( function () {

	const _v1 = new THREE.Vector3();
	const _v2 = new THREE.Vector3();
	const _v3 = new THREE.Vector3();
	const EPS = 1e-10;
	class Capsule {

		constructor( start = new THREE.Vector3( 0, 0, 0 ), end = new THREE.Vector3( 0, 1, 0 ), radius = 1 ) {

			this.start = start;
			this.end = end;
			this.radius = radius;

		}
		clone() {

			return new Capsule( this.start.clone(), this.end.clone(), this.radius );

		}
		set( start, end, radius ) {

			this.start.copy( start );
			this.end.copy( end );
			this.radius = radius;

		}
		copy( capsule ) {

			this.start.copy( capsule.start );
			this.end.copy( capsule.end );
			this.radius = capsule.radius;

		}
		getCenter( target ) {

			return target.copy( this.end ).add( this.start ).multiplyScalar( 0.5 );

		}
		translate( v ) {

			this.start.add( v );
			this.end.add( v );

		}
		checkAABBAxis( p1x, p1y, p2x, p2y, minx, maxx, miny, maxy, radius ) {

			return ( minx - p1x < radius || minx - p2x < radius ) && ( p1x - maxx < radius || p2x - maxx < radius ) && ( miny - p1y < radius || miny - p2y < radius ) && ( p1y - maxy < radius || p2y - maxy < radius );

		}
		intersectsBox( box ) {

			return this.checkAABBAxis( this.start.x, this.start.y, this.end.x, this.end.y, box.min.x, box.max.x, box.min.y, box.max.y, this.radius ) && this.checkAABBAxis( this.start.x, this.start.z, this.end.x, this.end.z, box.min.x, box.max.x, box.min.z, box.max.z, this.radius ) && this.checkAABBAxis( this.start.y, this.start.z, this.end.y, this.end.z, box.min.y, box.max.y, box.min.z, box.max.z, this.radius );

		}
		lineLineMinimumPoints( line1, line2 ) {

			const r = _v1.copy( line1.end ).sub( line1.start );
			const s = _v2.copy( line2.end ).sub( line2.start );
			const w = _v3.copy( line2.start ).sub( line1.start );
			const a = r.dot( s ),
				b = r.dot( r ),
				c = s.dot( s ),
				d = s.dot( w ),
				e = r.dot( w );
			let t1, t2;
			const divisor = b * c - a * a;
			if ( Math.abs( divisor ) < EPS ) {

				const d1 = - d / c;
				const d2 = ( a - d ) / c;
				if ( Math.abs( d1 - 0.5 ) < Math.abs( d2 - 0.5 ) ) {

					t1 = 0;
					t2 = d1;

				} else {

					t1 = 1;
					t2 = d2;

				}

			} else {

				t1 = ( d * a + e * c ) / divisor;
				t2 = ( t1 * a - d ) / c;

			}

			t2 = Math.max( 0, Math.min( 1, t2 ) );
			t1 = Math.max( 0, Math.min( 1, t1 ) );
			const point1 = r.multiplyScalar( t1 ).add( line1.start );
			const point2 = s.multiplyScalar( t2 ).add( line2.start );
			return [ point1, point2 ];

		}

	}

	THREE.Capsule = Capsule;

} )();