This operator sends a ray from the position
P along the direction
specified by the direction
D. The length of the
D vector represents the
farthest distance considered when checking for occlusion.
The operator returns 1 if there are no occluding objects found, and 0 0 if the ray hit any object in between.
If the position (
P) input is not connected, the global variable by the
same name will be used instead. In the Shadow context, you will normally
connect the global
Ps variable to the
P input, and the global
variable to the