Support Release Velocity in the 16 vintage codebase (#1267)

OK so I got a linnstrument, alright? Release velocity is super useful
and I should have done this forever ago. Basically plumb it through as
a modulation source in the DSP engine; hook it up properly in the VST3;
and modify the GUI so the Velocity modulator is an either-or modulator.
This results in the ability to modulate with release velocity just
as you can with anything else, albeit in a bit of a clumsy fashion.

Closes #811

src/common/ModulationSource.h

@@ -45,6 +45,7 @@ enum modsources
    ms_slfo6,
    // ms_arpeggiator,
    ms_timbre,
+   ms_releasevelocity,
    n_modsources,
    /*ms_stepseq1,
    ms_stepseq2,
@@ -60,7 +61,7 @@ const char modsource_abberations_button[n_modsources][32] = {
     "Off",       "Velocity", "Keytrack", "Poly AT", "Channel AT", "Pitchbend", "Modwheel", "Ctrl 1",
     "Ctrl 2",    "Ctrl 3",   "Ctrl 4",   "Ctrl 5",  "Ctrl 6",   "Ctrl 7",    "Ctrl 8",   "Amp EG",
     "Filter EG", "LFO 1",    "LFO 2",    "LFO 3",   "LFO 4",    "LFO 5",     "LFO 6",    "SLFO 1",
-    "SLFO 2",    "SLFO 3",   "SLFO 4",   "SLFO 5",  "SLFO 6",   "Timbre" /*,"Arpeggio"*/};
+    "SLFO 2",    "SLFO 3",   "SLFO 4",   "SLFO 5",  "SLFO 6",   "Timbre", "Rel. Velcty" /*,"Arpeggio"*/};
 
 const char modsource_abberations[n_modsources][32] = {"Off",
                                                       "Velocity",
@@ -91,27 +92,29 @@ const char modsource_abberations[n_modsources][32] = {"Off",
                                                       "Scene LFO 4",
                                                       "Scene LFO 5",
                                                       "Scene LFO 6",
-                                                      "Timbre" /*,"Arpeggio"*/};
+                                                      "Timbre",
+                                                      "Release Velocity"
+                                                      /*,"Arpeggio"*/};
 
 const char modsource_abberations_short[n_modsources][32] = {
     "off",   "velocity", "keytrack", "Poly AT", "Ch. AT", "Pitch Bend", "Modwheel", "CTRL1",
     "CTRL2", "CTRL3",    "CTRL4",    "CTRL5",   "CTRL6",  "CTRL7",      "CTRL8",    "AEG",
     "FEG",   "LFO1",     "LFO2",     "LFO3",    "LFO4",   "LFO5",       "LFO6",     "SLFO1",
-    "SLFO2", "SLFO3",    "SLFO4",    "SLFO5",   "SLFO6",  "TIMBR" /*,"Arpeggio"*/};
+    "SLFO2", "SLFO3",    "SLFO4",    "SLFO5",   "SLFO6",  "TIMBR", "RELVEL" /*,"Arpeggio"*/};
 
 const int modsource_grid_xy[n_modsources][2] = {
     {0, 0}, {0, 0}, {1, 0}, {2, 0},  {3, 0}, {4, 0}, {5, 0},          // vel -> mw
     {7, 0}, {8, 0}, {9, 0}, {10, 0}, {7, 3}, {8, 3}, {9, 3}, {10, 3}, // ctrl 1-8
     {6, 2}, {6, 4},                                                   // EGs
     {0, 2}, {1, 2}, {2, 2}, {3, 2},  {4, 2}, {5, 2},                  // LFO
     {0, 4}, {1, 4}, {2, 4}, {3, 4},  {4, 4}, {5, 4},                  // SLFO
-    {6, 0}                                                            // Timbre
+    {6, 0}, {0, 0}                                                            // Timbre, relvel is special
 };
 
 inline bool isScenelevel(modsources ms)
 {
    return ((ms <= ms_ctrl8) || ((ms >= ms_slfo1) && (ms <= ms_slfo6))) && (ms != ms_velocity) &&
-          (ms != ms_keytrack) && (ms != ms_polyaftertouch) && (ms != ms_timbre);
+      (ms != ms_keytrack) && (ms != ms_polyaftertouch) && (ms != ms_timbre) && (ms != ms_releasevelocity);
 }
 
 inline bool canModulateMonophonicTarget(modsources ms)

src/common/SurgeSynthesizer.cpp

@@ -527,6 +527,15 @@ void SurgeSynthesizer::releaseNote(char channel, char key, char velocity)
    int channelmask =
        ((channel == 0) ? 3 : 0) || ((channel == 1) ? 1 : 0) || ((channel == 2) ? 2 : 0);
 
+   for( int s=0; s<2; ++s )
+   {
+      for( auto *v : voices[s] )
+      {
+         if ((v->state.key == key) && (v->state.channel == channel))
+            v->state.releasevelocity = velocity;
+      }
+   }
+
    // if(channelmask&1)
    {
       if (!channelState[channel].hold)
@@ -541,6 +550,7 @@ void SurgeSynthesizer::releaseNote(char channel, char key, char velocity)
       else
          holdbuffer[1].push_back(key); // hold pedal is down, add to bufffer
    }
+
 }
 
 void SurgeSynthesizer::releaseNotePostHoldCheck(int scene, char channel, char key, char velocity)

src/common/dsp/SurgeVoice.cpp

@@ -71,9 +71,14 @@ SurgeVoice::SurgeVoice(SurgeStorage* storage,
    age = 0;
    age_release = 0;
    state.key = key;
-   state.velocity = velocity;
    state.channel = channel;
+
+   state.velocity = velocity;
    state.fvel = velocity / 127.f;
+
+   state.releasevelocity = 0;
+   state.freleasevel = 0;
+
    state.scene_id = scene_id;
    state.detune = detune;
    state.uberrelease = false;
@@ -125,11 +130,15 @@ SurgeVoice::SurgeVoice(SurgeStorage* storage,
       modsources[ms_lfo1 + i] = &lfo[i];
    }
    modsources[ms_velocity] = &velocitySource;
+   modsources[ms_releasevelocity] = &releaseVelocitySource;
    modsources[ms_keytrack] = &keytrackSource;
    modsources[ms_polyaftertouch] = &polyAftertouchSource;
    polyAftertouchSource.init(storage->poly_aftertouch[state.scene_id & 1][state.key & 127]);
+
    velocitySource.output = state.fvel;
+   releaseVelocitySource.output = state.freleasevel;
    keytrackSource.output = 0;
+
    ampEGSource.init(storage, &scene->adsr[0], localcopy, &state);
    filterEGSource.init(storage, &scene->adsr[1], localcopy, &state);
    modsources[ms_ampeg] = &ampEGSource;
@@ -302,6 +311,7 @@ void SurgeVoice::release()
       lfo[i].release();
 
    state.gate = false;
+   releaseVelocitySource.output = state.releasevelocity / 127.0f;
 }
 
 void SurgeVoice::uber_release()

src/common/dsp/SurgeVoice.h

@@ -164,7 +164,7 @@ class alignas(16) SurgeVoice
 
    std::array<ModulationSource*, n_modsources> modsources;
 
-   ModulationSource velocitySource;
+   ModulationSource velocitySource, releaseVelocitySource;
    ModulationSource keytrackSource;
    ControllerModulationSource polyAftertouchSource;
    ModulationSource monoAftertouchSource;

src/common/dsp/SurgeVoiceState.h

@@ -7,12 +7,12 @@ struct SurgeVoiceState
 {
    bool gate;
    bool keep_playing, uberrelease;
-   float pitch, fvel, pkey, detune;
+   float pitch, fvel, pkey, detune, freleasevel;
    MidiKeyState* keyState;
    MidiChannelState* mainChannelState;
    MidiChannelState* voiceChannelState;
-   int key, velocity, channel, scene_id;
+   int key, velocity, channel, scene_id, releasevelocity;
    float portasrc_key, portaphase;
 
    float getPitch();
-};
+};

src/common/gui/CModulationSourceButton.cpp

@@ -173,7 +173,15 @@ void CModulationSourceButton::draw(CDrawContext* dc)
    dc->drawRect(framer, kDrawFilled);
    dc->setFillColor(FillCol);
    dc->drawRect(fillr, kDrawFilled);
-   dc->drawString(label, txtbox, kCenterText, true);
+
+   if( hasAlternate && useAlternate )
+   {
+      dc->drawString(alternateLabel.c_str(), txtbox, kCenterText, true);
+   }
+   else
+   {
+      dc->drawString(label, txtbox, kCenterText, true);
+   }
 
    if (is_metacontroller)
    {

src/common/gui/CModulationSourceButton.h

@@ -4,6 +4,8 @@
 #pragma once
 #include "vstcontrols.h"
 #include "SurgeBitmaps.h"
+#include <iostream>
+
 
 class CModulationSourceButton : public CCursorHidingControl
 {
@@ -52,6 +54,18 @@ class CModulationSourceButton : public CCursorHidingControl
    {
       return state;
    }
+
+   bool hasAlternate = false;
+   int alternateId;
+   std::string alternateLabel;
+   virtual void setAlternate( int alt, const std::string &altLabel ) {
+      hasAlternate = true;
+      this->alternateId = alt;
+      this->alternateLabel = altLabel;
+   }
+   bool useAlternate = false;
+   void setUseAlternate( bool f ) { useAlternate = f; if( hasAlternate ) { invalid(); setDirty(); } }
+
    virtual void draw(VSTGUI::CDrawContext* dc);
    // virtual void mouse (VSTGUI::CDrawContext *pContext, VSTGUI::CPoint &where, long button = -1);
    virtual VSTGUI::CMouseEventResult onMouseDown(VSTGUI::CPoint& where, const VSTGUI::CButtonState& buttons);