transform-functions.hpp

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/*
 * Copyright (C) 2023  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 <http://www.gnu.org/licenses/>.
 */
 
#ifndef ANTKEEPER_MATH_TRANSFORM_FUNCTIONS_HPP
#define ANTKEEPER_MATH_TRANSFORM_FUNCTIONS_HPP
 
#include <engine/math/transform-type.hpp>
#include <engine/math/quaternion.hpp>
 
namespace math {
 
template <class T>
[[nodiscard]] transform<T> inverse(const transform<T>& t);
 
template <class T>
[[nodiscard]] matrix<T, 4, 4> matrix_cast(const transform<T>& t);
 
template <class T>
[[nodiscard]] transform<T> mul(const transform<T>& x, const transform<T>& y);
 
template <class T>
[[nodiscard]] vector<T, 3> mul(const transform<T>& t, const vector<T, 3>& v);
 
template <class T>
transform<T> inverse(const transform<T>& t)
{
    transform<T> inverse_t;
    inverse_t.scale = {T(1) / t.scale.x(), T(1) / t.scale.y(), T(1) / t.scale.z()};
    inverse_t.rotation = conjugate(t.rotation);
    inverse_t.translation = negate(mul(inverse_t.rotation, t.translation));
    return inverse_t;
}
 
template <class T>
matrix<T, 4, 4> matrix_cast(const transform<T>& t)
{
    matrix<T, 4, 4> transformation = matrix<T, 4, 4>(matrix<T, 3, 3>(t.rotation));
    transformation[3] = {t.translation[0], t.translation[1], t.translation[2], T(1)};
    return scale(transformation, t.scale);
}
 
template <class T>
transform<T> mul(const transform<T>& x, const transform<T>& y)
{
    return
        {
            mul(x, y.translation),
            normalize(mul(x.rotation, y.rotation)),
            mul(x.scale, y.scale)
        };
}
 
template <class T>
vector<T, 3> mul(const transform<T>& t, const vector<T, 3>& v)
{
    return add(t.translation, (mul(t.rotation, mul(v, t.scale))));
}
 
} // namespace math
 
#endif // ANTKEEPER_MATH_TRANSFORM_FUNCTIONS_HPP