Version 3.2

src/Envelope.cpp

@@ -0,0 +1,122 @@
+/*******************************************/
+/*  Envelope Class, Perry R. Cook, 1995-96 */
+/*                                         */
+/*  This is the base class for envelopes.  */
+/*  This one is capable of ramping state   */
+/*  from where it is to a target value by  */
+/*  a rate.  It also responds to simple    */
+/*  KeyOn and KeyOff messages, ramping to  */         
+/*  1.0 on keyon and to 0.0 on keyoff.     */
+/*  There are two tick (update value)      */
+/*  methods, one returns the value, and    */
+/*  other returns 0 if the envelope is at  */
+/*  the target value (the state bit).      */
+/*******************************************/
+
+#include "Envelope.h"    
+
+Envelope :: Envelope() : Object()
+{    
+  target = (MY_FLOAT) 0.0;
+  value = (MY_FLOAT) 0.0;
+  rate = (MY_FLOAT) 0.001;
+  state = 0;
+}
+
+Envelope :: ~Envelope()
+{    
+}
+
+void Envelope :: keyOn()
+{
+  target = (MY_FLOAT) 1.0;
+  if (value != target) state = 1;
+}
+
+void Envelope :: keyOff()
+{
+  target = (MY_FLOAT) 0.0;
+  if (value != target) state = 1;
+}
+
+void Envelope :: setRate(MY_FLOAT aRate)
+{
+  if (aRate < 0.0) {
+    printf("negative rates not allowed!!, correcting\n");
+    rate = -aRate;
+  }
+  else rate = aRate;
+}
+
+void Envelope :: setTime(MY_FLOAT aTime)
+{
+  if (aTime < 0.0) {
+    printf("negative times not allowed!!, correcting\n");
+    rate = ONE_OVER_SRATE / -aTime ;
+  }
+  else rate = ONE_OVER_SRATE / aTime ;
+}
+
+void Envelope :: setTarget(MY_FLOAT aTarget)
+{
+  target = aTarget;
+  if (value != target) state = 1;
+}
+
+void Envelope :: setValue(MY_FLOAT aValue)
+{
+  state = 0;
+  target = aValue;
+  value = aValue;
+}
+
+MY_FLOAT Envelope :: tick()
+{
+  if (state)  {
+    if (target > value)    {
+      value += rate;
+      if (value >= target)    {
+        value = target;
+        state = 0;
+      }
+    }
+    else    {
+      value -= rate;
+      if (value <= target)    {
+        value = target;
+        state = 0;
+      }
+    }
+  }
+  return value;
+}
+
+int Envelope :: informTick()
+{
+  this->tick();
+  return state;
+}
+
+MY_FLOAT Envelope :: lastOut()
+{
+  return value;
+}
+
+/************  Test Main  ************************/
+/*
+void main()
+{
+    long i;
+    Envelope test;
+    
+    test.setRate(0.15);
+    test.keyOn();
+    for (i=0;i<10;i++) printf("%lf\n",test.tick());
+    test.setRate(0.1);
+    test.setTarget(0.5);
+    while (test.informTick()) printf("%lf\n",test.lastOut());
+    test.setRate(0.05);
+    test.keyOff();
+    while(test.informTick()) printf("%lf\n",test.lastOut());
+}
+*/