[chuck-users] spline envelopes

[mike clemow]

Dimitris,

I do this all the time now:

//
// CurveTable Envelope
//

class CurveEnvelope
{
	// members and default params
	Phasor drive => CurveTable curvetable => Gain multiplier;
	3 => multiplier.op;				// this is what makes the CurveTable an envelope!
	0. => multiplier.gain;			// we use this to gait the output, so start at 0.
	
	UGen source, out;
	
	0 => drive.op;					// stop the driver for now
	
	dac @=> out;
	1. => float gain;
	1::second => dur length;
	[0., 0., 0.,  1., 1., 0.,  2., 0.] => curvetable.coefs;	// triangle window
	
	// methods
	fun void setEnvelopeCoefs( float _coefs[] )
	{
		_coefs => curvetable.coefs;
	}
	
	fun void connectSource( UGen src )
	{
		src @=> source;
	}
	
	fun void connectOutput( UGen destination )
	{
		destination @=> out;
	}
	
	fun void trigger()
	{
		source => multiplier => out;			// connect things
		gain => multiplier.gain;				// open gait
		1 => drive.op;
		0. => drive.phase;						// reset driver to beginning of envelope curve
		1. / (length / second) => drive.freq;	// calculate speed of driver in Hz
		length => now;							// let it happen...
		0. => multiplier.gain;					// close gait
		0 => drive.op;
		source =< multiplier =< out;			// disconnect things
	}
}

// demo

CurveEnvelope ce;
SinOsc s;
ce.connectSource( s );
ce.connectOutput( dac );
ce.trigger();
TriOsc t;
ce.connectSource( t );
ce.connectOutput( dac );
ce.trigger();

<<< "done" >>>;


---
It's fast.  I use it for grain envelopes.  The GenX UGens are similarly helpful.

-Mike

On Wed, Aug 12, 2009 at 3:38 AM, Hans Aberg<haberg at math.su.se> wrote:
> On 12 Aug 2009, at 04:17, Kassen wrote:
>
>>> has anybody implemented in ChucK or elsewhere else envelopes with the use
>>> of bezier or other spline curves?
>>
>> Doesn't one of the Gen[n] UGens cover those? If not we might put that on
>> the wish list.
>
> It might be nice to have it some general functions. - I was thinking of
> using it for implementing scale stretch.
>
>  Hans
>
>
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