getblurP VEX function
Returns the blurred point position (P) vector at a fractional time between frames.
vector getblurP(float delta)
Returns the position (
P) of the current shading point at fractional time delta between the previous and next frame. For example,
getblurP(0.5) returns the point’s blurred position half-way through the current exposure.
When shading micropolygons, P will always store the initial position of the point (at time = 0). For raytracing, P will store the final position after motion transformation for the sample being shaded.
To always perform lookups within the point cloud at the initial (rest) position, you should add a point attribute to store this position, then do the lookup in the shader using the rest position.
vector p0 = getblurP(0); int handle = pcopen("pcloud.pc", p0, ...);