Allow the modulations to be notified of release

src/sfizz/Voice.cpp

@@ -174,6 +174,8 @@ void sfz::Voice::release(int delay) noexcept
     } else {
         egEnvelope.startRelease(delay);
     }
+
+    resources.modMatrix.releaseVoice(id, region->getId(), delay);
 }
 
 void sfz::Voice::off(int delay) noexcept

src/sfizz/modulations/ModGenerator.h

@@ -40,6 +40,15 @@ public:
      */
     virtual void init(const ModKey& sourceKey, NumericId<Voice> voiceId, unsigned delay) = 0;
 
+    /**
+     * @brief Send the generator a release notification.
+     *
+     * @param sourceKey identifier of the source to release
+     * @param voiceId the particular voice to initialize, if per-voice
+     * @param delay the frame time when it happens
+     */
+    virtual void release(const ModKey& sourceKey, NumericId<Voice> voiceId, unsigned delay) { (void)sourceKey; (void)voiceId; (void)delay; }
+
     /**
      * @brief Generate a cycle of the modulator
      *

src/sfizz/modulations/ModMatrix.cpp

@@ -211,6 +211,17 @@ void ModMatrix::initVoice(NumericId<Voice> voiceId, NumericId<Region> regionId,
     }
 }
 
+void ModMatrix::releaseVoice(NumericId<Voice> voiceId, NumericId<Region> regionId, unsigned delay)
+{
+    Impl& impl = *impl_;
+
+    for (Impl::Source &source : impl.sources_) {
+        const int flags = source.key.flags();
+        if ((flags & kModIsPerVoice) && source.key.region() == regionId)
+            source.gen->release(source.key, voiceId, delay);
+    }
+}
+
 void ModMatrix::beginCycle(unsigned numFrames)
 {
     Impl& impl = *impl_;

src/sfizz/modulations/ModMatrix.h

@@ -108,6 +108,12 @@ public:
      */
     void initVoice(NumericId<Voice> voiceId, NumericId<Region> regionId, unsigned delay);
 
+    /**
+     * @brief Release modulation source for a given voice.
+     * This must be called when a voice enters released state.
+     */
+    void releaseVoice(NumericId<Voice> voiceId, NumericId<Region> regionId, unsigned delay);
+
     /**
      * @brief Start modulation processing for the entire cycle.
      * This clears all the buffers.