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Color Temperature to RGB
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// From http://www.tannerhelland.com/4435/convert-temperature-rgb-algorithm-code/ | |
// Start with a temperature, in Kelvin, somewhere between 1000 and 40000. (Other values may work, | |
// but I can't make any promises about the quality of the algorithm's estimates above 40000 K.) | |
function colorTemperatureToRGB(kelvin){ | |
var temp = kelvin / 100; | |
var red, green, blue; | |
if( temp <= 66 ){ | |
red = 255; | |
green = temp; | |
green = 99.4708025861 * Math.log(green) - 161.1195681661; | |
if( temp <= 19){ | |
blue = 0; | |
} else { | |
blue = temp-10; | |
blue = 138.5177312231 * Math.log(blue) - 305.0447927307; | |
} | |
} else { | |
red = temp - 60; | |
red = 329.698727446 * Math.pow(red, -0.1332047592); | |
green = temp - 60; | |
green = 288.1221695283 * Math.pow(green, -0.0755148492 ); | |
blue = 255; | |
} | |
return { | |
r : clamp(red, 0, 255), | |
g : clamp(green, 0, 255), | |
b : clamp(blue, 0, 255) | |
} | |
} | |
function clamp( x, min, max ) { | |
if(x<min){ return min; } | |
if(x>max){ return max; } | |
return x; | |
} |
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