50 lines
1.2 KiB
C++
50 lines
1.2 KiB
C++
/*
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* This file is part of libgim.
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*
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* libgim is free software: you can redistribute it and/or modify it under the
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* terms of the GNU General Public License as published by the Free Software
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* Foundation, either version 3 of the License, or (at your option) any later
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* version.
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*
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* libgim is distributed in the hope that it will be useful, but WITHOUT ANY
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* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License
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* along with libgim. If not, see <http://www.gnu.org/licenses/>.
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*
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* Copyright 2011 Danny Robson <danny@blubinc.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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double
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lerp::sigmoid (double val) {
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return -1.0 + 2.0 / (1.0 + exp (-2.0 * val));
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}
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double
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lerp::linear (double a, double b, double weight) {
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check (weight >= 0 && weight <= 1.0);
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return (1.0 - weight) * a + weight * b;
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}
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double
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lerp::cosine (double a, double b, double weight) {
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check (weight >= 0 && weight <= 1.0);
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double ft = weight * PI;
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double f = (1.0 - cos (ft)) * 0.5;
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return a * (1.0 - f) + b * f;
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}
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