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officialAccount/node_modules/three/examples/jsm/loaders/DRACOLoader.js

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2025-05-26 08:59:24 +08:00
import {
BufferAttribute,
BufferGeometry,
Color,
ColorManagement,
FileLoader,
Loader,
LinearSRGBColorSpace,
SRGBColorSpace
} from 'three';
const _taskCache = new WeakMap();
/**
* A loader for the Draco format.
*
* [Draco]{@link https://google.github.io/draco/} is an open source library for compressing
* and decompressing 3D meshes and point clouds. Compressed geometry can be significantly smaller,
* at the cost of additional decoding time on the client device.
*
* Standalone Draco files have a `.drc` extension, and contain vertex positions, normals, colors,
* and other attributes. Draco files do not contain materials, textures, animation, or node hierarchies –
* to use these features, embed Draco geometry inside of a glTF file. A normal glTF file can be converted
* to a Draco-compressed glTF file using [glTF-Pipeline]{@link https://github.com/CesiumGS/gltf-pipeline}.
* When using Draco with glTF, an instance of `DRACOLoader` will be used internally by {@link GLTFLoader}.
*
* It is recommended to create one DRACOLoader instance and reuse it to avoid loading and creating
* multiple decoder instances.
*
* `DRACOLoader` will automatically use either the JS or the WASM decoding library, based on
* browser capabilities.
*
* ```js
* const loader = new DRACOLoader();
* loader.setDecoderPath( '/examples/jsm/libs/draco/' );
*
* const geometry = await dracoLoader.loadAsync( 'models/draco/bunny.drc' );
* geometry.computeVertexNormals(); // optional
*
* dracoLoader.dispose();
* ```
*
* @augments Loader
* @three_import import { DRACOLoader } from 'three/addons/loaders/DRACOLoader.js';
*/
class DRACOLoader extends Loader {
/**
* Constructs a new Draco loader.
*
* @param {LoadingManager} [manager] - The loading manager.
*/
constructor( manager ) {
super( manager );
this.decoderPath = '';
this.decoderConfig = {};
this.decoderBinary = null;
this.decoderPending = null;
this.workerLimit = 4;
this.workerPool = [];
this.workerNextTaskID = 1;
this.workerSourceURL = '';
this.defaultAttributeIDs = {
position: 'POSITION',
normal: 'NORMAL',
color: 'COLOR',
uv: 'TEX_COORD'
};
this.defaultAttributeTypes = {
position: 'Float32Array',
normal: 'Float32Array',
color: 'Float32Array',
uv: 'Float32Array'
};
}
/**
* Provides configuration for the decoder libraries. Configuration cannot be changed after decoding begins.
*
* @param {string} path - The decoder path.
* @return {DRACOLoader} A reference to this loader.
*/
setDecoderPath( path ) {
this.decoderPath = path;
return this;
}
/**
* Provides configuration for the decoder libraries. Configuration cannot be changed after decoding begins.
*
* @param {{type:('js'|'wasm')}} config - The decoder config.
* @return {DRACOLoader} A reference to this loader.
*/
setDecoderConfig( config ) {
this.decoderConfig = config;
return this;
}
/**
* Sets the maximum number of Web Workers to be used during decoding.
* A lower limit may be preferable if workers are also for other tasks in the application.
*
* @param {number} workerLimit - The worker limit.
* @return {DRACOLoader} A reference to this loader.
*/
setWorkerLimit( workerLimit ) {
this.workerLimit = workerLimit;
return this;
}
/**
* Starts loading from the given URL and passes the loaded Draco asset
* to the `onLoad()` callback.
*
* @param {string} url - The path/URL of the file to be loaded. This can also be a data URI.
* @param {function(BufferGeometry)} onLoad - Executed when the loading process has been finished.
* @param {onProgressCallback} onProgress - Executed while the loading is in progress.
* @param {onErrorCallback} onError - Executed when errors occur.
*/
load( url, onLoad, onProgress, onError ) {
const loader = new FileLoader( this.manager );
loader.setPath( this.path );
loader.setResponseType( 'arraybuffer' );
loader.setRequestHeader( this.requestHeader );
loader.setWithCredentials( this.withCredentials );
loader.load( url, ( buffer ) => {
this.parse( buffer, onLoad, onError );
}, onProgress, onError );
}
/**
* Parses the given Draco data.
*
* @param {ArrayBuffer} buffer - The raw Draco data as an array buffer.
* @param {function(BufferGeometry)} onLoad - Executed when the loading/parsing process has been finished.
* @param {onErrorCallback} onError - Executed when errors occur.
*/
parse( buffer, onLoad, onError = ()=>{} ) {
this.decodeDracoFile( buffer, onLoad, null, null, SRGBColorSpace, onError ).catch( onError );
}
//
decodeDracoFile( buffer, callback, attributeIDs, attributeTypes, vertexColorSpace = LinearSRGBColorSpace, onError = () => {} ) {
const taskConfig = {
attributeIDs: attributeIDs || this.defaultAttributeIDs,
attributeTypes: attributeTypes || this.defaultAttributeTypes,
useUniqueIDs: !! attributeIDs,
vertexColorSpace: vertexColorSpace,
};
return this.decodeGeometry( buffer, taskConfig ).then( callback ).catch( onError );
}
decodeGeometry( buffer, taskConfig ) {
const taskKey = JSON.stringify( taskConfig );
// Check for an existing task using this buffer. A transferred buffer cannot be transferred
// again from this thread.
if ( _taskCache.has( buffer ) ) {
const cachedTask = _taskCache.get( buffer );
if ( cachedTask.key === taskKey ) {
return cachedTask.promise;
} else if ( buffer.byteLength === 0 ) {
// Technically, it would be possible to wait for the previous task to complete,
// transfer the buffer back, and decode again with the second configuration. That
// is complex, and I don't know of any reason to decode a Draco buffer twice in
// different ways, so this is left unimplemented.
throw new Error(
'THREE.DRACOLoader: Unable to re-decode a buffer with different ' +
'settings. Buffer has already been transferred.'
);
}
}
//
let worker;
const taskID = this.workerNextTaskID ++;
const taskCost = buffer.byteLength;
// Obtain a worker and assign a task, and construct a geometry instance
// when the task completes.
const geometryPending = this._getWorker( taskID, taskCost )
.then( ( _worker ) => {
worker = _worker;
return new Promise( ( resolve, reject ) => {
worker._callbacks[ taskID ] = { resolve, reject };
worker.postMessage( { type: 'decode', id: taskID, taskConfig, buffer }, [ buffer ] );
// this.debug();
} );
} )
.then( ( message ) => this._createGeometry( message.geometry ) );
// Remove task from the task list.
// Note: replaced '.finally()' with '.catch().then()' block - iOS 11 support (#19416)
geometryPending
.catch( () => true )
.then( () => {
if ( worker && taskID ) {
this._releaseTask( worker, taskID );
// this.debug();
}
} );
// Cache the task result.
_taskCache.set( buffer, {
key: taskKey,
promise: geometryPending
} );
return geometryPending;
}
_createGeometry( geometryData ) {
const geometry = new BufferGeometry();
if ( geometryData.index ) {
geometry.setIndex( new BufferAttribute( geometryData.index.array, 1 ) );
}
for ( let i = 0; i < geometryData.attributes.length; i ++ ) {
const result = geometryData.attributes[ i ];
const name = result.name;
const array = result.array;
const itemSize = result.itemSize;
const attribute = new BufferAttribute( array, itemSize );
if ( name === 'color' ) {
this._assignVertexColorSpace( attribute, result.vertexColorSpace );
attribute.normalized = ( array instanceof Float32Array ) === false;
}
geometry.setAttribute( name, attribute );
}
return geometry;
}
_assignVertexColorSpace( attribute, inputColorSpace ) {
// While .drc files do not specify colorspace, the only 'official' tooling
// is PLY and OBJ converters, which use sRGB. We'll assume sRGB when a .drc
// file is passed into .load() or .parse(). GLTFLoader uses internal APIs
// to decode geometry, and vertex colors are already Linear-sRGB in there.
if ( inputColorSpace !== SRGBColorSpace ) return;
const _color = new Color();
for ( let i = 0, il = attribute.count; i < il; i ++ ) {
_color.fromBufferAttribute( attribute, i );
ColorManagement.toWorkingColorSpace( _color, SRGBColorSpace );
attribute.setXYZ( i, _color.r, _color.g, _color.b );
}
}
_loadLibrary( url, responseType ) {
const loader = new FileLoader( this.manager );
loader.setPath( this.decoderPath );
loader.setResponseType( responseType );
loader.setWithCredentials( this.withCredentials );
return new Promise( ( resolve, reject ) => {
loader.load( url, resolve, undefined, reject );
} );
}
preload() {
this._initDecoder();
return this;
}
_initDecoder() {
if ( this.decoderPending ) return this.decoderPending;
const useJS = typeof WebAssembly !== 'object' || this.decoderConfig.type === 'js';
const librariesPending = [];
if ( useJS ) {
librariesPending.push( this._loadLibrary( 'draco_decoder.js', 'text' ) );
} else {
librariesPending.push( this._loadLibrary( 'draco_wasm_wrapper.js', 'text' ) );
librariesPending.push( this._loadLibrary( 'draco_decoder.wasm', 'arraybuffer' ) );
}
this.decoderPending = Promise.all( librariesPending )
.then( ( libraries ) => {
const jsContent = libraries[ 0 ];
if ( ! useJS ) {
this.decoderConfig.wasmBinary = libraries[ 1 ];
}
const fn = DRACOWorker.toString();
const body = [
'/* draco decoder */',
jsContent,
'',
'/* worker */',
fn.substring( fn.indexOf( '{' ) + 1, fn.lastIndexOf( '}' ) )
].join( '\n' );
this.workerSourceURL = URL.createObjectURL( new Blob( [ body ] ) );
} );
return this.decoderPending;
}
_getWorker( taskID, taskCost ) {
return this._initDecoder().then( () => {
if ( this.workerPool.length < this.workerLimit ) {
const worker = new Worker( this.workerSourceURL );
worker._callbacks = {};
worker._taskCosts = {};
worker._taskLoad = 0;
worker.postMessage( { type: 'init', decoderConfig: this.decoderConfig } );
worker.onmessage = function ( e ) {
const message = e.data;
switch ( message.type ) {
case 'decode':
worker._callbacks[ message.id ].resolve( message );
break;
case 'error':
worker._callbacks[ message.id ].reject( message );
break;
default:
console.error( 'THREE.DRACOLoader: Unexpected message, "' + message.type + '"' );
}
};
this.workerPool.push( worker );
} else {
this.workerPool.sort( function ( a, b ) {
return a._taskLoad > b._taskLoad ? - 1 : 1;
} );
}
const worker = this.workerPool[ this.workerPool.length - 1 ];
worker._taskCosts[ taskID ] = taskCost;
worker._taskLoad += taskCost;
return worker;
} );
}
_releaseTask( worker, taskID ) {
worker._taskLoad -= worker._taskCosts[ taskID ];
delete worker._callbacks[ taskID ];
delete worker._taskCosts[ taskID ];
}
debug() {
console.log( 'Task load: ', this.workerPool.map( ( worker ) => worker._taskLoad ) );
}
dispose() {
for ( let i = 0; i < this.workerPool.length; ++ i ) {
this.workerPool[ i ].terminate();
}
this.workerPool.length = 0;
if ( this.workerSourceURL !== '' ) {
URL.revokeObjectURL( this.workerSourceURL );
}
return this;
}
}
/* WEB WORKER */
function DRACOWorker() {
let decoderConfig;
let decoderPending;
onmessage = function ( e ) {
const message = e.data;
switch ( message.type ) {
case 'init':
decoderConfig = message.decoderConfig;
decoderPending = new Promise( function ( resolve/*, reject*/ ) {
decoderConfig.onModuleLoaded = function ( draco ) {
// Module is Promise-like. Wrap before resolving to avoid loop.
resolve( { draco: draco } );
};
DracoDecoderModule( decoderConfig ); // eslint-disable-line no-undef
} );
break;
case 'decode':
const buffer = message.buffer;
const taskConfig = message.taskConfig;
decoderPending.then( ( module ) => {
const draco = module.draco;
const decoder = new draco.Decoder();
try {
const geometry = decodeGeometry( draco, decoder, new Int8Array( buffer ), taskConfig );
const buffers = geometry.attributes.map( ( attr ) => attr.array.buffer );
if ( geometry.index ) buffers.push( geometry.index.array.buffer );
self.postMessage( { type: 'decode', id: message.id, geometry }, buffers );
} catch ( error ) {
console.error( error );
self.postMessage( { type: 'error', id: message.id, error: error.message } );
} finally {
draco.destroy( decoder );
}
} );
break;
}
};
function decodeGeometry( draco, decoder, array, taskConfig ) {
const attributeIDs = taskConfig.attributeIDs;
const attributeTypes = taskConfig.attributeTypes;
let dracoGeometry;
let decodingStatus;
const geometryType = decoder.GetEncodedGeometryType( array );
if ( geometryType === draco.TRIANGULAR_MESH ) {
dracoGeometry = new draco.Mesh();
decodingStatus = decoder.DecodeArrayToMesh( array, array.byteLength, dracoGeometry );
} else if ( geometryType === draco.POINT_CLOUD ) {
dracoGeometry = new draco.PointCloud();
decodingStatus = decoder.DecodeArrayToPointCloud( array, array.byteLength, dracoGeometry );
} else {
throw new Error( 'THREE.DRACOLoader: Unexpected geometry type.' );
}
if ( ! decodingStatus.ok() || dracoGeometry.ptr === 0 ) {
throw new Error( 'THREE.DRACOLoader: Decoding failed: ' + decodingStatus.error_msg() );
}
const geometry = { index: null, attributes: [] };
// Gather all vertex attributes.
for ( const attributeName in attributeIDs ) {
const attributeType = self[ attributeTypes[ attributeName ] ];
let attribute;
let attributeID;
// A Draco file may be created with default vertex attributes, whose attribute IDs
// are mapped 1:1 from their semantic name (POSITION, NORMAL, ...). Alternatively,
// a Draco file may contain a custom set of attributes, identified by known unique
// IDs. glTF files always do the latter, and `.drc` files typically do the former.
if ( taskConfig.useUniqueIDs ) {
attributeID = attributeIDs[ attributeName ];
attribute = decoder.GetAttributeByUniqueId( dracoGeometry, attributeID );
} else {
attributeID = decoder.GetAttributeId( dracoGeometry, draco[ attributeIDs[ attributeName ] ] );
if ( attributeID === - 1 ) continue;
attribute = decoder.GetAttribute( dracoGeometry, attributeID );
}
const attributeResult = decodeAttribute( draco, decoder, dracoGeometry, attributeName, attributeType, attribute );
if ( attributeName === 'color' ) {
attributeResult.vertexColorSpace = taskConfig.vertexColorSpace;
}
geometry.attributes.push( attributeResult );
}
// Add index.
if ( geometryType === draco.TRIANGULAR_MESH ) {
geometry.index = decodeIndex( draco, decoder, dracoGeometry );
}
draco.destroy( dracoGeometry );
return geometry;
}
function decodeIndex( draco, decoder, dracoGeometry ) {
const numFaces = dracoGeometry.num_faces();
const numIndices = numFaces * 3;
const byteLength = numIndices * 4;
const ptr = draco._malloc( byteLength );
decoder.GetTrianglesUInt32Array( dracoGeometry, byteLength, ptr );
const index = new Uint32Array( draco.HEAPF32.buffer, ptr, numIndices ).slice();
draco._free( ptr );
return { array: index, itemSize: 1 };
}
function decodeAttribute( draco, decoder, dracoGeometry, attributeName, attributeType, attribute ) {
const numComponents = attribute.num_components();
const numPoints = dracoGeometry.num_points();
const numValues = numPoints * numComponents;
const byteLength = numValues * attributeType.BYTES_PER_ELEMENT;
const dataType = getDracoDataType( draco, attributeType );
const ptr = draco._malloc( byteLength );
decoder.GetAttributeDataArrayForAllPoints( dracoGeometry, attribute, dataType, byteLength, ptr );
const array = new attributeType( draco.HEAPF32.buffer, ptr, numValues ).slice();
draco._free( ptr );
return {
name: attributeName,
array: array,
itemSize: numComponents
};
}
function getDracoDataType( draco, attributeType ) {
switch ( attributeType ) {
case Float32Array: return draco.DT_FLOAT32;
case Int8Array: return draco.DT_INT8;
case Int16Array: return draco.DT_INT16;
case Int32Array: return draco.DT_INT32;
case Uint8Array: return draco.DT_UINT8;
case Uint16Array: return draco.DT_UINT16;
case Uint32Array: return draco.DT_UINT32;
}
}
}
export { DRACOLoader };