pwm

packages/superdough/synth.mjs

@@ -133,6 +133,66 @@ export function registerSynthSounds() {
     { prebake: true, type: 'synth' },
   );
 
+
+  registerSound(
+    'pwm',
+    (begin, value, onended) => {
+      const ac = getAudioContext();
+      let { duration, n } = value;
+      const frequency = getFrequencyFromValue(value);
+
+      const [attack, decay, sustain, release] = getADSRValues(
+        [value.attack, value.decay, value.sustain, value.release],
+        'linear',
+        [0.001, 0.05, 0.6, 0.01],
+      );
+
+      const holdend = begin + duration;
+      const end = holdend + release + 0.01;
+
+      let o = getWorklet(
+        ac,
+        'pwm-oscillator',
+        {
+          frequency,
+          begin,
+          end,
+          pulsewidth: 1
+        },
+        {
+          outputChannelCount: [2],
+        },
+      );
+
+      getPitchEnvelope(o.parameters.get('detune'), value, begin, holdend);
+      // const vibratoOscillator = getVibratoOscillator(o.parameters.get('detune'), value, begin);
+      const fm = applyFM(o.parameters.get('frequency'), value, begin);
+      let envGain = gainNode(1);
+      envGain = o.connect(envGain);
+
+      webAudioTimeout(
+        ac,
+        () => {
+          o.disconnect();
+          envGain.disconnect();
+          onended();
+          fm?.stop();
+          // vibratoOscillator?.stop();
+        },
+        begin,
+        end,
+      );
+
+      getParamADSR(envGain.gain, attack, decay, sustain, release, 0, 0.3, begin, holdend, 'linear');
+
+      return {
+        node: envGain,
+        stop: (time) => {},
+      };
+    },
+    { prebake: true, type: 'synth' },
+  );
+
   [...noises].forEach((s) => {
     registerSound(
       s,

packages/superdough/worklets.mjs

@@ -648,3 +648,99 @@ class PhaseVocoderProcessor extends OLAProcessor {
 }
 
 registerProcessor('phase-vocoder-processor', PhaseVocoderProcessor);
+
+// SelfPMpwmWorklet.js
+
+class PwmOscillatorProcessor extends AudioWorkletProcessor {
+ 
+
+  constructor() {
+    super();
+    this.pi = _PI;
+    this.phi = -this.pi; // phase
+    this.Y0 = 0; // feedback memories
+    this.Y1 = 0;
+    this.PW = this.pi; // pulse width
+    this.B = 2.3; // feedback coefficient
+    this.dphif = 0; // filtered phase increment
+    this.envf = 0; // filtered envelope
+  }
+
+
+  static get parameterDescriptors() {
+    return [
+      {
+        name: 'begin',
+        defaultValue: 0,
+        max: Number.POSITIVE_INFINITY,
+        min: 0,
+      },
+
+      {
+        name: 'end',
+        defaultValue: 0,
+        max: Number.POSITIVE_INFINITY,
+        min: 0,
+      },
+
+      {
+        name: 'frequency',
+        defaultValue: 440,
+        min: Number.EPSILON,
+      },
+      {
+        name: 'pulsewidth',
+        defaultValue: 1,
+        min: 0,
+        max: Number.POSITIVE_INFINITY,
+      },
+    ];
+  }
+
+  process(inputs, outputs, params) {
+     if (currentTime <= params.begin[0]) {
+      return true;
+    }
+    if (currentTime >= params.end[0]) {
+      return false;
+    }
+    const output = outputs[0];
+    let  env = 1, dphi;
+    let freq = params.frequency[0]
+    let pw = params.pulsewidth[0] * _PI
+
+    for (let i = 0; i < (output[0].length ?? 0); i++) {
+      dphi = freq * (this.pi / (sampleRate * .5)); // phase increment
+      this.dphif += 0.1 * (dphi - this.dphif);
+
+      env *= 0.9998; // exponential decay envelope
+      this.envf += 0.1 * (env - this.envf);
+
+      // Feedback coefficient control
+      this.B = 2.3 * (1 - 0.0001 * freq); // feedback limitation
+      if (this.B < 0) this.B = 0;
+
+      // Waveform generation (half-Tomisawa oscillators)
+      this.phi += this.dphif; // phase increment
+      if (this.phi >= this.pi) this.phi -= 2 * this.pi; // phase wrapping
+
+      // First half-Tomisawa generator
+      let out0 = Math.cos(this.phi + this.B * this.Y0); // self-phase modulation
+      this.Y0 = 0.5 * (out0 + this.Y0); // anti-hunting filter
+
+      // Second half-Tomisawa generator (with phase offset for pulse width)
+      let out1 = Math.cos(this.phi + this.B * this.Y1 + pw);
+      this.Y1 = 0.5 * (out1 + this.Y1); // anti-hunting filter
+      
+      for (let o = 0; o < output.length; o++) {
+        // Combination of both oscillators with envelope applied
+        output[o][i] = 0.15 * (out0 - out1) * this.envf;
+      }
+
+    }
+
+    return true; // keep the audio processing going
+  }
+}
+
+registerProcessor('pwm-oscillator', PwmOscillatorProcessor);