diff options
Diffstat (limited to 'alc/effects/pshifter.cpp')
| -rw-r--r-- | alc/effects/pshifter.cpp | 32 |
1 files changed, 17 insertions, 15 deletions
diff --git a/alc/effects/pshifter.cpp b/alc/effects/pshifter.cpp index 62057f50..8d4aa630 100644 --- a/alc/effects/pshifter.cpp +++ b/alc/effects/pshifter.cpp @@ -57,19 +57,21 @@ static_assert(StftSize%OversampleFactor == 0, "Factor must be a clean divisor of constexpr size_t StftStep{StftSize / OversampleFactor}; /* Define a Hann window, used to filter the STFT input and output. */ -std::array<double,StftSize> InitHannWindow() -{ - std::array<double,StftSize> ret; - /* Create lookup table of the Hann window for the desired size. */ - for(size_t i{0};i < StftHalfSize;i++) +struct Windower { + alignas(16) std::array<double,StftSize> mData; + + Windower() { - constexpr double scale{al::numbers::pi / double{StftSize}}; - const double val{std::sin((static_cast<double>(i)+0.5) * scale)}; - ret[i] = ret[StftSize-1-i] = val * val; + /* Create lookup table of the Hann window for the desired size. */ + for(size_t i{0};i < StftHalfSize;i++) + { + constexpr double scale{al::numbers::pi / double{StftSize}}; + const double val{std::sin((static_cast<double>(i)+0.5) * scale)}; + mData[i] = mData[StftSize-1-i] = val * val; + } } - return ret; -} -alignas(16) const std::array<double,StftSize> HannWindow = InitHannWindow(); +}; +const Windower gWindow{}; struct FrequencyBin { @@ -182,9 +184,9 @@ void PshifterState::process(const size_t samplesToDo, * forward FFT to get the frequency-domain signal. */ for(size_t src{mPos}, k{0u};src < StftSize;++src,++k) - mFftBuffer[k] = mFIFO[src] * HannWindow[k]; + mFftBuffer[k] = mFIFO[src] * gWindow.mData[k]; for(size_t src{0u}, k{StftSize-mPos};src < mPos;++src,++k) - mFftBuffer[k] = mFIFO[src] * HannWindow[k]; + mFftBuffer[k] = mFIFO[src] * gWindow.mData[k]; forward_fft(al::as_span(mFftBuffer)); /* Analyze the obtained data. Since the real FFT is symmetric, only @@ -277,9 +279,9 @@ void PshifterState::process(const size_t samplesToDo, static constexpr double scale{4.0 / OversampleFactor / StftSize}; for(size_t dst{mPos}, k{0u};dst < StftSize;++dst,++k) - mOutputAccum[dst] += HannWindow[k]*mFftBuffer[k].real() * scale; + mOutputAccum[dst] += gWindow.mData[k]*mFftBuffer[k].real() * scale; for(size_t dst{0u}, k{StftSize-mPos};dst < mPos;++dst,++k) - mOutputAccum[dst] += HannWindow[k]*mFftBuffer[k].real() * scale; + mOutputAccum[dst] += gWindow.mData[k]*mFftBuffer[k].real() * scale; /* Copy out the accumulated result, then clear for the next iteration. */ std::copy_n(mOutputAccum.begin() + mPos, StftStep, mFIFO.begin() + mPos); |