Add support for bypassing web worker for mesh decompression

Source/Scene/Model.js

@@ -36,6 +36,7 @@ define([
         '../ThirdParty/gltfDefaults',
         '../ThirdParty/Uri',
         '../ThirdParty/when',
+        './decompressOpen3DGC',
         './getModelAccessor',
         './ModelAnimationCache',
         './ModelAnimationCollection',
@@ -81,6 +82,7 @@ define([
         gltfDefaults,
         Uri,
         when,
+        decompressOpen3DGC,
         getModelAccessor,
         ModelAnimationCache,
         ModelAnimationCollection,
@@ -1301,34 +1303,58 @@ define([
 
     ///////////////////////////////////////////////////////////////////////////
 
-    var decompressTaskProcessor = new TaskProcessor('decompressMesh');
+    var open3dgcTaskProcessor = new TaskProcessor('decompressOpen3DGC');
 
-    function createDecompressedView(model) {
-        var loadResources = model._loadResources;
-        var decompressedViews = model.gltf.extensions.mesh_compression_open3dgc.decompressedViews;
+    function decompressOpen3dgcSync(buffer, decompressedView) {
+        var compressedBuffer = getSubarray(buffer, decompressedView.byteOffset, decompressedView.byteLength);
 
-        var name = loadResources.decompressedViewsToCreate.dequeue();
-        var decompressedView = decompressedViews[name];
+        var decompressedArrayBuffer = decompressOpen3DGC(decompressedView.decompressedByteLength, compressedBuffer);
 
-        var buffer = loadResources.buffers[decompressedView.buffer];
+        return when(decompressedArrayBuffer);
+    }
+
+    function decompressOpen3dgcAsync(buffer, decompressedView) {
         var compressedBuffer = copySubarray(buffer, decompressedView.byteOffset, decompressedView.byteLength);
 
-        var decompressPromise = decompressTaskProcessor.scheduleTask({
+        return open3dgcTaskProcessor.scheduleTask({
             decompressedByteLength : decompressedView.decompressedByteLength,
             compressedBuffer : compressedBuffer
         }, [compressedBuffer.buffer]);
+    }
 
-        if (!defined(decompressPromise)) {
-            loadResources.decompressedViewsToCreate.enqueue(name);
-            return;
+    function decompressOpen3dgc(model, name) {
+        var decompressedViews = model.gltf.extensions.mesh_compression_open3dgc.decompressedViews;
+
+        var loadResources = model._loadResources;
+        var decompressedView = decompressedViews[name];
+        var buffer = loadResources.buffers[decompressedView.buffer];
+
+        var forceSynchronous = false;
+
+        if (forceSynchronous) {
+            return decompressOpen3dgcSync(buffer, decompressedView);
+        }
+
+        var decompressPromise = decompressOpen3dgcAsync(buffer, decompressedView);
+        if (defined(decompressPromise)) {
+            return when(decompressPromise).then(function(result) {
+                return result.decompressedArrayBuffer;
+            });
+        } else {
+            return decompressOpen3dgcSync(buffer, decompressedView);
         }
+    }
+
+    function createDecompressedView(model) {
+        var loadResources = model._loadResources;
 
         loadResources.decompressionInFlight++;
 
-        when(decompressPromise).then(function(result) {
-            var decompressedArrayBuffer = result.decompressedArrayBuffer;
-            loadResources.decompressedViews[name] = new Uint8Array(decompressedArrayBuffer);
+        var name = loadResources.decompressedViewsToCreate.dequeue();
 
+        var decompressPromise = decompressOpen3dgc(model, name);
+        decompressPromise.then(function(decompressedArrayBuffer) {
+            loadResources.decompressedViews[name] = new Uint8Array(decompressedArrayBuffer);
             loadResources.decompressionInFlight--;
         });
     }

Source/Workers/decompressMesh.js → Source/Scene/decompressOpen3DGC.js

@@ -1,10 +1,8 @@
 /*global define*/
 define([
-        '../ThirdParty/o3dgc',
-        './createTaskProcessorWorker'
+        '../ThirdParty/o3dgc'
     ], function(
-        o3dgc,
-        createTaskProcessorWorker ) {
+        o3dgc) {
     "use strict";
 
     function alignOffset(offset, alignment) {
@@ -13,12 +11,8 @@ define([
         return (Math.ceil(offset / alignment) * alignment) | 0;
     }
 
-    function decompressMesh(parameters, transferableObjects) {
-        var decompressedByteLength = parameters.decompressedByteLength;
-        var compressedBuffer = parameters.compressedBuffer;
-
+    function decompressOpen3DGC(decompressedByteLength, compressedBuffer) {
         var decompressedArrayBuffer = new ArrayBuffer(decompressedByteLength);
-        transferableObjects.push(decompressedArrayBuffer);
 
         // Mostly copied from https://github.com/amd/rest3d/blob/master/server/o3dgc/js/index.php
 
@@ -78,10 +72,8 @@ define([
         //console.log("DecodePlayload: " + timer.GetElapsedTime());
         //console.log(decoder.GetStats());
 
-        return {
-            decompressedArrayBuffer : decompressedArrayBuffer
-        };
+        return decompressedArrayBuffer;
     }
 
-    return createTaskProcessorWorker(decompressMesh);
+    return decompressOpen3DGC;
 });

Source/Workers/decompressOpen3DGC.js

@@ -0,0 +1,23 @@
+/*global define*/
+define([
+        '../Scene/decompressOpen3DGC',
+        './createTaskProcessorWorker'
+    ], function(
+        decompressOpen3DGC,
+        createTaskProcessorWorker) {
+    "use strict";
+
+    function decompressOpen3DGCWorker(parameters, transferableObjects) {
+        var decompressedByteLength = parameters.decompressedByteLength;
+        var compressedBuffer = parameters.compressedBuffer;
+
+        var decompressedArrayBuffer = decompressOpen3DGC(decompressedByteLength, compressedBuffer);
+
+        transferableObjects.push(decompressedArrayBuffer);
+        return {
+            decompressedArrayBuffer : decompressedArrayBuffer
+        };
+    }
+
+    return createTaskProcessorWorker(decompressOpen3DGCWorker);
+});