getblurP VEX function

Returns the blurred point position (P) vector at a fractional time between frames.

  1. 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.

For example:

vector p0 = getblurP(0);
int handle = pcopen("pcloud.pc", p0, ...);