nl_tokens: Calculates the bilinear fetch for a certain edge combination .
pl_tokens: function bilinear ( e ) { const a = lerp ( e [ 0 ] , e [ 1 ] , 1.0 - 0.25 ) ; const b = lerp ( e [ 2 ] , e [ 3 ] , 1.0 - 0.25 ) ; <mask> lerp ( a , b , 1.0 - 0.125 ) ; }