A color in Oklab is represented with three coordinates, similar to how CIELAB works, but with better perceptual properties. Oklab uses a D65 whitepoint, since this is what sRGB and other common color spaces use.
The RGB pixel
Converts from linearized sRGB (in 0..1 range) to Oklab
Converts Oklab to linear sRGB (in 0..1 range)
Converts Oklab to regular 8-bit sRGB color
Converts regular 8-bit sRGB color to Oklab