[PD-dev] help designing multichannel aware externals

[Christof Ressi]

> you'd just write
>     signal_setchans(sp[2], ouchans).
That's what I had originally suggested, but you rightfully pointed out 
that changing the channel number in place can be problematic if signals 
are reused...

So it would have to be at least:

sp[2] = signal_setchans(sp[2], outchans);

> empty output signals (channels=length=vec=0)
But then what is the point of having the signal if it does not provide 
any information?

Christof

On 25.01.2023 17:09, Miller Puckette wrote:
> I think I hadn't pushed them, oops.  And now I'm thinking again - maybe it's
> more elegant yet to provide empty output signals (channels=length=vec=0)
> and instead of (for example)
>     sp[2] = signal_swapforchans(sp[2], outchans);
> you'd just write
>     signal_setchans(sp[2], ouchans).
>
> cheers
> Miller
>
> On Wed, Jan 25, 2023 at 03:42:15PM +0100, Christof Ressi wrote:
>> Cool!
>>
>> I don't see these changes yet. Did you forget to push them or are you still
>> working on it?
>>
>> (I am working on some clone multi-channel bugfixes and I would need the new
>> signal_swapforchans() function :-)
>>
>> Christof
>>
>> On 25.01.2023 05:46, Miller Puckette via Pd-dev wrote:
>>> OK, just now changed this - there's a one-channel signal created for all
>>> signal outputs.  Now if you want more than one channel you have to call
>>> signal_swapforchans() (see d_arithmentic for example).
>>>
>>> cheers
>>> M
>>>
>>> On Tue, Jan 24, 2023 at 08:07:22AM +0100, IOhannes m zmoelnig wrote:
>>>> On 1/24/23 04:54, Alexandre Torres Porres wrote:
>>>>> Em seg., 23 de jan. de 2023 às 14:34, IOhannes m zmoelnig <zmoelnig at iem.at>
>>>>> escreveu:
>>>>>
>>>>>> multichannel objects must create the output signals themselves.
>>>>>> (as the object might change the number of channels).
>>>>>>
>>>>> even with [nchs~] where I'd have a fixed number of inputs/outputs?
>>>> yes.
>>>> with all multichannel aware externals.
>>>> how would Pd know the fixed number of outputs, if you don't tell it?
>>>>
>>>>>> see the example (mostly: pack~)
>>>>>>
>>>>> I saw it and it's quite simple, withou a 'perform' routine it uses a copy
>>>>> function.
>>>> the interesting part is the "dsp" method.
>>>> you cannot change the number of output signals in the perform routine (that
>>>> is: every tick).
>>>> but you can change  (or rather: must set) it when the DSP-graph is created,
>>>> thus in the "dsp" method.
>>>>
>>>>
>>>> mgfdsrfad
>>>> IOhannes
>>>
>>>
>>>> _______________________________________________
>>>> Pd-dev mailing list
>>>> Pd-dev at lists.iem.at
>>>> https://urldefense.com/v3/__https://lists.puredata.info/listinfo/pd-dev__;!!Mih3wA!E_5bIP-O1UTLD7F5f7i9Dk8oo0HG_TrZ092w4Og25eSX8i6DqXeMOObvGcx0pqosUm-4qtGLqPF-qQ$
>>>
>>>
>>> _______________________________________________
>>> Pd-dev mailing list
>>> Pd-dev at lists.iem.at
>>> https://urldefense.com/v3/__https://lists.puredata.info/listinfo/pd-dev__;!!Mih3wA!E_5bIP-O1UTLD7F5f7i9Dk8oo0HG_TrZ092w4Og25eSX8i6DqXeMOObvGcx0pqosUm-4qtGLqPF-qQ$