Basic stringy sound, highpass filters

notes.txt

@@ -6,8 +6,8 @@ c5 = bottom of divider chain = midi C3 = 130.81Hz
 
 RC networks = capacitor and effectively 10k because of the diode and 27.6k resistor network
 
-c1=2842
-c6 = 
+c1= 5n6/10k 2842Hz
+c6 = 180n/10k 80Hz
 
 Each key drives two sets of gates, for 4' (violin) and 8' (viola/trumpet/horn)
 Five sets of gates apiece

plugin/assigner.cpp

@@ -17,8 +17,8 @@
 */
 
 #include "assigner.hpp"
-
-// #define DEBUG
+#include "generator.hpp"
+#define DEBUG
 
 void Assigner::dumpTables() {
 #ifdef DEBUG
@@ -32,7 +32,7 @@ void Assigner::dumpTables() {
 #endif
 }
 
-Assigner::Assigner() {
+Assigner::Assigner(Voice *v) {
     d_debug("assigner constructor");
 
     // set up the assigner tables
@@ -40,6 +40,7 @@ Assigner::Assigner() {
         voiceTbl[i] = i;
         noteTbl[i] = 0x80;
     }
+    voices = v;
 }
 
 void Assigner::handleMidi(MidiEvent *ev) {
@@ -135,5 +136,7 @@ void Assigner::noteOn(uint8_t note) {
     // printf("at end, l=%d e=%d\n", l,e);
     noteTbl[v] = note;
 
+    voices[v].startNote(note, 48000);
+
     d_debug("send voice on %3d to voice %d", note, v);
 }

plugin/assigner.hpp

@@ -21,9 +21,11 @@
 
 #include "DistrhoPlugin.hpp"
 
+#include "generator.hpp"
+
 class Assigner {
    public:
-    Assigner();
+    Assigner(Voice *v);
     void handleMidi(MidiEvent *ev);
     uint8_t noteTbl[NUM_VOICES];   // note played by voice
 
@@ -32,6 +34,8 @@ class Assigner {
     void noteOff(uint8_t note);    // incoming note off
     uint8_t voiceTbl[NUM_VOICES];  // voices in order of use
 
+   Voice *voices;
+
     void dumpTables();
 };
 

plugin/generator.cpp

@@ -38,7 +38,6 @@ void Generator::setupGenerator(double sampleRate) {
 }
 
 void Generator::runBlock(float *output, uint8_t *noteTable, uint32_t frames) {
-
     memset(output, 0, frames * sizeof(float));
 
     for (uint32_t i = 0; i < frames; i++) {
@@ -46,14 +45,26 @@ void Generator::runBlock(float *output, uint8_t *noteTable, uint32_t frames) {
             phase[p] += omega[p];
         }
 
-        for (uint8_t k=0; k<NUM_VOICES; k++) {
-            uint8_t n1 = noteTable[k] % 12, n2 = (noteTable[k]/12 - 2);
-            output[i] +=  ((phase[n1] & (0x80000000 >> n2)) ? 0.1 : -0.1) * (noteTable[k]&0x80?0:1);
+        for (uint8_t k = 0; k < NUM_VOICES; k++) {
+            uint8_t n1 = noteTable[k] % 12, n2 = (noteTable[k] / 12 - 3);
+            float n = ((phase[n1] & (0x80000000 >> n2)) ? 0.25 : -0.25);
+
+            voices[k].vc34 = ((n - voices[k].vc34) * voices[k].c34) + voices[k].vc34;
+
+            n -= voices[k].vc34;
+            n *= (phase[n1] & (0x80000000 >> n2)) ? 1 : 0;
+
+            output[i] += n * (noteTable[k] & 0x80 ? 0 : 1);
         }
-
-
-
     }
-
-
+}
+
+void Voice::startNote(uint8_t key, double sampleRate) {
+    // start a new note
+    // float fc = 88.4 * powf(2, 0.083334 * (key - 36));
+    // c34 = powf((1 - 2 * fc / sampleRate), 2);
+    float fc = 88.4 * powf(2, 0.083334 * (key - 36));
+    float coef = 1 - exp(-6.283 * fc / 48000.0);
+    c34 = coef;
+    printf("key = %d, shaper cutoff = %f, coefficient = %f %f\n", key, fc, coef, c34);
 }

plugin/generator.hpp

@@ -21,16 +21,33 @@
 
 #include <stdint.h>
 
+#include "DistrhoPluginInfo.h"
+
+class Generator;
+
+class Voice {
+    friend Generator;
+
+   public:
+    void startNote(uint8_t key, double sampleRate);
+
+   private:
+    uint8_t semi, oct;
+    float c34=0, vc34=0;
+};
+
+
 class Generator {
    public:
     Generator();
-
     void setupGenerator(double sampleRate);
-
     void runBlock(float *output, uint8_t *noteTable, uint32_t frames);
+    Voice voices[NUM_VOICES];
 
+   private:
     uint32_t phase[12];
     uint32_t omega[12];
 };
 
+
 #endif

plugin/sonnenlicht.cpp

@@ -24,8 +24,8 @@ START_NAMESPACE_DISTRHO
 
 Sonnenlicht::Sonnenlicht() : Plugin(kParameterCount, 0, 0), fSampleRate(getSampleRate()) {
     printf("initialiser called\n");
-    assigner = new Assigner;
     genny.setupGenerator(fSampleRate);
+    assigner = new Assigner(genny.voices);
 }
 
 Sonnenlicht::~Sonnenlicht() {