HRTF panner should handle the case of no loaded HRTF database

Currently, the panner node checks to see if the HRTF database is
loaded and does the copy of the input if necessary.  This is the wrong
abstraction; the HRTF panner should copy the input if the database is
not ready.

In this way, the panner doesn't need to know about this implementation
detail, and we also get the correct distance and cone gains applied.

BUG=629858
TEST=

Review-Url: https://codereview.chromium.org/2170973002
Cr-Commit-Position: refs/heads/master@{#406988}

third_party/WebKit/Source/modules/webaudio/PannerNode.cpp

@@ -131,16 +131,10 @@ void PannerHandler::process(size_t framesToProcess)
     MutexTryLocker tryListenerLocker(listener()->listenerLock());
 
     if (tryLocker.locked() && tryListenerLocker.locked()) {
-        // HRTFDatabase should be loaded before proceeding when the panning model is HRTF.
-        if (m_panningModel == Panner::PanningModelHRTF && !listener()->isHRTFDatabaseLoaded()) {
-            if (context()->hasRealtimeConstraint()) {
-                // Realtime AudioContext's cannot block on the HRTFDatabase
-                // loader.  Instead, copy the input to the output so we can at
-                // least hear something until the database is ready.
-                destination->copyFrom(*source, m_channelInterpretation);
-                return;
-            }
-
+        if (!context()->hasRealtimeConstraint() && m_panningModel == Panner::PanningModelHRTF) {
+            // For an OfflineAudioContext, we need to make sure the HRTFDatabase
+            // is loaded before proceeding.  For realtime contexts, we don't
+            // have to wait.  The HRTF panner handles that case itself.
             listener()->waitForHRTFDatabaseLoaderThreadCompletion();
         }
 
@@ -161,7 +155,7 @@ void PannerHandler::process(size_t framesToProcess)
 
             azimuthElevation(&azimuth, &elevation);
 
-            m_panner->pan(azimuth, elevation, source, destination, framesToProcess);
+            m_panner->pan(azimuth, elevation, source, destination, framesToProcess, internalChannelInterpretation());
 
             // Get the distance and cone gain.
             float totalGain = distanceConeGain();
@@ -231,7 +225,7 @@ void PannerHandler::processSampleAccurateValues(AudioBus* destination, const Aud
         totalGain[k] = calculateDistanceConeGain(pannerPosition, orientation, listenerPosition);
     }
 
-    m_panner->panWithSampleAccurateValues(azimuth, elevation, source, destination, framesToProcess);
+    m_panner->panWithSampleAccurateValues(azimuth, elevation, source, destination, framesToProcess, internalChannelInterpretation());
     destination->copyWithSampleAccurateGainValuesFrom(*destination, totalGain, framesToProcess);
 }
 

third_party/WebKit/Source/platform/audio/EqualPowerPanner.cpp

@@ -36,7 +36,7 @@ EqualPowerPanner::EqualPowerPanner(float sampleRate)
 {
 }
 
-void EqualPowerPanner::pan(double azimuth, double /*elevation*/, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess)
+void EqualPowerPanner::pan(double azimuth, double /*elevation*/, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess, AudioBus::ChannelInterpretation)
 {
     bool isInputSafe = inputBus && (inputBus->numberOfChannels() == 1 || inputBus->numberOfChannels() == 2) && framesToProcess <= inputBus->length();
     ASSERT(isInputSafe);
@@ -153,7 +153,7 @@ void EqualPowerPanner::calculateDesiredGain(double& desiredGainL, double& desire
     desiredGainR = std::sin(piOverTwoDouble * desiredPanPosition);
 }
 
-void EqualPowerPanner::panWithSampleAccurateValues(double* azimuth, double* /*elevation*/, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess)
+void EqualPowerPanner::panWithSampleAccurateValues(double* azimuth, double* /*elevation*/, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess, AudioBus::ChannelInterpretation)
 {
     bool isInputSafe = inputBus && (inputBus->numberOfChannels() == 1 || inputBus->numberOfChannels() == 2) && framesToProcess <= inputBus->length();
     DCHECK(isInputSafe);

third_party/WebKit/Source/platform/audio/EqualPowerPanner.h

@@ -35,8 +35,8 @@ class PLATFORM_EXPORT EqualPowerPanner final : public Panner {
 public:
     EqualPowerPanner(float sampleRate);
 
-    void pan(double azimuth, double elevation, const AudioBus* inputBus, AudioBus* outputBuf, size_t framesToProcess) override;
-    void panWithSampleAccurateValues(double* azimuth, double* elevation, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess) override;
+    void pan(double azimuth, double elevation, const AudioBus* inputBus, AudioBus* outputBuf, size_t framesToProcess, AudioBus::ChannelInterpretation) override;
+    void panWithSampleAccurateValues(double* azimuth, double* elevation, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess, AudioBus::ChannelInterpretation) override;
 
     void reset() override { }
 

third_party/WebKit/Source/platform/audio/HRTFPanner.cpp

@@ -117,7 +117,7 @@ int HRTFPanner::calculateDesiredAzimuthIndexAndBlend(double azimuth, double& azi
     return desiredAzimuthIndex;
 }
 
-void HRTFPanner::pan(double desiredAzimuth, double elevation, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess)
+void HRTFPanner::pan(double desiredAzimuth, double elevation, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess, AudioBus::ChannelInterpretation channelInterpretation)
 {
     unsigned numInputChannels = inputBus ? inputBus->numberOfChannels() : 0;
 
@@ -134,9 +134,8 @@ void HRTFPanner::pan(double desiredAzimuth, double elevation, const AudioBus* in
     }
 
     HRTFDatabase* database = m_databaseLoader->database();
-    ASSERT(database);
     if (!database) {
-        outputBus->zero();
+        outputBus->copyFrom(*inputBus, channelInterpretation);
         return;
     }
 
@@ -292,7 +291,7 @@ void HRTFPanner::pan(double desiredAzimuth, double elevation, const AudioBus* in
     }
 }
 
-void HRTFPanner::panWithSampleAccurateValues(double* desiredAzimuth, double* elevation, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess)
+void HRTFPanner::panWithSampleAccurateValues(double* desiredAzimuth, double* elevation, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess, AudioBus::ChannelInterpretation channelInterpretation)
 {
     // Sample-accurate (a-rate) HRTF panner is not implemented, just k-rate.  Just grab the current
     // azimuth/elevation and use that.
@@ -302,7 +301,7 @@ void HRTFPanner::panWithSampleAccurateValues(double* desiredAzimuth, double* ele
     // one output sample for each possibly different impulse response.  That N^2.  Previously, we
     // used an FFT to do them all at once for a complexity of N/log2(N).  Hence, N/log2(N) times
     // more complex.)
-    pan(desiredAzimuth[0], elevation[0], inputBus, outputBus, framesToProcess);
+    pan(desiredAzimuth[0], elevation[0], inputBus, outputBus, framesToProcess, channelInterpretation);
 }
 
 double HRTFPanner::tailTime() const

third_party/WebKit/Source/platform/audio/HRTFPanner.h

@@ -38,8 +38,8 @@ public:
     ~HRTFPanner() override;
 
     // Panner
-    void pan(double azimuth, double elevation, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess) override;
-    void panWithSampleAccurateValues(double* azimuth, double* elevation, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess) override;
+    void pan(double azimuth, double elevation, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess, AudioBus::ChannelInterpretation) override;
+    void panWithSampleAccurateValues(double* azimuth, double* elevation, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess, AudioBus::ChannelInterpretation) override;
 
     void reset() override;
 

third_party/WebKit/Source/platform/audio/Panner.h

@@ -30,6 +30,7 @@
 #define Panner_h
 
 #include "platform/PlatformExport.h"
+#include "platform/audio/AudioBus.h"
 #include "wtf/Allocator.h"
 #include "wtf/Noncopyable.h"
 #include "wtf/build_config.h"
@@ -37,7 +38,6 @@
 
 namespace blink {
 
-class AudioBus;
 class HRTFDatabaseLoader;
 
 // Abstract base class for panning a mono or stereo source.
@@ -58,8 +58,8 @@ public:
 
     virtual ~Panner() { };
 
-    virtual void pan(double azimuth, double elevation, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess) = 0;
-    virtual void panWithSampleAccurateValues(double* azimuth, double* elevation, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess) = 0;
+    virtual void pan(double azimuth, double elevation, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess, AudioBus::ChannelInterpretation) = 0;
+    virtual void panWithSampleAccurateValues(double* azimuth, double* elevation, const AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess, AudioBus::ChannelInterpretation) = 0;
 
     virtual void reset() = 0;