<!-- NEW3 — TEST 3 · THE RIVER'S JOURNEY · part 287 -->


	/**
	 * Sets the elements of the matrix from the given array.
	 *
	 * @param {Array<number>} array - The matrix elements in column-major order.
	 * @param {number} [offset=0] - Index of the first element in the array.
	 * @return {Matrix2} A reference to this matrix.
	 */
	fromArray( array, offset = 0 ) {

		for ( let i = 0; i < 4; i ++ ) {

			this.elements[ i ] = array[ i + offset ];

		}

		return this;

	}

	/**
	 * Sets the elements of the matrix.The arguments are supposed to be
	 * in row-major order.
	 *
	 * @param {number} n11 - 1-1 matrix element.
	 * @param {number} n12 - 1-2 matrix element.
	 * @param {number} n21 - 2-1 matrix element.
	 * @param {number} n22 - 2-2 matrix element.
	 * @return {Matrix2} A reference to this matrix.
	 */
	set( n11, n12, n21, n22 ) {

		const te = this.elements;

		te[ 0 ] = n11; te[ 2 ] = n12;
		te[ 1 ] = n21; te[ 3 ] = n22;

		return this;

	}

}

const _vector$4 = /*@__PURE__*/ new Vector2();

/**
 * Represents an axis-aligned bounding box (AABB) in 2D space.
 */
class Box2 {

	/**
	 * Constructs a new bounding box.
	 *
	 * @param {Vector2} [min=(Infinity,Infinity)] - A vector representing the lower boundary of the box.
	 * @param {Vector2} [max=(-Infinity,-Infinity)] - A vector representing the upper boundary of the box.
	 */
	constructor( min = new Vector2( + Infinity, + Infinity ), max = new Vector2( - Infinity, - Infinity ) ) {

		/**
		 * This flag can be used for type testing.
		 *
		 * @type {boolean}
		 * @readonly
		 * @default true
		 */
		this.isBox2 = true;

		/**
		 * The lower boundary of the box.
		 *
		 * @type {Vector2}
		 */
		this.min = min;

		/**
		 * The upper boundary of the box.
		 *
		 * @type {Vector2}
		 */
		this.max = max;

	}

	/**
	 * Sets the lower and upper boundaries of this box.
	 * Please note that this method only copies the values from the given objects.
	 *
	 * @param {Vector2} min - The lower boundary of the box.
	 * @param {Vector2} max - The upper boundary of the box.
	 * @return {Box2} A reference to this bounding box.
	 */
	set( min, max ) {

		this.min.copy( min );
		this.max.copy( max );

		return this;

	}

	/**
	 * Sets the upper and lower bounds of this box so it encloses the position data
	 * in the given array.
	 *
	 * @param {Array<Vector2>} points - An array holding 2D position data as instances of {@link Vector2}.
	 * @return {Box2} A reference to this bounding box.
	 */
	setFromPoints( points ) {

		this.makeEmpty();

		for ( let i = 0, il = points.length; i < il; i ++ ) {

			this.expandByPoint( points[ i ] );

		}

		return this;

	}

	/**
	 * Centers this box on the given center vector and sets this box's width, height and
	 * depth to the given size values.
	 *
	 * @param {Vector2} center - The center of the box.
	 * @param {Vector2} size - The x and y dimensions of the box.
	 * @return {Box2} A reference to this bounding box.
	 */
	setFromCenterAndSize( center, size ) {

		const halfSize = _vector$4.copy( size ).multiplyScalar( 0.5 );
		this.min.copy( center ).sub( halfSize );
		this.max.copy( center ).add( halfSize );

		return this;

	}

	/**
	 * Returns a new box with copied values from this instance.
	 *
	 * @return {Box2} A clone of this instance.
	 */
	clone() {

		return new this.constructor().copy( this );

	}

	/**
	 * Copies the values of the given box to this instance.
	 *
	 * @param {Box2} box - The box to copy.
	 * @return {Box2} A reference to this bounding box.
	 */
	copy( box ) {

		this.min.copy( box.min );
		this.max.copy( box.max );

		return this;

	}

	/**
	 * Makes this box empty which means in encloses a zero space in 2D.
	 *
	 * @return {Box2} A reference to this bounding box.
	 */
	makeEmpty() {

		this.min.x = this.min.y = + Infinity;
		this.max.x = this.max.y = - Infinity;

		return this;

	}

	/**
	 * Returns true if this box includes zero points within its bounds.
	 * Note that a box with equal lower and upper bounds still includes one
	 * point, the one both bounds share.
	 *
	 * @return {boolean} Whether this box is empty or not.
	 */
	isEmpty() {

		// this is a more robust check for empty than ( volume <= 0 ) because volume can get positive with two negative axes

		return ( this.max.x < this.min.x ) || ( this.max.y < this.min.y );

	}

	/**
	 * Returns the center point of this box.
	 *
	 * @param {Vector2} target - The target vector that is used to store the method's result.
	 * @return {Vector2} The center point.
	 */
	getCenter( target ) {

		return this.isEmpty() ? target.set( 0, 0 ) : target.addVectors( this.min, this.max ).multiplyScalar( 0.5 );

	}

	/**
	 * Returns the dimensions of this box.
	 *
	 * @param {Vector2} target - The target vector that is used to store the method's result.
	 * @return {Vector2} The size.
	 */
	getSize( target ) {

		return this.isEmpty() ? target.set( 0, 0 ) : target.subVectors( this.max, this.min );

	}

	/**
	 * Expands the boundaries of this box to include the given point.