///////////////////////////////////////////////////////////////////////////////////
/// OpenGL Mathematics (glm.g-truc.net)
///
/// Copyright (c) 2005 - 2015 G-Truc Creation (www.g-truc.net)
/// Permission is hereby granted, free of charge, to any person obtaining a copy
/// of this software and associated documentation files (the "Software"), to deal
/// in the Software without restriction, including without limitation the rights
/// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
/// copies of the Software, and to permit persons to whom the Software is
/// furnished to do so, subject to the following conditions:
/// 
/// The above copyright notice and this permission notice shall be included in
/// all copies or substantial portions of the Software.
/// 
/// Restrictions:
///             By making use of the Software for military purposes, you choose to make
///             a Bunny unhappy.
/// 
/// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
/// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
/// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
/// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
/// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
/// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
/// THE SOFTWARE.
///
/// @ref gtx_vector_angle
/// @file glm/gtx/vector_angle.inl
/// @date 2005-12-30 / 2011-06-07
/// @author Christophe Riccio
///////////////////////////////////////////////////////////////////////////////////

namespace glm
{
        template <typename genType> 
        GLM_FUNC_QUALIFIER genType angle
        (
                genType const & x,
                genType const & y
        )
        {
                GLM_STATIC_ASSERT(std::numeric_limits<genType>::is_iec559, "'angle' only accept floating-point inputs");
                return acos(clamp(dot(x, y), genType(-1), genType(1)));
        }

        template <typename T, precision P, template <typename, precision> class vecType> 
        GLM_FUNC_QUALIFIER T angle
        (
                vecType<T, P> const & x,
                vecType<T, P> const & y
        )
        {
                GLM_STATIC_ASSERT(std::numeric_limits<T>::is_iec559, "'angle' only accept floating-point inputs");
                return acos(clamp(dot(x, y), T(-1), T(1)));
        }

        //! \todo epsilon is hard coded to 0.01
        template <typename T, precision P>
        GLM_FUNC_QUALIFIER T orientedAngle
        (
                tvec2<T, P> const & x,
                tvec2<T, P> const & y
        )
        {
                GLM_STATIC_ASSERT(std::numeric_limits<T>::is_iec559, "'orientedAngle' only accept floating-point inputs");
                T const Angle(acos(clamp(dot(x, y), T(-1), T(1))));

                if(all(epsilonEqual(y, glm::rotate(x, Angle), T(0.0001))))
                        return Angle;
                else
                        return -Angle;
        }

        template <typename T, precision P>
        GLM_FUNC_QUALIFIER T orientedAngle
        (
                tvec3<T, P> const & x,
                tvec3<T, P> const & y,
                tvec3<T, P> const & ref
        )
        {
                GLM_STATIC_ASSERT(std::numeric_limits<T>::is_iec559, "'orientedAngle' only accept floating-point inputs");

                T const Angle(acos(clamp(dot(x, y), T(-1), T(1))));
                return mix(Angle, -Angle, dot(ref, cross(x, y)) < T(0));
        }
}//namespace glm