ArcCurve extends EllipseCurve {

	/**
	 * Constructs a new arc curve.
	 *
	 * @param {number} [aX=0] - The X center of the ellipse.
	 * @param {number} [aY=0] - The Y center of the ellipse.
	 * @param {number} [aRadius=1] - The radius of the ellipse in the x direction.
	 * @param {number} [aStartAngle=0] - The start angle of the curve in radians starting from the positive X axis.
	 * @param {number} [aEndAngle=Math.PI*2] - The end angle of the curve in radians starting from the positive X axis.
	 * @param {boolean} [aClockwise=false] - Whether the ellipse is drawn clockwise or not.
	 */
	constructor( aX, aY, aRadius, aStartAngle, aEndAngle, aClockwise ) {

		super( aX, aY, aRadius, aRadius, aStartAngle, aEndAngle, aClockwise );

		/**
		 * This flag can be used for type testing.
		 *
		 * @type {boolean}
		 * @readonly
		 * @default true
		 */
		this.isArcCurve = true;

		this.type = 'ArcCurve';

	}

}

function CubicPoly() {

	/**
	 * Centripetal CatmullRom Curve - which is useful for avoiding
	* cusps and self-intersections in non-uniform catmull rom curves.
	* http://www.cemyuksel.com/research/catmullrom_param/catmullrom.pdf
	*
	* curve.type accepts centripetal(default), chordal and catmullrom
	* curve.tension is used for catmullrom which defaults to 0.5
	*/

	/*
	Based on an optimized c++ solution in
	- http://stackoverflow.com/questions/9489736/catmull-rom-curve-with-no-cusps-and-no-self-intersections/
	- http://ideone.com/NoEbVM

	This CubicPoly class could be used for reusing some variables and calculations,
	but for three.js curve use, it could be possible inlined and flatten into a single function call
	which can be placed in CurveUtils.
	*/

	let c0 = 0, c1 = 0, c2 = 0, c3 = 0;

	/*
	 * Compute coefficients for a cubic polynomial
	 *   p(s) = c0 + c1*s + c2*s^2 + c3*s^3
	 * such that
	 *   p(0) = x0, p(1) = x1
	 *  and
	 *   p'(0) = t0, p'(1) = t1.
	 */
	function init( x0, x1, t0, t1 ) {

		c0 = x0;
		c1 = t0;
		c2 = -3 * x0 + 3 * x1 - 2 * t0 - t1;
		c3 = 2 * x0 - 2 * x1 + t0 + t1;

	}

	return {

		initCatmullRom: function ( x0, x1, x2, x3, tension ) {

			init( x1, x2, tension * ( x2 - x0 ), tension * ( x3 - x1 ) );

		},

		initNonuniformCatmullRom: function ( x0, x1, x2, x3, dt0, dt1, dt2 ) {

			// compute tangents when parameterized in [t1,t2]
			let t1 = ( x1 - x0 ) / dt0 - ( x2 - x0 ) / ( dt0 + dt1 ) + ( x2 - x1 ) / dt1;
			let t2 = ( x2 - x1 ) / dt1 - ( x3 - x1 ) / ( dt1 + dt2 ) + ( x3 - x2 ) / dt2;

			// rescale tangents for parametrization in [0,1]
			t1 *= dt1;
			t2 *= dt1;

			init( x1, x2, t1, t2 );

		},

		calc: function ( t ) {

			const t2 = t * t;
			const t3 = t2 * t;
			return c0 + c1 * t + c2 * t2 + c3 * t3;

		}

	};

}

//

const tmp = /*@__PURE__*/ new Vector3();
const tmp2 = /*@__PURE__*/ new Vector3();
const px = /*@__PURE__*/ new CubicPoly();
const py = /*@__PURE__*/ new CubicPoly();
const pz = /*@__PURE__*/ new CubicPoly();

/**
 * A curve representing a Catmull-Rom spline.
 *
 * ```js
 * //Create a closed wavey loop
 * const curve = new THREE.CatmullRomCurve3( [
 * 	new THREE.Vector3( -10, 0, 10 ),
 * 	new THREE.Vector3( -5, 5, 5 ),
 * 	new THREE.Vector3( 0, 0, 0 ),
 * 	new THREE.Vector3( 5, -5, 5 ),
 * 	new THREE.Vector3( 10, 0, 10 )
 * ] );
 *
 * const points = curve.getPoints( 50 );
 * const geometry = new THREE.BufferGeometry().setFromPoints( points );
 *
 * const material = new THREE.LineBasicMateria