Dima353/openal-soft
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Do in-place initialization for the bsinc filters

Browse Source 
Requires less dynamic allocations and less troublesome return values of large
arrays. Also reduces repetition with specified parameters.
This commit is contained in:
Chris Robinson
2020-10-18 05:34:27 -07:00
parent 24c7ddbac2
commit 20cc3882b4
1 changed files with 93 additions and 90 deletions
Download Patch File Download Diff File Expand all files Collapse all files
alc/bsinc_tables.cpp
+31 -28
View File
@@ -155,13 +155,17 @@ constexpr BSincHeader bsinc24_hdr{GenerateBSincHeader(60, 23)};
* big. This requires using heap space, which is not allowed in a constexpr
* function (maybe in C++20).
*/
template<size_t total_size>
std::array<float,total_size> GenerateBSincCoeffs(const BSincHeader &hdr)
{
auto filter = std::make_unique<double[][BSincPhaseCount+1][BSincPointsMax]>(BSincScaleCount);
template<const BSincHeader &hdr>
struct BSincFilterArray {
alignas(16) std::array<float, hdr.total_size> mTable;
/* Calculate the Kaiser-windowed Sinc filter coefficients for each scale
* and phase index.
BSincFilterArray()
{
using filter_type = double[][BSincPhaseCount+1][BSincPointsMax];
auto filter = std::make_unique<filter_type>(BSincScaleCount);
/* Calculate the Kaiser-windowed Sinc filter coefficients for each
* scale and phase index.
*/
for(unsigned int si{0};si < BSincScaleCount;++si)
{
@@ -172,8 +176,8 @@ std::array<float,total_size> GenerateBSincCoeffs(const BSincHeader &hdr)
const double scale{hdr.scaleBase + (hdr.scaleRange * si / (BSincScaleCount - 1))};
const double cutoff{scale - (hdr.scaleBase * std::max(0.5, scale) * 2.0)};
/* Do one extra phase index so that the phase delta has a proper target
* for its last index.
/* Do one extra phase index so that the phase delta has a proper
* target for its last index.
*/
for(int pi{0};pi <= BSincPhaseCount;++pi)
{
@@ -188,9 +192,7 @@ std::array<float,total_size> GenerateBSincCoeffs(const BSincHeader &hdr)
}
}
auto ret = std::make_unique<std::array<float,total_size>>();
size_t idx{0};
for(unsigned int si{0};si < BSincScaleCount-1;++si)
{
const int m{((hdr.a[si]*2) + 3) & ~3};
@@ -198,11 +200,11 @@ std::array<float,total_size> GenerateBSincCoeffs(const BSincHeader &hdr)
for(int pi{0};pi < BSincPhaseCount;++pi)
{
/* Write out the filter. Also calculate and write out the phase and
* scale deltas.
/* Write out the filter. Also calculate and write out the phase
* and scale deltas.
*/
for(int i{0};i < m;++i)
(*ret)[idx++] = static_cast<float>(filter[si][pi][o+i]);
mTable[idx++] = static_cast<float>(filter[si][pi][o+i]);
/* Linear interpolation between phases is simplified by pre-
* calculating the delta (b - a) in: x = a + f (b - a)
@@ -210,7 +212,7 @@ std::array<float,total_size> GenerateBSincCoeffs(const BSincHeader &hdr)
for(int i{0};i < m;++i)
{
const double phDelta{filter[si][pi+1][o+i] - filter[si][pi][o+i]};
(*ret)[idx++] = static_cast<float>(phDelta);
mTable[idx++] = static_cast<float>(phDelta);
}
/* Linear interpolation between scales is also simplified.
@@ -221,7 +223,7 @@ std::array<float,total_size> GenerateBSincCoeffs(const BSincHeader &hdr)
for(int i{0};i < m;++i)
{
const double scDelta{filter[si+1][pi][o+i] - filter[si][pi][o+i]};
(*ret)[idx++] = static_cast<float>(scDelta);
mTable[idx++] = static_cast<float>(scDelta);
}
/* This last simplification is done to complete the bilinear
@@ -231,12 +233,14 @@ std::array<float,total_size> GenerateBSincCoeffs(const BSincHeader &hdr)
{
const double spDelta{(filter[si+1][pi+1][o+i] - filter[si+1][pi][o+i]) -
(filter[si][pi+1][o+i] - filter[si][pi][o+i])};
(*ret)[idx++] = static_cast<float>(spDelta);
mTable[idx++] = static_cast<float>(spDelta);
}
}
}
{
/* The last scale index doesn't have any scale or scale-phase deltas. */
/* The last scale index doesn't have any scale or scale-phase
* deltas.
*/
const unsigned int si{BSincScaleCount - 1};
const int m{((hdr.a[si]*2) + 3) & ~3};
const int o{BSincPointsHalf - (m/2)};
@@ -244,28 +248,27 @@ std::array<float,total_size> GenerateBSincCoeffs(const BSincHeader &hdr)
for(int pi{0};pi < BSincPhaseCount;++pi)
{
for(int i{0};i < m;++i)
(*ret)[idx++] = static_cast<float>(filter[si][pi][o+i]);
mTable[idx++] = static_cast<float>(filter[si][pi][o+i]);
for(int i{0};i < m;++i)
{
const double phDelta{filter[si][pi+1][o+i] - filter[si][pi][o+i]};
(*ret)[idx++] = static_cast<float>(phDelta);
mTable[idx++] = static_cast<float>(phDelta);
}
for(int i{0};i < m;++i)
(*ret)[idx++] = 0.0f;
mTable[idx++] = 0.0f;
for(int i{0};i < m;++i)
(*ret)[idx++] = 0.0f;
mTable[idx++] = 0.0f;
}
}
assert(idx == total_size);
return *ret;
assert(idx == hdr.total_size);
}
};
/* FIXME: These can't be constexpr due to the calls reaching the compiler's
* step limit.
*/
alignas(16) const auto bsinc12_table = GenerateBSincCoeffs<bsinc12_hdr.total_size>(bsinc12_hdr);
alignas(16) const auto bsinc24_table = GenerateBSincCoeffs<bsinc24_hdr.total_size>(bsinc24_hdr);
const BSincFilterArray<bsinc12_hdr> bsinc12_filter{};
const BSincFilterArray<bsinc24_hdr> bsinc24_filter{};
constexpr BSincTable GenerateBSincTable(const BSincHeader &hdr, const float *tab)
@@ -284,5 +287,5 @@ constexpr BSincTable GenerateBSincTable(const BSincHeader &hdr, const float *tab
} // namespace
const BSincTable bsinc12{GenerateBSincTable(bsinc12_hdr, &bsinc12_table.front())};
const BSincTable bsinc24{GenerateBSincTable(bsinc24_hdr, &bsinc24_table.front())};
const BSincTable bsinc12{GenerateBSincTable(bsinc12_hdr, &bsinc12_filter.mTable.front())};
const BSincTable bsinc24{GenerateBSincTable(bsinc24_hdr, &bsinc24_filter.mTable.front())};