On Sun, Apr 18, 2010 at 01:28:02PM +0200, Matteo Sisti Sette wrote:
Actually I meant two write "take a [samphold~] of the original phasor". Taking a snapshot~ or rather, a vsnapshot~ is something I have also tried, but it gives the wrong results. See attached example for a comparison of [vsnapshot~]->[vline~] with Mike's [samphold~] solution (which I simplified a bit). Lesson to learn: [vsnapshot~]->[vline~] won't do what you may expect it to do.
Very very interesting. Basically you have to take into account that vsnapshot~ samples the signal with a delay of one block~ (and it couldn't be otherwise), which renders it useless for the phasor~ accurate reset application.
Pd alternates message and dsp computations. So the order here is: vsnapshot~ analyses dsp, then produces a message, then vline~ gets this one during the following message pass which is already too late to change its own signal result in the previous block. Duh.
So while both vsnapshot~ and vline~ are subsample-accurate in a block, the combination is not. The samplehold~ approach also uses vline~ to schedule an accurate impulse, but as samphold~ works entirely in the signal realm, no delaying message pass is needed in between.
Ciao
Frank