HRTFDatabaseLoader is not an absolute condition to run audioContext

Source/modules/webaudio/PannerNode.cpp

Index: Source/modules/webaudio/PannerNode.cpp
diff --git a/Source/modules/webaudio/PannerNode.cpp b/Source/modules/webaudio/PannerNode.cpp
index 80e5099488100a0b98b6fe253d10b98f0d5688eb..d4bd5a1b0da42c9d1764ca2dad66ab3d6b67b303 100644
--- a/Source/modules/webaudio/PannerNode.cpp
+++ b/Source/modules/webaudio/PannerNode.cpp
@@ -52,6 +52,9 @@ PannerNode::PannerNode(AudioContext* context, float sampleRate)
     , m_lastGain(-1.0)
     , m_connectionCount(0)
 {
+    // HRTFDatabaseLoader should be created and load database for pannerNode asynchronously.
+    m_hrtfDatabaseLoader = HRTFDatabaseLoader::createAndLoadAsynchronouslyIfNecessary(context->sampleRate());
+
     ScriptWrappable::init(this);
     addInput(adoptPtr(new AudioNodeInput(this)));
     addOutput(adoptPtr(new AudioNodeOutput(this, 2)));
@@ -106,12 +109,21 @@ void PannerNode::process(size_t framesToProcess)
     }
 
     AudioBus* source = input(0)->bus();
-
     if (!source) {
         destination->zero();
         return;
     }
 
+    // HRTFDatabaseLoader and HRTFDatabase should be loaded before proceed.

[Raymond Toy (Google), 2014/02/24 23:01:22]

Comment seems incorrect.  Change "before proceed" to "before proceeding for an
offline audio context. "

Also, is it possible for the offline audio context to check for completion
instead of here?

[KhNo, 2014/02/25 02:00:25]

Yes. It seems to be not correct comment. I will fix it.

OfflineAudioDestination::offlinerender() had a wait loader completion logic, I
have moved it to here. This change means that checking routine of HRTFDatabase
on pannerNode itself be located before transferring processed buffers to next
node or destination on audio thread as previous code did. It just moves checking
time early.

+    if (!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()) {
@@ -141,7 +153,7 @@ 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();
 }
@@ -196,7 +208,7 @@ bool PannerNode::setPanningModel(unsigned model)
             // 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;
         }