123 lines
3.5 KiB
C++
123 lines
3.5 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 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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//-----------------------------------------------------------------------------
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template <typename T>
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T
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util::lerp::sigmoid (T val)
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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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return -1 + 2 / (1 + std::exp (-2 * val));
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}
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template float util::lerp::sigmoid (float);
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template double util::lerp::sigmoid (double);
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//-----------------------------------------------------------------------------
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template <typename T>
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T
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util::lerp::trunc (T a, T, T weight)
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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;
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}
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template float util::lerp::trunc (float, float, float);
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template double util::lerp::trunc (double, double, double);
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//-----------------------------------------------------------------------------
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template <typename T>
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T
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util::lerp::linear (T a, T b, T weight)
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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 float util::lerp::linear (float, float, float);
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template double util::lerp::linear (double, double, double);
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//-----------------------------------------------------------------------------
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template <typename T>
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T
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util::lerp::cosine (T a, T b, T weight)
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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 float util::lerp::cosine (float, float, float);
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template double util::lerp::cosine (double, double, double);
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//-----------------------------------------------------------------------------
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template <typename T>
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T
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util::lerp::cubic (T a, T b, T weight)
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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 float util::lerp::cubic (float, float, float);
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template double util::lerp::cubic (double, double, double);
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//-----------------------------------------------------------------------------
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template <typename T>
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T
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util::lerp::quintic (T a, T b, T weight)
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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 float util::lerp::quintic (float, float, float);
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template double util::lerp::quintic (double, double, double);
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