1 files changed, 219 insertions, 0 deletions
diff --git a/alc/mixer/mixer_c.cpp b/alc/mixer/mixer_c.cpp
new file mode 100644
index 00000000..fad33746
--- /dev/null
+++ b/alc/mixer/mixer_c.cpp
@@ -0,0 +1,219 @@
+#include "config.h"
+
+#include <cassert>
+
+#include <limits>
+
+#include "alcmain.h"
+#include "alu.h"
+
+#include "defs.h"
+#include "hrtfbase.h"
+
+
+namespace {
+
+inline float do_point(const InterpState&, const float *RESTRICT vals, const ALuint)
+{ return vals[0]; }
+inline float do_lerp(const InterpState&, const float *RESTRICT vals, const ALuint frac)
+{ return lerp(vals[0], vals[1], static_cast<float>(frac)*(1.0f/FRACTIONONE)); }
+inline float do_cubic(const InterpState&, const float *RESTRICT vals, const ALuint frac)
+{ return cubic(vals[0], vals[1], vals[2], vals[3], static_cast<float>(frac)*(1.0f/FRACTIONONE)); }
+inline float do_bsinc(const InterpState &istate, const float *RESTRICT vals, const ALuint frac)
+{
+    const size_t m{istate.bsinc.m};
+
+    // Calculate the phase index and factor.
+#define FRAC_PHASE_BITDIFF (FRACTIONBITS-BSINC_PHASE_BITS)
+    const ALuint pi{frac >> FRAC_PHASE_BITDIFF};
+    const float pf{static_cast<float>(frac & ((1<<FRAC_PHASE_BITDIFF)-1)) *
+        (1.0f/(1<<FRAC_PHASE_BITDIFF))};
+#undef FRAC_PHASE_BITDIFF
+
+    const float *fil{istate.bsinc.filter + m*pi*4};
+    const float *phd{fil + m};
+    const float *scd{phd + m};
+    const float *spd{scd + m};
+
+    // Apply the scale and phase interpolated filter.
+    float r{0.0f};
+    for(size_t j_f{0};j_f < m;j_f++)
+        r += (fil[j_f] + istate.bsinc.sf*scd[j_f] + pf*(phd[j_f] + istate.bsinc.sf*spd[j_f])) * vals[j_f];
+    return r;
+}
+inline float do_fastbsinc(const InterpState &istate, const float *RESTRICT vals, const ALuint frac)
+{
+    const size_t m{istate.bsinc.m};
+
+    // Calculate the phase index and factor.
+#define FRAC_PHASE_BITDIFF (FRACTIONBITS-BSINC_PHASE_BITS)
+    const ALuint pi{frac >> FRAC_PHASE_BITDIFF};
+    const float pf{static_cast<float>(frac & ((1<<FRAC_PHASE_BITDIFF)-1)) *
+        (1.0f/(1<<FRAC_PHASE_BITDIFF))};
+#undef FRAC_PHASE_BITDIFF
+
+    const float *fil{istate.bsinc.filter + m*pi*4};
+    const float *phd{fil + m};
+
+    // Apply the phase interpolated filter.
+    float r{0.0f};
+    for(size_t j_f{0};j_f < m;j_f++)
+        r += (fil[j_f] + pf*phd[j_f]) * vals[j_f];
+    return r;
+}
+
+using SamplerT = float(&)(const InterpState&, const float*RESTRICT, const ALuint);
+template<SamplerT Sampler>
+const float *DoResample(const InterpState *state, const float *RESTRICT src, ALuint frac,
+    ALuint increment, const al::span<float> dst)
+{
+    const InterpState istate{*state};
+    auto proc_sample = [&src,&frac,istate,increment]() -> float
+    {
+        const float ret{Sampler(istate, src, frac)};
+
+        frac += increment;
+        src  += frac>>FRACTIONBITS;
+        frac &= FRACTIONMASK;
+
+        return ret;
+    };
+    std::generate(dst.begin(), dst.end(), proc_sample);
+
+    return dst.begin();
+}
+
+inline void ApplyCoeffs(float2 *RESTRICT Values, const ALuint IrSize, const HrirArray &Coeffs,
+    const float left, const float right)
+{
+    ASSUME(IrSize >= 4);
+    for(ALuint c{0};c < IrSize;++c)
+    {
+        Values[c][0] += Coeffs[c][0] * left;
+        Values[c][1] += Coeffs[c][1] * right;
+    }
+}
+
+} // namespace
+
+template<>
+const ALfloat *Resample_<CopyTag,CTag>(const InterpState*, const ALfloat *RESTRICT src, ALuint,
+    ALuint, const al::span<float> dst)
+{
+#if defined(HAVE_SSE) || defined(HAVE_NEON)
+    /* Avoid copying the source data if it's aligned like the destination. */
+    if((reinterpret_cast<intptr_t>(src)&15) == (reinterpret_cast<intptr_t>(dst.data())&15))
+        return src;
+#endif
+    std::copy_n(src, dst.size(), dst.begin());
+    return dst.begin();
+}
+
+template<>
+const ALfloat *Resample_<PointTag,CTag>(const InterpState *state, const ALfloat *RESTRICT src,
+    ALuint frac, ALuint increment, const al::span<float> dst)
+{ return DoResample<do_point>(state, src, frac, increment, dst); }
+
+template<>
+const ALfloat *Resample_<LerpTag,CTag>(const InterpState *state, const ALfloat *RESTRICT src,
+    ALuint frac, ALuint increment, const al::span<float> dst)
+{ return DoResample<do_lerp>(state, src, frac, increment, dst); }
+
+template<>
+const ALfloat *Resample_<CubicTag,CTag>(const InterpState *state, const ALfloat *RESTRICT src,
+    ALuint frac, ALuint increment, const al::span<float> dst)
+{ return DoResample<do_cubic>(state, src-1, frac, increment, dst); }
+
+template<>
+const ALfloat *Resample_<BSincTag,CTag>(const InterpState *state, const ALfloat *RESTRICT src,
+    ALuint frac, ALuint increment, const al::span<float> dst)
+{ return DoResample<do_bsinc>(state, src-state->bsinc.l, frac, increment, dst); }
+
+template<>
+const ALfloat *Resample_<FastBSincTag,CTag>(const InterpState *state, const ALfloat *RESTRICT src,
+    ALuint frac, ALuint increment, const al::span<float> dst)
+{ return DoResample<do_fastbsinc>(state, src-state->bsinc.l, frac, increment, dst); }
+
+
+template<>
+void MixHrtf_<CTag>(const float *InSamples, float2 *AccumSamples, const ALuint IrSize,
+    MixHrtfFilter *hrtfparams, const size_t BufferSize)
+{ MixHrtfBase<ApplyCoeffs>(InSamples, AccumSamples, IrSize, hrtfparams, BufferSize); }
+
+template<>
+void MixHrtfBlend_<CTag>(const float *InSamples, float2 *AccumSamples, const ALuint IrSize,
+    const HrtfFilter *oldparams, MixHrtfFilter *newparams, const size_t BufferSize)
+{
+    MixHrtfBlendBase<ApplyCoeffs>(InSamples, AccumSamples, IrSize, oldparams, newparams,
+        BufferSize);
+}
+
+template<>
+void MixDirectHrtf_<CTag>(FloatBufferLine &LeftOut, FloatBufferLine &RightOut,
+    const al::span<const FloatBufferLine> InSamples, float2 *AccumSamples, DirectHrtfState *State,
+    const size_t BufferSize)
+{ MixDirectHrtfBase<ApplyCoeffs>(LeftOut, RightOut, InSamples, AccumSamples, State, BufferSize); }
+
+
+template<>
+void Mix_<CTag>(const al::span<const float> InSamples, const al::span<FloatBufferLine> OutBuffer,
+    float *CurrentGains, const float *TargetGains, const size_t Counter, const size_t OutPos)
+{
+    const ALfloat delta{(Counter > 0) ? 1.0f / static_cast<ALfloat>(Counter) : 0.0f};
+    const bool reached_target{InSamples.size() >= Counter};
+    const auto min_end = reached_target ? InSamples.begin() + Counter : InSamples.end();
+    for(FloatBufferLine &output : OutBuffer)
+    {
+        ALfloat *RESTRICT dst{al::assume_aligned<16>(output.data()+OutPos)};
+        ALfloat gain{*CurrentGains};
+        const ALfloat diff{*TargetGains - gain};
+
+        auto in_iter = InSamples.begin();
+        if(std::fabs(diff) > std::numeric_limits<float>::epsilon())
+        {
+            const ALfloat step{diff * delta};
+            ALfloat step_count{0.0f};
+            while(in_iter != min_end)
+            {
+                *(dst++) += *(in_iter++) * (gain + step*step_count);
+                step_count += 1.0f;
+            }
+            if(reached_target)
+                gain = *TargetGains;
+            else
+                gain += step*step_count;
+            *CurrentGains = gain;
+        }
+        ++CurrentGains;
+        ++TargetGains;
+
+        if(!(std::fabs(gain) > GAIN_SILENCE_THRESHOLD))
+            continue;
+        while(in_iter != InSamples.end())
+            *(dst++) += *(in_iter++) * gain;
+    }
+}
+
+/* Basically the inverse of the above. Rather than one input going to multiple
+ * outputs (each with its own gain), it's multiple inputs (each with its own
+ * gain) going to one output. This applies one row (vs one column) of a matrix
+ * transform. And as the matrices are more or less static once set up, no
+ * stepping is necessary.
+ */
+template<>
+void MixRow_<CTag>(const al::span<float> OutBuffer, const al::span<const float> Gains,
+    const float *InSamples, const size_t InStride)
+{
+    for(const float gain : Gains)
+    {
+        const float *RESTRICT input{InSamples};
+        InSamples += InStride;
+
+        if(!(std::fabs(gain) > GAIN_SILENCE_THRESHOLD))
+            continue;
+
+        auto do_mix = [gain](const float cur, const float src) noexcept -> float
+        { return cur + src*gain; };
+        std::transform(OutBuffer.begin(), OutBuffer.end(), input, OutBuffer.begin(), do_mix);
+    }
+}