audio.js

"use strict";

const AudioContext = window.AudioContext || window.webkitAudioContext;
let audio_context;
let sounds = new Map();
let playbacks = [];
let sound_key_next = 1;
let playback_key_next = 1;

function audio_init() {
    if (audio_context == null) {
        audio_context = new AudioContext();
        let audio_listener = audio_context.listener;

        {
            let AudioContext = window.AudioContext || window.webkitAudioContext;
            let ctx = new AudioContext();
            var fixAudioContext = function (e) {
                console.log("fix");

                // On newer Safari AudioContext starts in a suspended state per
                // spec but is only resumable by a call running in an event
                // handler triggered by the user. Do it here. Reference:
                // https://stackoverflow.com/questions/56768576/safari-audiocontext-suspended-even-with-onclick-creation
                audio_context.resume();

                // On older Safari, audio context should be explicitly unpaused
                // in a mouse/touch input event even if it was created after
                // first input event on the page thanks to:
                // https://gist.github.com/kus/3f01d60569eeadefe3a1

                // Create empty buffer
                var buffer = ctx.createBuffer(1, 1, 22050);
                var source = ctx.createBufferSource();
                source.buffer = buffer;
                // Connect to output (speakers)
                source.connect(ctx.destination);
                // Play sound
                if (source.start) {
                    source.start(0);
                } else if (source.play) {
                    source.play(0);
                } else if (source.noteOn) {
                    source.noteOn(0);
                }

                // Remove event handlers
                document.removeEventListener('touchstart', fixAudioContext);
                document.removeEventListener('touchend', fixAudioContext);
                document.removeEventListener('mousedown', fixAudioContext);
                document.removeEventListener('keydown', fixAudioContext);
            };
            // iOS 6-8
            document.addEventListener('touchstart', fixAudioContext);
            // iOS 9
            document.addEventListener('touchend', fixAudioContext);
            // Mac
            document.addEventListener('mousedown', fixAudioContext);
            document.addEventListener('keydown', fixAudioContext);
        }
    }
}

function audio_add_buffer(content, content_len) {
    let content_array = wasm_memory.buffer.slice(content, content + content_len);

    let sound_key = sound_key_next;
    sound_key_next += 1;

    audio_context.decodeAudioData(content_array, function(buffer) {
        sounds.set(sound_key, buffer);
    }, function(e) {
        // fail
        console.error("Failed to decode audio buffer", e);
    });
    return sound_key;
}

function audio_source_is_loaded(sound_key) {
    return sounds.has(sound_key) && sounds.get(sound_key) != undefined;
}

function recycle_playback() {
    let playback = playbacks.find(playback => playback.sound_key === 0);

    if (playback != null) {
        playback.source = audio_context.createBufferSource();
    } else {
        playback = {
            sound_key: 0,
            playback_key: 0,
            source: audio_context.createBufferSource(),
            gain_node: audio_context.createGain(),
            ended: null,
        };

        playbacks.push(playback);
    }

    return playback;
}

function stop(playback) {
    try {
        playback.source.removeEventListener('ended', playback.ended);

        playback.source.disconnect();
        playback.gain_node.disconnect();

        playback.sound_key = 0;
        playback.playback_key = 0;
    } catch (e) {
        console.error("Error stopping sound", e);
    }
}

function audio_play_buffer(sound_key, volume, repeat) {
    let playback_key = playback_key_next++;

    let pb = recycle_playback();

    pb.sound_key = sound_key;
    pb.playback_key = playback_key;

    pb.source.connect(pb.gain_node);
    pb.gain_node.connect(audio_context.destination);

    pb.gain_node.gain.value = volume;
    pb.source.loop = repeat;

    pb.ended = function() {
        stop(pb);
    };
    pb.source.addEventListener('ended', pb.ended);

    try {
        pb.source.buffer = sounds.get(sound_key);
        pb.source.start(0);
    } catch (e) {
        console.error("Error starting sound", e);
    }

    return playback_key;
}

function audio_source_set_volume(sound_key, volume) {
    playbacks.forEach(playback => {
        if (playback.sound_key === sound_key) {
            playback.gain_node.gain.value = volume;
        }
    });
}

function audio_source_stop(sound_key) {
    playbacks.forEach(playback => {
        playback.sound_key === sound_key && stop(playback);
    });
}

function audio_source_delete(sound_key) {
    audio_source_stop(sound_key);

    sounds.delete(sound_key);
}

function audio_playback_stop(playback_key) {
    let playback = playbacks.find(playback => playback.playback_key === playback_key);

    playback != null && stop(playback);
}

function audio_playback_set_volume(playback_key, volume) {
    let playback = playbacks.find(playback => playback.playback_key === playback_key);

    if (playback != null) {
        playback.gain_node.gain.value = volume;
    }
}

function register_plugin(importObject) {
    importObject.env.audio_init = audio_init;
    importObject.env.audio_add_buffer = audio_add_buffer;
    importObject.env.audio_play_buffer = audio_play_buffer;
    importObject.env.audio_source_is_loaded = audio_source_is_loaded;
    importObject.env.audio_source_set_volume = audio_source_set_volume;
    importObject.env.audio_source_stop = audio_source_stop;
    importObject.env.audio_source_delete = audio_source_delete;
    importObject.env.audio_playback_stop = audio_playback_stop;
    importObject.env.audio_playback_set_volume = audio_playback_set_volume;
}

miniquad_add_plugin({ register_plugin, version: 1, name: "macroquad_audio" });