--- /dev/null
+declare name "envelop";
+declare version "1.0";
+declare author "Grame";
+declare license "BSD";
+declare copyright "(c)GRAME 2006";
+
+import("music.lib");
+
+//-------------------------------------------------
+// ADSR Envelop Generator
+// The 'state' of the envelop generator is
+// defined by a phase signal p2 allowing to
+// distinguish the attack and the decay-sustain
+// phases, and the envelop signal y itself.
+//-------------------------------------------------
+
+envelop(a,d,s,r,t) = adsr ~ (_,_) : (!,_) // The 2 'state' signal are feedback
+ with {
+ adsr (p2,y) = (t>0) & (p2|(y>=1)), // p2 = decay-sustain phase
+ y + p1*a - (p2&(y>s))*d*y - p3*r*y // y = envelop signal
+ with {
+ p1 = (p2==0) & (t>0) & (y<1); // p1 = attack phase
+ p3 = (t<=0) & (y>0); // p3 = release phase
+ };
+ };
+
+
+attack = 1.0/(SR*nentry("[1:]attack [unit:ms][style:knob]", 20, 1, 1000, 1)/1000);
+decay = nentry("[2:]decay[style:knob]", 2, 1, 100, 0.1)/100000;
+sustain = nentry("[3:]sustain [unit:pc][style:knob]", 10, 1, 100, 0.1)/100;
+release = nentry("[4:]release[style:knob]", 10, 1, 100, 0.1)/100000;
+
+
+process = button("play"): hgroup("", envelop(attack, decay, sustain, release) : *(noise));
+