EnvGate singleton fade envelope

Convenience class for an envelope generator combining fadeTime and gate arguments.

Returns an EnvGen.

*new(i_level, gate, fadeTime, doneAction, curve)

i_level initial level of envelope (if set to 1, it starts open)

gate a gate input 

if nil, EnvGate creates a NamedControl named 'gate'

fadeTime an input for both attack and decay time

if nil, EnvGate creates a NamedControl named 'fadeTime' (default time: 0.02)

doneAction doneAction of the EnvGen (default: 2)

curve envelope curve (default: 'sin')

// examples

a = { LPF.ar(Saw.ar(200), 600) * EnvGate.new }.play;

a.set(\fadeTime, 2);

a.release;

// the same as:

a.set(\gate, 0);

// several env gates can coexist in one synth def.

(

a = {

var sound1 = LPF.ar(Saw.ar(80), 600) * EnvGate.new;

var sound2 = RLPF.ar(Saw.ar(200) * 0.5, 6000 * EnvGate.new + 60, 0.1) * EnvGate.new;

sound1 + sound2

}.play;

)

a.set(\fadeTime, 5);

a.release;