2 Copyright (C) 2012-2014 Carl Hetherington <cth@carlh.net>
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 #include "gamma_lut.h"
21 #include "lut_cache.h"
26 LUTCache<GammaLUT> GammaLUT::cache;
28 GammaLUT::GammaLUT (int bit_depth, float gamma, bool linearised)
29 : _bit_depth (bit_depth)
31 , _linearised (linearised)
33 _lut = new float[int(std::pow(2.0f, _bit_depth))];
34 int const bit_length = pow (2, _bit_depth);
37 for (int i = 0; i < bit_length; ++i) {
38 float const p = static_cast<float> (i) / (bit_length - 1);
40 _lut[i] = pow ((p + 0.055) / 1.055, gamma);
46 for (int i = 0; i < bit_length; ++i) {
47 _lut[i] = pow(float(i) / (bit_length - 1), gamma);