100 lines
2.6 KiB
C++
100 lines
2.6 KiB
C++
/*
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* This file is part of libgim.
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*
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* libgim is free software: you can redistribute it and/or modify it under the
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* terms of the GNU General Public License as published by the Free Software
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* Foundation, either version 3 of the License, or (at your option) any later
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* version.
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*
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* libgim is distributed in the hope that it will be useful, but WITHOUT ANY
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* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License
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* along with libgim. If not, see <http://www.gnu.org/licenses/>.
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*
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* Copyright 2015 Danny Robson <danny@nerdcruft.net>
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*/
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#include "ray.hpp"
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#include "debug.hpp"
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//-----------------------------------------------------------------------------
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template <size_t S, typename T>
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util::ray<S,T>::ray (util::point<S,T> _p,
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util::vector<S,T> _d):
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p (_p),
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d (_d)
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{
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CHECK_EQ (d.magnitude2 (), 1);
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}
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///----------------------------------------------------------------------------
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/// returns the distance along the ray in a ray-plane intersection
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///
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/// returns inf if parallel
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/// returns 0 if corayar
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template <size_t S, typename T>
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T
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util::ray<S,T>::intersect (plane<S,T> q) const
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{
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return dot (q.p - p, q.n) / dot (d, q.n);
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}
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///----------------------------------------------------------------------------
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/// returns the distance from origin to AABB intersection
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///
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/// returns NaN on miss
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/// returns -ve if behind
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template <size_t S, typename T>
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T
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util::ray<S,T>::intersect (AABB<S,T> r) const
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{
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auto t1 = (r.p0 - p) / d;
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auto t2 = (r.p1 - p) / d;
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auto vmin = min (t1, t2);
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auto vmax = max (t1, t2);
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auto tmin = max (vmin);
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auto tmax = min (vmax);
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if (tmax < 0)
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return tmax;
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if (tmin > tmax)
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return std::numeric_limits<T>::quiet_NaN ();
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return tmin;
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}
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///----------------------------------------------------------------------------
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/// returns the closest parameter along the ray to a given point
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template <size_t S, typename T>
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T
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util::ray<S,T>::closest (point<S,T> q) const
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{
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// project the origin-point difference onto the direction
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return dot (p - q, d);
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}
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//-----------------------------------------------------------------------------
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template <size_t S, typename T>
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util::point<S,T>
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util::ray<S,T>::at (T t) const
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{
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return p + d * t;
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}
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//-----------------------------------------------------------------------------
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template struct util::ray<2,float>;
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template struct util::ray<3,float>;
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