Compute LUTs at run-time.dynamic-lut

1 files changed, 24 insertions, 0 deletions

diff --git a/src/xyz_srgb_lut.cc b/src/xyz_srgb_lut.cc
new file mode 100644
index 00000000..3d207195
--- /dev/null
+++ b/src/xyz_srgb_lut.cc
@@ -0,0 +1,24 @@
+#include <iostream>
+#include <cmath>
+#include "xyz_srgb_lut.h"
+
+using namespace libdcp;
+
+LUTCache<XYZsRGBLUT> XYZsRGBLUT::cache;
+
+XYZsRGBLUT::XYZsRGBLUT(int bits, float gamma)
+	: LUT<int> (bits, gamma)
+{
+	int const bit_length = pow(2, bits);
+
+	for (int i = 0; i < bit_length; ++i) {
+		float v = float(i) / (bit_length - 1);
+		if (v < (0.04045 / 12.92)) {
+			v *= 12.92;
+		} else {
+			v = (1.055 * pow (v, (1 / gamma))) - 0.055;
+		}
+
+		_lut[i] = int(v * 255);
+	}
+}