90 lines
2.3 KiB
C++
90 lines
2.3 KiB
C++
/*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Copyright 2015 Danny Robson <danny@nerdcruft.net>
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*/
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#ifndef __UTIL_GEOM_ELLIPSE_HPP
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#define __UTIL_GEOM_ELLIPSE_HPP
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#include <cstdlib>
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#include "fwd.hpp"
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#include "../point.hpp"
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#include "../vector.hpp"
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namespace util::geom {
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///////////////////////////////////////////////////////////////////////////
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template <size_t S, typename ValueT>
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struct ellipse {
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// the centre point of the ellipsoid
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util::point<S,ValueT> origin;
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// the distance from the centre along each axis to the shape's edge
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util::vector<S,ValueT> radius;
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// the orientation of up for the shape
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util::vector<S,ValueT> up;
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};
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template <size_t DimensionV, typename ValueT>
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point<DimensionV,ValueT>
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project (
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ray<DimensionV,ValueT>,
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ellipse<DimensionV,ValueT>
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);
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/// returns the distance along a ray to the surface of an ellipse.
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///
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/// returns infinity if there is no intersection
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template <size_t DimensionV, typename ValueT>
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ValueT
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distance (
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ray<DimensionV,ValueT>,
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ellipse<DimensionV,ValueT>
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);
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using ellipse3f = ellipse<3,float>;
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}
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///////////////////////////////////////////////////////////////////////////////
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#include "sample.hpp"
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#include <cmath>
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#include <random>
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namespace util::geom {
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template <typename T, template <size_t,typename> class K, typename G>
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struct sampler<2,T,K,G>
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{
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static util::point<2,T> fn (K<2,T> k, G &g)
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{
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std::uniform_real_distribution<T> dist;
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float phi = dist (g) * 2 * pi<T>;
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float rho = std::sqrt (dist (g));
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return util::point<2,T> {
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std::cos (phi),
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std::sin (phi)
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} * rho * k.radius + k.origin.template as<util::vector> ();
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}
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};
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}
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#endif
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