92 lines
2.9 KiB
C++
92 lines
2.9 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 2012-2015 Danny Robson <danny@nerdcruft.net>
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*/
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#ifdef __UTIL_NOISE_BASIS_VALUE_IPP
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#error
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#endif
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#define __UTIL_NOISE_BASIS_VALIE_IPP
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#include "../rand.hpp"
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#include "../../types.hpp"
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namespace util { namespace noise { namespace basis {
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///////////////////////////////////////////////////////////////////////////
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template <size_t S, typename T, template <typename> class L>
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value<S,T,L>::value (seed_t _seed):
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m_seed (_seed)
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{ ; }
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//-------------------------------------------------------------------------
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template <size_t S, typename T, template <typename> class L>
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util::range<T>
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value<S,T,L>::bounds (void) const
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{
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return { -1, 1 };
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}
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//-------------------------------------------------------------------------
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template <size_t S, typename T, template <typename> class L>
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seed_t
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value<S,T,L>::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 <size_t S, typename T, template <typename> class L>
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seed_t
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value<S,T,L>::seed (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 <size_t S, typename T, template <typename> class L>
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T
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value<S,T,L>::operator() (util::point<S,T> p) const noexcept
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{
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// extract integer and fractional parts. be careful to always round down
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auto p_int = floor (p).template cast<intmax_t> ();
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auto p_rem = p - p_int;
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// generate the corner points
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std::array<pointi<S>,pow(2,S)> p_;
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std::transform (std::begin (this->CORNERS), std::end (this->CORNERS),
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std::begin (p_),
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[p_int] (auto i) { return p_int + i; });
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// Generate the corner values
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std::array<T,pow(2,S)> g_;
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std::transform (std::begin (p_), std::end (p_),
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std::begin (g_),
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[this] (auto i) { return rand::scalar<value_t> (m_seed, i) * 2 - 1; });
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// Interpolate on one dimension, then the other.
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T l_[pow(2,S)];
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std::copy (std::begin (g_), std::end (g_), std::begin (l_));
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for (size_t i = S; i; --i)
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for (size_t j = 0; j < std::pow(2,i); j += 2)
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l_[j / 2] = L<T>() (l_[j], l_[j+1], p_rem[S-i]);
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return l_[0];
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}
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} } }
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