lisyarus/psemek
1
0
Fork 1
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Add slerp implementation for vectors

Browse source
This commit is contained in:
Nikita Lisitsa 2020-10-08 10:56:55 +03:00
parent dc0f08e5c3
commit 420695a42b
1 changed files with 23 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

23
libs/geom/include/psemek/geom/vector.hpp
View file

@ -290,6 +290,29 @@ namespace psemek::geom
return v0 * (T(1) - t) + v1 * t;
}
template <typename T, std::size_t N>
vector<T, N> slerp(vector<T, N> const & v0, vector<T, N> const & v1, T const & t)
{
// threshold is chosen so that for abs(x) < threshold the second term in
// sin(x) Taylor series is less than the minimum value representable by T
static auto const threshold = std::pow(6 * std::numeric_limits<T>::min(), T{1}/T{3});
auto const omega = std::acos(dot(normalized(v0), normalized(v1)));
// NB: the case of omega ~ pi is ambiguous and isn't handled in any special way
if (std::abs(omega) < threshold)
{
// prevent division by zero
return normalized(lerp(v0, v1, t));
}
else
{
auto const s = std::sin(omega);
return v0 * std::sin((1 - t) * omega) / s + v1 * std::sin(t * omega) / s;
}
}
template <typename Stream, typename T, std::size_t N>
Stream & operator << (Stream & os, vector<T, N> const & v)
{