83 lines
2.4 KiB
C++
83 lines
2.4 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 2015-2018 Danny Robson <danny@nerdcruft.net>
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*/
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#ifndef __UTIL_GEOM_SAMPLE_HPP
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#define __UTIL_GEOM_SAMPLE_HPP
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#include "../coord/fwd.hpp"
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#include "../extent.hpp"
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#include "ops.hpp"
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#include <cstddef>
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///////////////////////////////////////////////////////////////////////////////
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namespace util::geom {
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/// a function object that selects a uniformly random point inside a shape
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/// using a provided random generator. the point will lie within the shape,
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/// inclusive of boundaries.
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///
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/// may be specialised for arbitrary shapes but uses rejection sampling
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/// as a safe default. this implies that execution may not take a constant
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/// time.
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///
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/// \tparam S coordinate type dimension
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/// \tparam T value type for the shape/coordinate
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/// \tparam K the shape type to test
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/// \tparam G a UniformRandomBitGenerator, eg std::min19937
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template <
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size_t S,
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typename T,
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template <size_t,typename> class K,
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typename G
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>
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struct sampler {
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static point<S,T>
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fn (K<S,T> k, G &g)
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{
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auto b = bounds (k);
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while (true) {
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auto p = sample (b, g);
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if (intersects (k, p))
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return p;
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}
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}
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};
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///////////////////////////////////////////////////////////////////////////
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/// a convenience function that calls sample::fn to select a random point
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/// in a provided shape.
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template <
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size_t S,
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typename T,
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template <size_t,typename> class K,
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typename G // random generator
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>
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point<S,T>
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sample (K<S,T> k, G &g)
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{
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return sampler<S,T,K,G>::fn (k, g);
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}
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std::vector<util::point2f>
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poisson_sample (util::extent2i, float distance, int samples);
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}
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#endif
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