iif: added slog10

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

diff --git a/iif/luts/slog.py b/iif/luts/slog.py
new file mode 100755 (executable)
index 0000000..86546e0
--- /dev/null
+++ b/iif/luts/slog.py
@@ -0,0 +1,58 @@
+#!/usr/bin/env python
+
+import math
+
+# IT's annoying that the 1023,4 and 4095,16 almost, but dont exactly, cancel. UGH
+# The intent is clearly to have the same mapping, but it's not done very well.
+# Sony engineers and/or the Academy should pick one of these mappings for both.
+
+def SLog10_to_lin(x):
+    return (math.pow(10.0,(((((x*1023.0)/4.0-16.0)/219.0)-0.616596-0.03)/0.432699))-0.037584)*0.9
+
+def SLog12_to_lin(x):
+    return (math.pow(10.0,(((((x*4095.0)/16.0-16.0)/219.0)-0.616596-0.03)/0.432699))-0.037584)*0.9
+
+
+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
+
+#
+# NOTE: The ctl matrix order is transposed compared to what OCIO expects
+#const float SGAMUT_TO_ACES_MTX[3][3] = {
+#      { 0.754338638,  0.021198141, -0.009756991 },
+#      #{ 0.133697046,  1.005410934,  0.004508563 },
+#      { 0.111968437, -0.026610548,  1.005253201 }
+
+NUM_SAMPLES = 2**11
+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(SLog10_to_lin(x))
+WriteSPI1D('slog10.spi1d', RANGE[0], RANGE[1], data)
+
+"""
+NUM_SAMPLES = 2**13
+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(SLog12_to_lin(x))
+WriteSPI1D('slog12.spi1d', RANGE[0], RANGE[1], data)
+"""