envelope, filter cutoff/resonance mapped to default modulators (with semi-random magic numbers)

Source/FluidSynthModel.cpp

@@ -4,6 +4,7 @@
 
 #include <iostream>
 #include "FluidSynthModel.h"
+#include "MidiConstants.h"
 
 using namespace std;
 
@@ -15,8 +16,8 @@ FluidSynthModel::FluidSynthModel(SharesParams& p)
           currentSampleRate(44100),
           initialised(false),
           sfont_id(0),
-          channel(0),
+          channel(0)/*,
-          mod(nullptr)
+          mod(nullptr)*/
 
 {}
 
@@ -27,7 +28,7 @@ FluidSynthModel::~FluidSynthModel() {
         delete_fluid_settings(settings);
 //        delete driver;
 //        delete settings;
-        delete_fluid_mod(mod);
+//        delete_fluid_mod(mod);
     }
 }
 
@@ -63,37 +64,73 @@ void FluidSynthModel::initialise() {
 
 //    changePreset(128, 13);
     
+    float env_amount(12700.0f);
     
-
+    fluid_mod_t *mod(new_fluid_mod());
-//    mod = new_fluid_mod();
-//
-//    // modulator's primary source controller and flags
-//    // fluid_mod_src:
-//    // https://github.com/FluidSynth/fluidsynth/blob/master/include/fluidsynth/mod.h#L61
-//    // fluid_mod_flags:
-//    // https://github.com/FluidSynth/fluidsynth/blob/master/include/fluidsynth/mod.h#L41
-//    // diagrams showing what negative and concave mean:
-//    // https://musescore.org/en/user/527826/blog/2016/05/23/volume-fluidsynth
-//    // fluid_gen_type:
-//    // https://github.com/FluidSynth/fluidsynth/blob/master/include/fluidsynth/gen.h#L36
-//    // https://github.com/FluidSynth/fluidsynth/blob/master/src/synth/fluid_gen.c#L27
-//    fluid_mod_set_source1(mod,
-//            FLUID_MOD_KEYPRESSURE,
-//            FLUID_MOD_CC |
-//                    FLUID_MOD_POSITIVE |
-//                    FLUID_MOD_UNIPOLAR |
-//                    FLUID_MOD_CONCAVE);
-//    // modulator's secondary source controller and flags
-//    // MIDI CC 74
-////    fluid_mod_set_source2(mod, 74, FLUID_MOD_CC);
-//    fluid_mod_set_source2(mod, 0, 0);
-//    // generator for filter cutoff
-//    fluid_mod_set_dest(mod, GEN_MODENVATTACK);
-//    fluid_mod_set_amount(mod, 13500.0f);
-//
-//    fluid_synth_add_default_mod(synth, mod, FLUID_SYNTH_ADD);
     
+    fluid_mod_set_source1(mod,
+                          static_cast<int>(SOUND_CTRL2), // MIDI CC 71 Timbre/Harmonic Intensity (filter resonance)
+                          FLUID_MOD_CC
+                          | FLUID_MOD_UNIPOLAR
+                          | FLUID_MOD_CONCAVE
+                          | FLUID_MOD_NEGATIVE);
+    fluid_mod_set_source2(mod, 0, 0);
+    fluid_mod_set_dest(mod, GEN_FILTERQ);
+    fluid_mod_set_amount(mod, FLUID_PEAK_ATTENUATION);
+    fluid_synth_add_default_mod(synth, mod, FLUID_SYNTH_ADD);
+    delete_fluid_mod(mod);
     
+    mod = new_fluid_mod();
+    fluid_mod_set_source1(mod,
+                          static_cast<int>(SOUND_CTRL3), // MIDI CC 72 Release time
+                          FLUID_MOD_CC
+                          | FLUID_MOD_BIPOLAR
+                          | FLUID_MOD_CONCAVE
+                          | FLUID_MOD_POSITIVE);
+    fluid_mod_set_source2(mod, 0, 0);
+    fluid_mod_set_dest(mod, GEN_VOLENVRELEASE);
+    fluid_mod_set_amount(mod, env_amount);
+    fluid_synth_add_default_mod(synth, mod, FLUID_SYNTH_ADD);
+    delete_fluid_mod(mod);
+    
+    mod = new_fluid_mod();
+    fluid_mod_set_source1(mod,
+                          static_cast<int>(SOUND_CTRL4), // MIDI CC 73 Attack time
+                          FLUID_MOD_CC
+                          | FLUID_MOD_BIPOLAR
+                          | FLUID_MOD_CONCAVE
+                          | FLUID_MOD_POSITIVE);
+    fluid_mod_set_source2(mod, 0, 0);
+    fluid_mod_set_dest(mod, GEN_VOLENVATTACK);
+    fluid_mod_set_amount(mod, env_amount);
+    fluid_synth_add_default_mod(synth, mod, FLUID_SYNTH_ADD);
+    delete_fluid_mod(mod);
+    
+    mod = new_fluid_mod();
+    fluid_mod_set_source1(mod,
+                          static_cast<int>(SOUND_CTRL5), // MIDI CC 74 Brightness (cutoff frequency, FILTERFC)
+                          FLUID_MOD_CC
+                          | FLUID_MOD_SWITCH
+                          | FLUID_MOD_UNIPOLAR
+                          | FLUID_MOD_POSITIVE);
+    fluid_mod_set_source2(mod, 0, 0);
+    fluid_mod_set_dest(mod, GEN_FILTERFC);
+    fluid_mod_set_amount(mod, -2400.0f);
+    fluid_synth_add_default_mod(synth, mod, FLUID_SYNTH_ADD);
+    delete_fluid_mod(mod);
+    
+    mod = new_fluid_mod();
+    fluid_mod_set_source1(mod,
+                          static_cast<int>(SOUND_CTRL6), // MIDI CC 75 Decay Time
+                          FLUID_MOD_CC
+                          | FLUID_MOD_BIPOLAR
+                          | FLUID_MOD_CONCAVE
+                          | FLUID_MOD_POSITIVE);
+    fluid_mod_set_source2(mod, 0, 0);
+    fluid_mod_set_dest(mod, GEN_VOLENVDECAY);
+    fluid_mod_set_amount(mod, env_amount);
+    fluid_synth_add_default_mod(synth, mod, FLUID_SYNTH_ADD);
+    delete_fluid_mod(mod);
 
     initialised = true;
 }

Source/FluidSynthModel.h

@@ -88,7 +88,7 @@ private:
     unsigned int sfont_id;
     unsigned int channel;
 
-    fluid_mod_t* mod;
+//    fluid_mod_t* mod;
 
     ListenerList<Listener> eventListeners;
 

Source/MidiConstants.h

@@ -1,7 +1,10 @@
 #pragma once
 
-/* Taken from fluidsynth/src/midi/fluid_midi.h
+/* Taken from:
+ * fluidsynth/src/midi/fluid_midi.h
+ * fluidsynth/src/utils/fluid_conv_tables.h
  * https://github.com/FluidSynth/fluidsynth/blob/master/src/midi/fluid_midi.h
+ * https://github.com/FluidSynth/fluidsynth/blob/master/src/utils/fluid_conv_tables.h
  *
  * FluidSynth - A Software Synthesizer
  *
@@ -128,3 +131,34 @@ enum fluid_midi_control_change
     POLY_OFF = 0x7E,
     POLY_ON = 0x7F
 };
+
+/*
+ Attenuation range in centibels.
+ Attenuation range is the dynamic range of the volume envelope generator
+ from 0 to the end of attack segment.
+ fluidsynth is a 24 bit synth, it could (should??) be 144 dB of attenuation.
+ However the spec makes no distinction between 16 or 24 bit synths, so use
+ 96 dB here.
+ 
+ Note about usefulness of 24 bits:
+ 1)Even fluidsynth is a 24 bit synth, this format is only relevant if
+ the sample format coming from the soundfont is 24 bits and the audio sample format
+ choosen by the application (audio.sample.format) is not 16 bits.
+ 
+ 2)When the sample soundfont is 16 bits, the internal 24 bits number have
+ 16 bits msb and lsb to 0. Consequently, at the DAC output, the dynamic range of
+ this 24 bit sample is reduced to the the dynamic of a 16 bits sample (ie 90 db)
+ even if this sample is produced by the audio driver using an audio sample format
+ compatible for a 24 bit DAC.
+ 
+ 3)When the audio sample format settings is 16 bits (audio.sample.format), the
+ audio driver will make use of a 16 bit DAC, and the dynamic will be reduced to 96 dB
+ even if the initial sample comes from a 24 bits soundfont.
+ 
+ In both cases (2) or (3), the real dynamic range is only 96 dB.
+ 
+ Other consideration for FLUID_NOISE_FLOOR related to case (1),(2,3):
+ - for case (1), FLUID_NOISE_FLOOR should be the noise floor for 24 bits (i.e -138 dB).
+ - for case (2) or (3), FLUID_NOISE_FLOOR should be the noise floor for 16 bits (i.e -90 dB).
+ */
+#define FLUID_PEAK_ATTENUATION  960.0f