Merge pull request #1110 from daslyfe/phasermodulation

Calculate phaser modulation phase based on time

packages/superdough/superdough.mjs

@@ -136,26 +136,25 @@ function getDelay(orbit, delaytime, delayfeedback, t) {
   return delays[orbit];
 }
 
-// each orbit will have its own lfo
+function getPhaser(time, end, frequency = 1, depth = 0.5, centerFrequency = 1000, sweep = 2000) {
-const phaserLFOs = {};
-function getPhaser(orbit, t, speed = 1, depth = 0.5, centerFrequency = 1000, sweep = 2000) {
   //gain
   const ac = getAudioContext();
   const lfoGain = ac.createGain();
-  lfoGain.gain.value = sweep;
+  lfoGain.gain.value = sweep * 2;
+  // centerFrequency = centerFrequency * 2;
+  // sweep = sweep * 1.5;
 
-  //LFO
+  const lfo = getWorklet(ac, 'lfo-processor', {
-  if (phaserLFOs[orbit] == null) {
+    frequency,
-    phaserLFOs[orbit] = ac.createOscillator();
+    depth: 1,
-    phaserLFOs[orbit].frequency.value = speed;
+    skew: 0,
-    phaserLFOs[orbit].type = 'sine';
+    phaseoffset: 0,
-    phaserLFOs[orbit].start();
+    time,
-  }
+    end,
-
+    shape: 1,
-  phaserLFOs[orbit].connect(lfoGain);
+    dcoffset: -0.5,
-  if (phaserLFOs[orbit].frequency.value != speed) {
+  });
-    phaserLFOs[orbit].frequency.setValueAtTime(speed, t);
+  lfo.connect(lfoGain);
-  }
 
   //filters
   const numStages = 2; //num of filters in series
@@ -485,7 +484,7 @@ export const superdough = async (value, t, hapDuration) => {
   }
   // phaser
   if (phaser !== undefined && phaserdepth > 0) {
-    const phaserFX = getPhaser(orbit, t, phaser, phaserdepth, phasercenter, phasersweep);
+    const phaserFX = getPhaser(t, t + hapDuration, phaser, phaserdepth, phasercenter, phasersweep);
     chain.push(phaserFX);
   }
 

packages/superdough/worklets.mjs

@@ -1,7 +1,139 @@
 // coarse, crush, and shape processors adapted from dktr0's webdirt: https://github.com/dktr0/WebDirt/blob/5ce3d698362c54d6e1b68acc47eb2955ac62c793/dist/AudioWorklets.js
 // LICENSE GNU General Public License v3.0 see https://github.com/dktr0/WebDirt/blob/main/LICENSE
-import { clamp } from './util.mjs';
+import { clamp, _mod } from './util.mjs';
+// const clamp = (num, min, max) => Math.min(Math.max(num, min), max);
 const blockSize = 128;
+// adjust waveshape to remove frequencies above nyquist to prevent aliasing
+// referenced from https://www.kvraudio.com/forum/viewtopic.php?t=375517
+function polyBlep(phase, dt) {
+  // 0 <= phase < 1
+  if (phase < dt) {
+    phase /= dt;
+    // 2 * (phase - phase^2/2 - 0.5)
+    return phase + phase - phase * phase - 1;
+  }
+
+  // -1 < phase < 0
+  else if (phase > 1 - dt) {
+    phase = (phase - 1) / dt;
+    // 2 * (phase^2/2 + phase + 0.5)
+    return phase * phase + phase + phase + 1;
+  }
+
+  // 0 otherwise
+  else {
+    return 0;
+  }
+}
+
+const waveshapes = {
+  tri(phase, skew = 0.5) {
+    const x = 1 - skew;
+    if (phase >= skew) {
+      return 1 / x - phase / x;
+    }
+    return phase / skew;
+  },
+  sine(phase) {
+    return Math.sin(Math.PI * 2 * phase) * 0.5 + 0.5;
+  },
+  ramp(phase) {
+    return phase;
+  },
+  saw(phase) {
+    return 1 - phase;
+  },
+
+  square(phase, skew = 0.5) {
+    if (phase >= skew) {
+      return 0;
+    }
+    return 1;
+  },
+  custom(phase, values = [0, 1]) {
+    const numParts = values.length - 1;
+    const currPart = Math.floor(phase * numParts);
+
+    const partLength = 1 / numParts;
+    const startVal = clamp(values[currPart], 0, 1);
+    const endVal = clamp(values[currPart + 1], 0, 1);
+    const y2 = endVal;
+    const y1 = startVal;
+    const x1 = 0;
+    const x2 = partLength;
+    const slope = (y2 - y1) / (x2 - x1);
+    return slope * (phase - partLength * currPart) + startVal;
+  },
+  sawblep(phase, dt) {
+    const v = 2 * phase - 1;
+    return v - polyBlep(phase, dt);
+  },
+};
+
+const waveShapeNames = Object.keys(waveshapes);
+class LFOProcessor extends AudioWorkletProcessor {
+  static get parameterDescriptors() {
+    return [
+      { name: 'time', defaultValue: 0 },
+      { name: 'end', defaultValue: 0 },
+      { name: 'frequency', defaultValue: 0.5 },
+      { name: 'skew', defaultValue: 0.5 },
+      { name: 'depth', defaultValue: 1 },
+      { name: 'phaseoffset', defaultValue: 0 },
+      { name: 'shape', defaultValue: 0 },
+      { name: 'dcoffset', defaultValue: 0 },
+    ];
+  }
+
+  constructor() {
+    super();
+    this.phase;
+  }
+
+  incrementPhase(dt) {
+    this.phase += dt;
+    if (this.phase > 1.0) {
+      this.phase = this.phase - 1;
+    }
+  }
+
+  process(inputs, outputs, parameters) {
+    // eslint-disable-next-line no-undef
+    if (currentTime >= parameters.end[0]) {
+      return false;
+    }
+
+    const output = outputs[0];
+    const frequency = parameters['frequency'][0];
+
+    const time = parameters['time'][0];
+    const depth = parameters['depth'][0];
+    const skew = parameters['skew'][0];
+    const phaseoffset = parameters['phaseoffset'][0];
+
+    const dcoffset = parameters['dcoffset'][0];
+    const shape = waveShapeNames[parameters['shape'][0]];
+
+    const blockSize = output[0].length ?? 0;
+
+    if (this.phase == null) {
+      this.phase = _mod(time * frequency + phaseoffset, 1);
+    }
+    // eslint-disable-next-line no-undef
+    const dt = frequency / sampleRate;
+    for (let n = 0; n < blockSize; n++) {
+      for (let i = 0; i < output.length; i++) {
+        const modval = (waveshapes[shape](this.phase, skew) + dcoffset) * depth;
+        output[i][n] = modval;
+      }
+      this.incrementPhase(dt);
+    }
+
+    return true;
+  }
+}
+registerProcessor('lfo-processor', LFOProcessor);
+
 class CoarseProcessor extends AudioWorkletProcessor {
   static get parameterDescriptors() {
     return [{ name: 'coarse', defaultValue: 1 }];
@@ -213,34 +345,7 @@ class DistortProcessor extends AudioWorkletProcessor {
 }
 registerProcessor('distort-processor', DistortProcessor);
 
-// adjust waveshape to remove frequencies above nyquist to prevent aliasing
+// SUPERSAW
-// referenced from https://www.kvraudio.com/forum/viewtopic.php?t=375517
-const polyBlep = (phase, dt) => {
-  // 0 <= phase < 1
-  if (phase < dt) {
-    phase /= dt;
-    // 2 * (phase - phase^2/2 - 0.5)
-    return phase + phase - phase * phase - 1;
-  }
-
-  // -1 < phase < 0
-  else if (phase > 1 - dt) {
-    phase = (phase - 1) / dt;
-    // 2 * (phase^2/2 + phase + 0.5)
-    return phase * phase + phase + phase + 1;
-  }
-
-  // 0 otherwise
-  else {
-    return 0;
-  }
-};
-
-const saw = (phase, dt) => {
-  const v = 2 * phase - 1;
-  return v - polyBlep(phase, dt);
-};
-
 function lerp(a, b, n) {
   return n * (b - a) + a;
 }
@@ -340,7 +445,7 @@ class SuperSawOscillatorProcessor extends AudioWorkletProcessor {
 
       for (let i = 0; i < output[0].length; i++) {
         this.phase[n] = this.phase[n] ?? Math.random();
-        const v = saw(this.phase[n], dt);
+        const v = waveshapes.sawblep(this.phase[n], dt);
 
         output[0][i] = output[0][i] + v * gainL;
         output[1][i] = output[1][i] + v * gainR;