diff options
| -rw-r--r-- | alc/effects/convolution.cpp | 17 |
1 files changed, 8 insertions, 9 deletions
diff --git a/alc/effects/convolution.cpp b/alc/effects/convolution.cpp index a98a0616..f3a7dbe3 100644 --- a/alc/effects/convolution.cpp +++ b/alc/effects/convolution.cpp @@ -410,13 +410,15 @@ void ConvolutionState::deviceUpdate(const DeviceBase *device, const BufferStorag /* Convert to, and pack in, a float buffer for PFFFT. Note that the * first bin stores the real component of the half-frequency bin in - * the imaginary component. + * the imaginary component. Also scale the FFT by its length so the + * iFFT'd output will be normalized. */ + static constexpr float fftscale{1.0f / float{ConvolveUpdateSize}}; for(size_t i{0};i < ConvolveUpdateSamples;++i) { - ffttmp[i*2 ] = static_cast<float>(fftbuffer[i].real()); + ffttmp[i*2 ] = static_cast<float>(fftbuffer[i].real()) * fftscale; ffttmp[i*2 + 1] = static_cast<float>((i == 0) ? - fftbuffer[ConvolveUpdateSamples+1].real() : fftbuffer[i].imag()); + fftbuffer[ConvolveUpdateSamples+1].real() : fftbuffer[i].imag()) * fftscale; } /* Reorder backward to make it suitable for pffft_zconvolve and the * subsequent pffft_transform(..., PFFFT_BACKWARD). @@ -553,7 +555,7 @@ void ConvolutionState::update(const ContextBase *context, const EffectSlot *slot mOutTarget = target.Main->Buffer; if(device->mRenderMode == RenderMode::Pairwise) { - /* Scales the azimuth of the given vector by 3 if it's in front. + /* Scales the azimuth of the given vector by 2 if it's in front. * Effectively scales +/-45 degrees to +/-90 degrees, leaving > +90 * and < -90 alone. */ @@ -682,12 +684,9 @@ void ConvolutionState::process(const size_t samplesToDo, pffft_transform(mFft.get(), mFftBuffer.data(), mFftBuffer.data(), mFftWorkBuffer.data(), PFFFT_BACKWARD); - /* The iFFT'd response is scaled up by the number of bins, so apply - * the inverse to normalize the output. - */ - static constexpr float fftscale{1.0f / float{ConvolveUpdateSize}}; + /* The filter was attenuated, so the response is already scaled. */ for(size_t i{0};i < ConvolveUpdateSamples;++i) - mOutput[c][i] = (mFftBuffer[i]+mOutput[c][ConvolveUpdateSamples+i]) * fftscale; + mOutput[c][i] = mFftBuffer[i] + mOutput[c][ConvolveUpdateSamples+i]; for(size_t i{0};i < ConvolveUpdateSamples;++i) mOutput[c][ConvolveUpdateSamples+i] = mFftBuffer[ConvolveUpdateSamples+i]; } |