From 02a60d10b1e7f037520161228bdf94f1b70086c8 Mon Sep 17 00:00:00 2001
From: Holger Wirtz <dcoredump@googlemail.com>
Date: Fri, 31 May 2019 18:02:41 +0200
Subject: [PATCH] Chorus works :-) but linear interpolation is not the best...
 will try splines...

---
 MicroMDAEPiano.ino          | 21 +++++++++++----------
 effect_modulated_chorus.cpp | 12 ++++--------
 2 files changed, 15 insertions(+), 18 deletions(-)

diff --git a/MicroMDAEPiano.ino b/MicroMDAEPiano.ino
index 992b253..8fde271 100644
--- a/MicroMDAEPiano.ino
+++ b/MicroMDAEPiano.ino
@@ -56,15 +56,15 @@ AudioAmplifier           volume_r;
 AudioAmplifier           volume_l;
 AudioModulatedEffectChorus   modchorus_r;
 AudioModulatedEffectChorus   modchorus_l;
-AudioSynthWaveformSine   mod_sine1;
+AudioSynthWaveform       modulator;
 AudioConnection          patchCord0(queue_r, peak_r);
 AudioConnection          patchCord1(queue_l, peak_l);
 AudioConnection          patchCord2(queue_r, freeverb_r);
 AudioConnection          patchCord3(queue_l, freeverb_l);
 AudioConnection          patchCord4(queue_r, 0, modchorus_r, 0);
 AudioConnection          patchCord5(queue_l, 0, modchorus_l, 0);
-AudioConnection          patchCord6(mod_sine1, 0, modchorus_r, 1);
-AudioConnection          patchCord7(mod_sine1, 0, modchorus_l, 1);
+AudioConnection          patchCord6(modulator, 0, modchorus_r, 1);
+AudioConnection          patchCord7(modulator, 0, modchorus_l, 1);
 AudioConnection          patchCord8(queue_r, 0, mixer_r, 0);
 AudioConnection          patchCord9(queue_l, 0, mixer_l, 0);
 AudioConnection          patchCord10(modchorus_r, 0, mixer_r, 2);
@@ -239,14 +239,15 @@ void setup()
   }
 
   // chorus modulation fixed
-  memset(r_delayline,0,sizeof(short)*CHORUS_DELAY_LENGTH);
-  memset(l_delayline,0,sizeof(short)*CHORUS_DELAY_LENGTH);
-  mod_sine1.amplitude(1.0);
-  mod_sine1.frequency(2.0);
-  mod_sine1.phase(0);
+  memset(r_delayline, 0, sizeof(short)*CHORUS_DELAY_LENGTH);
+  memset(l_delayline, 0, sizeof(short)*CHORUS_DELAY_LENGTH);
+  modulator.begin(WAVEFORM_TRIANGLE);
+  modulator.amplitude(0.1);
+  modulator.frequency(1.0);
+  modulator.phase(0);
   // chorus level fixed
-  mixer_r.gain(2, 1.0);
-  mixer_l.gain(2, 1.0);
+  mixer_r.gain(2, 0.5);
+  mixer_l.gain(2, 0.5);
 
   AudioInterrupts();
 
diff --git a/effect_modulated_chorus.cpp b/effect_modulated_chorus.cpp
index bf25d5e..d7203e5 100644
--- a/effect_modulated_chorus.cpp
+++ b/effect_modulated_chorus.cpp
@@ -131,18 +131,14 @@ void AudioModulatedEffectChorus::update(void)
 
       // linear interpolation
       x1 = int(mod_idx);
-      y1 = *(block->data + x1);
+      y1 = l_delayline[x1];
       if (x1 + 1 >= delay_length)
-      {
         x2 = 0;
-        y2 = *bp;
-      }
       else
-      {
         x2 = x1 + 1;
-        y2 = *bp + x2;
-      }
-      *bp = (*bp >> 1) + (int((float(y2 - y1) / (x2 - x1) * (mod_idx - x1) + y1) + 0.5) >> 1); // mix original signal 1:1 with modulated signal
+      y2 = l_delayline[x2];
+      
+      *bp = (int((float(y2 - y1) / (x2 - x1) * (mod_idx - x1) + y1) + 0.5) >> 1); // mix original signal 1:1 with modulated signal
       bp++;
       mp++;
       l_circ_idx++;