Further optimized glm::sign for signed and unsigned int #271

This commit is contained in:
Christophe Riccio 2014-11-21 23:43:48 +01:00
parent f98f2b107a
commit 38161f01f8
3 changed files with 37 additions and 2 deletions

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@ -128,6 +128,36 @@ namespace detail
return a ? y : x;
}
};
template <typename T, precision P, template <class, precision> class vecType, bool isFloat = true, bool isSigned = true>
struct compute_sign
{
GLM_FUNC_QUALIFIER static vecType<T, P> call(vecType<T, P> const & x)
{
return vecType<T, P>(glm::lessThan(vecType<T, P>(0), x)) - vecType<T, P>(glm::lessThan(x, vecType<T, P>(0)));
}
};
template <typename T, precision P, template <class, precision> class vecType>
struct compute_sign<T, P, vecType, false, false>
{
GLM_FUNC_QUALIFIER static vecType<T, P> call(vecType<T, P> const & x)
{
return glm::abs(x);
}
};
template <typename T, precision P, template <class, precision> class vecType>
struct compute_sign<T, P, vecType, false, true>
{
GLM_FUNC_QUALIFIER static vecType<T, P> call(vecType<T, P> const & x)
{
T const Shift(static_cast<T>(sizeof(T) * 8 - 1));
vecType<T, P> const y(vecType<typename make_unsigned<T>::type, P>(-x) >> typename make_unsigned<T>::type(Shift));
return (x >> Shift) | y;
}
};
}//namespace detail
// abs
@ -159,7 +189,7 @@ namespace detail
std::numeric_limits<genFIType>::is_iec559 || (std::numeric_limits<genFIType>::is_signed && std::numeric_limits<genFIType>::is_integer),
"'sign' only accept signed inputs");
return static_cast<genFIType>(static_cast<genFIType>(0) < x) - static_cast<genFIType>(x < static_cast<genFIType>(0));
return detail::compute_sign<genFIType, defaultp, tvec1, std::numeric_limits<genFIType>::is_iec559>::call(tvec1<genFIType>(x)).x;
}
template <typename T, precision P, template <typename, precision> class vecType>
@ -169,7 +199,9 @@ namespace detail
std::numeric_limits<T>::is_iec559 || (std::numeric_limits<T>::is_signed && std::numeric_limits<T>::is_integer),
"'sign' only accept signed inputs");
return vecType<T, P>(glm::lessThan(vecType<T, P>(0), x)) - vecType<T, P>(glm::lessThan(x, vecType<T, P>(0)));
return detail::compute_sign<T, P, vecType, std::numeric_limits<T>::is_iec559>::call(x);
//return vecType<T, P>(glm::lessThan(vecType<T, P>(0), x)) - vecType<T, P>(glm::lessThan(x, vecType<T, P>(0)));
}
// floor

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@ -76,6 +76,7 @@ Improvements:
- Removed <iostream> in GLM tests
- Used std features within GLM without redeclaring
- Optimized glm::cot #272
- Optimized glm::sign #272
Fixes:
- Fixed std::nextafter not supported with C++11 on Android #217

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@ -844,6 +844,8 @@ namespace sign
{
type<glm::int32> const Data[] =
{
{ std::numeric_limits<glm::int32>::max(), 1},
{ std::numeric_limits<glm::int32>::min(), -1},
{ 0, 0},
{ 1, 1},
{ 2, 1},