pandemonium_engine/platform/javascript/js/libs/audio.worklet.js

/*************************************************************************/
/*  audio.worklet.js                                                     */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
/*************************************************************************/
/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
/*                                                                       */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the       */
/* "Software"), to deal in the Software without restriction, including   */
/* without limitation the rights to use, copy, modify, merge, publish,   */
/* distribute, sublicense, and/or sell copies of the Software, and to    */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions:                                             */
/*                                                                       */
/* The above copyright notice and this permission notice shall be        */
/* included in all copies or substantial portions of the Software.       */
/*                                                                       */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
/*************************************************************************/

class RingBuffer {
    constructor(p_buffer, p_state, p_threads) {
        this.buffer = p_buffer;
        this.avail = p_state;
        this.threads = p_threads;
        this.rpos = 0;
        this.wpos = 0;
    }

    data_left() {
        return this.threads ? Atomics.load(this.avail, 0) : this.avail;
    }

    space_left() {
        return this.buffer.length - this.data_left();
    }

    read(output) {
        const size = this.buffer.length;
        let from = 0;
        let to_write = output.length;
        if (this.rpos + to_write > size) {
            const high = size - this.rpos;
            output.set(this.buffer.subarray(this.rpos, size));
            from = high;
            to_write -= high;
            this.rpos = 0;
        }
        if (to_write) {
            output.set(this.buffer.subarray(this.rpos, this.rpos + to_write), from);
        }
        this.rpos += to_write;
        if (this.threads) {
            Atomics.add(this.avail, 0, -output.length);
            Atomics.notify(this.avail, 0);
        } else {
            this.avail -= output.length;
        }
    }

    write(p_buffer) {
        const to_write = p_buffer.length;
        const mw = this.buffer.length - this.wpos;
        if (mw >= to_write) {
            this.buffer.set(p_buffer, this.wpos);
            this.wpos += to_write;
            if (mw === to_write) {
                this.wpos = 0;
            }
        } else {
            const high = p_buffer.subarray(0, mw);
            const low = p_buffer.subarray(mw);
            this.buffer.set(high, this.wpos);
            this.buffer.set(low);
            this.wpos = low.length;
        }
        if (this.threads) {
            Atomics.add(this.avail, 0, to_write);
            Atomics.notify(this.avail, 0);
        } else {
            this.avail += to_write;
        }
    }
}

class PandemoniumProcessor extends AudioWorkletProcessor {
    constructor() {
        super();
        this.threads = false;
        this.running = true;
        this.lock = null;
        this.notifier = null;
        this.output = null;
        this.output_buffer = new Float32Array();
        this.input = null;
        this.input_buffer = new Float32Array();
        this.port.onmessage = (event) => {
            const cmd = event.data['cmd'];
            const data = event.data['data'];
            this.parse_message(cmd, data);
        };
    }

    process_notify() {
        if (this.notifier) {
            Atomics.add(this.notifier, 0, 1);
            Atomics.notify(this.notifier, 0);
        }
    }

    parse_message(p_cmd, p_data) {
        if (p_cmd === 'start' && p_data) {
            const state = p_data[0];
            let idx = 0;
            this.threads = true;
            this.lock = state.subarray(idx, ++idx);
            this.notifier = state.subarray(idx, ++idx);
            const avail_in = state.subarray(idx, ++idx);
            const avail_out = state.subarray(idx, ++idx);
            this.input = new RingBuffer(p_data[1], avail_in, true);
            this.output = new RingBuffer(p_data[2], avail_out, true);
        } else if (p_cmd === 'stop') {
            this.running = false;
            this.output = null;
            this.input = null;
        } else if (p_cmd === 'start_nothreads') {
            this.output = new RingBuffer(p_data[0], p_data[0].length, false);
        } else if (p_cmd === 'chunk') {
            this.output.write(p_data);
        }
    }

    static array_has_data(arr) {
        return arr.length && arr[0].length && arr[0][0].length;
    }

    process(inputs, outputs, parameters) {
        if (!this.running) {
            return false; // Stop processing.
        }
        if (this.output === null) {
            return true; // Not ready yet, keep processing.
        }
        const process_input = PandemoniumProcessor.array_has_data(inputs);
        if (process_input) {
            const input = inputs[0];
            const chunk = input[0].length * input.length;
            if (this.input_buffer.length !== chunk) {
                this.input_buffer = new Float32Array(chunk);
            }
            if (!this.threads) {
                PandemoniumProcessor.write_input(this.input_buffer, input);
                this.port.postMessage({
                    'cmd': 'input',
                    'data': this.input_buffer
                });
            } else if (this.input.space_left() >= chunk) {
                PandemoniumProcessor.write_input(this.input_buffer, input);
                this.input.write(this.input_buffer);
            } else {
                this.port.postMessage('Input buffer is full! Skipping input frame.');
            }
        }
        const process_output = PandemoniumProcessor.array_has_data(outputs);
        if (process_output) {
            const output = outputs[0];
            const chunk = output[0].length * output.length;
            if (this.output_buffer.length !== chunk) {
                this.output_buffer = new Float32Array(chunk);
            }
            if (this.output.data_left() >= chunk) {
                this.output.read(this.output_buffer);
                PandemoniumProcessor.write_output(output, this.output_buffer);
                if (!this.threads) {
                    this.port.postMessage({
                        'cmd': 'read',
                        'data': chunk
                    });
                }
            } else {
                this.port.postMessage('Output buffer has not enough frames! Skipping output frame.');
            }
        }
        this.process_notify();
        return true;
    }

    static write_output(dest, source) {
        const channels = dest.length;
        for (let ch = 0; ch < channels; ch++) {
            for (let sample = 0; sample < dest[ch].length; sample++) {
                dest[ch][sample] = source[sample * channels + ch];
            }
        }
    }

    static write_input(dest, source) {
        const channels = source.length;
        for (let ch = 0; ch < channels; ch++) {
            for (let sample = 0; sample < source[ch].length; sample++) {
                dest[sample * channels + ch] = source[ch][sample];
            }
        }
    }
}

registerProcessor('pandemonium-processor', PandemoniumProcessor);