bouncemask

int  bouncemask(string labels)

labels

A label or space-separated list of labels.

Returns

A bitmask that matches any of the labels.

Mantra tags different types of rays using shading component labels, such as “diffuse”, “reflect”, “refract”, “volume”, and “sss”. A custom BSDF can also specify its own labels in addition to existing ones (see cvex_bsdf for more information).

Some VEX functions take or return a component bitmask, which specifies a combination of one or more of these labels using the bits of an integer.

To get the bit value associated with a label, use bouncemask, for example bouncemask("diffuse"). To get a mask that matches multiple labels, use a space-separated list:

reflect_or_refract = bouncemask("reflect refract")

To construct a bitmask that matches all labels, use bouncemask("all"). To match no labels, use 0.

When you get a bitmask as a return value, you can check if it matches a certain label using &. For example:

mask = getbounces(mybsdf)
if (mask & bouncemask("reflect")) {
    ...
}

(As an alternative to basic uses of bouncemask(), you can #import "pbr.h" and work with the constants PBR_DIFFUSE_MASK, PBR_REFLECT_MASK, PBR_REFRACT_MASK, PBR_VOLUME_MASK, PBR_SSS_MASK, as well as PBR_ALL_MASK and PBR_NO_MASK. You can combine the constants using |, for example reflect_or_refract = PBR_REFLECT_MASK | PBR_REFRACT_MASK.)