audio.ts

import {SoundDetails} from 'scene'
import * as mat4 from 'toybox/math/mat4'
import {bytesToBase64} from 'toybox/util/base64'


let music_ = new Audio();
let secret_ = new Audio();
let samples_: HTMLAudioElement[] = [];
let soundMap_ = new Int16Array(0);
let soundDetails_: SoundDetails[] = [];
let listenerTransform_ = mat4.newZero();

let playedTrackMask: number[] = [];

// Browsers these days prevent audio from playing before the user has interacted
// with the page. So if a request for audio is made at the start of the level
// (e.g. Lara's home in TR1), enqueue the track number until the first valid
// interaction.
let pendingTrack: {track: number, mask: number} = null;
let userInteracted = false;
let listeners = [
  'mousedown', 'scroll', 'keydown', 'click', 'touchstart',
];

function detectInteraction(e: any) {
  if (e.key == "Meta" || e.key == "Shift" || e.key == "Control" || e.key == "Alt") {
    // Special keys don't count as iterating with the page (at least in Chrome).
    return;
  }

  userInteracted = true;
  for (let listener of listeners) {
    document.body.removeEventListener(listener, detectInteraction);
  }
  if (pendingTrack != null) {
    playTrackImpl(pendingTrack.track, pendingTrack.mask);
    pendingTrack = null;
  }
}

export function init(soundMap: Int16Array, soundDetails: SoundDetails[],
                     samples: Uint8Array, sampleIndices: Uint32Array) {
  soundMap_ = soundMap;
  soundDetails_ = soundDetails;

  samples_ = [];
  for (let i = 0; i < sampleIndices.length; ++i) {
    let begin = sampleIndices[i];
    let end;
    if (i + 1 < sampleIndices.length) {
      end = sampleIndices[i + 1];
    } else {
      end = samples.length;
    }
    let base64 = bytesToBase64(samples, begin, end - begin);

    let sample = new Audio();
    sample.src = 'data:audio/wav;base64,' + base64;
    samples_.push(sample);
  }

  for (let listener of listeners) {
    document.body.addEventListener(listener, detectInteraction);
  }
}


// TODO(tom): playSample also needs to queue audio
export function playSample(idx: number, x: number, y: number, z: number) {
  if (!userInteracted) {
    console.log(`Ignoring playSample(${idx}), user hasn't interacted yet`);
    return;
  }

  idx = soundMap_[idx];
  if (idx == -1) {
    console.log(`Sample ${idx} not found!`);
    return;
  }
  let dx = x - listenerTransform_[12];
  let dy = y - listenerTransform_[13];
  let dz = z - listenerTransform_[14];
  let disSqr = dx * dx + dy * dy + dz * dz;

  // TODO(tom): maxDis should be taken from the sound details.
  let maxDis = 8 * 1024;
  let maxDisSqr = maxDis * maxDis;
  if (disSqr > maxDisSqr) {
    return;
  }
  let falloff = 1 / (1 + 16 * disSqr / maxDisSqr);
  let details = soundDetails_[idx];
  let numSamples = details.numSamples();
  idx = details.sample + Math.floor(Math.random() * numSamples);
  samples_[idx].volume = falloff * details.volume / 32767;
  samples_[idx].currentTime = 0;
  samples_[idx].play();
}


/** Plays the secret found audio sting. */
export function playSecret() {
  secret_.src = 'music/13.mp3';
  secret_.play();
}


/** Plays a music track with the given index.  */
export function playTrack(track: number, mask: number) {
  if (userInteracted) {
    playTrackImpl(track, mask);
  } else {
    pendingTrack = {track, mask};
  }
}

function playTrackImpl(track: number, mask: number) {
  let oldMask = playedTrackMask[track] || 0;
  playedTrackMask[track] = oldMask | mask;

  if ((oldMask & mask) == 0) {
    console.log(`playTrack(${track}, ${mask}) disabled`);
    return;

    music_.src = 'music/' + track + '.mp3';
    music_.play();
  }
}

export function setListenerTransform(transform: mat4.Type) {
  mat4.setFromMat(listenerTransform_, transform);
}