HRTFDatabaseLoader is not an absolute condition to run audioContext

Source/modules/webaudio/PannerNode.cpp

 /*
  * Copyright (C) 2010, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 34 matching lines @@
     if (std::isnan(x) || std::isinf(x))
         x = 0.0;
 }
 
 PannerNode::PannerNode(AudioContext* context, float sampleRate)
     : AudioNode(context, sampleRate)
     , m_panningModel(Panner::PanningModelHRTF)
     , m_lastGain(-1.0)
     , m_connectionCount(0)
 {
+    // Load the HRTF database asynchronously so we don't block the Javascript thread while create the HRTF database.

[Raymond Toy (Google), 2014/02/25 17:13:58]

Nit: "create" -> "creating"

+    // The HRTF panner will return zeroes until the database is loaded.
+    m_hrtfDatabaseLoader = HRTFDatabaseLoader::createAndLoadAsynchronouslyIfNecessary(context->sampleRate());
+
     ScriptWrappable::init(this);
     addInput(adoptPtr(new AudioNodeInput(this)));
     addOutput(adoptPtr(new AudioNodeOutput(this, 2)));
 
     // Node-specific default mixing rules.
     m_channelCount = 2;
     m_channelCountMode = ClampedMax;
     m_channelInterpretation = AudioBus::Speakers;
 
     m_distanceGain = AudioParam::create(context, "distanceGain", 1.0, 0.0, 1.0);
@@ skipping 34 matching lines @@
 void PannerNode::process(size_t framesToProcess)
 {
     AudioBus* destination = output(0)->bus();
 
     if (!isInitialized() || !input(0)->isConnected() || !m_panner.get()) {
         destination->zero();
         return;
     }
 
     AudioBus* source = input(0)->bus();
-
     if (!source) {
         destination->zero();
         return;
     }
 
+    // HRTFDatabase should be loaded before proceeding for offline audio context when panningModel() is "HRTF".
+    if (panningModel() == "HRTF" && !m_hrtfDatabaseLoader->isLoaded()) {
+        if (context()->isOfflineContext()) {
+            m_hrtfDatabaseLoader->waitForLoaderThreadCompletion();
+        } else {
+            destination->zero();
+            return;
+        }
+    }
+
     // The audio thread can't block on this lock, so we call tryLock() instead.
     MutexTryLocker tryLocker(m_pannerLock);
     if (tryLocker.locked()) {
         // Apply the panning effect.
         double azimuth;
         double elevation;
         getAzimuthElevation(&azimuth, &elevation);
         m_panner->pan(azimuth, elevation, source, destination, framesToProcess);
 
         // Get the distance and cone gain.
         double totalGain = distanceConeGain();
 
         // Snap to desired gain at the beginning.
         if (m_lastGain == -1.0)
             m_lastGain = totalGain;
 
         // Apply gain in-place with de-zippering.
         destination->copyWithGainFrom(*destination, &m_lastGain, totalGain);
     } else {
         // Too bad - The tryLock() failed. We must be in the middle of changing the panner.
         destination->zero();
     }
 }
 
 void PannerNode::initialize()
 {
     if (isInitialized())
         return;
 
-    m_panner = Panner::create(m_panningModel, sampleRate(), context()->hrtfDatabaseLoader());
+    m_panner = Panner::create(m_panningModel, sampleRate(), m_hrtfDatabaseLoader.get());
 
     AudioNode::initialize();
 }
 
 void PannerNode::uninitialize()
 {
     if (!isInitialized())
         return;
 
     m_panner.clear();
@@ skipping 34 matching lines @@
 
 bool PannerNode::setPanningModel(unsigned model)
 {
     switch (model) {
     case EQUALPOWER:
     case HRTF:
         if (!m_panner.get() || model != m_panningModel) {
             // This synchronizes with process().
             MutexLocker processLocker(m_pannerLock);
 
-            OwnPtr<Panner> newPanner = Panner::create(model, sampleRate(), context()->hrtfDatabaseLoader());
+            OwnPtr<Panner> newPanner = Panner::create(model, sampleRate(), m_hrtfDatabaseLoader.get());
             m_panner = newPanner.release();
             m_panningModel = model;
         }
         break;
     case SOUNDFIELD:
         // FIXME: Implement sound field model. See // https://bugs.webkit.org/show_bug.cgi?id=77367.
         context()->executionContext()->addConsoleMessage(JSMessageSource, WarningMessageLevel, "'soundfield' panning model not implemented.");
         break;
     default:
         return false;
@@ skipping 201 matching lines @@
                     notifyAudioSourcesConnectedToNode(connectedNode, visitedNodes); // recurse
                 }
             }
         }
     }
 }
 
 } // namespace WebCore
 
 #endif // ENABLE(WEB_AUDIO)