Added Modal example

Added Modal resonator example, updated readme

README.md

@@ -12,7 +12,7 @@ to the PJRC Teensy 4.x. This library allows you to use the features of the Teens
  
 DaisySP consists mostly of code collected from other projects - Csound, Soundpipe, and Mutable Instruments eurorack modules. DaisySP is quite similar to Soundpipe but much better written and documented. I ported Soundpipe first and then realized DaisySP is much better.
 
-DaisySP uses floating point for all DSP operations and as such will run slowly on the Teensy 3.x - this has not been tested. On a Teensy 4.x each DaisySP function call consumes roughly 1% of the CPU so you could create a polyphonic synth with 10 oscillators, 10 envelope generators and 10 filters and still have lots of CPU left. The sine oscillator uses up more CPU since its implemented as a trig function. DaisySP has antialiased polyblep oscillators which are quite CPU efficient - much better than the simplistic and noisy waveform generators in the Teensy Audio library.
+DaisySP uses floating point for all DSP operations and as such will run slowly on the Teensy 3.x - this has not been tested. On a Teensy 4.x most DaisySP functions (oscillators, envelope generators etc) consume roughly 1% of the CPU so you could create a polyphonic synth with 10 oscillators, 10 envelope generators and 10 filters and still have lots of CPU left. The physical modelling functions use quite a lot of CPU. The sine oscillator uses up more CPU since its implemented as a trig function. DaisySP has antialiased polyblep oscillators which are quite CPU efficient - much better than the simplistic and noisy waveform generators in the Teensy Audio library.
 
 This implementation adds a DaisySP Teensy Audio synth object to the Teensy Audio library. An Audio Library synth object has no inputs and it outputs a single stream of audio samples. The library currently supports only one instance of a DaisySP object - more may be possible but I'm not good enough with C++ to figure it out. 
 The simplest setup is a DaisySP object to the Teensy Audio Shield object which is set up like this:

examples/modal/modal.ino

@@ -0,0 +1,226 @@
+
+// test of DaisySP synth object for the Teensy audio library
+// modal synth - not very polyphonic because it uses about 30% CPU for one resonator
+// its a good starting point for polyphonic instruments in any case
+// some of this code was cribbed from the Faust for Teensy Additivesynth example
+// RH March 28 2021
+
+#include <Audio.h>
+#include <Metro.h>
+
+//#define DEBUG   // comment out to remove debug code
+
+#ifdef DEBUG
+Metro five_sec=Metro(5000); // Set up a 5 second Metro for performance stats
+#endif
+
+// constants for integer to float and float to integer conversion
+#define MULT_16 2147483647
+#define DIV_16 4.6566129e-10
+
+#include "daisysp.h"
+using namespace daisysp;
+
+// including the source files is a pain but that way you compile in only the modules you need
+// DaisySP statically allocates memory and some modules e.g. reverb use a lot of ram
+#include "physicalmodeling/resonator.cpp"
+#include "physicalmodeling/modalvoice.cpp"
+#include "effects/reverbsc.cpp"  // uses a LOT of ram
+
+float samplerate=AUDIO_SAMPLE_RATE_EXACT;
+
+// create daisySP processing objects
+
+#define VOICES 1   // uses too much CPU for more than 2 and more than 1 doesn't work anyway
+daisysp::ModalVoice voice[VOICES];
+ReverbSc   verb;  
+
+// this is the function called by the AudioSynthDaisySP object when it needs a block of samples
+void AudioSynthDaisySP::update(void)
+{
+  float out,sig,wetvl, wetvr;
+  audio_block_t *block;
+
+  block = allocate(); // grab an audio block
+  if (!block) {
+    return;
+  }
+
+  for (int i=0; i < AUDIO_BLOCK_SAMPLES; i++) {
+
+//**** insert daisySP generators here
+
+    sig=0; // process and sum the string voices
+    for (int i=0; i< VOICES;++i) {
+      sig+=voice[i].Process();
+    }
+    sig=sig/VOICES; // scale the sum 
+//  sig=sig*5; // crank the level a bit
+    verb.Process(sig, sig, &wetvl, &wetvr); 
+
+    out=sig + wetvl*0.2;   // add in some reverb
+    
+// convert generated float value -1.0 to +1.0 to int16 used by Teensy Audio    
+    int32_t val = out*MULT_16;
+    block->data[i] = val >> 16;
+  }
+  transmit(block);
+  release(block);
+}
+
+// teensy audio objects and patch creation
+
+AudioOutputI2S out;
+//AudioOutputUSB outUSB;
+AudioControlSGTL5000 audioShield;
+
+AudioSynthDaisySP synth;  // create the daisysp synth audio object
+
+AudioConnection patchCord20(synth,0,out,0);
+AudioConnection patchCord21(synth,0,out,1);
+//AudioConnection patchCord22(synth,0,outUSB,0);
+//AudioConnection patchCord23(synth,0,outUSB,1);
+
+// frequencies for all 127 MIDI Note numbers.
+//     C         C#        D         D#        E         F         F#        G         G#        A         A#        B
+
+const float NoteNumToFreq[] = {
+    8.18,     8.66,     9.18,     9.72,    10.30,    10.91,    11.56,    12.25,    12.98,    13.75,    14.57,    15.43,    
+   16.35,    17.32,    18.35,    19.45,    20.60,    21.83,    23.12,    24.50,    25.96,    27.50,    29.14,    30.87,    
+   32.70,    34.65,    36.71,    38.89,    41.20,    43.65,    46.25,    49.00,    51.91,    55.00,    58.27,    61.74,   
+   65.41,    69.30,    73.42,    77.78,    82.41,    87.31,    92.50,    98.00,   103.82,   110.00,   116.54,   123.47, 
+  130.81,   138.59,   146.83,   155.56,   164.81,   174.61,   184.99,   195.99,   207.65,   220.00,   233.08,   246.94,   
+  261.63,   277.18,   293.66,   311.13,   329.63,   349.23,   369.99,   391.99,   415.31,   440.00,   466.16,   493.88,   
+  523.25,   554.37,   587.33,   622.25,   659.26,   698.46,   739.99,   783.99,   830.61,   880.00,   932.32,   987.77,   
+ 1046.50,  1108.73,  1174.66,  1244.51,  1318.51,  1396.91,  1479.98,  1567.98,  1661.22,  1760.00,  1864.66,  1975.53,  
+ 2093.00,  2217.46,  2349.32,  2489.02,  2637.02,  2793.83,  2959.96,  3135.96,  3322.44,  3520.00,  3729.31,  3951.07,  
+ 4186.01,  4434.92,  4698.64,  4978.03,  5274.04,  5587.65,  5919.91,  6271.93,  6644.88,  7040.00,  7458.62,  7902.13,  
+ 8372.02,  8869.84,  9397.27,  9956.06, 10548.08, 11175.30, 11839.82, 12543.85 };
+
+// for polyphony - an array of all current notes. 
+// Value -1 means the note is off (not sounding).
+
+int StoredNotes[VOICES];
+
+void setup() { 
+  Serial.begin(38400);
+
+#ifdef DEBUG
+  while (!Serial) {
+    // wait for Arduino Serial Monitor to be ready
+  }
+  Serial.println("starting setup");  
+#endif
+
+  for (int i=0; i< VOICES;++i) {  
+      StoredNotes[i]=-1;  // initialize the note allocation array
+      voice[i].Init(samplerate);       // initialize the voice object
+  }
+
+// initialize the reverb object and set its initial parameters
+  verb.Init(samplerate);
+  verb.SetFeedback(0.87);
+  verb.SetLpFreq(10000.0f);
+    
+  // Enable the AudioShield
+  AudioMemory(10);  // only uses 2 blocks
+  Serial.println("enabling audio shield");    
+  audioShield.enable();
+  audioShield.volume(0.4);
+
+
+  // Handles for the USB MIDI callbacks
+  usbMIDI.setHandleNoteOn(myNoteOn);
+  usbMIDI.setHandleNoteOff(myNoteOff);
+  usbMIDI.setHandleControlChange(myControlChange);
+  usbMIDI.setHandleAfterTouchPoly(myAfterTouch);
+#ifdef DEBUG  
+  Serial.println("finished setup");  
+#endif
+}
+
+
+// Only looking for incoming MIDI events in the loop()
+// myNoteOn(), myNoteOff() and myControlChange() will be processed on incoming MIDI messages.
+
+void loop() {
+  usbMIDI.read();
+
+#ifdef DEBUG
+  // DEBUG - Microcontroller Load Check
+    if (five_sec.check() == 1)
+    {
+      Serial.print("Proc = ");
+      Serial.print(AudioProcessorUsage());
+      Serial.print(" (");    
+      Serial.print(AudioProcessorUsageMax());
+      Serial.print("),  Mem = ");
+      Serial.print(AudioMemoryUsage());
+      Serial.print(" (");    
+      Serial.print(AudioMemoryUsageMax());
+      Serial.println(")");
+    }
+#endif 
+}
+
+// Callback for incoming NoteOn messages
+// Handling the voice allocation here.
+
+void myNoteOn(byte channel, byte note, byte velocity) {
+  for (int i=0; i <= VOICES; ++i){
+    if (StoredNotes[i] == -1) {  // if voice is idle
+      StoredNotes[i] = int(note); // allocate this voice
+      voice[i].SetFreq(NoteNumToFreq[note]);  
+      voice[i].Trig();
+    }
+  }  
+}
+
+// Callback for incoming NoteOff messages
+// Releasing voices to be re-allocated here.
+
+void myNoteOff(byte channel, byte note, byte velocity) {
+  for (int i=0; i < VOICES; ++i){
+    int k = int(note); 
+    if (StoredNotes[i] == k) { // if this voice matches the note we are silencing
+      StoredNotes[i] = -1; // deallocate the voice
+    }
+  }
+}
+
+
+// Callback for incoming CC messages
+// I'm using an external MIDI controller (Arturia Beatstep) to set voice parameters
+// you can also do this with pots and AnalogRead()
+
+void myControlChange(byte channel, byte control, byte value) {
+  float val = float(value) / 127; // convert to 0-1
+
+  for (int i=0; i < VOICES; ++i){
+    switch (control) {
+      case 101:
+        voice[i].SetBrightness(val);
+        break;
+      case 102:
+        voice[i].SetDamping(val);    
+        break;
+      case 103:
+        voice[i].SetStructure(val);    
+        break;
+      default:
+        break;
+    }
+  }
+}
+
+// Callback for incoming Aftertouch messages
+
+void myAfterTouch(byte channel, byte note, byte value) {
+    float val = float(value) / 127; // convert to 0-1
+    
+}
+  
+
+
+
+