Sprout/sprout/math/atan2.hpp
2013-02-14 18:02:43 +09:00

62 lines
2.5 KiB
C++

#ifndef SPROUT_MATH_ATAN2_HPP
#define SPROUT_MATH_ATAN2_HPP
#include <limits>
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/math/detail/config.hpp>
#include <sprout/math/atan.hpp>
#include <sprout/math/constants.hpp>
#include <sprout/type_traits/float_promote.hpp>
#include <sprout/type_traits/enabler_if.hpp>
namespace sprout {
namespace math {
namespace detail {
template<
typename FloatType,
typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR FloatType
atan2(FloatType y, FloatType x) {
return y == 0
? x == 0 ? FloatType(0)
: x < 0 ? sprout::math::pi<FloatType>()
: FloatType(0)
: x == 0 ? (y < 0 ? -1 : 1) * sprout::math::half_pi<FloatType>()
: x == -std::numeric_limits<FloatType>::infinity()
? y == std::numeric_limits<FloatType>::infinity() ? sprout::math::three_quarters_pi<FloatType>()
: y == -std::numeric_limits<FloatType>::infinity() ? -sprout::math::three_quarters_pi<FloatType>()
: (y < 0 ? -1 : 1) * sprout::math::half_pi<FloatType>()
: x == std::numeric_limits<FloatType>::infinity()
? y == std::numeric_limits<FloatType>::infinity() ? sprout::math::quarter_pi<FloatType>()
: y == -std::numeric_limits<FloatType>::infinity() ? -sprout::math::quarter_pi<FloatType>()
: FloatType(0)
: y == std::numeric_limits<FloatType>::infinity() ? sprout::math::half_pi<FloatType>()
: y == -std::numeric_limits<FloatType>::infinity() ? -sprout::math::half_pi<FloatType>()
: x < 0 ? sprout::math::atan(y / x) + (y < 0 ? -1 : 1) * sprout::math::pi<FloatType>()
: sprout::math::atan(y / x)
;
}
template<
typename ArithmeticType1,
typename ArithmeticType2,
typename sprout::enabler_if<
std::is_arithmetic<ArithmeticType1>::value && std::is_arithmetic<ArithmeticType2>::value
>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR typename sprout::float_promote<ArithmeticType1, ArithmeticType2>::type
atan2(ArithmeticType1 y, ArithmeticType2 x) {
typedef typename sprout::float_promote<ArithmeticType1, ArithmeticType2>::type type;
return sprout::math::detail::atan2(static_cast<type>(y), static_cast<type>(x));
}
} // namespace detail
using NS_SPROUT_MATH_DETAIL::atan2;
} // namespace math
using sprout::math::atan2;
} // namespace sprout
#endif // #ifndef SPROUT_MATH_ATAN2_HPP