[PD-dev] outlet_anything() & threads

[IOhannes m zmoelnig]

Hans-Christoph Steiner wrote:
> 
> Those trigger examples don't really make sense because you wouldn't do 
> that in the real world.  If [hid] allows multiple instances to access 
> the same device, then the data needs to be the same.  Here's an example
> of where it matters: what if you were doing a comparison of the data 
> streams from two [hid 0] to test to see when a certain transform is 
> active or not.  If the data that comes out of each [hid 0] is different, 
> the comparison totally break down.

do i misunderstand you in that the use-case is as follows:

[hid 0]
|
[scale on/off]  <-- this is a modified which can be turned on/off
|
| [hid 0]
| |
[-]
|
[select 0]
|
[scale is turned off(

> If you want to acquire the data twice, you send two bangs.  But when two 
> [hid 0] instances are banged at the same logical time, they should 
> output the exact same data.

hmm, but what if the data has changed in the meantime?
let's assume quantum-physics: querying data modifies the data.

imagine your joystick being twisted via the feedback-engine based on the 
  current position of the stick and immediately queried again.

does the hid-api explicitely state that querying the data must not 
modify it? i know a lot of devices (non of them are hid, though) which 
reset their values each time they are queried.

couldn't this be an application of this very object too?

>> again: [hid]->[t a a] is not the same as [t b b]=>[hid]->[hid] !!
> 
> The fact that everything in Pd runs at the same logical time is a core 
> concept of Pd and should not be dismissed.  Your example of finding 
> which instance executes first demonstrates that: the logical time in 
> between the execution of each instance will be 0.

yes i am totally with you here.
otoh, "same logical time" does not prohibit the internal state of an 
object to be changed.

>>
>> no i don't...wini just mentioned it today (totally unrelated though); 
>> i will hask him when he reappears. (probably just a rumour: 
>> http://www.linux-club.de/ftopic31817.html)
> 
> Well, if the kernel HID stuff is causing you problems, the [hid] object 
> is least of your worries.

true. but it seemed so fit...

> 
> You misunderstand me, I don't discount what IEM does at all.  I 
> generally think of the IEM sound cube when I am talking like this.  As 
> much we would like to have one, very few people in the world have a 
> 24-speaker ambisonic setup to play with.  You guys do stuff on a much 
> grander scale than the vast majority of Pd users, who are stuck with 4 
> year old laptops (like me).

but a lot of "ordinary" Pd users have startet to use professional 
multichannel soundcards. (with 24 channels, even if they don't have the 
IEM CUBE at hand).
what i am trying to express is, that günther and wini had a hard time 
getting the modifications to the OSS driver model to support 
multi(!)channel into the kernel, because people (like you) insisted that 
"nobody but you special guys need a soundcard with 24 channels; we don't 
bother; go away"
(note that i was not part of this story, so i might be completely wrong)

i am glad that the (OSS) hammerfall drivers made it into the kernel, 
they are still the drivers which allowed for the lowest latency i(!) 
achieved with vanilla pd.

>>> I've run [hid] with a poll time of 1.5ms and got no clicks. In the 
>>> realm of instrument design, that is very low latency.  The HID API 
>>> has its own
>>
>> by the way, the polling interval is not the latency.
>> my crappy shitty laptop-soundcard polls at 44.1kHz but still my 
>> latency is about 80ms...
> 
> While its true that polling != latency, that was not my point.  My point 

well, my problem is that often i cannot resist...

> I am sorry I can't keep up with all three platforms.  I do what I can.  
> The code is there, anyone could have fixed it, esp. those of use using a 
> 2.6 kernel on a daily basis.

well, i committed some changes...

> 
> Are you saying that [hid] causes clicks on your machine?  I use a 800 

no i don't.



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IOhannes