利用者:Juicyfruit/Blackbody/

Overview

To get from a the blackbody temperature to the rgb values we take a few steps.

• Calculate the wavelength of the radiation by planck's law
• Use CIE color matching functions to calculate the XYZ coordinates in CIE space ( lookuptable + linear interpolation seems to be most used )
• Convert that to RGB space ( simple vector matrix multiplication with a constant matrix)

Tanner Helland made a pretty interresting direct [1]

Links

• Planck's law http://en.wikipedia.org/wiki/Planck%27s_law
• CIE http://en.wikipedia.org/wiki/International_Commission_on_Illumination

• table of temperatures and RGB's (both CIE 1931 and 1964 ) http://www.vendian.org/mncharity/dir3/blackbody/UnstableURLs/bbr_color.html

• Tanner Hellend's approximation algorithm http://www.tannerhelland.com/4435/convert-temperature-rgb-algorithm-code/
• OSL implementation https://github.com/imageworks/OpenShadingLanguage/pull/74/files
• Color conversion theory http://www.cs.rit.edu/~ncs/color/t_convert.html