libcruft-util/geom/plane.hpp

70 lines
2.0 KiB
C++

/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Copyright 2015 Danny Robson <danny@nerdcruft.net>
*/
#ifndef __UTIL_PLANE_HPP
#define __UTIL_PLANE_HPP
#include "../point.hpp"
#include "../vector.hpp"
#include "../matrix.hpp"
namespace util::geom {
/// represents an S dimensional plane in parametric form: ax + by + cz + d = 0
template <size_t S, typename T>
struct plane {
plane () = default;
plane (util::point<S,T> base, util::vector<S,T> normal);
explicit plane (util::vector<S+1,T> _coefficients):
coefficients (_coefficients)
{ ; }
util::vector<S+1,T> coefficients;
};
///////////////////////////////////////////////////////////////////////////
/// returns the normal for a plane
template <size_t S, typename T>
util::vector<S,T>
normal (plane<S,T> p)
{
return p.coefficients.template redim<S> ();
}
///////////////////////////////////////////////////////////////////////////
/// normalises a plane's parametric form
///
/// useful only after manually modifying the coefficients (as in default
/// construction and piecewise initialisation). a plane will otherwise be
/// assumed to be in normal form.
template <size_t S, typename T>
plane<S,T>
normalised (plane<S,T> p)
{
const auto mag = norm (normal (p));
CHECK_NEZ (mag);
return plane<S,T> (p.coefficients / mag);
}
typedef plane<2,float> plane2f;
typedef plane<3,float> plane3f;
}
#endif