Fixed not playing releases

Author: oleg68

src/grandorgue/sound/GOSoundFader.cpp

@@ -36,28 +36,51 @@ void GOSoundFader::Process(
   externalVolume *= m_VelocityVolume;
 
   float startTargetVolumePoint = m_LastTargetVolumePoint;
+
   // Calculate new m_LastTargetVolumePoint
   // the target volume will be changed from startTargetVolumePoint to
   // m_LastTargetVolumePoint during the nFrames
-  float targetVolumeDeltaPerFrame
-    = m_IncreasingDeltaPerFrame + m_DecreasingDeltaPerFrame;
 
-  if (targetVolumeDeltaPerFrame != 0.0f) {
-    m_LastTargetVolumePoint = std::clamp(
-      startTargetVolumePoint + targetVolumeDeltaPerFrame * nFrames,
-      0.0f,
-      m_TargetVolume);
+  unsigned framesLeftAfterIncreasing = nFrames;
+
+  // increasing section
+  if (m_IncreasingDeltaPerFrame > 0.0f) {
+    // we are increasing now
+    float newTargetVolumePoint
+      = m_LastTargetVolumePoint + m_IncreasingDeltaPerFrame * nFrames;
+
+    if (newTargetVolumePoint < m_TargetVolume) {
+      framesLeftAfterIncreasing = 0; // we are increase during the whole period
+      m_LastTargetVolumePoint = newTargetVolumePoint;
+    } else {
+      // we reach m_TargetVolume inside this nFrames period
 
-    if (m_LastTargetVolumePoint >= m_TargetVolume)
-      // target volume is reached. Stop increasing
+      // stop increasing
       m_IncreasingDeltaPerFrame = 0.0f;
-    else if (m_LastTargetVolumePoint <= 0.0f)
-      // Decreasing is finished. Stop it.
-      m_DecreasingDeltaPerFrame = 0.0f;
+
+      // calculate how many frames left after increasing
+      framesLeftAfterIncreasing = nFrames
+        - unsigned((m_TargetVolume - m_LastTargetVolumePoint)
+                   / m_IncreasingDeltaPerFrame);
+
+      m_LastTargetVolumePoint = m_TargetVolume;
+    }
   }
 
-  if (m_LastExternalVolumePoint < 0.0f) // The first Process() call
-    m_LastExternalVolumePoint = externalVolume;
+  // decreasing section
+  if (framesLeftAfterIncreasing && m_DecreasingDeltaPerFrame > 0.0f) {
+    // decrease the volume
+    float newTargetVolumePoint = m_LastTargetVolumePoint
+      - m_DecreasingDeltaPerFrame * framesLeftAfterIncreasing;
+
+    if (newTargetVolumePoint > 0.0f) {
+      m_LastTargetVolumePoint = newTargetVolumePoint;
+    } else {
+      // stop decreasing
+      m_DecreasingDeltaPerFrame = 0.0f;
+      m_LastTargetVolumePoint = 0.0f;
+    }
+  }
 
   float startExternalVolumePoint = m_LastExternalVolumePoint;
   // Calculate new m_LastExternalVolumePoint

src/grandorgue/sound/GOSoundFader.h

@@ -8,6 +8,8 @@
 #ifndef GOSOUNDFADER_H_
 #define GOSOUNDFADER_H_
 
+#include <assert.h>
+
 /**
  * This class is responsible for smoothly changing a volume of samples.
  *
@@ -69,11 +71,22 @@ class GOSoundFader {
    * @param nFrames number of frames for full decay
    */
   inline void StartDecreasingVolume(unsigned nFrames) {
-    // stop increasing the volume if it has not yet finished
-    m_IncreasingDeltaPerFrame = 0.0f;
     // maybe m_TargetVolume has not yet been reached, but the velocity of
     // decreasing should be the same as it has reached
-    m_DecreasingDeltaPerFrame = -(m_TargetVolume / nFrames);
+    m_DecreasingDeltaPerFrame = m_TargetVolume / nFrames;
+    if (m_IncreasingDeltaPerFrame > 0.0f) {
+      /*
+        The increasing has not yet finished. We are starting a "virtual"
+        decreasing from m_TargetVolume to 0.
+        The increasing processus will continue until it meet the "virtual"
+        decreasing one at the new m_TargetVolume. Let's calculate it
+       */
+      assert(m_LastTargetVolumePoint < m_TargetVolume);
+      m_TargetVolume = (m_TargetVolume - m_LastTargetVolumePoint)
+          * m_IncreasingDeltaPerFrame
+          / (m_IncreasingDeltaPerFrame + m_DecreasingDeltaPerFrame)
+        + m_LastTargetVolumePoint;
+    }
   }
 
   inline float GetVelocityVolume() const { return m_VelocityVolume; }