More tests.

[libdcp.git] / src / gamma_lut.cc

diff --git a/src/gamma_lut.cc b/src/gamma_lut.cc
index acc80af07b31a9cdbb80109ab1c10c38a7d95049..abe35b7cf24e13dc051d28a456c12db08adde13a 100644 (file)
--- a/src/gamma_lut.cc
+++ b/src/gamma_lut.cc
@@ -1,16 +1,50 @@
-#include <cmath>
+/*
+    Copyright (C) 2012-2014 Carl Hetherington <cth@carlh.net>
+
+    This program 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 2 of the License, or
+    (at your option) any later version.
+
+    This program 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 this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
 #include "gamma_lut.h"
 #include "lut_cache.h"
+#include <cmath>
 
-using namespace libdcp;
+using namespace dcp;
 
 LUTCache<GammaLUT> GammaLUT::cache;
 
-GammaLUT::GammaLUT(int bits, float gamma)
-       : LUT<float> (bits, gamma)
+GammaLUT::GammaLUT (int bit_depth, float gamma, bool linearised)
+       : _bit_depth (bit_depth)
+       , _gamma (gamma)
+       , _linearised (linearised)
 {
-       int const bit_length = pow(2, bits);
-       for (int i = 0; i < bit_length; ++i) {
-               _lut[i] = pow(float(i) / (bit_length - 1), gamma);
+       _lut = new float[int(std::pow(2.0f, _bit_depth))];
+       int const bit_length = pow (2, _bit_depth);
+
+       if (_linearised) {
+               for (int i = 0; i < bit_length; ++i) {
+                       float const p = static_cast<float> (i) / (bit_length - 1);
+                       if (p > 0.04045) {
+                               _lut[i] = pow ((p + 0.055) / 1.055, gamma);
+                       } else {
+                               _lut[i] = p / 12.92;
+                       }
+               }
+       } else {
+               for (int i = 0; i < bit_length; ++i) {
+                       _lut[i] = pow(float(i) / (bit_length - 1), gamma);
+               }
        }
 }