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@ibober
Last active Jan 17, 2022
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internal static class LightsUtils
{
public static int[] GetRgbFromTemperature(double temperature)
{
// Temperature must fit between 1000 and 40000 degrees.
temperature = MathUtils.Clamp(temperature, 1000, 40000);
// All calculations require temperature / 100, so only do the conversion once.
temperature /= 100;
// Compute each color in turn.
int red, green, blue;
// First: red.
if (temperature <= 66)
{
red = 255;
}
else
{
// Note: the R-squared value for this approximation is 0.988.
red = (int)(329.698727446 * (Math.Pow(temperature - 60, -0.1332047592)));
red = MathUtils.Clamp(red, 0, 255);
}
// Second: green.
if (temperature <= 66)
{
// Note: the R-squared value for this approximation is 0.996.
green = (int)(99.4708025861 * Math.Log(temperature) - 161.1195681661);
}
else
{
// Note: the R-squared value for this approximation is 0.987.
green = (int)(288.1221695283 * (Math.Pow(temperature - 60, -0.0755148492)));
}
green = MathUtils.Clamp(green, 0, 255);
// Third: blue.
if (temperature >= 66)
{
blue = 255;
}
else if (temperature <= 19)
{
blue = 0;
}
else
{
// Note: the R-squared value for this approximation is 0.998.
blue = (int)(138.5177312231 * Math.Log(temperature - 10) - 305.0447927307);
blue = MathUtils.Clamp(blue, 0, 255);
}
return new[] { red, green, blue };
}
}
public static class MathUtils
{
public static T Clamp<T>(T value, T min, T max)
where T : IComparable<T>
{
if (value.CompareTo(min) < 0)
{
value = min;
}
else if (value.CompareTo(max) > 0)
{
value = max;
}
return value;
}
}
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