three.js/src/extras/helpers/BoxHelper.js

/**
 * @author mrdoob / http://mrdoob.com/
 */

THREE.BoxHelper = function ( object ) {

	var geometry = new THREE.BufferGeometry();
	geometry.addAttribute( 'position', new THREE.BufferAttribute( new Float32Array( 72 ), 3 ) );

	THREE.Line.call( this, geometry, new THREE.LineBasicMaterial( { color: 0xffff00 } ), THREE.LinePieces );

	if ( object !== undefined ) {

		this.update( object );

	}

};

THREE.BoxHelper.prototype = Object.create( THREE.Line.prototype );
THREE.BoxHelper.prototype.constructor = THREE.BoxHelper;

THREE.BoxHelper.prototype.update = function ( object ) {

	var geometry = object.geometry;

	if ( geometry.boundingBox === null ) {

		geometry.computeBoundingBox();

	}

	var min = geometry.boundingBox.min;
	var max = geometry.boundingBox.max;

	/*
	  5____4
	1/___0/|
	| 6__|_7
	2/___3/

	0: max.x, max.y, max.z
	1: min.x, max.y, max.z
	2: min.x, min.y, max.z
	3: max.x, min.y, max.z
	4: max.x, max.y, min.z
	5: min.x, max.y, min.z
	6: min.x, min.y, min.z
	7: max.x, min.y, min.z
	*/

	var vertices = this.geometry.attributes.position.array;

	vertices[  0 ] = max.x; vertices[  1 ] = max.y; vertices[  2 ] = max.z;
	vertices[  3 ] = min.x; vertices[  4 ] = max.y; vertices[  5 ] = max.z;

	vertices[  6 ] = min.x; vertices[  7 ] = max.y; vertices[  8 ] = max.z;
	vertices[  9 ] = min.x; vertices[ 10 ] = min.y; vertices[ 11 ] = max.z;

	vertices[ 12 ] = min.x; vertices[ 13 ] = min.y; vertices[ 14 ] = max.z;
	vertices[ 15 ] = max.x; vertices[ 16 ] = min.y; vertices[ 17 ] = max.z;

	vertices[ 18 ] = max.x; vertices[ 19 ] = min.y; vertices[ 20 ] = max.z;
	vertices[ 21 ] = max.x; vertices[ 22 ] = max.y; vertices[ 23 ] = max.z;

	//

	vertices[ 24 ] = max.x; vertices[ 25 ] = max.y; vertices[ 26 ] = min.z;
	vertices[ 27 ] = min.x; vertices[ 28 ] = max.y; vertices[ 29 ] = min.z;

	vertices[ 30 ] = min.x; vertices[ 31 ] = max.y; vertices[ 32 ] = min.z;
	vertices[ 33 ] = min.x; vertices[ 34 ] = min.y; vertices[ 35 ] = min.z;

	vertices[ 36 ] = min.x; vertices[ 37 ] = min.y; vertices[ 38 ] = min.z;
	vertices[ 39 ] = max.x; vertices[ 40 ] = min.y; vertices[ 41 ] = min.z;

	vertices[ 42 ] = max.x; vertices[ 43 ] = min.y; vertices[ 44 ] = min.z;
	vertices[ 45 ] = max.x; vertices[ 46 ] = max.y; vertices[ 47 ] = min.z;

	//

	vertices[ 48 ] = max.x; vertices[ 49 ] = max.y; vertices[ 50 ] = max.z;
	vertices[ 51 ] = max.x; vertices[ 52 ] = max.y; vertices[ 53 ] = min.z;

	vertices[ 54 ] = min.x; vertices[ 55 ] = max.y; vertices[ 56 ] = max.z;
	vertices[ 57 ] = min.x; vertices[ 58 ] = max.y; vertices[ 59 ] = min.z;

	vertices[ 60 ] = min.x; vertices[ 61 ] = min.y; vertices[ 62 ] = max.z;
	vertices[ 63 ] = min.x; vertices[ 64 ] = min.y; vertices[ 65 ] = min.z;

	vertices[ 66 ] = max.x; vertices[ 67 ] = min.y; vertices[ 68 ] = max.z;
	vertices[ 69 ] = max.x; vertices[ 70 ] = min.y; vertices[ 71 ] = min.z;

	this.geometry.attributes.position.needsUpdate = true;

	this.geometry.computeBoundingSphere();

	this.matrix = object.matrixWorld;
	this.matrixAutoUpdate = false;

};