michael@0: /*
michael@0:  * Copyright (C) 2010, Google Inc. All rights reserved.
michael@0:  *
michael@0:  * Redistribution and use in source and binary forms, with or without
michael@0:  * modification, are permitted provided that the following conditions
michael@0:  * are met:
michael@0:  * 1.  Redistributions of source code must retain the above copyright
michael@0:  *    notice, this list of conditions and the following disclaimer.
michael@0:  * 2.  Redistributions in binary form must reproduce the above copyright
michael@0:  *    notice, this list of conditions and the following disclaimer in the
michael@0:  *    documentation and/or other materials provided with the distribution.
michael@0:  *
michael@0:  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
michael@0:  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
michael@0:  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
michael@0:  * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
michael@0:  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
michael@0:  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
michael@0:  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
michael@0:  * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
michael@0:  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
michael@0:  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0:  */
michael@0: 
michael@0: #ifndef HRTFPanner_h
michael@0: #define HRTFPanner_h
michael@0: 
michael@0: #include "FFTConvolver.h"
michael@0: #include "DelayBuffer.h"
michael@0: #include "mozilla/MemoryReporting.h"
michael@0: 
michael@0: namespace mozilla {
michael@0: struct AudioChunk;
michael@0: }
michael@0: 
michael@0: namespace WebCore {
michael@0: 
michael@0: class HRTFDatabaseLoader;
michael@0: 
michael@0: using mozilla::AudioChunk;
michael@0: 
michael@0: class HRTFPanner {
michael@0: public:
michael@0:     HRTFPanner(float sampleRate, mozilla::TemporaryRef<HRTFDatabaseLoader> databaseLoader);
michael@0:     ~HRTFPanner();
michael@0: 
michael@0:     // chunk durations must be 128
michael@0:     void pan(double azimuth, double elevation, const AudioChunk* inputBus, AudioChunk* outputBus);
michael@0:     void reset();
michael@0: 
michael@0:     size_t fftSize() const { return m_convolverL1.fftSize(); }
michael@0: 
michael@0:     float sampleRate() const { return m_sampleRate; }
michael@0: 
michael@0:     int maxTailFrames() const;
michael@0: 
michael@0:     size_t sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
michael@0: 
michael@0: private:
michael@0:     // Given an azimuth angle in the range -180 -> +180, returns the corresponding azimuth index for the database,
michael@0:     // and azimuthBlend which is an interpolation value from 0 -> 1.
michael@0:     int calculateDesiredAzimuthIndexAndBlend(double azimuth, double& azimuthBlend);
michael@0: 
michael@0:     mozilla::RefPtr<HRTFDatabaseLoader> m_databaseLoader;
michael@0: 
michael@0:     float m_sampleRate;
michael@0: 
michael@0:     // We maintain two sets of convolvers for smooth cross-faded interpolations when
michael@0:     // then azimuth and elevation are dynamically changing.
michael@0:     // When the azimuth and elevation are not changing, we simply process with one of the two sets.
michael@0:     // Initially we use CrossfadeSelection1 corresponding to m_convolverL1 and m_convolverR1.
michael@0:     // Whenever the azimuth or elevation changes, a crossfade is initiated to transition
michael@0:     // to the new position. So if we're currently processing with CrossfadeSelection1, then
michael@0:     // we transition to CrossfadeSelection2 (and vice versa).
michael@0:     // If we're in the middle of a transition, then we wait until it is complete before
michael@0:     // initiating a new transition.
michael@0: 
michael@0:     // Selects either the convolver set (m_convolverL1, m_convolverR1) or (m_convolverL2, m_convolverR2).
michael@0:     enum CrossfadeSelection {
michael@0:         CrossfadeSelection1,
michael@0:         CrossfadeSelection2
michael@0:     };
michael@0: 
michael@0:     CrossfadeSelection m_crossfadeSelection;
michael@0: 
michael@0:     // azimuth/elevation for CrossfadeSelection1.
michael@0:     int m_azimuthIndex1;
michael@0:     double m_elevation1;
michael@0: 
michael@0:     // azimuth/elevation for CrossfadeSelection2.
michael@0:     int m_azimuthIndex2;
michael@0:     double m_elevation2;
michael@0: 
michael@0:     // A crossfade value 0 <= m_crossfadeX <= 1.
michael@0:     float m_crossfadeX;
michael@0: 
michael@0:     // Per-sample-frame crossfade value increment.
michael@0:     float m_crossfadeIncr;
michael@0: 
michael@0:     FFTConvolver m_convolverL1;
michael@0:     FFTConvolver m_convolverR1;
michael@0:     FFTConvolver m_convolverL2;
michael@0:     FFTConvolver m_convolverR2;
michael@0: 
michael@0:     mozilla::DelayBuffer m_delayLine;
michael@0: 
michael@0:     AudioFloatArray m_tempL1;
michael@0:     AudioFloatArray m_tempR1;
michael@0:     AudioFloatArray m_tempL2;
michael@0:     AudioFloatArray m_tempR2;
michael@0: };
michael@0: 
michael@0: } // namespace WebCore
michael@0: 
michael@0: #endif // HRTFPanner_h