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authorCarl Hetherington <cth@carlh.net>2022-05-05 17:38:48 +0200
committerCarl Hetherington <cth@carlh.net>2022-05-05 18:53:39 +0200
commit969c9c28c87e83f4e3fcb7b52a921773d363511f (patch)
tree361713cfbb0246b75af7442f257375c27655083b /src/gamma_transfer_function.cc
parent504955b1e8036a25b1dc196625e530808ac42e99 (diff)
Use two LUTs.inaccurate-gamma
Diffstat (limited to 'src/gamma_transfer_function.cc')
-rw-r--r--src/gamma_transfer_function.cc5
1 files changed, 3 insertions, 2 deletions
diff --git a/src/gamma_transfer_function.cc b/src/gamma_transfer_function.cc
index 1875221e..33513b78 100644
--- a/src/gamma_transfer_function.cc
+++ b/src/gamma_transfer_function.cc
@@ -55,13 +55,14 @@ GammaTransferFunction::GammaTransferFunction (double gamma)
double *
-GammaTransferFunction::make_lut (int bit_depth, bool inverse) const
+GammaTransferFunction::make_lut (double from, double to, int bit_depth, bool inverse) const
{
int const bit_length = int(std::pow(2.0f, bit_depth));
auto lut = new double[bit_length];
double const gamma = inverse ? (1 / _gamma) : _gamma;
for (int i = 0; i < bit_length; ++i) {
- lut[i] = pow(double(i) / (bit_length - 1), gamma);
+ double const x = double(i) / (bit_length - 1);
+ lut[i] = pow((x * (to - from)) + from, gamma);
}
return lut;