core/mixer/defs.h

   1 #ifndef CORE_MIXER_DEFS_H
   2 #define CORE_MIXER_DEFS_H
   3
   4 #include <array>
   5 #include <cstdint>
   6 #include <cstdlib>
   7 #include <utility>
   8 #include <variant>
   9
  10 #include "alspan.h"
  11 #include "core/bufferline.h"
  12 #include "core/cubic_defs.h"
  13
  14 struct HrtfChannelState;
  15 struct HrtfFilter;
  16 struct MixHrtfFilter;
  17
  18 using uint = unsigned int;
  19 using float2 = std::array<float,2>;
  20
  21
  22 inline constexpr int MixerFracBits{16};
  23 inline constexpr int MixerFracOne{1 << MixerFracBits};
  24 inline constexpr int MixerFracMask{MixerFracOne - 1};
  25 inline constexpr int MixerFracHalf{MixerFracOne >> 1};
  26
  27 inline constexpr float GainSilenceThreshold{0.00001f}; /* -100dB */
  28
  29
  30 enum class Resampler : std::uint8_t {
  31     Point,
  32     Linear,
  33     Spline,
  34     Gaussian,
  35     FastBSinc12,
  36     BSinc12,
  37     FastBSinc24,
  38     BSinc24,
  39
  40     Max = BSinc24
  41 };
  42
  43 /* Interpolator state. Kind of a misnomer since the interpolator itself is
  44  * stateless. This just keeps it from having to recompute scale-related
  45  * mappings for every sample.
  46  */
  47 struct BsincState {
  48     float sf; /* Scale interpolation factor. */
  49     uint m; /* Coefficient count. */
  50     uint l; /* Left coefficient offset. */
  51     /* Filter coefficients, followed by the phase, scale, and scale-phase
  52      * delta coefficients. Starting at phase index 0, each subsequent phase
  53      * index follows contiguously.
  54      */
  55     al::span<const float> filter;
  56 };
  57
  58 struct CubicState {
  59     /* Filter coefficients, and coefficient deltas. Starting at phase index 0,
  60      * each subsequent phase index follows contiguously.
  61      */
  62     al::span<const CubicCoefficients,CubicPhaseCount> filter;
  63     CubicState(al::span<const CubicCoefficients,CubicPhaseCount> f) : filter{f} { }
  64 };
  65
  66 using InterpState = std::variant<std::monostate,CubicState,BsincState>;
  67
  68 using ResamplerFunc = void(*)(const InterpState *state, const al::span<const float> src, uint frac,
  69     const uint increment, const al::span<float> dst);
  70
  71 ResamplerFunc PrepareResampler(Resampler resampler, uint increment, InterpState *state);
  72
  73
  74 template<typename TypeTag, typename InstTag>
  75 void Resample_(const InterpState *state, const al::span<const float> src, uint frac,
  76     const uint increment, const al::span<float> dst);
  77
  78 template<typename InstTag>
  79 void Mix_(const al::span<const float> InSamples, const al::span<FloatBufferLine> OutBuffer,
  80     const al::span<float> CurrentGains, const al::span<const float> TargetGains,
  81     const size_t Counter, const size_t OutPos);
  82 template<typename InstTag>
  83 void Mix_(const al::span<const float> InSamples, const al::span<float> OutBuffer,
  84     float &CurrentGain, const float TargetGain, const size_t Counter);
  85
  86 template<typename InstTag>
  87 void MixHrtf_(const al::span<const float> InSamples, const al::span<float2> AccumSamples,
  88     const uint IrSize, const MixHrtfFilter *hrtfparams, const size_t SamplesToDo);
  89 template<typename InstTag>
  90 void MixHrtfBlend_(const al::span<const float> InSamples, const al::span<float2> AccumSamples,
  91     const uint IrSize, const HrtfFilter *oldparams, const MixHrtfFilter *newparams,
  92     const size_t SamplesToDo);
  93 template<typename InstTag>
  94 void MixDirectHrtf_(const FloatBufferSpan LeftOut, const FloatBufferSpan RightOut,
  95     const al::span<const FloatBufferLine> InSamples, const al::span<float2> AccumSamples,
  96     const al::span<float,BufferLineSize> TempBuf, const al::span<HrtfChannelState> ChanState,
  97     const size_t IrSize, const size_t SamplesToDo);
  98
  99 /* Vectorized resampler helpers */
 100 template<size_t N>
 101 constexpr void InitPosArrays(uint pos, uint frac, const uint increment,
 102     const al::span<uint,N> frac_arr, const al::span<uint,N> pos_arr)
 103 {
 104     static_assert(pos_arr.size() == frac_arr.size());
 105     pos_arr[0] = pos;
 106     frac_arr[0] = frac;
 107     for(size_t i{1};i < pos_arr.size();++i)
 108     {
 109         const uint frac_tmp{frac_arr[i-1] + increment};
 110         pos_arr[i] = pos_arr[i-1] + (frac_tmp>>MixerFracBits);
 111         frac_arr[i] = frac_tmp&MixerFracMask;
 112     }
 113 }
 114
 115 #endif /* CORE_MIXER_DEFS_H */