No-op; Fix GPL address and mention libdcp by name.

[libdcp.git] / src / modified_gamma_transfer_function.cc

diff --git a/src/modified_gamma_transfer_function.cc b/src/modified_gamma_transfer_function.cc
index 7878773bdb957148977f03ea92e5913015118158..ac638fc9f9666f93cc15c7fdc5a15ee187d2714a 100644 (file)
--- a/src/modified_gamma_transfer_function.cc
+++ b/src/modified_gamma_transfer_function.cc
@@ -1,19 +1,20 @@
 /*
     Copyright (C) 2012-2014 Carl Hetherington <cth@carlh.net>
 
-    This program is free software; you can redistribute it and/or modify
+    This file is part of libdcp.
+
+    libdcp 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,
+    libdcp 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.
+    along with libdcp.  If not, see <http://www.gnu.org/licenses/>.
 
 */
 
@@ -25,7 +26,7 @@ using boost::shared_ptr;
 using boost::dynamic_pointer_cast;
 using namespace dcp;
 
-ModifiedGammaTransferFunction::ModifiedGammaTransferFunction (float power, float threshold, float A, float B)
+ModifiedGammaTransferFunction::ModifiedGammaTransferFunction (double power, double threshold, double A, double B)
        : _power (power)
        , _threshold (threshold)
        , _A (A)
@@ -34,17 +35,29 @@ ModifiedGammaTransferFunction::ModifiedGammaTransferFunction (float power, float
 
 }
 
-float *
-ModifiedGammaTransferFunction::make_lut (int bit_depth) const
+double *
+ModifiedGammaTransferFunction::make_lut (int bit_depth, bool inverse) const
 {
-       int const bit_length = pow (2, bit_depth);
-       float* lut = new float[int(std::pow(2.0f, bit_depth))];
-       for (int i = 0; i < bit_length; ++i) {
-               float const p = static_cast<float> (i) / (bit_length - 1);
-               if (p > _threshold) {
-                       lut[i] = pow ((p + _A) / (1 + _A), _power);
-               } else {
-                       lut[i] = p / _B;
+       int const bit_length = int(std::pow(2.0f, bit_depth));
+       double* lut = new double[bit_length];
+       if (inverse) {
+               double const threshold = _threshold / _B;
+               for (int i = 0; i < bit_length; ++i) {
+                       double const p = static_cast<double> (i) / (bit_length - 1);
+                       if (p > threshold) {
+                               lut[i] = (1 + _A) * pow (p, 1 / _power) - _A;
+                       } else {
+                               lut[i] = p * _B;
+                       }
+               }
+       } else {
+               for (int i = 0; i < bit_length; ++i) {
+                       double const p = static_cast<double> (i) / (bit_length - 1);
+                       if (p > _threshold) {
+                               lut[i] = pow ((p + _A) / (1 + _A), _power);
+                       } else {
+                               lut[i] = p / _B;
+                       }
                }
        }
 
@@ -52,7 +65,7 @@ ModifiedGammaTransferFunction::make_lut (int bit_depth) const
 }
 
 bool
-ModifiedGammaTransferFunction::about_equal (shared_ptr<const TransferFunction> other, float epsilon) const
+ModifiedGammaTransferFunction::about_equal (shared_ptr<const TransferFunction> other, double epsilon) const
 {
        shared_ptr<const ModifiedGammaTransferFunction> o = dynamic_pointer_cast<const ModifiedGammaTransferFunction> (other);
        if (!o) {