Add MIDI velocity to PlaySynthMusic example

examples/Synthesis/PlaySynthMusic/PlaySynthMusic.h

@@ -31,5 +31,40 @@ const float tune_frequencies2_PGM[128] =
 #define CMD_RESTART	0xe0	/* restart the score from the beginning */
 #define CMD_STOP	0xf0	/* stop playing */
 
+const float velocity2amplitude[127] = {
+0.01778,0.01966,0.02164,0.02371,0.02588,0.02814,0.03049,0.03294,0.03549,0.03812,
+0.04086,0.04369,0.04661,0.04963,0.05274,0.05594,0.05924,0.06264,0.06613,0.06972,
+0.07340,0.07717,0.08104,0.08500,0.08906,0.09321,0.09746,0.10180,0.10624,0.11077,
+0.11539,0.12011,0.12493,0.12984,0.13484,0.13994,0.14513,0.15042,0.15581,0.16128,
+0.16685,0.17252,0.17828,0.18414,0.19009,0.19613,0.20227,0.20851,0.21484,0.22126,
+0.22778,0.23439,0.24110,0.24790,0.25480,0.26179,0.26887,0.27605,0.28333,0.29070,
+0.29816,0.30572,0.31337,0.32112,0.32896,0.33690,0.34493,0.35306,0.36128,0.36960,
+0.37801,0.38651,0.39511,0.40381,0.41260,0.42148,0.43046,0.43953,0.44870,0.45796,
+0.46732,0.47677,0.48631,0.49595,0.50569,0.51552,0.52544,0.53546,0.54557,0.55578,
+0.56609,0.57648,0.58697,0.59756,0.60824,0.61902,0.62989,0.64085,0.65191,0.66307,
+0.67432,0.68566,0.69710,0.70863,0.72026,0.73198,0.74380,0.75571,0.76771,0.77981,
+0.79201,0.80430,0.81668,0.82916,0.84174,0.85440,0.86717,0.88003,0.89298,0.90602,
+0.91917,0.93240,0.94573,0.95916,0.97268,0.98629,1.00000
+};
+/*
+#! /usr/bin/perl
+# The Interpretation of MIDI Velocity
+# Roger B. Dannenberg
+# School of Computer Science, Carnegie Mellon University
+$dynamic_range = 35;
+$r = 10 ** ($dynamic_range / 20);
+$b = 127 / (126 * sqrt($r)) - 1/126;
+$m = (1 - $b) / 127;
+print "const float velocity2amplitude[127] = {\n";
+for ($v=1; $v <= 127; $v++) {
+	$a = ($m * $v + $b) ** 2;
+	printf "%.5f", $a;
+	print "," if $v < 127;
+	print "\n" if ($v % 10) == 0;
+}
+print "\n};\n";
+*/
+
+
 // User must supply this score array
 extern unsigned char score[];

examples/Synthesis/PlaySynthMusic/PlaySynthMusic.ino

@@ -239,9 +239,12 @@ if(1) {
   
   // Play the note on 'chan'
   if(opcode == CMD_PLAYNOTE) {
+    unsigned char note = *sp++;
+    unsigned char velocity = *sp++;
     AudioNoInterrupts();
-    waves[chan]->begin(AMPLITUDE, tune_frequencies2_PGM[*sp++],
-                        wave_type[chan]);
+    waves[chan]->begin(AMPLITUDE * velocity2amplitude[velocity-1],
+                       tune_frequencies2_PGM[note],
+                       wave_type[chan]);
     envs[chan]->noteOn();
     AudioInterrupts();
     return;

examples/Synthesis/PlaySynthMusic/miditones/miditonesV1.6.c

@@ -942,7 +942,7 @@ int main(int argc,char *argv[]) {
                           fprintf (outfile, "0x%02X,%d, ", CMD_PLAYNOTE | tgnum, shifted_note);
                           outfile_items(2);
                         } else {
-                          fprintf (outfile, "0x%02X,%d,%d ", CMD_PLAYNOTE | tgnum, shifted_note, trk->velocity);
+                          fprintf (outfile, "0x%02X,%d,%d, ", CMD_PLAYNOTE | tgnum, shifted_note, trk->velocity);
                           outfile_items(3);
                         }
                     }