[PD] Trying to implement switch ramp

[Roman Haefeli]

On Wed, 2007-10-03 at 09:26 -0400, Thomas O Fredericks wrote:
> vsnapshot~? Where can I find it's help?  (I use Ubuntu PD(not
> extended) and PD 0.40-2)
> 
there is no help-file for [vsnapshot~] yet, afaik. but the way it works
could probably be derived from the name, respectively from the 'v' in
its name. as [vline~] it uses timetagged messages, so that it doesn't
only make a snapshot of samples on the block boundaries, but of a sample
somewhere in between (depending on the time tag). *)
beware that the result will output one block later and this is also the
reason, why it's not possible to use [vsnapshot~] in combination with
[vline~] to implement the 'switch and ramp' technique (you would need to
delay the second signal by one block).

*) i am not sure how it is actually implemented and whether it uses a
time tag or whatsoever, but for me it is a sufficient explanation for
how these objects work. 

> I still see inconsistencies in the patch I submitted
> I will try to make something a little clearer: please try the new
> attached patches and tell me why the little bit before the ramp
> changes size (I suspect that is the size of one block, sometimes
> there, sometimes not). How can I make this consistent?

ther reason here is that you use the direct output of [metro] to trigger
[tabwrite~] and the [line~] in [mix.switch.ramp~] is triggered exactly
5ms later (because of the [del 5]). the problem is, that [tabwrite~] as
well as [line~] execute only on block boundaries. since they are 5ms
apart from each other and 5ms is not a multiple of the blocksize (1.45ms
in that case), the shift you see is just a rounding error. 

roman 



		
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