Support integer LUTs.

[libdcp.git] / src / transfer_function.cc

diff --git a/src/transfer_function.cc b/src/transfer_function.cc
index 7b17fd363f8035542fddf2e605969e0dcdb88aa3..39c8db0a9d8c5a358592f832dcccaea1f771ffc4 100644 (file)
--- a/src/transfer_function.cc
+++ b/src/transfer_function.cc
@@ -50,26 +50,64 @@ using namespace dcp;
 
 
 vector<double> const&
-TransferFunction::lut (double from, double to, int bit_depth, bool inverse) const
+TransferFunction::double_lut(double from, double to, int bit_depth, bool inverse) const
 {
        boost::mutex::scoped_lock lm (_mutex);
+       return double_lut_unlocked(from, to, bit_depth, inverse);
+}
+
+
+vector<double> const&
+TransferFunction::double_lut_unlocked(double from, double to, int bit_depth, bool inverse) const
+{
+       auto const descriptor = LUTDescriptor{from, to, bit_depth, inverse, 1};
+
+       auto i = _double_luts.find(descriptor);
+       if (i != _double_luts.end()) {
+               return i->second;
+       }
+
+       _double_luts[descriptor] = make_double_lut(from, to, bit_depth, inverse);
+       return _double_luts[descriptor];
+}
 
-       auto const descriptor = LUTDescriptor{from, to, bit_depth, inverse};
 
-       auto i = _luts.find(descriptor);
-       if (i != _luts.end()) {
+vector<int> const&
+TransferFunction::int_lut(double from, double to, int bit_depth, bool inverse, int scale) const
+{
+       boost::mutex::scoped_lock lm (_mutex);
+
+       auto const descriptor = LUTDescriptor{from, to, bit_depth, inverse, scale};
+
+       auto i = _int_luts.find(descriptor);
+       if (i != _int_luts.end()) {
                return i->second;
        }
 
-       _luts[descriptor] = make_lut(from, to, bit_depth, inverse);
-       return _luts[descriptor];
+       _int_luts[descriptor] = make_int_lut(from, to, bit_depth, inverse, scale);
+       return _int_luts[descriptor];
+}
+
+
+/* Caller must hold lock on _mutex */
+vector<int>
+TransferFunction::make_int_lut(double from, double to, int bit_depth, bool inverse, int scale) const
+{
+       auto source_lut = double_lut_unlocked(from, to, bit_depth, inverse);
+       auto const size = source_lut.size();
+       vector<int> lut(size);
+       for (size_t i = 0; i < size; ++i) {
+               lut[i] = lrint(source_lut[i] * scale);
+       }
+
+       return lut;
 }
 
 
 bool
 TransferFunction::LUTDescriptor::operator==(TransferFunction::LUTDescriptor const& other) const
 {
-       return from == other.from && to == other.to && bit_depth == other.bit_depth && inverse == other.inverse;
+       return from == other.from && to == other.to && bit_depth == other.bit_depth && inverse == other.inverse && scale == other.scale;
 }
 
 
@@ -79,6 +117,7 @@ TransferFunction::LUTDescriptorHasher::operator()(TransferFunction::LUTDescripto
        return std::hash<double>()(desc.from) ^
                std::hash<double>()(desc.to) ^
                std::hash<int>()(desc.bit_depth) ^
-               std::hash<bool>()(desc.inverse);
+               std::hash<bool>()(desc.inverse) ^
+               std::hash<int>()(desc.scale);
 }