http://lolengine.net/blog/2013/07/27/rgb-to-hsv-in-glsl

https://www.easyrgb.com/en/math.php, conversion to XYZ, then LAB LAB is usually in 0-100,-200-200,-200-200 range, but we convert it all to 0-1 for eas

never inline just to make it show up easily in profiles (inlining this lengthly function doesn't really help anyways)

[DllImport(dll, CharSet = cSet, CallingConvention = call)] public static extern FovInfo device_display_get_fov ();