libcruft-util/ray.cpp

152 lines
4.0 KiB
C++
Raw Normal View History

2015-02-19 13:28:56 +11:00
/*
2015-04-13 18:05:28 +10:00
* 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
2015-02-19 13:28:56 +11:00
*
2015-04-13 18:05:28 +10:00
* http://www.apache.org/licenses/LICENSE-2.0
2015-02-19 13:28:56 +11:00
*
2015-04-13 18:05:28 +10:00
* 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.
2015-02-19 13:28:56 +11:00
*
* Copyright 2015 Danny Robson <danny@nerdcruft.net>
*/
2015-03-11 22:31:35 +11:00
#include "ray.hpp"
2015-02-19 13:28:56 +11:00
#include "debug.hpp"
2015-04-15 18:00:37 +10:00
using util::ray;
2015-02-19 13:28:56 +11:00
2015-04-15 14:25:35 +10:00
///////////////////////////////////////////////////////////////////////////////
2015-02-19 13:28:56 +11:00
template <size_t S, typename T>
2015-04-15 18:00:37 +10:00
ray<S,T>::ray (util::point<S,T> _origin,
util::vector<S,T> _direction):
2015-04-15 14:25:35 +10:00
origin (_origin),
direction (_direction)
2015-02-19 13:28:56 +11:00
{
2015-04-15 14:25:35 +10:00
CHECK (direction.is_normalised ());
2015-02-19 13:28:56 +11:00
}
//-----------------------------------------------------------------------------
template <size_t S, typename T>
ray<S,T>
ray<S,T>::make (util::point<S,T> origin,
util::point<S,T> target)
{
return {
origin,
(target - origin).normalised ()
};
}
2015-04-15 14:25:35 +10:00
///////////////////////////////////////////////////////////////////////////////
2015-03-11 22:31:35 +11:00
/// returns the distance along the ray in a ray-plane intersection
2015-02-19 13:28:56 +11:00
///
/// returns inf if parallel
2015-03-11 22:31:35 +11:00
/// returns 0 if corayar
2015-02-19 13:28:56 +11:00
template <size_t S, typename T>
T
2015-04-15 18:00:37 +10:00
ray<S,T>::intersect (plane<S,T> q) const
2015-02-19 13:28:56 +11:00
{
2015-04-15 14:25:35 +10:00
return dot (q.p - origin, q.n) / dot (direction, q.n);
}
2015-03-06 17:53:08 +11:00
///----------------------------------------------------------------------------
/// returns the distance from origin to AABB intersection
///
/// returns NaN on miss
/// returns NaN if behind
2015-03-06 17:53:08 +11:00
template <size_t S, typename T>
T
2015-04-15 18:00:37 +10:00
ray<S,T>::intersect (AABB<S,T> r) const
2015-03-06 17:53:08 +11:00
{
2015-04-15 14:25:35 +10:00
auto t1 = (r.p0 - origin) / direction;
auto t2 = (r.p1 - origin) / direction;
2015-03-06 17:53:08 +11:00
auto vmin = min (t1, t2);
auto vmax = max (t1, t2);
2015-03-06 17:53:08 +11:00
auto tmin = max (vmin);
auto tmax = min (vmax);
2015-03-06 17:53:08 +11:00
// closest intersection is behind us
2015-03-06 17:53:08 +11:00
if (tmax < 0)
return std::numeric_limits<T>::quiet_NaN ();
2015-03-06 17:53:08 +11:00
// missed intersection
2015-03-06 17:53:08 +11:00
if (tmin > tmax)
return std::numeric_limits<T>::quiet_NaN ();
return tmin;
}
2015-04-13 21:47:51 +10:00
///----------------------------------------------------------------------------
/// returns the smallest distance from ray origin to a sphere intersection
///
/// returns NaN on miss
/// returns NaN if behind
2015-04-13 21:47:51 +10:00
template <size_t S, typename T>
T
2015-04-15 18:00:37 +10:00
ray<S,T>::intersect (sphere<S,T> s) const
2015-04-13 21:47:51 +10:00
{
2015-04-15 14:29:20 +10:00
T b = dot (direction, origin - s.centre);
T c = dot (origin - s.centre, origin - s.centre) - s.radius * s.radius;
2015-04-13 21:47:51 +10:00
T D = b * b - c;
if (D < 0)
return std::numeric_limits<T>::quiet_NaN ();
auto t_ = std::sqrt (D);
auto t0 = -b + t_;
auto t1 = -b - t_;
return t1 >= 0 ? t1 :
t0 >= 0 ? t0 :
std::numeric_limits<T>::quiet_NaN ();
}
2015-04-15 14:25:35 +10:00
///////////////////////////////////////////////////////////////////////////////
2015-03-11 22:31:35 +11:00
/// returns the closest parameter along the ray to a given point
template <size_t S, typename T>
T
2015-04-15 18:00:37 +10:00
ray<S,T>::closest (point<S,T> q) const
{
// project the origin-point difference onto the direction
2015-04-15 14:25:35 +10:00
return dot (origin - q, direction);
2015-02-19 13:28:56 +11:00
}
//-----------------------------------------------------------------------------
template <size_t S, typename T>
util::point<S,T>
2015-04-15 18:00:37 +10:00
ray<S,T>::at (T t) const
2015-02-19 13:28:56 +11:00
{
2015-04-15 14:25:35 +10:00
return origin + direction * t;
2015-02-19 13:28:56 +11:00
}
2015-04-15 18:00:45 +10:00
///////////////////////////////////////////////////////////////////////////////
template <size_t S, typename T>
std::ostream&
util::operator<< (std::ostream &os, ray<S,T> r)
{
return os << "ray(" << r.origin << ',' << r.direction << ')';
}
template std::ostream& util::operator<< (std::ostream&, ray<3,float>);
template std::ostream& util::operator<< (std::ostream&, ray<3,double>);
2015-04-15 14:25:35 +10:00
///////////////////////////////////////////////////////////////////////////////
2015-03-11 22:31:35 +11:00
template struct util::ray<2,float>;
template struct util::ray<3,float>;