path: root/src/library_openal.js

//"use strict";

var LibraryOpenAL = {
  $AL__deps: ['$Browser'],
  $AL: {
    contexts: [],
    currentContext: null,
    QUEUE_INTERVAL: 25,
    QUEUE_LOOKAHEAD: 100,

    updateSources: function updateSources(context) {
      for (var i = 0; i < context.src.length; i++) {
        AL.updateSource(context.src[i]);
      }
    },

    updateSource: function updateSource(src) {
#if OPENAL_DEBUG
      var idx = AL.currentContext.src.indexOf(src);
#endif
      if (src.state !== 0x1012 /* AL_PLAYING */) {
        return;
      }

      var currentTime = AL.currentContext.ctx.currentTime;
      var startTime = src.bufferPosition;

      for (var i = src.buffersPlayed; i < src.queue.length; i++) {
        var entry = src.queue[i];

        var startOffset = startTime - currentTime;
        var endTime = startTime + entry.buffer.duration;

        // Clean up old buffers.
        if (currentTime >= endTime) {
          // Update our location in the queue.
          src.bufferPosition = endTime;
          src.buffersPlayed = i + 1;

          // Stop / restart the source when we hit the end.
          if (src.buffersPlayed >= src.queue.length) {
            if (src.loop) {
              AL.setSourceState(src, 0x1012 /* AL_PLAYING */);
            } else {
              AL.setSourceState(src, 0x1014 /* AL_STOPPED */);
            }
          }
        }
        // Process all buffers that'll be played before the next tick.
        else if (startOffset < (AL.QUEUE_LOOKAHEAD / 1000) && !entry.src) {
          // If the start offset is negative, we need to offset the actual buffer.
          var offset = Math.abs(Math.min(startOffset, 0));

          entry.src = AL.currentContext.ctx.createBufferSource();
          entry.src.buffer = entry.buffer;
          entry.src.connect(src.gain);
          entry.src.start(startTime, offset);
          
#if OPENAL_DEBUG
          console.log('updateSource queuing buffer ' + i + ' for source ' + idx + ' at ' + startTime + ' (offset by ' + offset + ')');
#endif
        }

        startTime = endTime;
      }
    },

    setSourceState: function setSourceState(src, state) {
#if OPENAL_DEBUG
      var idx = AL.currentContext.src.indexOf(src);
#endif
      if (state === 0x1012 /* AL_PLAYING */) {
        if (src.state !== 0x1013 /* AL_PAUSED */) {
          src.state = 0x1012 /* AL_PLAYING */;
          // Reset our position.
          src.bufferPosition = AL.currentContext.ctx.currentTime;
          src.buffersPlayed = 0;
#if OPENAL_DEBUG
          console.log(