1 files changed, 121 insertions, 0 deletions
diff --git a/arts/modules/synth/synth_envelope_adsr_impl.cc b/arts/modules/synth/synth_envelope_adsr_impl.cc
new file mode 100644
index 00000000..51ddf76c
--- /dev/null
+++ b/arts/modules/synth/synth_envelope_adsr_impl.cc
@@ -0,0 +1,121 @@
+    /*
+
+    Copyright (C) 2000 Stefan Westerfeld
+                       stefan@space.twc.de
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Library General Public
+    License as published by the Free Software Foundation; either
+    version 2 of the License, or (at your option) any later version.
+  
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Library General Public License for more details.
+   
+    You should have received a copy of the GNU Library General Public License
+    along with this library; see the file COPYING.LIB.  If not, write to
+    the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+    Boston, MA 02111-1307, USA.
+
+    */
+
+#include "artsmodulessynth.h"
+#include "debug.h"
+#include "stdsynthmodule.h"
+
+using namespace Arts;
+
+class Synth_ENVELOPE_ADSR_impl : virtual public Synth_ENVELOPE_ADSR_skel,
+							virtual public StdSynthModule
+{
+protected:
+	enum { NOOUT, ATTACK, SUSTAIN, DECAY, RELEASE } currentphase;
+	float level,increment,decrement;
+public:
+	void streamInit()
+	{
+		currentphase = NOOUT;
+		level = 0;
+	}
+	void calculateBlock(unsigned long samples);
+};
+
+void Synth_ENVELOPE_ADSR_impl::calculateBlock(unsigned long samples)
+{
+	/* FIXME:
+     * should be rewritten as generic envelope, would certainly
+	 * be faster & more flexible
+	 */
+	unsigned long i;
+
+	for(i=0;i<samples;i++)
+	{
+		done[i] = 0;
+		if(active[i] < 0.5)
+		{
+			if(currentphase == NOOUT)
+			{
+				level = 0;
+				done[i] = 1;
+			}
+			else
+			{
+				if(currentphase != RELEASE) {
+					artsdebug("ADSR: entering release phase\n");
+					currentphase = RELEASE;
+					decrement = level / (release[i] * samplingRateFloat);
+				}
+				level -= decrement;
+				if(level <= 0)
+				{
+					level = 0;
+					currentphase = NOOUT;
+				}
+			}
+		}
+		else
+		{
+			switch(currentphase)
+			{
+				//quickly kill the note that is still there (channel busy ;)
+				case RELEASE:
+						level -= 1/200;
+						if(level <= 0) {
+							currentphase = NOOUT;
+							level = 0;
+						}
+					break;
+				case NOOUT:
+						artsdebug("ADSR: entering attack\n");
+						increment = 1 / (attack[i] * samplingRateFloat);
+						currentphase = ATTACK;
+					break;
+				case ATTACK:
+						level += increment;
+						if (level >= 1)
+						{
+							level = 1;
+							currentphase = DECAY;
+							decrement = (1-sustain[i]) /
+										(decay[i] * samplingRateFloat);
+						}
+					break;
+				case DECAY:
+						level -= decrement;
+						if (level <= sustain[i])
+						{
+							level = sustain[i];
+							currentphase = SUSTAIN;
+						}
+					break;
+				case SUSTAIN:
+						level = sustain[i];
+					break;
+			}
+		}
+		outvalue[i] = invalue[i] * level;
+	}
+}
+
+REGISTER_IMPLEMENTATION(Synth_ENVELOPE_ADSR_impl);