--- linuxsampler/trunk/src/engines/gig/EGDecay.h	2005/02/26 02:01:14	411
+++ linuxsampler/trunk/src/engines/gig/EGDecay.h	2005/08/16 17:14:25	738
@@ -5,18 +5,18 @@
  *   Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck   *
  *   Copyright (C) 2005 Christian Schoenebeck                              *
  *                                                                         *
- *   This program is free software; you can redistribute it and/or modify  *
+ *   This library is free software; you can redistribute it and/or modify  *
  *   it under the terms of the GNU General Public License as published by  *
  *   the Free Software Foundation; either version 2 of the License, or     *
  *   (at your option) any later version.                                   *
  *                                                                         *
- *   This program is distributed in the hope that it will be useful,       *
+ *   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 General Public License for more details.                          *
  *                                                                         *
  *   You should have received a copy of the GNU General Public License     *
- *   along with this program; if not, write to the Free Software           *
+ *   along with this library; if not, write to the Free Software           *
  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston,                 *
  *   MA  02111-1307  USA                                                   *
  ***************************************************************************/
@@ -25,42 +25,78 @@
 #define __LS_GIG_EGDECAY_H__
 
 #include "../../common/global.h"
-
-#if DEBUG_HEADERS
-# warning EGDecay.h included
-#endif // DEBUG_HEADERS
-
 #include "../../common/RTMath.h"
-#include "../common/Event.h"
-#include "Engine.h"
 
 namespace LinuxSampler { namespace gig {
 
-    // just symbol prototyping
-    class Engine;
-
-    /**
-     * Decay Envelope Generator
+    /** @brief Decay Envelope Generator (linear)
      *
-     * Simple Envelope Generator with only one stage: 'Decay'. We currently use
-     * this specific EG only for pitch and thus it's not generalized yet, means
-     * the initial envelope level (given by 'Depth') will raise / drop in
-     * 'DecayTime' seconds to a level of exactly 1.0. If the initial level
-     * ('Depth') is already 1.0, nothing happens. Beside that, the EG just
-     * multiplies it's levels to the synthesis parameter sequence.
+     * Simple Envelope Generator with only one stage: 'Decay' which is a
+     * linear segment. The initial envelope level (given by 'Depth') will
+     * raise / drop in 'DecayTime' seconds to a level of exactly 1.0. If
+     * the initial level ('Depth') is already 1.0, nothing happens.
      */
     class EGDecay {
         public:
-            EGDecay(gig::Engine* pEngine, Event::destination_t ModulationDestination);
-            bool Process(uint Samples);
-            void Trigger(float Depth, double DecayTime, uint Delay);
-        protected:
-            gig::Engine* pEngine;
-            Event::destination_t ModulationDestination;
-            uint  TriggerDelay;    ///< number of sample points triggering should be delayed
-            float Level;
-            float DecayCoeff;
-            long  DecayStepsLeft;
+            EGDecay();
+
+            /**
+             * Will be called by the voice when the key / voice was
+             * triggered and initialize the envelope generator.
+             *
+             * @param Depth      - initial level of the envelope
+             * @param DecayTime  - decay time of the envelope (0.000 - 10.000s)
+             * @param SampleRate - sample rate of used audio driver
+             */
+            void trigger(float Depth, float DecayTime, unsigned int SampleRate); //FIXME: we should better use 'float' for SampleRate
+
+            /**
+             * Returns true if envelope is still in stage 'Decay', returns
+             * false if end of envelope is reached.
+             */
+            inline bool active() {
+                return (bool) Coeff;
+            }
+
+            /**
+             * Advance envelope by \a SamplePoints steps.
+             */
+            inline void increment(const int SamplePoints) {
+                StepsLeft = RTMath::Max(0, StepsLeft - SamplePoints);
+            }
+
+            /**
+             * Returns amount of steps until end of envelope is reached.
+             */
+            inline int toEndLeft() {
+                return StepsLeft;
+            }
+
+            /**
+             * Should be called once the end of the envelope is reached. It
+             * will neutralize the envelope coefficient to not alter the
+             * envelope anymore and will set the output level to final level
+             * of exactly 1.0f. So after this call, render() can still
+             * safely be called from the sampler's main synthesis loop.
+             */
+            inline void update() {
+                Level = 1.0f;
+                Coeff = 0.0f;
+            }
+
+            /**
+             * Calculates exactly one level of the envelope.
+             *
+             * @returns next envelope level
+             */
+            inline float render() {
+                return (Level += Coeff);
+            }
+
+        private:
+            float Level;     ///< current EG output level
+            float Coeff;     ///< linear coefficient for changing the output level in time
+            int   StepsLeft; ///< how many steps left until end is reached
     };
 
 }} // namespace LinuxSampler::gig