Feature: Draco PNTS proposal alternative (#329)

* support draco * update readme * fix lint * clearer name * Consolidate draco changes to PNTSLoader * Update dts * Fixes * Final fixes? --------- Co-authored-by: George Madges <[email protected]>
NASA-AMMOS · May 12, 2023 · dbc3c20 · dbc3c20
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diff --git a/README.md b/README.md
@@ -154,6 +154,21 @@ const tilesRenderer = new TilesRenderer( './path/to/tileset.json' );
 tilesRenderer.manager.addHandler( /\.gltf$/, loader );
 ```
 
+Adding support for DRACO decompression within the PNTS files.
+
+```js
+
+// Note the DRACO compression files need to be supplied via an explicit source.
+// We use unpkg here but in practice should be provided by the application.
+const dracoLoader = new DRACOLoader();
+dracoLoader.setDecoderPath( 'https://unpkg.com/[email protected]/examples/js/libs/draco/gltf/' );
+
+
+const tilesRenderer = new TilesRenderer( './path/to/tileset.json' );
+tilesRenderer.manager.addHandler( /\.drc$/, loader );
+```
+
+
 ## Loading from Cesium Ion
 
 Loading from Cesium Ion requires some extra fetching of the ion url endpoint, as well as a temporary bearer access token. A full example is found in the ionExample.js file in the examples folder.

diff --git a/src/three/PNTSLoader.js b/src/three/PNTSLoader.js
@@ -1,5 +1,16 @@
 import { PNTSLoaderBase } from '../base/PNTSLoaderBase.js';
-import { Points, PointsMaterial, BufferGeometry, BufferAttribute, DefaultLoadingManager } from 'three';
+import {
+	Points,
+	PointsMaterial,
+	BufferGeometry,
+	BufferAttribute,
+	DefaultLoadingManager,
+} from 'three';
+
+const DRACO_ATTRIBUTE_MAP = {
+	RGB: 'color',
+	POSITION: 'position',
+};
 
 export class PNTSLoader extends PNTSLoaderBase {
 
@@ -12,68 +23,114 @@ export class PNTSLoader extends PNTSLoaderBase {
 
 	parse( buffer ) {
 
-		return super
-			.parse( buffer )
-			.then( result => {
+		return super.parse( buffer ).then( async ( result ) => {
 
-				const { featureTable } = result;
+			const { featureTable } = result;
 
-				const POINTS_LENGTH = featureTable.getData( 'POINTS_LENGTH' );
-				const POSITION = featureTable.getData( 'POSITION', POINTS_LENGTH, 'FLOAT', 'VEC3' );
-				const RGB = featureTable.getData( 'RGB', POINTS_LENGTH, 'UNSIGNED_BYTE', 'VEC3' );
+			const material = new PointsMaterial();
+			const extensions = featureTable.header.extensions;
+			let geometry;
+
+			// handle loading the draco data
+			if ( extensions && extensions[ '3DTILES_draco_point_compression' ] ) {
+
+				const { byteOffset, byteLength, properties } = extensions[ '3DTILES_draco_point_compression' ];
+				const dracoLoader = this.manager.getHandler( 'draco.drc' );
+				if ( dracoLoader == null ) {
+
+					throw new Error( 'PNTSLoader: dracoLoader not available.' );
+
+				}
 
-				[
-					'QUANTIZED_VOLUME_OFFSET',
-					'QUANTIZED_VOLUME_SCALE',
-					'CONSTANT_RGBA',
-					'BATCH_LENGTH',
-					'POSITION_QUANTIZED',
-					'RGBA',
-					'RGB565',
-					'NORMAL',
-					'NORMAL_OCT16P',
-				].forEach( feature => {
+				// map PNTS keys to draco types
+				const attributeIDs = {};
+				for ( const key in properties ) {
 
-					if ( feature in featureTable.header ) {
+					if ( key in DRACO_ATTRIBUTE_MAP && key in properties ) {
 
-						console.warn( `PNTSLoader: Unsupported FeatureTable feature "${ feature }" detected.` );
+						const mappedKey = DRACO_ATTRIBUTE_MAP[ key ];
+						attributeIDs[ mappedKey ] = properties[ key ];
 
 					}
 
-				} );
+				}
+
+				// decode the geometry
+				const taskConfig = {
+					attributeIDs,
+					attributeTypes: {
+						position: 'Float32Array',
+						color: 'Uint8Array',
+					},
+					useUniqueIDs: true,
+				};
 
-				const geometry = new BufferGeometry();
-				geometry.setAttribute( 'position', new BufferAttribute( POSITION, 3, false ) );
+				const buffer = featureTable.getBuffer( byteOffset, byteLength );
+				geometry = await dracoLoader.decodeGeometry( buffer, taskConfig );
+				if ( geometry.attributes.color ) {
+
+					material.vertexColors = true;
+
+				}
 
-				const material = new PointsMaterial();
-				material.size = 2;
-				material.sizeAttenuation = false;
+			} else {
 
+				// handle non compressed case
+				const POINTS_LENGTH = featureTable.getData( 'POINTS_LENGTH' );
+				const POSITION = featureTable.getData( 'POSITION', POINTS_LENGTH, 'FLOAT', 'VEC3' );
+				const RGB = featureTable.getData( 'RGB', POINTS_LENGTH, 'UNSIGNED_BYTE', 'VEC3' );
+
+				geometry = new BufferGeometry();
+				geometry.setAttribute( 'position', new BufferAttribute( POSITION, 3, false ) );
 				if ( RGB !== null ) {
 
 					geometry.setAttribute( 'color', new BufferAttribute( RGB, 3, true ) );
 					material.vertexColors = true;
 
 				}
 
-				const object = new Points( geometry, material );
-				result.scene = object;
-				result.scene.featureTable = featureTable;
+			}
 
-				const rtcCenter = featureTable.getData( 'RTC_CENTER' );
+			[
+				'QUANTIZED_VOLUME_OFFSET',
+				'QUANTIZED_VOLUME_SCALE',
+				'CONSTANT_RGBA',
+				'BATCH_LENGTH',
+				'POSITION_QUANTIZED',
+				'RGBA',
+				'RGB565',
+				'NORMAL',
+				'NORMAL_OCT16P',
+			].forEach( ( feature ) => {
 
-				if ( rtcCenter ) {
+				if ( feature in featureTable.header ) {
 
-					result.scene.position.x += rtcCenter[ 0 ];
-					result.scene.position.y += rtcCenter[ 1 ];
-					result.scene.position.z += rtcCenter[ 2 ];
+					console.warn(
+						`PNTSLoader: Unsupported FeatureTable feature "${feature}" detected.`
+					);
 
 				}
 
-				return result;
-
 			} );
 
+			const object = new Points( geometry, material );
+			result.scene = object;
+			result.scene.featureTable = featureTable;
+
+			const rtcCenter = featureTable.getData( 'RTC_CENTER' );
+
+			if ( rtcCenter ) {
+
+				result.scene.position.x += rtcCenter[ 0 ];
+				result.scene.position.y += rtcCenter[ 1 ];
+				result.scene.position.z += rtcCenter[ 2 ];
+
+			}
+
+			return result;
+
+		} );
+
 	}
 
 }
diff --git a/src/utilities/FeatureTable.d.ts b/src/utilities/FeatureTable.d.ts
@@ -1,5 +1,14 @@
+interface FeatureTableHeader {
+
+	extensions?: Object;
+	extras?: any;
+
+}
+
 export class FeatureTable {
 
+	header: FeatureTableHeader;
+
 	constructor(
 		buffer : ArrayBuffer,
 		start : Number,
@@ -16,6 +25,8 @@ export class FeatureTable {
 		defaultType? : String | null
 	) : Number | String | ArrayBufferView;
 
+	getBuffer( byteOffset : Number, byteLength : Number ) : ArrayBuffer;
+
 }
 
 export class BatchTable {

diff --git a/src/utilities/FeatureTable.js b/src/utilities/FeatureTable.js
@@ -141,6 +141,13 @@ export class FeatureTable {
 
 	}
 
+	getBuffer( byteOffset, byteLength ) {
+
+		const { buffer, binOffset } = this;
+		return buffer.slice( binOffset + byteOffset, binOffset + byteOffset + byteLength );
+
+	}
+
 }
 
 export class BatchTable extends FeatureTable {