Version 0.99

Envelope.cpp

@@ -0,0 +1,113 @@
+/*******************************************/
+/*  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 = 0.0;
+    value = 0.0;
+    rate = 0.001;
+    state = 0;
+}
+
+Envelope :: ~Envelope()
+{    
+}
+
+void Envelope :: keyOn()
+{
+    target = 1.0;
+    if (value != target) state = 1;
+}
+
+void Envelope :: keyOff()
+{
+    target = 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;
+    rate = rate * RATE_NORM;	/*  SEE Object.h  */
+}
+
+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());
+}
+*/