118 lines
3.1 KiB
C++
118 lines
3.1 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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#if defined(__UTIL_NOISE_BASIS_PATCH_IPP)
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#error
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#endif
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#define __UTIL_NOISE_BASIS_PATCH_IPP
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///////////////////////////////////////////////////////////////////////////////
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template <typename T>
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util::noise::basis::patch<T>::patch (seed_t _seed):
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m_seed (_seed)
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{ ; }
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///////////////////////////////////////////////////////////////////////////////
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template <typename T>
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util::range<T>
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util::noise::basis::patch<T>::bounds (void) const
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{
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return { T{0}, T{1} };
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}
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///////////////////////////////////////////////////////////////////////////////
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template <typename T>
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T
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util::noise::basis::patch<T>::operator () (point2<T> p) const
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{
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// extract integer and fractional parts. be careful to always round down
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// (particularly with negatives) and avoid rounding errors.
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auto p_int = p.template cast<intmax_t> ();
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if (p.x < 0) p_int.x -= 1;
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if (p.y < 0) p_int.y -= 1;
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auto p_rem = (p - p_int).template as<point> ();
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T closest = std::numeric_limits<T>::infinity ();
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T value;
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for (signed y = -1; y <= 1; ++y)
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for (signed x = -1; x <= 1; ++x) {
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util::vector2i offset {x, y};
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auto c = centroid (p_int + offset);
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auto d = util::distance (p_rem, c + offset);
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if (d < closest) {
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closest = d;
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value = generate (p_int + offset);
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}
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}
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return value;
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}
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///////////////////////////////////////////////////////////////////////////////
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template <typename T>
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util::noise::seed_t
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util::noise::basis::patch<T>::seed (void) const
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{
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return m_seed;
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}
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//-----------------------------------------------------------------------------
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template <typename T>
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util::noise::seed_t
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util::noise::basis::patch<T>::seed (util::noise::seed_t _seed)
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{
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return m_seed = _seed;
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}
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///////////////////////////////////////////////////////////////////////////////
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template <typename T>
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util::point2<T>
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util::noise::basis::patch<T>::centroid (util::point2i p) const
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{
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using util::hash::murmur2::mix;
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auto u = mix (m_seed, mix (uint64_t (p.x), uint64_t (p.y)));
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auto v = mix (u, m_seed);
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auto r = util::point<2,T> {
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(u & 0xffff) / T{0xffff},
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(v & 0xffff) / T{0xffff}
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};
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CHECK_LIMIT (r, T{0}, T{1});
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return r;
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}
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//-----------------------------------------------------------------------------
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template <typename T>
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T
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util::noise::basis::patch<T>::generate (util::point2i p) const
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{
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using util::hash::murmur2::mix;
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auto u = mix (m_seed, mix (uint64_t (p.x), uint64_t (p.y)));
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return (u & 0xffff) / T{0xffff};
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}
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