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:  *
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:  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
michael@0:  *     its contributors may be used to endorse or promote products derived
michael@0:  *     from this software without specific prior written permission.
michael@0:  *
michael@0:  * THIS SOFTWARE IS PROVIDED BY APPLE 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 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
michael@0:  * ON 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
michael@0:  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0:  */
michael@0: 
michael@0: #ifndef HRTFKernel_h
michael@0: #define HRTFKernel_h
michael@0: 
michael@0: #include "nsAutoPtr.h"
michael@0: #include "nsAutoRef.h"
michael@0: #include "nsTArray.h"
michael@0: #include "mozilla/FFTBlock.h"
michael@0: #include "mozilla/MemoryReporting.h"
michael@0: 
michael@0: namespace WebCore {
michael@0: 
michael@0: using mozilla::FFTBlock;
michael@0: 
michael@0: // HRTF stands for Head-Related Transfer Function.
michael@0: // HRTFKernel is a frequency-domain representation of an impulse-response used as part of the spatialized panning system.
michael@0: // For a given azimuth / elevation angle there will be one HRTFKernel for the left ear transfer function, and one for the right ear.
michael@0: // The leading delay (average group delay) for each impulse response is extracted:
michael@0: //      m_fftFrame is the frequency-domain representation of the impulse response with the delay removed
michael@0: //      m_frameDelay is the leading delay of the original impulse response.
michael@0: class HRTFKernel {
michael@0: public:
michael@0:     // Note: this is destructive on the passed in |impulseResponse|.
michael@0:     // The |length| of |impulseResponse| must be a power of two.
michael@0:     // The size of the DFT will be |2 * length|.
michael@0:     static nsReturnRef<HRTFKernel> create(float* impulseResponse, size_t length, float sampleRate);
michael@0: 
michael@0:     static nsReturnRef<HRTFKernel> create(nsAutoPtr<FFTBlock> fftFrame, float frameDelay, float sampleRate);
michael@0: 
michael@0:     // Given two HRTFKernels, and an interpolation factor x: 0 -> 1, returns an interpolated HRTFKernel.
michael@0:     static nsReturnRef<HRTFKernel> createInterpolatedKernel(HRTFKernel* kernel1, HRTFKernel* kernel2, float x);
michael@0:   
michael@0:     FFTBlock* fftFrame() { return m_fftFrame.get(); }
michael@0:     
michael@0:     size_t fftSize() const { return m_fftFrame->FFTSize(); }
michael@0:     float frameDelay() const { return m_frameDelay; }
michael@0: 
michael@0:     float sampleRate() const { return m_sampleRate; }
michael@0:     double nyquist() const { return 0.5 * sampleRate(); }
michael@0: 
michael@0:     size_t sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
michael@0:     {
michael@0:         size_t amount = aMallocSizeOf(this);
michael@0:         amount += m_fftFrame->SizeOfIncludingThis(aMallocSizeOf);
michael@0:         return amount;
michael@0:     }
michael@0: 
michael@0: private:
michael@0:     HRTFKernel(const HRTFKernel& other) MOZ_DELETE;
michael@0:     void operator=(const HRTFKernel& other) MOZ_DELETE;
michael@0: 
michael@0:     // Note: this is destructive on the passed in |impulseResponse|.
michael@0:     HRTFKernel(float* impulseResponse, size_t fftSize, float sampleRate);
michael@0:     
michael@0:     HRTFKernel(nsAutoPtr<FFTBlock> fftFrame, float frameDelay, float sampleRate)
michael@0:         : m_fftFrame(fftFrame)
michael@0:         , m_frameDelay(frameDelay)
michael@0:         , m_sampleRate(sampleRate)
michael@0:     {
michael@0:     }
michael@0:     
michael@0:     nsAutoPtr<FFTBlock> m_fftFrame;
michael@0:     float m_frameDelay;
michael@0:     float m_sampleRate;
michael@0: };
michael@0: 
michael@0: typedef nsTArray<nsAutoRef<HRTFKernel> > HRTFKernelList;
michael@0: 
michael@0: } // namespace WebCore
michael@0: 
michael@0: template <>
michael@0: class nsAutoRefTraits<WebCore::HRTFKernel> :
michael@0:     public nsPointerRefTraits<WebCore::HRTFKernel> {
michael@0: public:
michael@0:     static void Release(WebCore::HRTFKernel* ptr) { delete(ptr); }
michael@0: };
michael@0: 
michael@0: namespace WebCore {
michael@0: 
michael@0: inline nsReturnRef<HRTFKernel> HRTFKernel::create(float* impulseResponse, size_t length, float sampleRate)
michael@0: {
michael@0:     return nsReturnRef<HRTFKernel>(new HRTFKernel(impulseResponse, length, sampleRate));
michael@0: }
michael@0: 
michael@0: inline nsReturnRef<HRTFKernel> HRTFKernel::create(nsAutoPtr<FFTBlock> fftFrame, float frameDelay, float sampleRate)
michael@0: {
michael@0:     return nsReturnRef<HRTFKernel>(new HRTFKernel(fftFrame, frameDelay, sampleRate));
michael@0: }
michael@0: 
michael@0: } // namespace WebCore
michael@0: #endif // HRTFKernel_h