How to sample a CHOP in a VOPCOP

[j00ey]

Hi

 

I've got a COPs problem to which I'm sure there must be an answer.

 

I have a CHOP with some noise, the sample length is derived from the YRES of a COP. Then in COPs, inside a VOPCOP I'm trying to use the noise to sample different parts of the image. It's a distortion effect essentially.

 

I put down a COPinput and promote the V parameter, then I need to write some expression to get the correct sample from COPs - something like

 

chopi("../noiseGenerator/OUT/noise",$V)

 

but I don't seem to have a $V or $Y or $IY or anything suitable. Can anyone tell me what I'm missing?
 

Thanks in advance 

 

* edit *

Test scene attached

sample_CHOPs_problem.hip

Edited November 12, 2015 by j00ey

[kgoossens]

Something Like this?

sample_CHOPs_problem-kim.hipnc

[j00ey]

Hi Kim

 

Thanks very much - that's an ingenious solution! I was trying to avoid the pixel COP, it being so slow, but at least it works!

 

I'm amazed that there's no U and V variable that I can use directly on the VOP, it's like not being able to do $PT/($NPT-1) in SOPs.

 

Thank you again

[j00ey]

I got this to work in my proper scene but I had to use another workaround - when I switched to a different resolution it was computing the red colour in a few buckets but most of the image was black so what I did in the end was to render out temporary files from the pixel COP then read them back in before the VOP - I thought that wouldn't work inside an HDA but it did...

 

Thanks for the help!