Cycles / Wavelength to RGB node:

* Added a node to convert wavelength (in nanometers, from 380nm to 780nm) to RGB values. This can be useful to match real world colors easier.

* Code cleanup:
** Moved color functions (xyz and hsv) into dedicated utility files.
** Remove svm_lerp(), use interp() instead. 

Documentation:
http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Nodes/More#Wavelength

Example render:
http://www.pasteall.org/pic/show.php?id=53202

This is part of my GSoC 2013. (revisions 57322, 57326, 57335 and 57367 from soc-2013-dingto). 

1 files changed, 20 insertions, 0 deletions

diff --git a/intern/cycles/kernel/shaders/node_color.h b/intern/cycles/kernel/shaders/node_color.h
index c6b5d740f6a..92bd39b5828 100644
--- a/intern/cycles/kernel/shaders/node_color.h
+++ b/intern/cycles/kernel/shaders/node_color.h
@@ -58,6 +58,26 @@ color color_unpremultiply(color c, float alpha)
 
 /* Color Operations */
 
+color xyY_to_xyz(float x, float y, float Y)
+{
+	float X, Z;
+
+	if (y != 0.0) X = (x / y) * Y;
+	else X = 0.0;
+
+	if (y != 0.0 && Y != 0.0) Z = ((1.0 - x - y) / y) * Y;
+	else Z = 0.0;
+
+	return color(X, Y, Z);
+}
+
+color xyz_to_rgb(float x, float y, float z)
+{
+	return color( 3.240479 * x + -1.537150 * y + -0.498535 * z,
+	             -0.969256 * x +  1.875991 * y +  0.041556 * z,
+	              0.055648 * x + -0.204043 * y +  1.057311 * z);
+}
+
 color rgb_to_hsv(color rgb)
 {
 	float cmax, cmin, h, s, v, cdelta;