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Add various interpolation routines for perlin

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This commit is contained in:
Danny Robson 2012-01-04 17:08:03 +11:00
parent f71f15ebf1
commit 9c63070718
3 changed files with 81 additions and 0 deletions
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2
Makefile.am
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@ -44,6 +44,8 @@ UTIL_FILES = \
ip.hpp \
json.cpp \
json.hpp \
lerp.cpp \
lerp.hpp \
maths.cpp \
maths.hpp \
maths/matrix.cpp \

49
lerp.cpp Normal file
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@ -0,0 +1,49 @@
/*
* This file is part of libgim.
*
* libgim is free software: you can redistribute it and/or modify it under the
* terms of the GNU General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any later
* version.
*
* libgim is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with libgim. If not, see <http://www.gnu.org/licenses/>.
*
* Copyright 2011 Danny Robson <danny@blubinc.net>
*/
#include "lerp.hpp"
#include "debug.hpp"
#include "maths.hpp"
#include <cmath>
double
lerp::sigmoid (double val) {
return -1.0 + 2.0 / (1.0 + exp (-2.0 * val));
}
double
lerp::linear (double a, double b, double weight) {
check (weight >= 0 && weight <= 1.0);
return (1.0 - weight) * a + weight * b;
}
double
lerp::cosine (double a, double b, double weight) {
check (weight >= 0 && weight <= 1.0);
double ft = weight * PI;
double f = (1.0 - cos (ft)) * 0.5;
return a * (1.0 - f) + b * f;
}

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lerp.hpp Normal file
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/*
* This file is part of libgim.
*
* libgim is free software: you can redistribute it and/or modify it under the
* terms of the GNU General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any later
* version.
*
* libgim is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with libgim. If not, see <http://www.gnu.org/licenses/>.
*
* Copyright 2011 Danny Robson <danny@blubinc.net>
*/
#ifndef __UTIL_LERP_HPP
#define __UTIL_LERP_HPP
namespace lerp {
double sigmoid (double val);
double linear (double a, double b, double weight);
double cosine (double a, double b, double weight);
}
#endif