1/*
2 * Copyright (C) 2010 Google Inc. All rights reserved.
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27 */
28
29#ifndef HRTFElevation_h
30#define HRTFElevation_h
31
32#include "HRTFKernel.h"
33#include <memory>
34#include <wtf/Noncopyable.h>
35#include <wtf/RefPtr.h>
36#include <wtf/text/WTFString.h>
37
38namespace WebCore {
39
40// HRTFElevation contains all of the HRTFKernels (one left ear and one right ear per azimuth angle) for a particular elevation.
41
42class HRTFElevation {
43 WTF_MAKE_NONCOPYABLE(HRTFElevation);
44public:
45 HRTFElevation(std::unique_ptr<HRTFKernelList> kernelListL, std::unique_ptr<HRTFKernelList> kernelListR, int elevation, float sampleRate)
46 : m_kernelListL(WTFMove(kernelListL))
47 , m_kernelListR(WTFMove(kernelListR))
48 , m_elevationAngle(elevation)
49 , m_sampleRate(sampleRate)
50 {
51 }
52
53 // Loads and returns an HRTFElevation with the given HRTF database subject name and elevation from browser (or WebKit.framework) resources.
54 // Normally, there will only be a single HRTF database set, but this API supports the possibility of multiple ones with different names.
55 // Interpolated azimuths will be generated based on InterpolationFactor.
56 // Valid values for elevation are -45 -> +90 in 15 degree increments.
57 static std::unique_ptr<HRTFElevation> createForSubject(const String& subjectName, int elevation, float sampleRate);
58
59 // Given two HRTFElevations, and an interpolation factor x: 0 -> 1, returns an interpolated HRTFElevation.
60 static std::unique_ptr<HRTFElevation> createByInterpolatingSlices(HRTFElevation* hrtfElevation1, HRTFElevation* hrtfElevation2, float x, float sampleRate);
61
62 // Returns the list of left or right ear HRTFKernels for all the azimuths going from 0 to 360 degrees.
63 HRTFKernelList* kernelListL() { return m_kernelListL.get(); }
64 HRTFKernelList* kernelListR() { return m_kernelListR.get(); }
65
66 double elevationAngle() const { return m_elevationAngle; }
67 unsigned numberOfAzimuths() const { return NumberOfTotalAzimuths; }
68 float sampleRate() const { return m_sampleRate; }
69
70 // Returns the left and right kernels for the given azimuth index.
71 // The interpolated delays based on azimuthBlend: 0 -> 1 are returned in frameDelayL and frameDelayR.
72 void getKernelsFromAzimuth(double azimuthBlend, unsigned azimuthIndex, HRTFKernel* &kernelL, HRTFKernel* &kernelR, double& frameDelayL, double& frameDelayR);
73
74 // Spacing, in degrees, between every azimuth loaded from resource.
75 static const unsigned AzimuthSpacing;
76
77 // Number of azimuths loaded from resource.
78 static const unsigned NumberOfRawAzimuths;
79
80 // Interpolates by this factor to get the total number of azimuths from every azimuth loaded from resource.
81 static const unsigned InterpolationFactor;
82
83 // Total number of azimuths after interpolation.
84 static const unsigned NumberOfTotalAzimuths;
85
86 // Given a specific azimuth and elevation angle, returns the left and right HRTFKernel.
87 // Valid values for azimuth are 0 -> 345 in 15 degree increments.
88 // Valid values for elevation are -45 -> +90 in 15 degree increments.
89 // Returns true on success.
90 static bool calculateKernelsForAzimuthElevation(int azimuth, int elevation, float sampleRate, const String& subjectName,
91 RefPtr<HRTFKernel>& kernelL, RefPtr<HRTFKernel>& kernelR);
92
93 // Given a specific azimuth and elevation angle, returns the left and right HRTFKernel in kernelL and kernelR.
94 // This method averages the measured response using symmetry of azimuth (for example by averaging the -30.0 and +30.0 azimuth responses).
95 // Returns true on success.
96 static bool calculateSymmetricKernelsForAzimuthElevation(int azimuth, int elevation, float sampleRate, const String& subjectName,
97 RefPtr<HRTFKernel>& kernelL, RefPtr<HRTFKernel>& kernelR);
98
99private:
100 std::unique_ptr<HRTFKernelList> m_kernelListL;
101 std::unique_ptr<HRTFKernelList> m_kernelListR;
102 double m_elevationAngle;
103 float m_sampleRate;
104};
105
106} // namespace WebCore
107
108#endif // HRTFElevation_h
109