Merge pull request #278 from shorepine/piano_retrigger

amy.c, oscillators.c: Avoid clicks when retriggering PARTIALs.

src/amy.c

@@ -1045,9 +1045,8 @@ void play_event(struct delta d) {
 
             // if there was a filter active for this voice, reset it
             if(synth[d.osc].filter_type != FILTER_NONE) reset_filter(d.osc);
-            // For repeatability, start at zero phase.
-            synth[d.osc].phase = 0;
-
+            // We no longer reset the phase here; instead, we reset phase when an oscillator falls silent.
+
             // restart the waveforms
             // Guess at the initial frequency depending only on const & note.  Envelopes not "developed" yet.
             float initial_logfreq = synth[d.osc].logfreq_coefs[COEF_CONST];
@@ -1306,7 +1305,10 @@ SAMPLE render_osc_wave(uint16_t osc, uint8_t core, SAMPLE* buf) {
             } else {
                 if ( (total_samples - synth[osc].zero_amp_clock) >= MIN_ZERO_AMP_TIME_SAMPS) {
                     //printf("h&m: time %f osc %d OFF\n", total_samples/(float)AMY_SAMPLE_RATE, osc);
+                    // Oscillator has fallen silent, stop executing it.
                     synth[osc].status = SYNTH_AUDIBLE_SUSPENDED;  // It *could* come back...
+                    // .. but force it to start at zero phase next time.
+                    synth[osc].phase = 0;
                 }
             }
         } else if (max_val == 0) {

src/oscillators.c

@@ -546,8 +546,6 @@ void partial_note_on(uint16_t osc) {
     float freq = freq_of_logfreq(msynth[osc].logfreq);
     float period_samples = (float)AMY_SAMPLE_RATE / freq;
     synth[osc].lut = choose_from_lutset(period_samples, sine_fxpt_lutset);
-    // Partials ramp up from zero.
-    msynth[osc].amp = 0;
 }
 
 void partial_note_off(uint16_t osc) {

test.py

@@ -222,13 +222,30 @@ def run(self):
     num_partials = 20
     amy.send(time=0, osc=base_osc, wave=amy.INTERP_PARTIALS, patch=0)
     for i in range(1, num_partials + 1):
-      # Set up each partial as the corresponding harmonic of the base_freq, with an amplitude of 1/N, 50ms attack, and a decay of 1 sec / N
       amy.send(osc=base_osc + i, wave=amy.PARTIAL)
     amy.send(time=50, osc=0, note=60, vel=0.1)
     amy.send(time=300, osc=0, note=67, vel=0.6)
     amy.send(time=550, osc=0, note=72, vel=1)
     amy.send(time=800, osc=0, vel=0)
 
+class TestInterpPartialsRetrigger(AmyTest):
+
+  def run(self):
+    # PARTIALS but each partial is interpolated from a table of pre-analyzed harmonic-sets.
+    base_osc = 0
+    num_partials = 20
+    amy.send(time=0, osc=base_osc, wave=amy.INTERP_PARTIALS, patch=0)
+    for i in range(1, num_partials + 1):
+      amy.send(osc=base_osc + i, wave=amy.PARTIAL)
+    amy.send(time=50, osc=0, note=52, vel=0.7)
+    amy.send(time=200, osc=0, note=52, vel=0.8)
+    amy.send(time=350, osc=0, note=52, vel=0.9)
+    amy.send(time=500, osc=0, vel=0)
+    amy.send(time=510, osc=40, wave=amy.SINE, bp0='3,1,500,0,50,0')
+    amy.send(time=550, osc=40, note=76, vel=1)
+    amy.send(time=700, osc=40, note=76, vel=1)
+    amy.send(time=850, osc=40, vel=0)
+
 class TestSineEnv(AmyTest):
 
   def run(self):
@@ -476,9 +493,9 @@ def run(self):
     # Uses a 0.25Hz sine wave at 0.5 phase (going down) to modify frequency of another sine wave
     amy.send(time=0, osc=1, wave=amy.SINE, amp=1, freq=0.25, phase=0.5)
     amy.send(time=0, osc=0, wave=amy.SINE, bp0="0,1,500,0,0,0", freq="261.63,1,0,0,0,2", mod_source=1)
-    amy.send(time=100, osc=0, note=84, vel=1)
-    amy.send(time=350, osc=0, note=84, vel=1)
-    amy.send(time=600, osc=0, note=84, vel=1)
+    amy.send(time=100, osc=0, note=84, vel=1, phase=0)
+    amy.send(time=350, osc=0, note=84, vel=1, phase=0)
+    amy.send(time=600, osc=0, note=84, vel=1, phase=0)
 
 class TestChainedOsc(AmyTest):
   """Two oscillators chained together."""