content/media/webaudio/blink/HRTFElevation.h
author Karl Tomlinson <karlt+@karlt.net>
Thu, 08 Aug 2013 21:38:30 +1200
changeset 142361 395fc5b9593cc2376f536012dc55e868c34164b5
parent 142359 9b01d3f61a1bb50c16666203ff8c114b036f602a
child 179102 7c18257d0163e793150777c8e2812cb660501adf
permissions -rw-r--r--
b=815643 Add Blink's HRTFElevation to the build r=ehsan

/*
 * 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.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE 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 OR ITS CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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 */

#ifndef HRTFElevation_h
#define HRTFElevation_h

#include "HRTFKernel.h"
#include "nsAutoRef.h"

struct SpeexResamplerState_;
typedef struct SpeexResamplerState_ SpeexResamplerState;

namespace WebCore {

// HRTFElevation contains all of the HRTFKernels (one left ear and one right ear per azimuth angle) for a particular elevation.

class HRTFElevation {
public:
    // Loads and returns an HRTFElevation with the given HRTF database subject name and elevation from browser (or WebKit.framework) resources.
    // Normally, there will only be a single HRTF database set, but this API supports the possibility of multiple ones with different names.
    // Interpolated azimuths will be generated based on InterpolationFactor.
    // Valid values for elevation are -45 -> +90 in 15 degree increments.
    static nsReturnRef<HRTFElevation> createBuiltin(int elevation, float sampleRate);

    // Given two HRTFElevations, and an interpolation factor x: 0 -> 1, returns an interpolated HRTFElevation.
    static nsReturnRef<HRTFElevation> createByInterpolatingSlices(HRTFElevation* hrtfElevation1, HRTFElevation* hrtfElevation2, float x, float sampleRate);

    double elevationAngle() const { return m_elevationAngle; }
    unsigned numberOfAzimuths() const { return NumberOfTotalAzimuths; }
    float sampleRate() const { return m_sampleRate; }
    
    // Returns the left and right kernels for the given azimuth index.
    // The interpolated delays based on azimuthBlend: 0 -> 1 are returned in frameDelayL and frameDelayR.
    void getKernelsFromAzimuth(double azimuthBlend, unsigned azimuthIndex, HRTFKernel* &kernelL, HRTFKernel* &kernelR, double& frameDelayL, double& frameDelayR);
    
    // Total number of azimuths after interpolation.
    static const unsigned NumberOfTotalAzimuths;

    static size_t fftSizeForSampleRate(float sampleRate);

private:
    HRTFElevation(const HRTFElevation& other) MOZ_DELETE;
    void operator=(const HRTFElevation& other) MOZ_DELETE;

    HRTFElevation(HRTFKernelList *kernelListL, int elevation, float sampleRate)
        : m_elevationAngle(elevation)
        , m_sampleRate(sampleRate)
    {
        m_kernelListL.SwapElements(*kernelListL);
    }

    // Returns the list of left ear HRTFKernels for all the azimuths going from 0 to 360 degrees.
    const HRTFKernelList& kernelListL() { return m_kernelListL; }

    // Given a specific azimuth and elevation angle, returns the left HRTFKernel.
    // Values for azimuth must be multiples of 15 in 0 -> 345,
    // but not all azimuths are available for elevations > +45.
    // Valid values for elevation are -45 -> +90 in 15 degree increments.
    static nsReturnRef<HRTFKernel> calculateKernelForAzimuthElevation(int azimuth, int elevation, SpeexResamplerState* resampler, float sampleRate);

    HRTFKernelList m_kernelListL;
    double m_elevationAngle;
    float m_sampleRate;
};

} // namespace WebCore

template <>
class nsAutoRefTraits<WebCore::HRTFElevation> :
    public nsPointerRefTraits<WebCore::HRTFElevation> {
public:
    static void Release(WebCore::HRTFElevation* ptr) { delete(ptr); }
};

#endif // HRTFElevation_h