mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
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125 lines
4.7 KiB
C++
125 lines
4.7 KiB
C++
/*=============================================================================
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Copyright (c) 2011-2016 Bolero MURAKAMI
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https://github.com/bolero-MURAKAMI/Sprout
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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#ifndef SPROUT_MATH_ATAN2_HPP
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#define SPROUT_MATH_ATAN2_HPP
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#include <type_traits>
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#include <sprout/config.hpp>
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#include <sprout/limits.hpp>
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#include <sprout/math/detail/config.hpp>
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#include <sprout/math/detail/float_compute.hpp>
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#include <sprout/math/constants.hpp>
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#include <sprout/math/isnan.hpp>
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#include <sprout/math/signbit.hpp>
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#include <sprout/math/copysign.hpp>
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#include <sprout/math/signbit.hpp>
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#include <sprout/math/atan.hpp>
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#include <sprout/type_traits/float_promote.hpp>
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#include <sprout/type_traits/enabler_if.hpp>
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namespace sprout {
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namespace math {
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namespace detail {
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#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
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inline SPROUT_CONSTEXPR float
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builtin_atan2(float y, float x) {
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return __builtin_atan2f(y, x);
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}
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inline SPROUT_CONSTEXPR double
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builtin_atan2(double y, double x) {
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return __builtin_atan2(y, x);
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}
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inline SPROUT_CONSTEXPR long double
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builtin_atan2(long double y, long double x) {
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return __builtin_atan2l(y, x);
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}
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#endif
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template<typename T>
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inline SPROUT_CONSTEXPR T
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atan2_impl(T y, T x) {
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return x < 0 ? sprout::math::atan(y / x) + (
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y < 0 ? -sprout::math::pi<T>()
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: sprout::math::pi<T>()
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)
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: sprout::math::atan(y / x)
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;
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}
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} // namespace detail
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//
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// atan2
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//
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// issue:
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// [ !(SPROUT_USE_BUILTIN_CMATH_FUNCTION || SPROUT_USE_BUILTIN_COPYSIGN_FUNCTION) ]
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// atan2(<28>}0, -0) returns <20>}ƒÎ .
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// # returns <20>}0 . ( same as atan2(<28>}0, +0) )
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// atan2(-0, x) returns -ƒÎ for x < 0.
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// # returns +ƒÎ . ( same as atan2(+0, x) )
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// atan2(-NaN, -NaN) returns -NaN .
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// # returns +NaN . ( same as atan2(+NaN, +NaN) )
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//
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template<
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typename FloatType,
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typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR FloatType
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atan2(FloatType y, FloatType x) {
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return sprout::math::isnan(y)
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? sprout::math::isnan(x)
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? sprout::math::signbit(y) && sprout::math::signbit(x) ? -sprout::numeric_limits<FloatType>::quiet_NaN()
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: sprout::numeric_limits<FloatType>::quiet_NaN()
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: y
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: sprout::math::isnan(x) ? x
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: x == -sprout::numeric_limits<FloatType>::infinity()
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? y == sprout::numeric_limits<FloatType>::infinity() ? sprout::math::three_quarters_pi<FloatType>()
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: y == -sprout::numeric_limits<FloatType>::infinity() ? -sprout::math::three_quarters_pi<FloatType>()
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: sprout::math::copysign(sprout::math::pi<FloatType>(), y)
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: x == sprout::numeric_limits<FloatType>::infinity()
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? y == sprout::numeric_limits<FloatType>::infinity() ? sprout::math::quarter_pi<FloatType>()
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: y == -sprout::numeric_limits<FloatType>::infinity() ? -sprout::math::quarter_pi<FloatType>()
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: FloatType(0) * y
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: y == sprout::numeric_limits<FloatType>::infinity() ? sprout::math::half_pi<FloatType>()
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: y == -sprout::numeric_limits<FloatType>::infinity() ? -sprout::math::half_pi<FloatType>()
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#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
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: sprout::math::detail::builtin_atan2(y, x)
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#else
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: y == 0
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? x < 0 ? sprout::math::copysign(sprout::math::pi<FloatType>(), y)
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: x > 0 ? FloatType(0) * y
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: sprout::math::signbit(x) ? sprout::math::copysign(sprout::math::pi<FloatType>(), y)
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: FloatType(0) * y
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: x == 0
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? y < 0 ? -sprout::math::half_pi<FloatType>()
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: sprout::math::half_pi<FloatType>()
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: static_cast<FloatType>(
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sprout::math::detail::atan2_impl(
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static_cast<typename sprout::math::detail::float_compute<FloatType>::type>(y),
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static_cast<typename sprout::math::detail::float_compute<FloatType>::type>(x)
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)
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)
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#endif
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;
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}
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template<
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typename ArithmeticType1,
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typename ArithmeticType2,
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typename sprout::enabler_if<
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std::is_arithmetic<ArithmeticType1>::value && std::is_arithmetic<ArithmeticType2>::value
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>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR typename sprout::float_promote<ArithmeticType1, ArithmeticType2>::type
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atan2(ArithmeticType1 y, ArithmeticType2 x) {
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typedef typename sprout::float_promote<ArithmeticType1, ArithmeticType2>::type type;
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return sprout::math::atan2(static_cast<type>(y), static_cast<type>(x));
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}
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} // namespace math
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using sprout::math::atan2;
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} // namespace sprout
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#endif // #ifndef SPROUT_MATH_ATAN2_HPP
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