Parallel Worker Construction

.proxyrc.js

@@ -0,0 +1,13 @@
+// Proxy serve so SharedArrayBuffer works locally
+export default function( app ) {
+
+	app.use( ( req, res, next ) => {
+
+		res.setHeader( 'Cross-Origin-Opener-Policy', 'same-origin' );
+		res.setHeader( 'Cross-Origin-Embedder-Policy', 'require-corp' );
+
+		next();
+
+	} );
+
+}

README.md

@@ -185,7 +185,7 @@ geometry.boundsTree = deserializedBVH;
 
 ## Asynchronous Generation
 
-_NOTE WebWorker syntax is inconsistently supported across bundlers and sometimes not supported at all so the GenerateMeshBVHWorker class is not exported from the package root. If needed the code from `src/worker` can be copied and modified to accomodate a particular build process._
+_NOTE WebWorker syntax is inconsistently supported across bundlers and sometimes not supported at all so the GenerateMeshBVHWorker class is not exported from the package root. If needed the code from `src/worker` can be copied and modified to accommodate a particular build process._
 
 ```js
 import { GenerateMeshBVHWorker } from 'three-mesh-bvh/src/workers/GenerateMeshBVHWorker.js';
@@ -201,6 +201,22 @@ worker.generate( geometry ).then( bvh => {
 } );
 ```
 
+_Parallel BVH generation is also supported using "ParallelMeshBVHWorker", which requires support for SharedArrayBuffer. If SharedArrayBuffer is not available it falls back to "GenerateMeshBVHWorker". It is recommended that geometry passed to this function have `position` and `index` with SharedArrayBuffer arrays, otherwise buffer copies must be made._
+
+```js
+import { ParallelMeshBVHWorker } from 'three-mesh-bvh/src/workers/ParallelMeshBVHWorker.js';
+
+// ...
+
+const geometry = new KnotBufferGeometry( 1, 0.5, 40, 10 );
+const worker = new ParallelMeshBVHWorker();
+worker.generate( geometry ).then( bvh => {
+
+    geometry.boundsTree = bvh;
+
+} );
+```
+
 ## BVH Queries in a Shader
 
 See the shader implementation in the [simple GPU Path Tracing example](https://github.com/gkjohnson/three-mesh-bvh/blob/master/example/gpuPathTracingSimple.js) for an example on how to perform BVH ray queries in a shader. Or the [GPU SDF Generation example](https://github.com/gkjohnson/three-mesh-bvh/blob/master/example/sdfGeneration.js) for how to perform distance and closest point to point queries in a shader.

example/asyncGenerate.js

@@ -1,14 +1,18 @@
 import * as THREE from 'three';
 import Stats from 'stats.js';
 import { GUI } from 'three/examples/jsm/libs/lil-gui.module.min.js';
-import { GenerateMeshBVHWorker } from '../src/workers/GenerateMeshBVHWorker.js';
-import { acceleratedRaycast, MeshBVH, MeshBVHHelper } from '..';
+import { ParallelMeshBVHWorker } from '../src/workers/ParallelMeshBVHWorker.js';
+import { AVERAGE, CENTER, MeshBVH, MeshBVHHelper, SAH } from '..';
 
-THREE.Mesh.raycast = acceleratedRaycast;
+// Parallel BVH generation is only supported with SharedArrayBuffer
+const sharedArrayBufferSupported = typeof SharedArrayBuffer !== 'undefined';
 
 const params = {
 
 	useWebWorker: true,
+	maxWorkerCount: sharedArrayBufferSupported ? navigator.hardwareConcurrency : 1,
+	strategy: CENTER,
+
 	radius: 1,
 	tube: 0.3,
 	tubularSegments: 500,
@@ -86,7 +90,8 @@ function init() {
 
 	}
 
-	bvhGenerationWorker = new GenerateMeshBVHWorker();
+	bvhGenerationWorker = new ParallelMeshBVHWorker();
+	window.WORKER = bvhGenerationWorker;
 
 	gui = new GUI();
 	const helperFolder = gui.addFolder( 'helper' );
@@ -112,16 +117,21 @@ function init() {
 	helperFolder.open();
 
 	const knotFolder = gui.addFolder( 'knot' );
-	knotFolder.add( params, 'useWebWorker' );
 	knotFolder.add( params, 'radius', 0.5, 2, 0.01 );
 	knotFolder.add( params, 'tube', 0.2, 1.2, 0.01 );
 	knotFolder.add( params, 'tubularSegments', 50, 2000, 1 );
 	knotFolder.add( params, 'radialSegments', 5, 2000, 1 );
 	knotFolder.add( params, 'p', 1, 10, 1 );
 	knotFolder.add( params, 'q', 1, 10, 1 );
-	knotFolder.add( { regenerateKnot }, 'regenerateKnot' ).name( 'regenerate' );
 	knotFolder.open();
 
+	const bvhFolder = gui.addFolder( 'bvh' );
+	bvhFolder.add( params, 'useWebWorker' );
+	bvhFolder.add( params, 'maxWorkerCount', 1, 16, 1 ).disable( ! sharedArrayBufferSupported );
+	bvhFolder.add( params, 'strategy', { CENTER, AVERAGE, SAH } );
+
+	gui.add( { regenerateKnot }, 'regenerateKnot' ).name( 'regenerate' );
+
 	regenerateKnot();
 
 	window.addEventListener( 'resize', function () {
@@ -173,6 +183,7 @@ function regenerateKnot() {
 	);
 	const geomTime = window.performance.now() - geomStartTime;
 	const startTime = window.performance.now();
+	const options = { strategy: params.strategy };
 	let totalStallTime;
 	if ( params.useWebWorker ) {
 
@@ -185,7 +196,8 @@ function regenerateKnot() {
 
 		};
 
-		bvhGenerationWorker.generate( knot.geometry, { onProgress } ).then( bvh => {
+		bvhGenerationWorker.maxWorkerCount = params.maxWorkerCount;
+		bvhGenerationWorker.generate( knot.geometry, { onProgress, ...options } ).then( bvh => {
 
 			loadContainer.style.visibility = 'hidden';
 
@@ -207,17 +219,18 @@ function regenerateKnot() {
 			group.add( helper );
 
 			outputContainer.textContent =
-				`Geometry Generation Time : ${ geomTime.toFixed( 3 ) }ms\n` +
-				`BVH Generation Time : ${ deltaTime.toFixed( 3 ) }ms\n` +
-				`Frame Stall Time : ${ totalStallTime.toFixed( 3 ) }`;
+				`Geometry Generation Time  : ${ geomTime.toFixed( 3 ) }ms\n` +
+				`BVH Generation Time       : ${ deltaTime.toFixed( 3 ) }ms\n` +
+				`Frame Stall Time          : ${ totalStallTime.toFixed( 3 ) }\n` +
+				`SharedArrayBuffer Support : ${ sharedArrayBufferSupported }`;
 
 		} );
 
 		totalStallTime = window.performance.now() - stallStartTime;
 
 	} else {
 
-		knot.geometry.boundsTree = new MeshBVH( knot.geometry );
+		knot.geometry.boundsTree = new MeshBVH( knot.geometry, options );
 		totalStallTime = window.performance.now() - stallStartTime;
 
 		group.add( knot );
@@ -231,9 +244,9 @@ function regenerateKnot() {
 		group.add( helper );
 
 		outputContainer.textContent =
-			`Geometry Generation Time : ${ geomTime.toFixed( 3 ) }ms\n` +
-			`BVH Generation Time : ${ deltaTime.toFixed( 3 ) }ms\n` +
-			`Frame Stall Time : ${ totalStallTime.toFixed( 3 ) }`;
+			`Geometry Generation Time  : ${ geomTime.toFixed( 3 ) }ms\n` +
+			`BVH Generation Time       : ${ deltaTime.toFixed( 3 ) }ms\n` +
+			`Frame Stall Time          : ${ totalStallTime.toFixed( 3 ) }`;
 
 	}