* Reference: * * [1] [Open PBR Specification - Coat Darkening] https://academysoftwarefoundation.github.io/OpenPBR/#model/coat/darkening * * 'rela

* 'relative_ior' is eta_t / eta_i with 'eta_t' the IOR of the glossy layer and * 'eta_i' the IOR of */

* Returns the radical inverse base 2 of a given number. * Used for generating 2D points following the Hammersley point set * * Reference: [Holger

* Returns true if the bounce was sampled successfully, * false otherwise (is the BSDF sample failed, if russian roulette killed the sample, ...) */

* The PDF is computed in area measure */

* Returns a pair of random numbers that should be used to sample the spatial neighbor disk of the current pixel * (i.e. pass the returned float2 to '

build a table that decodes both magnitude and value of small ACs in one go.

decode image to YCbCr format