three.js/src/loaders/BufferGeometryLoader.js

import { Sphere } from '../math/Sphere.js';
import { Vector3 } from '../math/Vector3.js';
import { BufferAttribute } from '../core/BufferAttribute.js';
import { BufferGeometry } from '../core/BufferGeometry.js';
import { FileLoader } from './FileLoader.js';
import { DefaultLoadingManager } from './LoadingManager.js';

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

function BufferGeometryLoader( manager ) {

	this.manager = ( manager !== undefined ) ? manager : DefaultLoadingManager;

}

Object.assign( BufferGeometryLoader.prototype, {

	load: function ( url, onLoad, onProgress, onError ) {

		var scope = this;

		var loader = new FileLoader( scope.manager );
		loader.setPath( scope.path );
		loader.load( url, function ( text ) {

			onLoad( scope.parse( JSON.parse( text ) ) );

		}, onProgress, onError );

	},

	parse: function ( json ) {

		var geometry = new BufferGeometry();

		var index = json.data.index;

		if ( index !== undefined ) {

			var typedArray = new TYPED_ARRAYS[ index.type ]( index.array );
			geometry.setIndex( new BufferAttribute( typedArray, 1 ) );

		}

		var attributes = json.data.attributes;

		for ( var key in attributes ) {

			var attribute = attributes[ key ];
			var typedArray = new TYPED_ARRAYS[ attribute.type ]( attribute.array );

			geometry.addAttribute( key, new BufferAttribute( typedArray, attribute.itemSize, attribute.normalized ) );

		}

		var groups = json.data.groups || json.data.drawcalls || json.data.offsets;

		if ( groups !== undefined ) {

			for ( var i = 0, n = groups.length; i !== n; ++ i ) {

				var group = groups[ i ];

				geometry.addGroup( group.start, group.count, group.materialIndex );

			}

		}

		var boundingSphere = json.data.boundingSphere;

		if ( boundingSphere !== undefined ) {

			var center = new Vector3();

			if ( boundingSphere.center !== undefined ) {

				center.fromArray( boundingSphere.center );

			}

			geometry.boundingSphere = new Sphere( center, boundingSphere.radius );

		}

		return geometry;

	},

	setPath: function ( value ) {

		this.path = value;
		return this;

	}

} );

var TYPED_ARRAYS = {
	Int8Array: Int8Array,
	Uint8Array: Uint8Array,
	// Workaround for IE11 pre KB2929437. See #11440
	Uint8ClampedArray: typeof Uint8ClampedArray !== 'undefined' ? Uint8ClampedArray : Uint8Array,
	Int16Array: Int16Array,
	Uint16Array: Uint16Array,
	Int32Array: Int32Array,
	Uint32Array: Uint32Array,
	Float32Array: Float32Array,
	Float64Array: Float64Array
};

export { BufferGeometryLoader };