strudel/packages/webaudio/webaudio.mjs

/*
webaudio.mjs - <short description TODO>
Copyright (C) 2022 Strudel contributors - see <https://codeberg.org/uzu/strudel/src/branch/main/packages/webaudio/webaudio.mjs>
This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details. You should have received a copy of the GNU Affero General Public License along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

import * as strudel from '@strudel/core';
import { superdough, getAudioContext, setLogger, doughTrigger, registerWorklet, setAudioContext, getSampleBufferSource, loadBuffer, getSampleInfo, getSound } from 'superdough';
import './supradough.mjs';
import { workletUrl } from 'supradough';

registerWorklet(workletUrl);

const { Pattern, logger, repl } = strudel;

setLogger(logger);

const hap2value = (hap) => {
  hap.ensureObjectValue();
  return hap.value;
};

// uses more precise, absolute t if available, see https://github.com/tidalcycles/strudel/pull/1004
// TODO: refactor output callbacks to eliminate deadline
export const webaudioOutput = (hap, _deadline, hapDuration, cps, t) => {
  return superdough(hap2value(hap), t, hapDuration, cps, hap.whole?.begin.valueOf());
};

export async function renderPatternAudio(pattern, cps, begin, end) {
  let audioContext = new OfflineAudioContext(2, (end - begin) / cps * 48000, 48000);
  setAudioContext(audioContext)
  logger('[webaudio] start rendering');
  console.log(audioContext)

  let haps = pattern.queryArc(begin, end, { _cps: cps })
  Promise.all(haps.map(async h => {
    let s;
    if (h.value.s) {
      if (h.value.bank) {
        s = `${h.value.bank}_${h.value.s}`;
      }
      else {
        s = h.value.s
      }
    }
    let bank = getSound(s).data.samples
    if (bank) {
      let { url: sampleUrl, label } = getSampleInfo(h.value, bank);
      await loadBuffer(sampleUrl, audioContext, label)
    }
  }))
  haps.forEach(async (hap) => {
    if (hap.hasOnset()) {
      hap.ensureObjectValue();
      await superdough(hap.value, hap.whole.begin.valueOf() / cps, hap.duration, cps, hap.whole?.begin.valueOf());
    }
  })

  let context = getAudioContext()
  context.startRendering().then((renderedBuffer) => {
    // console.log(renderedBuffer)
    const wavBuffer = audioBufferToWav(renderedBuffer);
    const blob = new Blob([wavBuffer], { type: 'audio/wav' });
    let downloadName = ''
    const url = URL.createObjectURL(blob);
    const a = document.createElement('a');
    a.href = url;
    // remove leading dash if they want an empty download name
    if (downloadName == '') {
      downloadName = `${new Date().toISOString()}.wav`;
    } else {
      downloadName = downloadName + `-${new Date().toISOString()}.wav`;
    }
    a.download = `${downloadName}`;
    document.body.appendChild(a);
    a.click();
    document.body.removeChild(a);
    URL.revokeObjectURL(url);
    setAudioContext(null)
  });
}

export function webaudioRepl(options = {}) {
  options = {
    getTime: () => getAudioContext().currentTime,
    defaultOutput: webaudioOutput,
    ...options,
  };
  return repl(options);
}

Pattern.prototype.dough = function () {
  return this.onTrigger(doughTrigger, 1);
};


function audioBufferToWav(buffer, opt) {
  opt = opt || {}

  var numChannels = buffer.numberOfChannels
  var sampleRate = buffer.sampleRate
  var format = opt.float32 ? 3 : 1
  var bitDepth = format === 3 ? 32 : 16

  var result
  if (numChannels === 2) {
    result = interleave(buffer.getChannelData(0), buffer.getChannelData(1))
  } else {
    result = buffer.getChannelData(0)
  }

  return encodeWAV(result, format, sampleRate, numChannels, bitDepth)
}

function encodeWAV(samples, format, sampleRate, numChannels, bitDepth) {
  var bytesPerSample = bitDepth / 8
  var blockAlign = numChannels * bytesPerSample

  var buffer = new ArrayBuffer(44 + samples.length * bytesPerSample)
  var view = new DataView(buffer)

  /* RIFF identifier */
  writeString(view, 0, 'RIFF')
  /* RIFF chunk length */
  view.setUint32(4, 36 + samples.length * bytesPerSample, true)
  /* RIFF type */
  writeString(view, 8, 'WAVE')
  /* format chunk identifier */
  writeString(view, 12, 'fmt ')
  /* format chunk length */
  view.setUint32(16, 16, true)
  /* sample format (raw) */
  view.setUint16(20, format, true)
  /* channel count */
  view.setUint16(22, numChannels, true)
  /* sample rate */
  view.setUint32(24, sampleRate, true)
  /* byte rate (sample rate * block align) */
  view.setUint32(28, sampleRate * blockAlign, true)
  /* block align (channel count * bytes per sample) */
  view.setUint16(32, blockAlign, true)
  /* bits per sample */
  view.setUint16(34, bitDepth, true)
  /* data chunk identifier */
  writeString(view, 36, 'data')
  /* data chunk length */
  view.setUint32(40, samples.length * bytesPerSample, true)
  if (format === 1) { // Raw PCM
    floatTo16BitPCM(view, 44, samples)
  } else {
    writeFloat32(view, 44, samples)
  }

  return buffer
}

function interleave(inputL, inputR) {
  var length = inputL.length + inputR.length
  var result = new Float32Array(length)

  var index = 0
  var inputIndex = 0

  while (index < length) {
    result[index++] = inputL[inputIndex]
    result[index++] = inputR[inputIndex]
    inputIndex++
  }
  return result
}

function writeFloat32(output, offset, input) {
  for (var i = 0; i < input.length; i++, offset += 4) {
    output.setFloat32(offset, input[i], true)
  }
}

function floatTo16BitPCM(output, offset, input) {
  for (var i = 0; i < input.length; i++, offset += 2) {
    var s = Math.max(-1, Math.min(1, input[i]))
    output.setInt16(offset, s < 0 ? s * 0x8000 : s * 0x7FFF, true)
  }
}

function writeString(view, offset, string) {
  for (var i = 0; i < string.length; i++) {
    view.setUint8(offset + i, string.charCodeAt(i))
  }
}