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using Pswitch and Pswitch1 (SC2)


Subject: 
              Re: Pswitch and Pswitch1
        Date: 
              Wed, 07 Feb 2001 14:40:40 +0100
        From: 
              Alberto de Campo 
    Reply-To: 
              sc-users@lists.io.com
 Organization: 
              CREATE
          To: 
              sc-users@lists.io.com
  References: 
              1




Hi Mike,

"Michael P. Whyte" wrote:

> I'm having some difficulty understanding Pswitch.
> Could someone who understands these objects forward me some sample code?
> I do understand the first arg is an array of patterns, and the second is the index.
> What i am confused about is:  (for example)
>
> Pswitch([pattern1, pattern2, pattern3], Pseq([2,1,3],inf));
>
> Why would you do this when you could use a Pseq and then order
> the patterns as you see fit?

Right. That would do same thing.
Except it would maybe be easier to generate a more complex
sequence of indices than Pseq([2,1,3],inf) algorithmically.


> The only reason to use Pswitch is to switch to a different pattern on cue, as
> opposed to Pseq, which will wait until the first pattern is done before moving on to the
> next one....right?

Sort of. PSwitch still finishes each pattern, but it could switch whenever
a new pattern starts. This patch shows both options:

(
var melody1, melody2, melody3, indexPattern, indexByMouse, melodyPatterns, mousex;

melody1 = Pseq([48, 53, 55], 2);
melody2 = Pseq([60, 61, 63, 64, 65, 66, 67], 1);
melody3 = Pseq([75, 76, 77, 78, 79], 1);

melodyPatterns = [ melody1, melody2, melody3 ];

  // repeat complete runs of [ melody1, melody3, melody2, melody3 ] 3 times.

indexPattern = Pseq([0, 2, 1, 2], 3);

// Or make an ExternalControlSource from mouse with 3 zones;
// in Pfunc, i.e. whenever a new pattern starts:
// poll the mouse position, and truncate it to integer (to make a legal index).

mousex = MouseX.new(0, 2.99);
indexByMouse = Pfunc({ mousex.value.asInteger });

            // try changing indexPattern1 to indexByMouse.
Pbind(
 \midinote, Pswitch(melodyPatterns, indexPattern1),
 \dur, 0.13
).scope;
)

>
> So I guess what I'm asking is how to send the index to get it to switch to the next
> pattern in the array when I tell it to, regardless of the state of the currently playing
> pattern.

That's what Pswitch1 is for.
It generates a new index for _each_ event, not just
when a pattern ends. So for each event it jumps to the stream
at that index, and gets only one next value from there;
for the event after that, the index may be different again.

>
> Also, what's the difference between Pswitch and Pswitch1?  I've read the source code, but
> lots of good that does me..;-)  (i understand ~10% of it..somethin' about streams...)

In other words, Pswitch1 can criss-cross between several streams,
and these streams are left in their state between index changes;
they just wait for the next time they are asked "next".

(If one of them ends early, the whole Pswitch1 stream stops.)

Three options here:
(
var melody1, melody2, melody3, simpleIndexPattern, longIndexPattern, indexByMouse, mousex;

     // all streams are infinite, and different lengths.
melody1 = Pseq([48, 53, 55], inf);
melody2 = Pseq([60, 61, 63, 64, 65, 66, 67], inf);
melody3 = Pseq([75, 76, 77, 78, 79], inf);

  // simple: One event each from [ melody1, melody3, melody2, melody3 ],
  //repeat 10x.
simpleIndexPattern = Pseq([0, 2, 1, 2], 10);

 // longer index dance:
 // get one event from each pattern, then two, three, and four.

longIndexPattern = Pseq(
 [ 0, 1, 2,
  0, 0, 1, 1, 2, 2,
  0, 0, 0, 1, 1, 1, 2, 2, 2,
  0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2
 ],
 3
);
    // interactive: With Pswitch1, indexByMouse runs for each new event,
    // i.e. even in mid-pattern.
mousex = MouseX.new(0, 2.99);
indexByMouse = Pfunc({ mousex.value.asInteger });

            // try all three.
Pbind(
 \midinote, Pswitch1([ melody1, melody2, melody3 ], simpleIndexPattern),
 \dur, 0.13
).scope;
)

Hope this helps,
best,
adc

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