iif: added arri alexa logc, ei800

[OpenColorIO-Configs.git] / iif / luts / logc800.py

diff --git a/iif/luts/logc800.py b/iif/luts/logc800.py
new file mode 100755 (executable)
index 0000000..fd5bf01
--- /dev/null
+++ b/iif/luts/logc800.py
@@ -0,0 +1,51 @@
+#!/usr/bin/env python
+
+import math
+
+"""
+
+// ARRI ALEXA IDT for ALEXA logC files
+//  with camera EI set to 800
+// Written by v3_IDT_maker.py v0.06 on Thursday 01 March 2012 by alex
+
+float
+normalizedLogCToRelativeExposure(float x) {
+       if (x > 0.149659)
+               return (pow(10,(x - 0.385537) / 0.247189) - 0.052272) / 5.555556;
+       else
+               return (x - 0.092809) / 5.367650;
+}
+
+"""
+
+def logCToLinear(x):
+       if (x > 0.149659):
+               return (math.pow(10.0,(x - 0.385537) / 0.247189) - 0.052272) / 5.555556
+       else:
+               return (x - 0.092809) / 5.367650
+
+def WriteSPI1D(filename, fromMin, fromMax, data):
+    f = file(filename,'w')
+    f.write("Version 1\n")
+    f.write("From %s %s\n" % (fromMin, fromMax))
+    f.write("Length %d\n" % len(data))
+    f.write("Components 1\n")
+    f.write("{\n")
+    for value in data:
+        f.write("        %s\n" % value)
+    f.write("}\n")
+    f.close()
+
+def Fit(value, fromMin, fromMax, toMin, toMax):
+    if fromMin == fromMax:
+        raise ValueError("fromMin == fromMax")
+    return (value - fromMin) / (fromMax - fromMin) * (toMax - toMin) + toMin
+
+NUM_SAMPLES = 2**14
+RANGE = (-0.125, 1.125)
+data = []
+for i in xrange(NUM_SAMPLES):
+    x = i/(NUM_SAMPLES-1.0)
+    x = Fit(x, 0.0, 1.0, RANGE[0], RANGE[1])
+    data.append(logCToLinear(x))
+WriteSPI1D('logc800.spi1d', RANGE[0], RANGE[1], data)