115 lines
3.2 KiB
C++
115 lines
3.2 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 2011-2015 Danny Robson <danny@nerdcruft.net>
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*/
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#include "lerp.hpp"
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#include "debug.hpp"
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#include "maths.hpp"
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#include <cmath>
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using util::lerp::linear;
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using util::lerp::cosine;
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using util::lerp::cubic;
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using util::lerp::quintic;
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//-----------------------------------------------------------------------------
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template <typename T>
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T
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util::lerp::truncate<T>::operator() (T a, T, T weight) noexcept
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{
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static_assert (std::is_floating_point<T>::value,
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"lerp is only defined for floating types");
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CHECK_LIMIT (weight, 0, 1);
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(void)weight;
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return a;
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}
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template struct util::lerp::truncate<float>;
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template struct util::lerp::truncate<double>;
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//-----------------------------------------------------------------------------
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template <typename T>
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T
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linear<T>::operator() (T a, T b, T weight) noexcept
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{
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static_assert (std::is_floating_point<T>::value,
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"lerp is only defined for floating types");
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CHECK_LIMIT (weight, 0, 1);
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return a * (1 - weight) + b * weight;
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}
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template struct util::lerp::linear<float>;
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template struct util::lerp::linear<double>;
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//-----------------------------------------------------------------------------
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template <typename T>
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T
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cosine<T>::operator() (T a, T b, T weight) noexcept
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{
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static_assert (std::is_floating_point<T>::value,
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"lerp is only defined for floating types");
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CHECK_LIMIT (weight, 0, 1);
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T t = (1 - std::cos (weight * PI<T>)) * T(0.5);
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return a * (1 - t) + b * t;
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}
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template struct util::lerp::cosine<float>;
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template struct util::lerp::cosine<double>;
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//-----------------------------------------------------------------------------
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template <typename T>
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T
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cubic<T>::operator() (T a, T b, T weight) noexcept
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{
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static_assert (std::is_floating_point<T>::value,
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"lerp is only defined for floating types");
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CHECK_LIMIT (weight, 0, 1);
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// -2w^3 * 3w^2
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T t = weight * weight * (3 - 2 * weight);
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return a * (1 - t) + b * t;
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}
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template struct util::lerp::cubic<float>;
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template struct util::lerp::cubic<double>;
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//-----------------------------------------------------------------------------
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template <typename T>
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T
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quintic<T>::operator() (T a, T b, T weight) noexcept
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{
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static_assert (std::is_floating_point<T>::value,
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"lerp is only defined for floating types");
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CHECK_LIMIT (weight, 0, 1);
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// from perlin's improved noise: 6w^5 -15w^4 +10w^3
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T t = weight * weight * weight * (weight * (weight * 6 - 15) + 10);
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return a * (1 - t) + b * t;
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}
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template struct util::lerp::quintic<float>;
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template struct util::lerp::quintic<double>;
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