nerdcruft/libcruft-util
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n/b/patch: use fast math where appropriate

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This commit is contained in:
Danny Robson 2015-07-29 16:12:22 +10:00
parent eb155d5bb0
commit c3b4dfc34d
1 changed files with 4 additions and 3 deletions
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7
noise/basis/patch.ipp
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@ -22,6 +22,7 @@
#include "../../types.hpp" #include "../../types.hpp"
#include "../../ray.hpp" #include "../../ray.hpp"
#include "../../vector.hpp" #include "../../vector.hpp"
#include "../../maths/fast.hpp"
namespace util { namespace noise { namespace basis { namespace util { namespace noise { namespace basis {
@ -74,7 +75,7 @@ namespace util { namespace noise { namespace basis {
T distances[COUNT]; T distances[COUNT];
for (size_t i = 0; i < COUNT; ++i) for (size_t i = 0; i < COUNT; ++i)
distances[i] = util::distance (p_rem, centres[i]); distances[i] = maths::fast::sqrt (util::distance2 (p_rem, centres[i]));
// sort the distances, using indices so we can use 'offsets' to generate values // sort the distances, using indices so we can use 'offsets' to generate values
unsigned indices[COUNT]; unsigned indices[COUNT];
@ -89,7 +90,7 @@ namespace util { namespace noise { namespace basis {
// calculate normalisation constants for the 9 nearest points. the // calculate normalisation constants for the 9 nearest points. the
// neighbourhood size is implicitly specified by the 1.5 unit maximum // neighbourhood size is implicitly specified by the 1.5 unit maximum
// distance. // distance.
constexpr auto MAX_DISTANCE = std::hypot (1.5f, 1.5f); constexpr auto MAX_DISTANCE = 2.1213203435596424f; // std::hypot (1.5f, 1.5f);
const auto lo = distances[indices[0]]; const auto lo = distances[indices[0]];
const auto hi = std::min (distances[indices[COUNT-1]], MAX_DISTANCE); const auto hi = std::min (distances[indices[COUNT-1]], MAX_DISTANCE);
@ -103,7 +104,7 @@ namespace util { namespace noise { namespace basis {
{ {
auto v = generate (p_int + OFFSETS[indices[i]]); auto v = generate (p_int + OFFSETS[indices[i]]);
auto d = (distances[indices[i]] - lo) / (hi - lo); auto d = (distances[indices[i]] - lo) / (hi - lo);
auto w = std::pow (1 - d, m_power); auto w = maths::fast::pow (1-d, m_power);
sumw += w; sumw += w;
out += v * w; out += v * w;