// However, pow() is relatively slow in GLSL, so we approximate this
// part by a minimax polynomial, whose coefficients are precalculated
// in Maple. (It is very hard to accurately model the curve as a whole
// However, pow() is relatively slow in GLSL, so we approximate this
// part by a minimax polynomial, whose coefficients are precalculated
// in Maple. (It is very hard to accurately model the curve as a whole