gecko-dev/dom/media/webaudio/PannerNode.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "PannerNode.h"
#include "AlignmentUtils.h"
#include "AudioDestinationNode.h"
#include "AudioNodeEngine.h"
#include "AudioNodeStream.h"
#include "AudioListener.h"
#include "PanningUtils.h"
#include "AudioBufferSourceNode.h"
#include "PlayingRefChangeHandler.h"
#include "blink/HRTFPanner.h"
#include "blink/HRTFDatabaseLoader.h"
#include "nsAutoPtr.h"

using WebCore::HRTFDatabaseLoader;
using WebCore::HRTFPanner;

namespace mozilla {
namespace dom {

using namespace std;

NS_IMPL_CYCLE_COLLECTION_CLASS(PannerNode)
NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(PannerNode, AudioNode)
NS_IMPL_CYCLE_COLLECTION_UNLINK(mPositionX, mPositionY, mPositionZ, mOrientationX, mOrientationY, mOrientationZ)
NS_IMPL_CYCLE_COLLECTION_UNLINK_END
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(PannerNode, AudioNode)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mPositionX, mPositionY, mPositionZ, mOrientationX, mOrientationY, mOrientationZ)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(PannerNode)
NS_INTERFACE_MAP_END_INHERITING(AudioNode)

NS_IMPL_ADDREF_INHERITED(PannerNode, AudioNode)
NS_IMPL_RELEASE_INHERITED(PannerNode, AudioNode)

class PannerNodeEngine final : public AudioNodeEngine
{
public:
  explicit PannerNodeEngine(AudioNode* aNode,
                            AudioDestinationNode* aDestination,
                            const AudioListenerEngine* aListenerEngine)
    : AudioNodeEngine(aNode)
    , mDestination(aDestination->Stream())
    , mListenerEngine(aListenerEngine)
    // Please keep these default values consistent with PannerNode::PannerNode
    // below.
    , mPanningModelFunction(&PannerNodeEngine::EqualPowerPanningFunction)
    , mDistanceModelFunction(&PannerNodeEngine::InverseGainFunction)
    , mPositionX(0.)
    , mPositionY(0.)
    , mPositionZ(0.)
    , mOrientationX(1.)
    , mOrientationY(0.)
    , mOrientationZ(0.)
    , mRefDistance(1.)
    , mMaxDistance(10000.)
    , mRolloffFactor(1.)
    , mConeInnerAngle(360.)
    , mConeOuterAngle(360.)
    , mConeOuterGain(0.)
    , mLeftOverData(INT_MIN)
  {
  }

  void RecvTimelineEvent(uint32_t aIndex, AudioTimelineEvent& aEvent) override
  {
    MOZ_ASSERT(mDestination);
    WebAudioUtils::ConvertAudioTimelineEventToTicks(aEvent,
                                                    mDestination);
    switch (aIndex) {
    case PannerNode::POSITIONX:
      mPositionX.InsertEvent<int64_t>(aEvent);
      break;
    case PannerNode::POSITIONY:
      mPositionY.InsertEvent<int64_t>(aEvent);
      break;
    case PannerNode::POSITIONZ:
      mPositionZ.InsertEvent<int64_t>(aEvent);
      break;
    case PannerNode::ORIENTATIONX:
      mOrientationX.InsertEvent<int64_t>(aEvent);
      break;
    case PannerNode::ORIENTATIONY:
      mOrientationY.InsertEvent<int64_t>(aEvent);
      break;
    case PannerNode::ORIENTATIONZ:
      mOrientationZ.InsertEvent<int64_t>(aEvent);
      break;
    default:
      NS_ERROR("Bad PannerNode TimelineParameter");
    }
  }

  void CreateHRTFPanner()
  {
    MOZ_ASSERT(NS_IsMainThread());
    if (mHRTFPanner) {
      return;
    }
    // HRTFDatabaseLoader needs to be fetched on the main thread.
    already_AddRefed<HRTFDatabaseLoader> loader =
      HRTFDatabaseLoader::createAndLoadAsynchronouslyIfNecessary(NodeMainThread()->Context()->SampleRate());
    mHRTFPanner = new HRTFPanner(NodeMainThread()->Context()->SampleRate(), std::move(loader));
  }

  void SetInt32Parameter(uint32_t aIndex, int32_t aParam) override
  {
    switch (aIndex) {
    case PannerNode::PANNING_MODEL:
      switch (PanningModelType(aParam)) {
        case PanningModelType::Equalpower:
          mPanningModelFunction = &PannerNodeEngine::EqualPowerPanningFunction;
          break;
        case PanningModelType::HRTF:
          mPanningModelFunction = &PannerNodeEngine::HRTFPanningFunction;
          break;
        default:
          MOZ_ASSERT_UNREACHABLE("We should never see alternate names here");
          break;
      }
      break;
    case PannerNode::DISTANCE_MODEL:
      switch (DistanceModelType(aParam)) {
        case DistanceModelType::Inverse:
          mDistanceModelFunction = &PannerNodeEngine::InverseGainFunction;
          break;
        case DistanceModelType::Linear:
          mDistanceModelFunction = &PannerNodeEngine::LinearGainFunction;
          break;
        case DistanceModelType::Exponential:
          mDistanceModelFunction = &PannerNodeEngine::ExponentialGainFunction;
          break;
        default:
          MOZ_ASSERT_UNREACHABLE("We should never see alternate names here");
          break;
      }
      break;
    default:
      NS_ERROR("Bad PannerNodeEngine Int32Parameter");
    }
  }
  void SetThreeDPointParameter(uint32_t aIndex, const ThreeDPoint& aParam) override
  {
    switch (aIndex) {
    case PannerNode::POSITION:
      mPositionX.SetValue(aParam.x);
      mPositionY.SetValue(aParam.y);
      mPositionZ.SetValue(aParam.z);
      break;
    case PannerNode::ORIENTATION:
      mOrientationX.SetValue(aParam.x);
      mOrientationY.SetValue(aParam.y);
      mOrientationZ.SetValue(aParam.z);
      break;
    default:
      NS_ERROR("Bad PannerNodeEngine ThreeDPointParameter");
    }
  }
  void SetDoubleParameter(uint32_t aIndex, double aParam) override
  {
    switch (aIndex) {
    case PannerNode::REF_DISTANCE: mRefDistance = aParam; break;
    case PannerNode::MAX_DISTANCE: mMaxDistance = aParam; break;
    case PannerNode::ROLLOFF_FACTOR: mRolloffFactor = aParam; break;
    case PannerNode::CONE_INNER_ANGLE: mConeInnerAngle = aParam; break;
    case PannerNode::CONE_OUTER_ANGLE: mConeOuterAngle = aParam; break;
    case PannerNode::CONE_OUTER_GAIN: mConeOuterGain = aParam; break;
    default:
      NS_ERROR("Bad PannerNodeEngine DoubleParameter");
    }
  }

  void ProcessBlock(AudioNodeStream* aStream,
                    GraphTime aFrom,
                    const AudioBlock& aInput,
                    AudioBlock* aOutput,
                    bool *aFinished) override
  {
    if (aInput.IsNull()) {
      // mLeftOverData != INT_MIN means that the panning model was HRTF and a
      // tail-time reference was added.  Even if the model is now equalpower,
      // the reference will need to be removed.
      if (mLeftOverData > 0 &&
          mPanningModelFunction == &PannerNodeEngine::HRTFPanningFunction) {
        mLeftOverData -= WEBAUDIO_BLOCK_SIZE;
      } else {
        if (mLeftOverData != INT_MIN) {
          mLeftOverData = INT_MIN;
          aStream->ScheduleCheckForInactive();
          mHRTFPanner->reset();

          RefPtr<PlayingRefChangeHandler> refchanged =
            new PlayingRefChangeHandler(aStream, PlayingRefChangeHandler::RELEASE);
          aStream->Graph()->DispatchToMainThreadAfterStreamStateUpdate(
            refchanged.forget());
        }
        aOutput->SetNull(WEBAUDIO_BLOCK_SIZE);
        return;
      }
    } else if (mPanningModelFunction == &PannerNodeEngine::HRTFPanningFunction) {
      if (mLeftOverData == INT_MIN) {
        RefPtr<PlayingRefChangeHandler> refchanged =
          new PlayingRefChangeHandler(aStream, PlayingRefChangeHandler::ADDREF);
        aStream->Graph()->DispatchToMainThreadAfterStreamStateUpdate(
          refchanged.forget());
      }
      mLeftOverData = mHRTFPanner->maxTailFrames();
    }

    StreamTime tick = mDestination->GraphTimeToStreamTime(aFrom);
    (this->*mPanningModelFunction)(aInput, aOutput, tick);
  }

  bool IsActive() const override
  {
    return mLeftOverData != INT_MIN;
  }

  void ComputeAzimuthAndElevation(const ThreeDPoint& position, float& aAzimuth, float& aElevation);
  float ComputeConeGain(const ThreeDPoint& position, const ThreeDPoint& orientation);
  // Compute how much the distance contributes to the gain reduction.
  double ComputeDistanceGain(const ThreeDPoint& position);

  void EqualPowerPanningFunction(const AudioBlock& aInput, AudioBlock* aOutput, StreamTime tick);
  void HRTFPanningFunction(const AudioBlock& aInput, AudioBlock* aOutput, StreamTime tick);

  float LinearGainFunction(double aDistance);
  float InverseGainFunction(double aDistance);
  float ExponentialGainFunction(double aDistance);

  ThreeDPoint ConvertAudioParamTimelineTo3DP(AudioParamTimeline& aX, AudioParamTimeline& aY, AudioParamTimeline& aZ, StreamTime& tick);

  size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const override
  {
    size_t amount = AudioNodeEngine::SizeOfExcludingThis(aMallocSizeOf);
    if (mHRTFPanner) {
      amount += mHRTFPanner->sizeOfIncludingThis(aMallocSizeOf);
    }

    return amount;
  }

  size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const override
  {
    return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
  }

  RefPtr<AudioNodeStream> mDestination;
  // This member is set on the main thread, but is not accessed on the rendering
  // thread untile mPanningModelFunction has changed, and this happens strictly
  // later, via a MediaStreamGraph ControlMessage.
  nsAutoPtr<HRTFPanner> mHRTFPanner;
  // This is set in the ctor, and guaranteed to live longer than this engine:
  // its lifetime is the same as the AudioContext itself.
  const AudioListenerEngine* mListenerEngine;
  typedef void (PannerNodeEngine::*PanningModelFunction)(const AudioBlock& aInput, AudioBlock* aOutput, StreamTime tick);
  PanningModelFunction mPanningModelFunction;
  typedef float (PannerNodeEngine::*DistanceModelFunction)(double aDistance);
  DistanceModelFunction mDistanceModelFunction;
  AudioParamTimeline mPositionX;
  AudioParamTimeline mPositionY;
  AudioParamTimeline mPositionZ;
  AudioParamTimeline mOrientationX;
  AudioParamTimeline mOrientationY;
  AudioParamTimeline mOrientationZ;
  double mRefDistance;
  double mMaxDistance;
  double mRolloffFactor;
  double mConeInnerAngle;
  double mConeOuterAngle;
  double mConeOuterGain;
  int mLeftOverData;
};

PannerNode::PannerNode(AudioContext* aContext)
  : AudioNode(aContext,
              2,
              ChannelCountMode::Clamped_max,
              ChannelInterpretation::Speakers)
  // Please keep these default values consistent with PannerNodeEngine::PannerNodeEngine above.
  , mPanningModel(PanningModelType::Equalpower)
  , mDistanceModel(DistanceModelType::Inverse)
  , mPositionX(new AudioParam(this, PannerNode::POSITIONX, this->NodeType(), 0.f))
  , mPositionY(new AudioParam(this, PannerNode::POSITIONY, this->NodeType(), 0.f))
  , mPositionZ(new AudioParam(this, PannerNode::POSITIONZ, this->NodeType(), 0.f))
  , mOrientationX(new AudioParam(this, PannerNode::ORIENTATIONX, this->NodeType(), 1.0f))
  , mOrientationY(new AudioParam(this, PannerNode::ORIENTATIONY, this->NodeType(), 0.f))
  , mOrientationZ(new AudioParam(this, PannerNode::ORIENTATIONZ, this->NodeType(), 0.f))
  , mRefDistance(1.)
  , mMaxDistance(10000.)
  , mRolloffFactor(1.)
  , mConeInnerAngle(360.)
  , mConeOuterAngle(360.)
  , mConeOuterGain(0.)
{
  mStream = AudioNodeStream::Create(
    aContext,
    new PannerNodeEngine(
      this, aContext->Destination(), aContext->Listener()->Engine()),
    AudioNodeStream::NO_STREAM_FLAGS,
    aContext->Graph());
}

/* static */ already_AddRefed<PannerNode>
PannerNode::Create(AudioContext& aAudioContext,
                   const PannerOptions& aOptions,
                   ErrorResult& aRv)
{
  if (aAudioContext.CheckClosed(aRv)) {
    return nullptr;
  }

  RefPtr<PannerNode> audioNode = new PannerNode(&aAudioContext);

  audioNode->Initialize(aOptions, aRv);
  if (NS_WARN_IF(aRv.Failed())) {
    return nullptr;
  }

  audioNode->SetPanningModel(aOptions.mPanningModel);
  audioNode->SetDistanceModel(aOptions.mDistanceModel);
  audioNode->SetPosition(aOptions.mPositionX, aOptions.mPositionY,
                         aOptions.mPositionZ);
  audioNode->SetOrientation(aOptions.mOrientationX, aOptions.mOrientationY,
                            aOptions.mOrientationZ);
  audioNode->SetRefDistance(aOptions.mRefDistance);
  audioNode->SetMaxDistance(aOptions.mMaxDistance);
  audioNode->SetRolloffFactor(aOptions.mRolloffFactor);
  audioNode->SetConeInnerAngle(aOptions.mConeInnerAngle);
  audioNode->SetConeOuterAngle(aOptions.mConeOuterAngle);
  audioNode->SetConeOuterGain(aOptions.mConeOuterGain);

  return audioNode.forget();
}

void PannerNode::SetPanningModel(PanningModelType aPanningModel)
{
  mPanningModel = aPanningModel;
  if (mPanningModel == PanningModelType::HRTF) {
    // We can set the engine's `mHRTFPanner` member here from the main thread,
    // because the engine will not touch it from the MediaStreamGraph
    // thread until the PANNING_MODEL message sent below is received.
    static_cast<PannerNodeEngine*>(mStream->Engine())->CreateHRTFPanner();
  }
  SendInt32ParameterToStream(PANNING_MODEL, int32_t(mPanningModel));
}

size_t
PannerNode::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
{
  return AudioNode::SizeOfExcludingThis(aMallocSizeOf);
}

size_t
PannerNode::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const
{
  return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
}

JSObject*
PannerNode::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
{
  return PannerNode_Binding::Wrap(aCx, this, aGivenProto);
}

// Those three functions are described in the spec.
float
PannerNodeEngine::LinearGainFunction(double aDistance)
{
  return 1 - mRolloffFactor * (std::max(std::min(aDistance, mMaxDistance), mRefDistance) - mRefDistance) / (mMaxDistance - mRefDistance);
}

float
PannerNodeEngine::InverseGainFunction(double aDistance)
{
  return mRefDistance / (mRefDistance + mRolloffFactor * (std::max(aDistance, mRefDistance) - mRefDistance));
}

float
PannerNodeEngine::ExponentialGainFunction(double aDistance)
{
  return pow(std::max(aDistance, mRefDistance) / mRefDistance, -mRolloffFactor);
}

void
PannerNodeEngine::HRTFPanningFunction(const AudioBlock& aInput,
                                      AudioBlock* aOutput,
                                      StreamTime tick)
{
  // The output of this node is always stereo, no matter what the inputs are.
  aOutput->AllocateChannels(2);

  float azimuth, elevation;

  ThreeDPoint position = ConvertAudioParamTimelineTo3DP(mPositionX, mPositionY, mPositionZ, tick);
  ThreeDPoint orientation = ConvertAudioParamTimelineTo3DP(mOrientationX, mOrientationY, mOrientationZ, tick);
  if (!orientation.IsZero()) {
    orientation.Normalize();
  }
  ComputeAzimuthAndElevation(position, azimuth, elevation);

  AudioBlock input = aInput;
  // Gain is applied before the delay and convolution of the HRTF.
  input.mVolume *= ComputeConeGain(position, orientation) * ComputeDistanceGain(position);

  mHRTFPanner->pan(azimuth, elevation, &input, aOutput);
}

ThreeDPoint
PannerNodeEngine::ConvertAudioParamTimelineTo3DP(AudioParamTimeline& aX, AudioParamTimeline& aY, AudioParamTimeline& aZ, StreamTime &tick)
{
  return ThreeDPoint(aX.GetValueAtTime(tick),
                     aY.GetValueAtTime(tick),
                     aZ.GetValueAtTime(tick));
}

void
PannerNodeEngine::EqualPowerPanningFunction(const AudioBlock& aInput,
                                            AudioBlock* aOutput,
                                            StreamTime tick)
{
  float azimuth, elevation, gainL, gainR, normalizedAzimuth, distanceGain, coneGain;
  int inputChannels = aInput.ChannelCount();

  // Optimize the case where the position and orientation is constant for this
  // processing block: we can just apply a constant gain on the left and right
  // channel
  if (mPositionX.HasSimpleValue() &&
      mPositionY.HasSimpleValue() &&
      mPositionZ.HasSimpleValue() &&
      mOrientationX.HasSimpleValue() &&
      mOrientationY.HasSimpleValue() &&
      mOrientationZ.HasSimpleValue()) {

    ThreeDPoint position = ConvertAudioParamTimelineTo3DP(mPositionX, mPositionY, mPositionZ, tick);
    ThreeDPoint orientation = ConvertAudioParamTimelineTo3DP(mOrientationX, mOrientationY, mOrientationZ, tick);
    if (!orientation.IsZero()) {
      orientation.Normalize();
    }

    // For a stereo source, when both the listener and the panner are in
    // the same spot, and no cone gain is specified, this node is noop.
    if (inputChannels == 2 && mListenerEngine->Position() == position &&
        mConeInnerAngle == 360 && mConeOuterAngle == 360) {
      *aOutput = aInput;
      return;
    }

    // The output of this node is always stereo, no matter what the inputs are.
    aOutput->AllocateChannels(2);

    ComputeAzimuthAndElevation(position, azimuth, elevation);
    coneGain = ComputeConeGain(position, orientation);

    // The following algorithm is described in the spec.
    // Clamp azimuth in the [-90, 90] range.
    azimuth = min(180.f, max(-180.f, azimuth));

    // Wrap around
    if (azimuth < -90.f) {
      azimuth = -180.f - azimuth;
    } else if (azimuth > 90) {
      azimuth = 180.f - azimuth;
    }

    // Normalize the value in the [0, 1] range.
    if (inputChannels == 1) {
      normalizedAzimuth = (azimuth + 90.f) / 180.f;
    } else {
      if (azimuth <= 0) {
        normalizedAzimuth = (azimuth + 90.f) / 90.f;
      } else {
        normalizedAzimuth = azimuth / 90.f;
      }
    }

    distanceGain = ComputeDistanceGain(position);

    // Actually compute the left and right gain.
    gainL = cos(0.5 * M_PI * normalizedAzimuth);
    gainR = sin(0.5 * M_PI * normalizedAzimuth);

    // Compute the output.
    ApplyStereoPanning(aInput, aOutput, gainL, gainR, azimuth <= 0);

    aOutput->mVolume = aInput.mVolume * distanceGain * coneGain;
  } else {
    float positionX[WEBAUDIO_BLOCK_SIZE];
    float positionY[WEBAUDIO_BLOCK_SIZE];
    float positionZ[WEBAUDIO_BLOCK_SIZE];
    float orientationX[WEBAUDIO_BLOCK_SIZE];
    float orientationY[WEBAUDIO_BLOCK_SIZE];
    float orientationZ[WEBAUDIO_BLOCK_SIZE];

    // The output of this node is always stereo, no matter what the inputs are.
    aOutput->AllocateChannels(2);

    if (!mPositionX.HasSimpleValue()) {
      mPositionX.GetValuesAtTime(tick, positionX, WEBAUDIO_BLOCK_SIZE);
    } else {
      positionX[0] = mPositionX.GetValueAtTime(tick);
    }
    if (!mPositionY.HasSimpleValue()) {
      mPositionY.GetValuesAtTime(tick, positionY, WEBAUDIO_BLOCK_SIZE);
    } else {
      positionY[0] = mPositionY.GetValueAtTime(tick);
    }
    if (!mPositionZ.HasSimpleValue()) {
      mPositionZ.GetValuesAtTime(tick, positionZ, WEBAUDIO_BLOCK_SIZE);
    } else {
      positionZ[0] = mPositionZ.GetValueAtTime(tick);
    }
    if (!mOrientationX.HasSimpleValue()) {
      mOrientationX.GetValuesAtTime(tick, orientationX, WEBAUDIO_BLOCK_SIZE);
    } else {
      orientationX[0] = mOrientationX.GetValueAtTime(tick);
    }
    if (!mOrientationY.HasSimpleValue()) {
      mOrientationY.GetValuesAtTime(tick, orientationY, WEBAUDIO_BLOCK_SIZE);
    } else {
      orientationY[0] = mOrientationY.GetValueAtTime(tick);
    }
    if (!mOrientationZ.HasSimpleValue()) {
      mOrientationZ.GetValuesAtTime(tick, orientationZ, WEBAUDIO_BLOCK_SIZE);
    } else {
      orientationZ[0] = mOrientationZ.GetValueAtTime(tick);
    }

    float buffer[3*WEBAUDIO_BLOCK_SIZE + 4];
    bool onLeft[WEBAUDIO_BLOCK_SIZE];

    float* alignedPanningL = ALIGNED16(buffer);
    float* alignedPanningR = alignedPanningL + WEBAUDIO_BLOCK_SIZE;
    float* alignedGain = alignedPanningR + WEBAUDIO_BLOCK_SIZE;
    ASSERT_ALIGNED16(alignedPanningL);
    ASSERT_ALIGNED16(alignedPanningR);
    ASSERT_ALIGNED16(alignedGain);

    for (size_t counter = 0; counter < WEBAUDIO_BLOCK_SIZE; ++counter) {
      ThreeDPoint position(mPositionX.HasSimpleValue() ? positionX[0] : positionX[counter],
                           mPositionY.HasSimpleValue() ? positionY[0] : positionY[counter],
                           mPositionZ.HasSimpleValue() ? positionZ[0] : positionZ[counter]);
      ThreeDPoint orientation(mOrientationX.HasSimpleValue() ? orientationX[0] : orientationX[counter],
                              mOrientationY.HasSimpleValue() ? orientationY[0] : orientationY[counter],
                              mOrientationZ.HasSimpleValue() ? orientationZ[0] : orientationZ[counter]);
      if (!orientation.IsZero()) {
        orientation.Normalize();
      }

      ComputeAzimuthAndElevation(position, azimuth, elevation);
      coneGain = ComputeConeGain(position, orientation);

      // The following algorithm is described in the spec.
      // Clamp azimuth in the [-90, 90] range.
      azimuth = min(180.f, max(-180.f, azimuth));

      // Wrap around
      if (azimuth < -90.f) {
        azimuth = -180.f - azimuth;
      } else if (azimuth > 90) {
        azimuth = 180.f - azimuth;
      }

      // Normalize the value in the [0, 1] range.
      if (inputChannels == 1) {
        normalizedAzimuth = (azimuth + 90.f) / 180.f;
      } else {
        if (azimuth <= 0) {
          normalizedAzimuth = (azimuth + 90.f) / 90.f;
        } else {
          normalizedAzimuth = azimuth / 90.f;
        }
      }

      distanceGain = ComputeDistanceGain(position);

      // Actually compute the left and right gain.
      float gainL = cos(0.5 * M_PI * normalizedAzimuth);
      float gainR = sin(0.5 * M_PI * normalizedAzimuth);


      alignedPanningL[counter] = gainL;
      alignedPanningR[counter] = gainR;
      alignedGain[counter] = aInput.mVolume * distanceGain * coneGain;
      onLeft[counter] = azimuth <= 0;
    }

    // Apply the panning to the output buffer
    ApplyStereoPanning(aInput, aOutput, alignedPanningL, alignedPanningR, onLeft);

    // Apply the input volume, cone and distance gain to the output buffer.
    float* outputL = aOutput->ChannelFloatsForWrite(0);
    float* outputR = aOutput->ChannelFloatsForWrite(1);
    AudioBlockInPlaceScale(outputL, alignedGain);
    AudioBlockInPlaceScale(outputR, alignedGain);
  }
}

// This algorithm is specified in the webaudio spec.
void
PannerNodeEngine::ComputeAzimuthAndElevation(const ThreeDPoint& position, float& aAzimuth, float& aElevation)
{
  ThreeDPoint sourceListener = position - mListenerEngine->Position();
  if (sourceListener.IsZero()) {
    aAzimuth = 0.0;
    aElevation = 0.0;
    return;
  }

  sourceListener.Normalize();

  // Project the source-listener vector on the x-z plane.
  const ThreeDPoint& listenerFront = mListenerEngine->FrontVector();
  const ThreeDPoint& listenerRight = mListenerEngine->RightVector();
  ThreeDPoint up = listenerRight.CrossProduct(listenerFront);

  double upProjection = sourceListener.DotProduct(up);
  aElevation = 90 - 180 * acos(upProjection) / M_PI;

  if (aElevation > 90) {
    aElevation = 180 - aElevation;
  } else if (aElevation < -90) {
    aElevation = -180 - aElevation;
  }

  ThreeDPoint projectedSource = sourceListener - up * upProjection;
  if (projectedSource.IsZero()) {
    // source - listener direction is up or down.
    aAzimuth = 0.0;
    return;
  }
  projectedSource.Normalize();

  // Actually compute the angle, and convert to degrees
  double projection = projectedSource.DotProduct(listenerRight);
  aAzimuth = 180 * acos(projection) / M_PI;

  // Compute whether the source is in front or behind the listener.
  double frontBack = projectedSource.DotProduct(listenerFront);
  if (frontBack < 0) {
    aAzimuth = 360 - aAzimuth;
  }
  // Rotate the azimuth so it is relative to the listener front vector instead
  // of the right vector.
  if ((aAzimuth >= 0) && (aAzimuth <= 270)) {
    aAzimuth = 90 - aAzimuth;
  } else {
    aAzimuth = 450 - aAzimuth;
  }
}

// This algorithm is described in the WebAudio spec.
float
PannerNodeEngine::ComputeConeGain(const ThreeDPoint& position,
                                  const ThreeDPoint& orientation)
{
  // Omnidirectional source
  if (orientation.IsZero() || ((mConeInnerAngle == 360) && (mConeOuterAngle == 360))) {
    return 1;
  }

  // Normalized source-listener vector
  ThreeDPoint sourceToListener = mListenerEngine->Position() - position;
  sourceToListener.Normalize();

  // Angle between the source orientation vector and the source-listener vector
  double dotProduct = sourceToListener.DotProduct(orientation);
  double angle = 180 * acos(dotProduct) / M_PI;
  double absAngle = fabs(angle);

  // Divide by 2 here since API is entire angle (not half-angle)
  double absInnerAngle = fabs(mConeInnerAngle) / 2;
  double absOuterAngle = fabs(mConeOuterAngle) / 2;
  double gain = 1;

  if (absAngle <= absInnerAngle) {
    // No attenuation
    gain = 1;
  } else if (absAngle >= absOuterAngle) {
    // Max attenuation
    gain = mConeOuterGain;
  } else {
    // Between inner and outer cones
    // inner -> outer, x goes from 0 -> 1
    double x = (absAngle - absInnerAngle) / (absOuterAngle - absInnerAngle);
    gain = (1 - x) + mConeOuterGain * x;
  }

  return gain;
}

double
PannerNodeEngine::ComputeDistanceGain(const ThreeDPoint& position)
{
  ThreeDPoint distanceVec = position - mListenerEngine->Position();
  float distance = sqrt(distanceVec.DotProduct(distanceVec));
  return std::max(0.0f, (this->*mDistanceModelFunction)(distance));
}

} // namespace dom
} // namespace mozilla