First Commit

externals/openal-soft/utils/makemhr/makemhr.h

@@ -0,0 +1,131 @@
+#ifndef MAKEMHR_H
+#define MAKEMHR_H
+
+#include <vector>
+#include <complex>
+
+#include "alcomplex.h"
+#include "polyphase_resampler.h"
+
+
+// The maximum path length used when processing filenames.
+#define MAX_PATH_LEN                 (256)
+
+// The limit to the number of 'distances' listed in the data set definition.
+// Must be less than 256
+#define MAX_FD_COUNT                 (16)
+
+// The limits to the number of 'elevations' listed in the data set definition.
+// Must be less than 256.
+#define MIN_EV_COUNT                 (5)
+#define MAX_EV_COUNT                 (181)
+
+// The limits for each of the 'azimuths' listed in the data set definition.
+// Must be less than 256.
+#define MIN_AZ_COUNT                 (1)
+#define MAX_AZ_COUNT                 (255)
+
+// The limits for the 'distance' from source to listener for each field in
+// the definition file.
+#define MIN_DISTANCE                 (0.05)
+#define MAX_DISTANCE                 (2.50)
+
+// The limits for the sample 'rate' metric in the data set definition and for
+// resampling.
+#define MIN_RATE                     (32000)
+#define MAX_RATE                     (96000)
+
+// The limits for the HRIR 'points' metric in the data set definition.
+#define MIN_POINTS                   (16)
+#define MAX_POINTS                   (8192)
+
+
+using uint = unsigned int;
+
+/* Complex double type. */
+using complex_d = std::complex<double>;
+
+
+enum ChannelModeT : bool {
+    CM_AllowStereo = false,
+    CM_ForceMono = true
+};
+
+// Sample and channel type enum values.
+enum SampleTypeT {
+    ST_S16 = 0,
+    ST_S24 = 1
+};
+
+// Certain iterations rely on these integer enum values.
+enum ChannelTypeT {
+    CT_NONE   = -1,
+    CT_MONO   = 0,
+    CT_STEREO = 1
+};
+
+// Structured HRIR storage for stereo azimuth pairs, elevations, and fields.
+struct HrirAzT {
+    double mAzimuth{0.0};
+    uint mIndex{0u};
+    double mDelays[2]{0.0, 0.0};
+    double *mIrs[2]{nullptr, nullptr};
+};
+
+struct HrirEvT {
+    double mElevation{0.0};
+    al::span<HrirAzT> mAzs;
+};
+
+struct HrirFdT {
+    double mDistance{0.0};
+    uint mEvStart{0u};
+    al::span<HrirEvT> mEvs;
+};
+
+// The HRIR metrics and data set used when loading, processing, and storing
+// the resulting HRTF.
+struct HrirDataT {
+    uint mIrRate{0u};
+    SampleTypeT mSampleType{ST_S24};
+    ChannelTypeT mChannelType{CT_NONE};
+    uint mIrPoints{0u};
+    uint mFftSize{0u};
+    uint mIrSize{0u};
+    double mRadius{0.0};
+    uint mIrCount{0u};
+
+    std::vector<double> mHrirsBase;
+    std::vector<HrirEvT> mEvsBase;
+    std::vector<HrirAzT> mAzsBase;
+
+    std::vector<HrirFdT> mFds;
+
+    /* GCC warns when it tries to inline this. */
+    ~HrirDataT();
+};
+
+
+bool PrepareHrirData(const al::span<const double> distances,
+    const al::span<const uint,MAX_FD_COUNT> evCounts,
+    const al::span<const std::array<uint,MAX_EV_COUNT>,MAX_FD_COUNT> azCounts, HrirDataT *hData);
+void MagnitudeResponse(const uint n, const complex_d *in, double *out);
+
+// Performs a forward FFT.
+inline void FftForward(const uint n, complex_d *inout)
+{ forward_fft(al::as_span(inout, n)); }
+
+// Performs an inverse FFT.
+inline void FftInverse(const uint n, complex_d *inout)
+{
+    inverse_fft(al::as_span(inout, n));
+    double f{1.0 / n};
+    for(uint i{0};i < n;i++)
+        inout[i] *= f;
+}
+
+// Performs linear interpolation.
+inline double Lerp(const double a, const double b, const double f)
+{ return a + f * (b - a); }
+
+#endif /* MAKEMHR_H */