libcruft-util/geom/ellipse.hpp

82 lines
2.2 KiB
C++
Raw Normal View History

2015-10-14 15:32:53 +11:00
/*
* 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
*
* 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_GEOM_ELLIPSE_HPP
#define __UTIL_GEOM_ELLIPSE_HPP
#include <cstdlib>
2018-04-16 15:57:35 +10:00
#include "fwd.hpp"
2015-10-14 15:32:53 +11:00
#include "../point.hpp"
#include "../vector.hpp"
2017-01-05 15:06:49 +11:00
namespace util::geom {
2015-10-14 15:32:53 +11:00
///////////////////////////////////////////////////////////////////////////
template <size_t S, typename ValueT>
2015-10-14 15:32:53 +11:00
struct ellipse {
2018-04-16 15:57:35 +10:00
// the centre point of the ellipsoid
util::point<S,ValueT> origin;
2018-04-16 15:57:35 +10:00
// the distance from the centre along each axis to the shape's edge
util::vector<S,ValueT> radius;
2018-04-16 15:57:35 +10:00
// the orientation of up for the shape
util::vector<S,ValueT> up;
2015-10-14 15:32:53 +11:00
};
2018-04-16 15:57:35 +10:00
/// returns the distance along a ray to the surface of an ellipse.
///
/// returns infinity if there is no intersection
template <size_t DimensionV, typename ValueT>
ValueT
distance (
ray<DimensionV,ValueT>,
ellipse<DimensionV,ValueT>
);
using ellipse3f = ellipse<3,float>;
2017-01-05 15:06:49 +11:00
}
2015-10-14 15:32:53 +11:00
///////////////////////////////////////////////////////////////////////////////
#include "sample.hpp"
#include <cmath>
#include <random>
namespace util::geom {
template <typename T, template <size_t,typename> class K, typename G>
struct sampler<2,T,K,G>
{
static util::point<2,T> fn (K<2,T> k, G &g)
{
std::uniform_real_distribution<T> dist;
float phi = dist (g) * 2 * pi<T>;
float rho = std::sqrt (dist (g));
return util::point<2,T> {
std::cos (phi),
std::sin (phi)
} * rho * k.radius + k.origin.template as<util::vector> ();
}
};
}
2015-10-14 15:32:53 +11:00
#endif