/*

 * 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

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY

 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

 * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY

 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES

 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;

 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON

 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#ifndef HRTFPanner_h

#define HRTFPanner_h

#include "FFTConvolver.h"

#include "DelayBuffer.h"

#include "mozilla/MemoryReporting.h"

namespace mozilla {

class AudioBlock;

} // namespace mozilla

namespace WebCore {

typedef nsTArray<float> AudioFloatArray;

class HRTFDatabaseLoader;

using mozilla::AudioBlock;

class HRTFPanner {

public:

    HRTFPanner(float sampleRate, already_AddRefed<HRTFDatabaseLoader> databaseLoader);

    ~HRTFPanner();

    // chunk durations must be 128

    void pan(double azimuth, double elevation, const AudioBlock* inputBus, AudioBlock* outputBus);

    void reset();

    size_t fftSize() const { return m_convolverL1.fftSize(); }

    float sampleRate() const { return m_sampleRate; }

    int maxTailFrames() const;

    size_t sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;

private:

    // Given an azimuth angle in the range -180 -> +180, returns the corresponding azimuth index for the database,

    // and azimuthBlend which is an interpolation value from 0 -> 1.

    int calculateDesiredAzimuthIndexAndBlend(double azimuth, double& azimuthBlend);

    RefPtr<HRTFDatabaseLoader> m_databaseLoader;

    float m_sampleRate;

    // We maintain two sets of convolvers for smooth cross-faded interpolations when

    // then azimuth and elevation are dynamically changing.

    // When the azimuth and elevation are not changing, we simply process with one of the two sets.

    // Initially we use CrossfadeSelection1 corresponding to m_convolverL1 and m_convolverR1.

    // Whenever the azimuth or elevation changes, a crossfade is initiated to transition

    // to the new position. So if we're currently processing with CrossfadeSelection1, then

    // we transition to CrossfadeSelection2 (and vice versa).

    // If we're in the middle of a transition, then we wait until it is complete before

    // initiating a new transition.

    // Selects either the convolver set (m_convolverL1, m_convolverR1) or (m_convolverL2, m_convolverR2).

    enum CrossfadeSelection {

        CrossfadeSelection1,

        CrossfadeSelection2

    };

    CrossfadeSelection m_crossfadeSelection;

    // azimuth/elevation for CrossfadeSelection1.

    int m_azimuthIndex1;

    double m_elevation1;

    // azimuth/elevation for CrossfadeSelection2.

    int m_azimuthIndex2;

    double m_elevation2;

    // A crossfade value 0 <= m_crossfadeX <= 1.

    float m_crossfadeX;

    // Per-sample-frame crossfade value increment.

    float m_crossfadeIncr;

    FFTConvolver m_convolverL1;

    FFTConvolver m_convolverR1;

    FFTConvolver m_convolverL2;

    FFTConvolver m_convolverR2;

    mozilla::DelayBuffer m_delayLine;

    AudioFloatArray m_tempL1;

    AudioFloatArray m_tempR1;

    AudioFloatArray m_tempL2;

    AudioFloatArray m_tempR2;

};

} // namespace WebCore

#endif // HRTFPanner_h