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- /*
- * Copyright (C) 2020 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_PLANE_HPP
- #define ANTKEEPER_PLANE_HPP
-
- #include <vmq/vmq.hpp>
-
- using vmq::vector;
- using namespace vmq::operators;
-
- template <class T>
- struct plane
- {
- vector<T, 3> normal;
- T distance;
-
- /**
- * Creates a plane given a normal vector and distance.
- */
- plane(const vector<T, 3>& normal, T distance);
-
- /**
- * Creates a plane given a normal vector and offset vector.
- */
- plane(const vector<T, 3>& normal, const vector<T, 3>& offset);
-
- /**
- * Creates a plane given three points.
- */
- plane(const vector<T, 3>& a, const vector<T, 3>& b, const vector<T, 3>& c);
-
- /**
- * Creates a plane given its coefficients.
- *
- * @param coefficients Vector containing the plane coefficients, A, B, C and D, as x, y, z, and w, respectively.
- */
- plane(const vector<T, 4>& coefficients);
-
- /// Creates an uninitialized plane.
- plane() = default;
- };
-
- template <class T>
- inline plane<T>::plane(const vector<T, 3>& normal, T distance):
- normal(normal),
- distance(distance)
- {}
-
- template <class T>
- plane<T>::plane(const vector<T, 3>& normal, const vector<T, 3>& offset):
- normal(normal),
- distance(-vmq::dot(normal, offset))
- {}
-
- template <class T>
- plane<T>::plane(const vector<T, 3>& a, const vector<T, 3>& b, const vector<T, 3>& c)
- {
- normal = vmq::normalize(vmq::cross(c - b, a - b));
- distance = -(vmq::dot(normal, b));
- }
-
- template <class T>
- plane<T>::plane(const vector<T, 4>& coefficients)
- {
- const vector<T, 3> abc = vmq::resize<3>(coefficients);
- const float inverse_length = T(1) / vmq::length(abc);
-
- normal = abc * inverse_length;
- distance = coefficients[3] * inverse_length;
- }
-
- /**
- * Calculates the signed distance between a plane and a vector.
- *
- * @param p Plane.
- * @param v Vector.
- * @return Signed distance between the plane and a vector.
- */
- template <class T>
- inline T signed_distance(const plane<T>& p, const vector<T, 3>& v)
- {
- return p.distance + vmq::dot(p.normal, v);
- }
-
- /**
- * Calculates the point of intersection between three planes.
- */
- template <class T>
- vector<T, 3> intersection(const plane<T>& p0, const plane<T>& p1, const plane<T>& p2)
- {
- return -(p0.distance * vmq::cross(p1.normal, p2.normal) + p1.distance * vmq::cross(p2.normal, p0.normal) + p2.distance * vmq::cross(p0.normal, p1.normal)) / vmq::dot(p0.normal, vmq::cross(p1.normal, p2.normal));
- }
-
- #endif // ANTKEEPER_PLANE_HPP
-
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