/*
* Copyright (C) 2021 Christopher J. Howard
*
* This file is part of Antkeeper source code.
*
* Antkeeper source code is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Antkeeper source code is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Antkeeper source code. If not, see .
*/
#ifndef ANTKEEPER_MATH_QUATERNION_TYPE_HPP
#define ANTKEEPER_MATH_QUATERNION_TYPE_HPP
#include
namespace math {
/**
* A quaternion type is a tuple made of a scalar (real) part and vector (imaginary) part.
*
* @tparam T Scalar type.
*/
template
struct quaternion
{
typedef T scalar_type;
scalar_type w;
scalar_type x;
scalar_type y;
scalar_type z;
/// Returns the rotation identity quaternion.
static constexpr quaternion identity();
/**
* Returns a quaternion representing a rotation about the x-axis.
*
* @param angle Angle of rotation, in radians.
* @return Quaternion representing an x-axis rotation.
*/
static quaternion rotate_x(scalar_type angle);
/**
* Returns a quaternion representing a rotation about the y-axis.
*
* @param angle Angle of rotation, in radians.
* @return Quaternion representing an y-axis rotation.
*/
static quaternion rotate_y(scalar_type angle);
/**
* Returns a quaternion representing a rotation about the z-axis.
*
* @param angle Angle of rotation, in radians.
* @return Quaternion representing an z-axis rotation.
*/
static quaternion rotate_z(scalar_type angle);
};
template
constexpr quaternion quaternion::identity()
{
return {T(1), T(0), T(0), T(0)};
};
template
quaternion quaternion::rotate_x(scalar_type angle)
{
return {std::cos(angle * T(0.5)), std::sin(angle * T(0.5)), T(0), T(0)};
}
template
quaternion quaternion::rotate_y(scalar_type angle)
{
return {std::cos(angle * T(0.5)), T(0), std::sin(angle * T(0.5)), T(0)};
}
template
quaternion quaternion::rotate_z(scalar_type angle)
{
return {std::cos(angle * T(0.5)), T(0), T(0), std::sin(angle * T(0.5))};
}
} // namespace math
#endif // ANTKEEPER_MATH_QUATERNION_TYPE_HPP