Implement a "fast" bsinc path

This takes advantage of the fact than when increment <= 1 (when not down-
sampling), the scale factor is always 0. As a result, the scale and scale-phase
deltas never contribute to the filtered output. Removing those multiply+add
operations cuts half of the work done by the inner loop.

Sounds that do need to down-sample (when played with a high pitch, or is 48khz
on 44.1khz output, for example), still go through the normal bsinc process.

1 files changed, 1 insertions, 1 deletions

diff --git a/alc/converter.cpp b/alc/converter.cpp
index 6622a997..b0efb839 100644
--- a/alc/converter.cpp
+++ b/alc/converter.cpp
@@ -171,7 +171,7 @@ SampleConverterPtr CreateSampleConverter(DevFmtType srcType, DevFmtType dstType,
             BsincPrepare(converter->mIncrement, &converter->mState.bsinc, &bsinc24);
         else if(resampler == Resampler::BSinc12)
             BsincPrepare(converter->mIncrement, &converter->mState.bsinc, &bsinc12);
-        converter->mResample = SelectResampler(resampler);
+        converter->mResample = SelectResampler(resampler, converter->mIncrement);
     }
 
     return converter;