diff options
Diffstat (limited to 'src/gamma_lut.cc')
| -rw-r--r-- | src/gamma_lut.cc | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/src/gamma_lut.cc b/src/gamma_lut.cc index 4d61e60c..abe35b7c 100644 --- a/src/gamma_lut.cc +++ b/src/gamma_lut.cc @@ -25,13 +25,26 @@ using namespace dcp; LUTCache<GammaLUT> GammaLUT::cache; -GammaLUT::GammaLUT (int bit_depth, float gamma) +GammaLUT::GammaLUT (int bit_depth, float gamma, bool linearised) : _bit_depth (bit_depth) , _gamma (gamma) + , _linearised (linearised) { _lut = new float[int(std::pow(2.0f, _bit_depth))]; int const bit_length = pow (2, _bit_depth); - for (int i = 0; i < bit_length; ++i) { - _lut[i] = pow(float(i) / (bit_length - 1), gamma); + + 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); + } } } |