diff options
| -rw-r--r-- | alc/bsinc_tables.cpp | 57 |
1 files changed, 27 insertions, 30 deletions
diff --git a/alc/bsinc_tables.cpp b/alc/bsinc_tables.cpp index d9ead41c..c1a7d054 100644 --- a/alc/bsinc_tables.cpp +++ b/alc/bsinc_tables.cpp @@ -110,45 +110,42 @@ constexpr double CalcKaiserBeta(const double rejection) struct BSincHeader { - double width; - double beta; - double scaleBase; - double scaleRange; - double besseli_0_beta; - - int a[BSINC_SCALE_COUNT]; - int total_size; -}; + double width{}; + double beta{}; + double scaleBase{}; + double scaleRange{}; + double besseli_0_beta{}; -constexpr BSincHeader GenerateBSincHeader(int Rejection, int Order) -{ - BSincHeader ret{}; - ret.width = CalcKaiserWidth(Rejection, Order); - ret.beta = CalcKaiserBeta(Rejection); - ret.scaleBase = ret.width / 2.0; - ret.scaleRange = 1.0 - ret.scaleBase; - ret.besseli_0_beta = BesselI_0(ret.beta); - - int num_points{Order+1}; - for(int si{0};si < BSincScaleCount;++si) + int a[BSINC_SCALE_COUNT]{}; + int total_size{}; + + constexpr BSincHeader(int Rejection, int Order) noexcept { - const double scale{ret.scaleBase + (ret.scaleRange * si / (BSincScaleCount - 1))}; - const int a{std::min(static_cast<int>(num_points / 2.0 / scale), num_points)}; - const int m{2 * a}; + width = CalcKaiserWidth(Rejection, Order); + beta = CalcKaiserBeta(Rejection); + scaleBase = width / 2.0; + scaleRange = 1.0 - scaleBase; + besseli_0_beta = BesselI_0(beta); + + int num_points{Order+1}; + for(int si{0};si < BSincScaleCount;++si) + { + const double scale{scaleBase + (scaleRange * si / (BSincScaleCount - 1))}; + const int a_{std::min(static_cast<int>(num_points / 2.0 / scale), num_points)}; + const int m{2 * a_}; - ret.a[si] = a; - ret.total_size += 4 * BSincPhaseCount * ((m+3) & ~3); + a[si] = a_; + total_size += 4 * BSincPhaseCount * ((m+3) & ~3); + } } - - return ret; -} +}; /* 11th and 23rd order filters (12 and 24-point respectively) with a 60dB drop * at nyquist. Each filter will scale up the order when downsampling, to 23rd * and 47th order respectively. */ -constexpr BSincHeader bsinc12_hdr{GenerateBSincHeader(60, 11)}; -constexpr BSincHeader bsinc24_hdr{GenerateBSincHeader(60, 23)}; +constexpr BSincHeader bsinc12_hdr{60, 11}; +constexpr BSincHeader bsinc24_hdr{60, 23}; /* FIXME: This should be constexpr, but the temporary filter arrays are too |