text: /**
   * @author Garrett Johnson / http://gkjohnson.github.io/
   * https://github.com/gkjohnson/collada-exporter-js
   *
   * Usage:
   *  var exporter = new THREE.ColladaExporter();
   *
   *  var data = exporter.parse(mesh);
   *
   * Format Definition:
   *  https://www.khronos.org/collada/
   */
  
  THREE.ColladaExporter = function () {};
  
  THREE.ColladaExporter.prototype = {
  
  	constructor: THREE.ColladaExporter,
  
  	parse: function ( object, onDone, options = {} ) {
  
  		options = Object.assign( {
  			version: '1.4.1',
  			author: null,
  			textureDirectory: '',
  		}, options );
  
  		if ( options.textureDirectory !== '' ) {
  
  			options.textureDirectory = `${ options.textureDirectory }/`
  				.replace( /\\/g, '/' )
  				.replace( /\/+/g, '/' );
  
  		}
  
  		var version = options.version;
  		if ( version !== '1.4.1' && version !== '1.5.0' ) {
  
  			console.warn( `ColladaExporter : Version ${ version } not supported for export. Only 1.4.1 and 1.5.0.` );
  			return null;
  
  		}
  
  		// Convert the urdf xml into a well-formatted, indented format
  		function format( urdf ) {
  
  			var IS_END_TAG = /^<\//;
  			var IS_SELF_CLOSING = /(\?>$)|(\/>$)/;
  			var HAS_TEXT = /<[^>]+>[^<]*<\/[^<]+>/;
  
  			var pad = ( ch, num ) => ( num > 0 ? ch + pad( ch, num - 1 ) : '' );
  
  			var tagnum = 0;
  			return urdf
  				.match( /(<[^>]+>[^<]+<\/[^<]+>)|(<[^>]+>)/g )
  				.map( tag => {
  
  					if ( ! HAS_TEXT.test( tag ) && ! IS_SELF_CLOSING.test( tag ) && IS_END_TAG.test( tag ) ) {
  
  						tagnum --;
  
  					}
  
  					var res = `${ pad( '  ', tagnum ) }${ tag }`;
  
  					if ( ! HAS_TEXT.test( tag ) && ! IS_SELF_CLOSING.test( tag ) && ! IS_END_TAG.test( tag ) ) {
  
  						tagnum ++;
  
  					}
  
  					return res;
  
  				} )
  				.join( '\n' );
  
  		}
  
  		// Convert an image into a png format for saving
  		function base64ToBuffer( str ) {
  
  			var b = atob( str );
  			var buf = new Uint8Array( b.length );
  
  			for ( var i = 0, l = buf.length; i < l; i ++ ) {
  
  				buf[ i ] = b.charCodeAt( i );
  
  			}
  
  			return buf;
  
  		}
  
  		var canvas, ctx;
  		function imageToData( image, ext ) {
  
  			canvas = canvas || document.createElement( 'canvas' );
  			ctx = ctx || canvas.getContext( '2d' );
  
  			canvas.width = image.naturalWidth;
  			canvas.height = image.naturalHeight;
  
  			ctx.drawImage( image, 0, 0 );
  
  			// Get the base64 encoded data
  			var base64data = canvas
  				.toDataURL( `image/${ ext }`, 1 )
  				.replace( /^data:image\/(png|jpg);base64,/, '' );
  
  			// Convert to a uint8 array
  			return base64ToBuffer( base64data );
  
  		}
  
  		// gets the attribute array. Generate a new array if the attribute is interleaved
  		var getFuncs = [ 'getX', 'getY', 'getZ', 'getW' ];
  		function attrBufferToArray( attr ) {
  
  			if ( attr.isInterleavedBufferAttribute ) {
  
  				// use the typed array constructor to save on memory
  				var arr = new attr.array.constructor( attr.count * attr.itemSize );
  				var size = attr.itemSize;
  				for ( var i = 0, l = attr.count; i < l; i ++ ) {
  
  					for ( var j = 0; j < size; j ++ ) {
  
  						arr[ i * size + j ] = attr[ getFuncs[ j ] ]( i );
  
  					}
  
  				}
  
  				return arr;
  
  			} else {
  
  				return attr.array;
  
  			}
  
  		}
  
  		// Returns an array of the same type starting at the `st` index,
  		// and `ct` length
  		function subArray( arr, st, ct ) {
  
  			if ( Array.isArray( arr ) ) return arr.slice( st, st + ct );
  			else return new arr.constructor( arr.buffer, st * arr.BYTES_PER_ELEMENT, ct );
  
  		}
  
  		// Returns the string for a geometry's attribute
  		function getAttribute( attr, name, params, type ) {
  
  			var array = attrBufferToArray( attr );
  			var res =
  					`<source id="${ name }">` +
  
  					`<float_array id="${ name }-array" count="${ array.length }">` +
  					array.join( ' ' ) +
  					'</float_array>' +
  
  					'<technique_common>' +
  					`<accessor source="#${ name }-array" count="${ Math.floor( array.length / attr.itemSize ) }" stride="${ attr.itemSize }">` +
  
  					params.map( n => `<param name="${ n }" type="${ type }" />` ).join( '' ) +
  
  					'</accessor>' +
  					'</technique_common>' +
  					'</source>';
  
  			return res;
  
  		}
  
  		// Returns the string for a node's transform information
  		var transMat;
  		function getTransform( o ) {
  
  			// ensure the object's matrix is up to date
  			// before saving the transform
  			o.updateMatrix();
  
  			transMat = transMat || new THREE.Matrix4();
  			transMat.copy( o.matrix );
  			transMat.transpose();
  			return `<matrix>${ transMat.toArray().join( ' ' ) }</matrix>`;
  
  		}
  
  		// Process the given piece of geometry into the geometry library
  		// Returns the mesh id
  		function processGeometry( g ) {
  
  			var info = geometryInfo.get( g );
  
  			if ( ! info ) {
  
  				// convert the geometry to bufferGeometry if it isn't already
  				var bufferGeometry = g;
  				if ( bufferGeometry instanceof THREE.Geometry ) {
  
  					bufferGeometry = ( new THREE.BufferGeometry() ).fromGeometry( bufferGeometry );
  
  				}
  
  				var meshid = `Mesh${ libraryGeometries.length + 1 }`;
  
  				var indexCount =
  					bufferGeometry.index ?
  						bufferGeometry.index.count * bufferGeometry.index.itemSize :
  						bufferGeometry.attributes.position.count;
  
  				var groups =
  					bufferGeometry.groups != null && bufferGeometry.groups.length !== 0 ?
  						bufferGeometry.groups :
  						[ { start: 0, count: indexCount, materialIndex: 0 } ];
  
  				var gnode = `<geometry id="${ meshid }" name="${ g.name }"><mesh>`;
  
  				// define the geometry node and the vertices for the geometry
  				var posName = `${ meshid }-position`;
  				var vertName = `${ meshid }-vertices`;
  				gnode += getAttribute( bufferGeometry.attributes.position, posName, [ 'X', 'Y', 'Z' ], 'float' );
  				gnode += `<vertices id="${ vertName }"><input semantic="POSITION" source="#${ posName }" /></vertices>`;
  
  				// NOTE: We're not optimizing the attribute arrays here, so they're all the same length and
  				// can therefore share the same triangle indices. However, MeshLab seems to have trouble opening
  				// models with attributes that share an offset.
  				// MeshLab Bug#424: https://sourceforge.net/p/meshlab/bugs/424/
  
  				// serialize normals
  				var triangleInputs = `<input semantic="VERTEX" source="#${ vertName }" offset="0" />`;
  				if ( 'normal' in bufferGeometry.attributes ) {
  
  					var normName = `${ meshid }-normal`;
  					gnode += getAttribute( bufferGeometry.attributes.normal, normName, [ 'X', 'Y', 'Z' ], 'float' );
  					triangleInputs += `<input semantic="NORMAL" source="#${ normName }" offset="0" />`;
  
  				}
  
  				// serialize uvs
  				if ( 'uv' in bufferGeometry.attributes ) {
  
  					var uvName = `${ meshid }-texcoord`;
  					gnode += getAttribute( bufferGeometry.attributes.uv, uvName, [ 'S', 'T' ], 'float' );
  					triangleInputs += `<input semantic="TEXCOORD" source="#${ uvName }" offset="0" set="0" />`;
  
  				}
  
  				// serialize colors
  				if ( 'color' in bufferGeometry.attributes ) {
  
  					var colName = `${ meshid }-color`;
  					gnode += getAttribute( bufferGeometry.attributes.color, colName, [ 'X', 'Y', 'Z' ], 'uint8' );
  					triangleInputs += `<input semantic="COLOR" source="#${ colName }" offset="0" />`;
  
  				}
  
  				var indexArray = null;
  				if ( bufferGeometry.index ) {
  
  					indexArray = attrBufferToArray( bufferGeometry.index );
  
  				} else {
  
  					indexArray = new Array( indexCount );
  					for ( var i = 0, l = indexArray.length; i < l; i ++ ) indexArray[ i ] = i;
  
  				}
  
  				for ( var i = 0, l = groups.length; i < l; i ++ ) {
  
  					var group = groups[ i ];
  					var subarr = subArray( indexArray, group.start, group.count );
  					var polycount = subarr.length / 3;
  					gnode += `<triangles material="MESH_MATERIAL_${ group.materialIndex }" count="${ polycount }">`;
  					gnode += triangleInputs;
  
  					gnode += `<p>${ subarr.join( ' ' ) }</p>`;
  					gnode += '</triangles>';
  
  				}
  
  				gnode += `</mesh></geometry>`;
  
  				libraryGeometries.push( gnode );
  
  				info = { meshid: meshid, bufferGeometry: bufferGeometry };
  				geometryInfo.set( g, info );
  
  			}
  
  			return info;
  
  		}
  
  		// Process the given texture into the image library
  		// Returns the image library
  		function processTexture( tex ) {
  
  			var texid = imageMap.get( tex );
  			if ( texid == null ) {
  
  				texid = `image-${ libraryImages.length + 1 }`;
  
  				var ext = 'png';
  				var name = tex.name || texid;
  				var imageNode = `<image id="${ texid }" name="${ name }">`;
  
  				if ( version === '1.5.0' ) {
  
  					imageNode += `<init_from><ref>${ options.textureDirectory }${ name }.${ ext }</ref></init_from>`;
  
  				} else {
  
  					// version image node 1.4.1
  					imageNode += `<init_from>${ options.textureDirectory }${ name }.${ ext }</init_from>`;
  
  				}
  
  				imageNode += '</image>';
  
  				libraryImages.push( imageNode );
  				imageMap.set( tex, texid );
  				textures.push( {
  					directory: options.textureDirectory,
  					name,
  					ext,
  					data: imageToData( tex.image, ext ),
  					original: tex
  				} );
  
  			}
  
  			return texid;
  
  		}
  
  		// Process the given material into the material and effect libraries
  		// Returns the material id
  		function processMaterial( m ) {
  
  			var matid = materialMap.get( m );
  
  			if ( matid == null ) {
  
  				matid = `Mat${ libraryEffects.length + 1 }`;
  
  				var type = 'phong';
  
  				if ( m instanceof THREE.MeshLambertMaterial ) {
  
  					type = 'lambert';
  
  				} else if ( m instanceof THREE.MeshBasicMaterial ) {
  
  					type = 'constant';
  
  					if ( m.map !== null ) {
  
  						// The Collada spec does not support diffuse texture maps with the
  						// constant shader type.
  						// mrdoob/three.js#15469
  						console.warn( 'ColladaExporter: Texture maps not supported with MeshBasicMaterial.' );
  
  					}
  
  				}
  
  				var emissive = m.emissive ? m.emissive : new THREE.Color( 0, 0, 0 );
  				var diffuse = m.color ? m.color : new THREE.Color( 0, 0, 0 );
  				var specular = m.specular ? m.specular : new THREE.Color( 1, 1, 1 );
  				var shininess = m.shininess || 0;
  				var reflectivity = m.reflectivity || 0;
  
  				// Do not export and alpha map for the reasons mentioned in issue (#13792)
  				// in THREE.js alpha maps are black and white, but collada expects the alpha
  				// channel to specify the transparency
  				var transparencyNode = '';
  				if ( m.transparent === true ) {
  
  					transparencyNode +=
  						`<transparent>` +
  						(
  							m.map ?
  								`<texture texture="diffuse-sampler"></texture>` :
  								'<float>1</float>'
  						) +
  						'</transparent>';
  
  					if ( m.opacity < 1 ) {
  
  						transparencyNode += `<transparency><float>${ m.opacity }</float></transparency>`;
  
  					}
  
  				}
  
  				var techniqueNode = `<technique sid="common"><${ type }>` +
  
  					'<emission>' +
  
  					(
  						m.emissiveMap ?
  							'<texture texture="emissive-sampler" texcoord="TEXCOORD" />' :
  							`<color sid="emission">${ emissive.r } ${ emissive.g } ${ emissive.b } 1</color>`
  					) +
  
  					'</emission>' +
  
  					(
  						type !== 'constant' ?
  							'<diffuse>' +
  
  						(
  							m.map ?
  								'<texture texture="diffuse-sampler" texcoord="TEXCOORD" />' :
  								`<color sid="diffuse">${ diffuse.r } ${ diffuse.g } ${ diffuse.b } 1</color>`
  						) +
  						'</diffuse>'
  							: ''
  					) +
  
  					(
  						type === 'phong' ?
  							`<specular><color sid="specular">${ specular.r } ${ specular.g } ${ specular.b } 1</color></specular>` +
  
  						'<shininess>' +
  
  						(
  							m.specularMap ?
  								'<texture texture="specular-sampler" texcoord="TEXCOORD" />' :
  								`<float sid="shininess">${ shininess }</float>`
  						) +
  
  						'</shininess>'
  							: ''
  					) +
  
  					`<reflective><color>${ diffuse.r } ${ diffuse.g } ${ diffuse.b } 1</color></reflective>` +
  
  					`<reflectivity><float>${ reflectivity }</float></reflectivity>` +
  
  					transparencyNode +
  
  					`</${ type }></technique>`;
  
  				var effectnode =
  					`<effect id="${ matid }-effect">` +
  					'<profile_COMMON>' +
  
  					(
  						m.map ?
  							'<newparam sid="diffuse-surface"><surface type="2D">' +
  							`<init_from>${ processTexture( m.map ) }</init_from>` +
  							'</surface></newparam>' +
  							'<newparam sid="diffuse-sampler"><sampler2D><source>diffuse-surface</source></sampler2D></newparam>' :
  							''
  					) +
  
  					(
  						m.specularMap ?
  							'<newparam sid="specular-surface"><surface type="2D">' +
  							`<init_from>${ processTexture( m.specularMap ) }</init_from>` +
  							'</surface></newparam>' +
  							'<newparam sid="specular-sampler"><sampler2D><source>specular-surface</source></sampler2D></newparam>' :
  							''
  					) +
  
  					(
  						m.emissiveMap ?
  							'<newparam sid="emissive-surface"><surface type="2D">' +
  							`<init_from>${ processTexture( m.emissiveMap ) }</init_from>` +
  							'</surface></newparam>' +
  							'<newparam sid="emissive-sampler"><sampler2D><source>emissive-surface</source></sampler2D></newparam>' :
  							''
  					) +
  
  					techniqueNode +
  
  					(
  						m.side === THREE.DoubleSide ?
  							`<extra><technique><double_sided sid="double_sided" type="int">1</double_sided></technique></extra>` :
  							''
  					) +
  
  					'</profile_COMMON>' +
  
  					'</effect>';
  
  				libraryMaterials.push( `<material id="${ matid }" name="${ m.name }"><instance_effect url="#${ matid }-effect" /></material>` );
  				libraryEffects.push( effectnode );
  				materialMap.set( m, matid );
  
  			}
  
  			return matid;
  
  		}
  
  		// Recursively process the object into a scene
  		function processObject( o ) {
  
  			var node = `<node name="${ o.name }">`;
  
  			node += getTransform( o );
  
  			if ( o instanceof THREE.Mesh && o.geometry != null ) {
  
  				// function returns the id associated with the mesh and a "BufferGeometry" version
  				// of the geometry in case it's not a geometry.
  				var geomInfo = processGeometry( o.geometry );
  				var meshid = geomInfo.meshid;
  				var geometry = geomInfo.bufferGeometry;
  
  				// ids of the materials to bind to the geometry
  				var matids = null;
  				var matidsArray = [];
  
  				// get a list of materials to bind to the sub groups of the geometry.
  				// If the amount of subgroups is greater than the materials, than reuse
  				// the materials.
  				var mat = o.material || new THREE.MeshBasicMaterial();
  				var materials = Array.isArray( mat ) ? mat : [ mat ];
  
  				if ( geometry.groups.length > materials.length ) {
  
  					matidsArray = new Array( geometry.groups.length );
  
  				} else {
  
  					matidsArray = new Array( materials.length );
  
  				}
  				matids = matidsArray.fill()
  					.map( ( v, i ) => processMaterial( materials[ i % materials.length ] ) );
  
  				node +=
  					`<instance_geometry url="#${ meshid }">` +
  
  					(
  						matids != null ?
  							'<bind_material><technique_common>' +
  							matids.map( ( id, i ) =>
  
  								`<instance_material symbol="MESH_MATERIAL_${ i }" target="#${ id }" >` +
  
  								'<bind_vertex_input semantic="TEXCOORD" input_semantic="TEXCOORD" input_set="0" />' +
  
  								'</instance_material>'
  							).join( '' ) +
  							'</technique_common></bind_material>' :
  							''
  					) +
  
  					'</instance_geometry>';
  
  			}
  
  			o.children.forEach( c => node += processObject( c ) );
  
  			node += '</node>';
  
  			return node;
  
  		}
  
  		var geometryInfo = new WeakMap();
  		var materialMap = new WeakMap();
  		var imageMap = new WeakMap();
  		var textures = [];
  
  		var libraryImages = [];
  		var libraryGeometries = [];
  		var libraryEffects = [];
  		var libraryMaterials = [];
  		var libraryVisualScenes = processObject( object );
  
  		var specLink = version === '1.4.1' ? 'http://www.collada.org/2005/11/COLLADASchema' : 'https://www.khronos.org/collada/';
  		var dae =
  			'<?xml version="1.0" encoding="UTF-8" standalone="no" ?>' +
  			`<COLLADA xmlns="${ specLink }" version="${ version }">` +
  			'<asset>' +
  			(
  				'<contributor>' +
  				'<authoring_tool>THREE.js Collada Exporter</authoring_tool>' +
  				( options.author !== null ? `<author>${ options.author }</author>` : '' ) +
  				'</contributor>' +
  				`<created>${ ( new Date() ).toISOString() }</created>` +
  				`<modified>${ ( new Date() ).toISOString() }</modified>` +
  				'<up_axis>Y_UP</up_axis>'
  			) +
  			'</asset>';
  
  		dae += `<library_images>${ libraryImages.join( '' ) }</library_images>`;
  
  		dae += `<library_effects>${ libraryEffects.join( '' ) }</library_effects>`;
  
  		dae += `<library_materials>${ libraryMaterials.join( '' ) }</library_materials>`;
  
  		dae += `<library_geometries>${ libraryGeometries.join( '' ) }</library_geometries>`;
  
  		dae += `<library_visual_scenes><visual_scene id="Scene" name="scene">${ libraryVisualScenes }</visual_scene></library_visual_scenes>`;
  
  		dae += '<scene><instance_visual_scene url="#Scene"/></scene>';
  
  		dae += '</COLLADA>';
  
  		var res = {
  			data: format( dae ),
  			textures
  		};
  
  		if ( typeof onDone === 'function' ) {
  
  			requestAnimationFrame( () => onDone( res ) );
  
  		}
  
  		return res;
  
  	}
  
  };
  