src/audio/emscripten/SDL_emscriptenaudio.c
author Ryan C. Gordon <icculus@icculus.org>
Sun, 18 Sep 2016 18:07:47 -0400
changeset 10355 ce8669efcd11
parent 10322 6167a989223c
child 10737 3406a0f8b041
permissions -rw-r--r--
emscripten: get even more aggressive about audio device closing.

I still get exceptions thrown sometimes on shutdown without this.
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/*
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  Simple DirectMedia Layer
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  Copyright (C) 1997-2016 Sam Lantinga <slouken@libsdl.org>
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  This software is provided 'as-is', without any express or implied
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  warranty.  In no event will the authors be held liable for any damages
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  arising from the use of this software.
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  Permission is granted to anyone to use this software for any purpose,
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  including commercial applications, and to alter it and redistribute it
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  freely, subject to the following restrictions:
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  1. The origin of this software must not be misrepresented; you must not
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     claim that you wrote the original software. If you use this software
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     in a product, an acknowledgment in the product documentation would be
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     appreciated but is not required.
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  2. Altered source versions must be plainly marked as such, and must not be
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     misrepresented as being the original software.
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  3. This notice may not be removed or altered from any source distribution.
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*/
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#include "../../SDL_internal.h"
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#if SDL_AUDIO_DRIVER_EMSCRIPTEN
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#include "SDL_audio.h"
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#include "SDL_log.h"
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#include "../SDL_audio_c.h"
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#include "SDL_emscriptenaudio.h"
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#include <emscripten/emscripten.h>
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static int
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copyData(_THIS)
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{
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    int byte_len;
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    if (this->hidden->write_off + this->convert.len_cvt > this->hidden->mixlen) {
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        if (this->hidden->write_off > this->hidden->read_off) {
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            SDL_memmove(this->hidden->mixbuf,
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                        this->hidden->mixbuf + this->hidden->read_off,
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                        this->hidden->mixlen - this->hidden->read_off);
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            this->hidden->write_off = this->hidden->write_off - this->hidden->read_off;
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        } else {
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            this->hidden->write_off = 0;
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        }
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        this->hidden->read_off = 0;
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    }
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    SDL_memcpy(this->hidden->mixbuf + this->hidden->write_off,
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               this->convert.buf,
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               this->convert.len_cvt);
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    this->hidden->write_off += this->convert.len_cvt;
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    byte_len = this->hidden->write_off - this->hidden->read_off;
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    return byte_len;
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}
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static void
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HandleAudioProcess(_THIS)
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{
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    Uint8 *buf = NULL;
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    int byte_len = 0;
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    int bytes = SDL_AUDIO_BITSIZE(this->spec.format) / 8;
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    /* Only do something if audio is enabled */
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    if (!SDL_AtomicGet(&this->enabled) || SDL_AtomicGet(&this->paused)) {
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        return;
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    }
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    if (this->convert.needed) {
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        const int bytes_in = SDL_AUDIO_BITSIZE(this->convert.src_format) / 8;
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        if (this->hidden->conv_in_len != 0) {
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            this->convert.len = this->hidden->conv_in_len * bytes_in * this->spec.channels;
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        }
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        (*this->spec.callback) (this->spec.userdata,
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                                 this->convert.buf,
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                                 this->convert.len);
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        SDL_ConvertAudio(&this->convert);
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        buf = this->convert.buf;
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        byte_len = this->convert.len_cvt;
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        /* size mismatch*/
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        if (byte_len != this->spec.size) {
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            if (!this->hidden->mixbuf) {
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                this->hidden->mixlen = this->spec.size > byte_len ? this->spec.size * 2 : byte_len * 2;
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                this->hidden->mixbuf = SDL_malloc(this->hidden->mixlen);
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            }
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            /* copy existing data */
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            byte_len = copyData(this);
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            /* read more data*/
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            while (byte_len < this->spec.size) {
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                (*this->spec.callback) (this->spec.userdata,
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                                         this->convert.buf,
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                                         this->convert.len);
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                SDL_ConvertAudio(&this->convert);
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                byte_len = copyData(this);
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            }
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            byte_len = this->spec.size;
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            buf = this->hidden->mixbuf + this->hidden->read_off;
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            this->hidden->read_off += byte_len;
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        }
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    } else {
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        if (!this->hidden->mixbuf) {
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            this->hidden->mixlen = this->spec.size;
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            this->hidden->mixbuf = SDL_malloc(this->hidden->mixlen);
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        }
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        (*this->spec.callback) (this->spec.userdata,
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                                 this->hidden->mixbuf,
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                                 this->hidden->mixlen);
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        buf = this->hidden->mixbuf;
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        byte_len = this->hidden->mixlen;
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    }
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    if (buf) {
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        EM_ASM_ARGS({
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            var numChannels = SDL2.audio.currentOutputBuffer['numberOfChannels'];
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            for (var c = 0; c < numChannels; ++c) {
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                var channelData = SDL2.audio.currentOutputBuffer['getChannelData'](c);
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                if (channelData.length != $1) {
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                    throw 'Web Audio output buffer length mismatch! Destination size: ' + channelData.length + ' samples vs expected ' + $1 + ' samples!';
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                }
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                for (var j = 0; j < $1; ++j) {
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                    channelData[j] = HEAPF32[$0 + ((j*numChannels + c) << 2) >> 2];
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                }
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            }
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        }, buf, byte_len / bytes / this->spec.channels);
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    }
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}
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static void
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HandleCaptureProcess(_THIS)
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{
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    Uint8 *buf;
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    int buflen;
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    /* Only do something if audio is enabled */
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    if (!SDL_AtomicGet(&this->enabled) || SDL_AtomicGet(&this->paused)) {
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        return;
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    }
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    if (this->convert.needed) {
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        buf = this->convert.buf;
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        buflen = this->convert.len_cvt;
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    } else {
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        if (!this->hidden->mixbuf) {
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            this->hidden->mixbuf = (Uint8 *) SDL_malloc(this->spec.size);
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            if (!this->hidden->mixbuf) {
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                return;  /* oh well. */
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            }
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        }
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        buf = this->hidden->mixbuf;
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        buflen = this->spec.size;
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    }
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    EM_ASM_ARGS({
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        var numChannels = SDL2.capture.currentCaptureBuffer.numberOfChannels;
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        if (numChannels == 1) {  /* fastpath this a little for the common (mono) case. */
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            var channelData = SDL2.capture.currentCaptureBuffer.getChannelData(0);
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            if (channelData.length != $1) {
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                throw 'Web Audio capture buffer length mismatch! Destination size: ' + channelData.length + ' samples vs expected ' + $1 + ' samples!';
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            }
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            for (var j = 0; j < $1; ++j) {
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                setValue($0 + (j * 4), channelData[j], 'float');
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            }
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        } else {
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            for (var c = 0; c < numChannels; ++c) {
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                var channelData = SDL2.capture.currentCaptureBuffer.getChannelData(c);
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                if (channelData.length != $1) {
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                    throw 'Web Audio capture buffer length mismatch! Destination size: ' + channelData.length + ' samples vs expected ' + $1 + ' samples!';
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                }
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                for (var j = 0; j < $1; ++j) {
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                    setValue($0 + (((j * numChannels) + c) * 4), channelData[j], 'float');
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                }
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            }
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        }
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    }, buf, (this->spec.size / sizeof (float)) / this->spec.channels);
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    /* okay, we've got an interleaved float32 array in C now. */
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    if (this->convert.needed) {
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        SDL_ConvertAudio(&this->convert);
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    }
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    /* Send it to the app. */
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    (*this->spec.callback) (this->spec.userdata, buf, buflen);
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}
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static void
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EMSCRIPTENAUDIO_CloseDevice(_THIS)
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{
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    EM_ASM_({
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        if ($0) {
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            if (SDL2.capture.silenceTimer !== undefined) {
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                clearTimeout(SDL2.capture.silenceTimer);
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            }
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            if (SDL2.capture.stream !== undefined) {
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                var tracks = SDL2.capture.stream.getAudioTracks();
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                for (var i = 0; i < tracks.length; i++) {
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                    SDL2.capture.stream.removeTrack(tracks[i]);
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                }
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                SDL2.capture.stream = undefined;
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            }
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            if (SDL2.capture.scriptProcessorNode !== undefined) {
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                SDL2.capture.scriptProcessorNode.onaudioprocess = function(audioProcessingEvent) {};
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                SDL2.capture.scriptProcessorNode.disconnect();
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                SDL2.capture.scriptProcessorNode = undefined;
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            }
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            if (SDL2.capture.mediaStreamNode !== undefined) {
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                SDL2.capture.mediaStreamNode.disconnect();
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                SDL2.capture.mediaStreamNode = undefined;
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            }
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            if (SDL2.capture.silenceBuffer !== undefined) {
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                SDL2.capture.silenceBuffer = undefined
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            }
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            SDL2.capture = undefined;
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        } else {
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            if (SDL2.audio.scriptProcessorNode != undefined) {
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                SDL2.audio.scriptProcessorNode.disconnect();
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                SDL2.audio.scriptProcessorNode = undefined;
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            }
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            SDL2.audio = undefined;
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        }
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        if ((SDL2.audioContext !== undefined) && (SDL2.audio === undefined) && (SDL2.capture === undefined)) {
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            SDL2.audioContext.close();
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            SDL2.audioContext = undefined;
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        }
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    }, this->iscapture);
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    SDL_free(this->hidden->mixbuf);
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    SDL_free(this->hidden);
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}
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static int
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EMSCRIPTENAUDIO_OpenDevice(_THIS, void *handle, const char *devname, int iscapture)
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{
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    SDL_bool valid_format = SDL_FALSE;
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    SDL_AudioFormat test_format;
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    int i;
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    float f;
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    int result;
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    /* based on parts of library_sdl.js */
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    /* create context (TODO: this puts stuff in the global namespace...)*/
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    result = EM_ASM_INT({
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        if(typeof(SDL2) === 'undefined') {
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            SDL2 = {};
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        }
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        if (!$0) {
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            SDL2.audio = {};
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        } else {
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            SDL2.capture = {};
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        }
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        if (!SDL2.audioContext) {
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            if (typeof(AudioContext) !== 'undefined') {
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                SDL2.audioContext = new AudioContext();
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            } else if (typeof(webkitAudioContext) !== 'undefined') {
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                SDL2.audioContext = new webkitAudioContext();
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            }
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        }
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        return SDL2.audioContext === undefined ? -1 : 0;
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    }, iscapture);
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    if (result < 0) {
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        return SDL_SetError("Web Audio API is not available!");
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    }
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    test_format = SDL_FirstAudioFormat(this->spec.format);
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    while ((!valid_format) && (test_format)) {
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        switch (test_format) {
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        case AUDIO_F32: /* web audio only supports floats */
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            this->spec.format = test_format;
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            valid_format = SDL_TRUE;
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            break;
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        }
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        test_format = SDL_NextAudioFormat();
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    }
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    if (!valid_format) {
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        /* Didn't find a compatible format :( */
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        return SDL_SetError("No compatible audio format!");
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    }
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    /* Initialize all variables that we clean on shutdown */
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    this->hidden = (struct SDL_PrivateAudioData *)
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        SDL_malloc((sizeof *this->hidden));
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    if (this->hidden == NULL) {
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        return SDL_OutOfMemory();
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    }
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    SDL_zerop(this->hidden);
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    /* limit to native freq */
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    const int sampleRate = EM_ASM_INT_V({
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        return SDL2.audioContext.sampleRate;
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    });
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    if(this->spec.freq != sampleRate) {
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        for (i = this->spec.samples; i > 0; i--) {
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            f = (float)i / (float)sampleRate * (float)this->spec.freq;
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            if (SDL_floor(f) == f) {
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                this->hidden->conv_in_len = SDL_floor(f);
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                break;
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   314
            }
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   315
        }
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   316
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        this->spec.freq = sampleRate;
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   318
    }
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   319
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    SDL_CalculateAudioSpec(&this->spec);
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   321
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    if (iscapture) {
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        /* The idea is to take the capture media stream, hook it up to an
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           audio graph where we can pass it through a ScriptProcessorNode
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           to access the raw PCM samples and push them to the SDL app's
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           callback. From there, we "process" the audio data into silence
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           and forget about it. */
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        /* This should, strictly speaking, use MediaRecorder for capture, but
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           this API is cleaner to use and better supported, and fires a
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           callback whenever there's enough data to fire down into the app.
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           The downside is that we are spending CPU time silencing a buffer
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           that the audiocontext uselessly mixes into any output. On the
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           upside, both of those things are not only run in native code in
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           the browser, they're probably SIMD code, too. MediaRecorder
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           feels like it's a pretty inefficient tapdance in similar ways,
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           to be honest. */
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   338
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        EM_ASM_({
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            var have_microphone = function(stream) {
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                //console.log('SDL audio capture: we have a microphone! Replacing silence callback.');
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                if (SDL2.capture.silenceTimer !== undefined) {
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                    clearTimeout(SDL2.capture.silenceTimer);
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                    SDL2.capture.silenceTimer = undefined;
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   345
                }
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                SDL2.capture.mediaStreamNode = SDL2.audioContext.createMediaStreamSource(stream);
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                SDL2.capture.scriptProcessorNode = SDL2.audioContext.createScriptProcessor($1, $0, 1);
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                SDL2.capture.scriptProcessorNode.onaudioprocess = function(audioProcessingEvent) {
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                    if ((SDL2 === undefined) || (SDL2.capture === undefined)) { return; }
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                    audioProcessingEvent.outputBuffer.getChannelData(0).fill(0.0);
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                    SDL2.capture.currentCaptureBuffer = audioProcessingEvent.inputBuffer;
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                    Runtime.dynCall('vi', $2, [$3]);
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                };
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                SDL2.capture.mediaStreamNode.connect(SDL2.capture.scriptProcessorNode);
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                SDL2.capture.scriptProcessorNode.connect(SDL2.audioContext.destination);
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                SDL2.capture.stream = stream;
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   357
            };
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   358
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            var no_microphone = function(error) {
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                //console.log('SDL audio capture: we DO NOT have a microphone! (' + error.name + ')...leaving silence callback running.');
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            };
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   362
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            /* we write silence to the audio callback until the microphone is available (user approves use, etc). */
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   364
            SDL2.capture.silenceBuffer = SDL2.audioContext.createBuffer($0, $1, SDL2.audioContext.sampleRate);
icculus@10274
   365
            SDL2.capture.silenceBuffer.getChannelData(0).fill(0.0);
icculus@10274
   366
            var silence_callback = function() {
icculus@10274
   367
                SDL2.capture.currentCaptureBuffer = SDL2.capture.silenceBuffer;
icculus@10274
   368
                Runtime.dynCall('vi', $2, [$3]);
icculus@10274
   369
            };
icculus@10274
   370
icculus@10276
   371
            SDL2.capture.silenceTimer = setTimeout(silence_callback, ($1 / SDL2.audioContext.sampleRate) * 1000);
icculus@10274
   372
icculus@10274
   373
            if ((navigator.mediaDevices !== undefined) && (navigator.mediaDevices.getUserMedia !== undefined)) {
icculus@10274
   374
                navigator.mediaDevices.getUserMedia({ audio: true, video: false }).then(have_microphone).catch(no_microphone);
icculus@10274
   375
            } else if (navigator.webkitGetUserMedia !== undefined) {
icculus@10274
   376
                navigator.webkitGetUserMedia({ audio: true, video: false }, have_microphone, no_microphone);
icculus@10274
   377
            }
icculus@10274
   378
        }, this->spec.channels, this->spec.samples, HandleCaptureProcess, this);
icculus@10274
   379
    } else {
icculus@10274
   380
        /* setup a ScriptProcessorNode */
icculus@10274
   381
        EM_ASM_ARGS({
icculus@10274
   382
            SDL2.audio.scriptProcessorNode = SDL2.audioContext['createScriptProcessor']($1, 0, $0);
icculus@10274
   383
            SDL2.audio.scriptProcessorNode['onaudioprocess'] = function (e) {
icculus@10355
   384
                if ((SDL2 === undefined) || (SDL2.audio === undefined)) { return; }
icculus@10274
   385
                SDL2.audio.currentOutputBuffer = e['outputBuffer'];
icculus@10274
   386
                Runtime.dynCall('vi', $2, [$3]);
icculus@10274
   387
            };
icculus@10274
   388
            SDL2.audio.scriptProcessorNode['connect'](SDL2.audioContext['destination']);
icculus@10274
   389
        }, this->spec.channels, this->spec.samples, HandleAudioProcess, this);
icculus@10274
   390
    }
icculus@10274
   391
icculus@9278
   392
    return 0;
icculus@9278
   393
}
icculus@9278
   394
icculus@9278
   395
static int
icculus@10281
   396
EMSCRIPTENAUDIO_Init(SDL_AudioDriverImpl * impl)
icculus@9278
   397
{
icculus@9278
   398
    /* Set the function pointers */
icculus@10281
   399
    impl->OpenDevice = EMSCRIPTENAUDIO_OpenDevice;
icculus@10281
   400
    impl->CloseDevice = EMSCRIPTENAUDIO_CloseDevice;
icculus@9278
   401
icculus@9278
   402
    impl->OnlyHasDefaultOutputDevice = 1;
icculus@9278
   403
icculus@9278
   404
    /* no threads here */
icculus@9278
   405
    impl->SkipMixerLock = 1;
icculus@9278
   406
    impl->ProvidesOwnCallbackThread = 1;
icculus@9278
   407
icculus@9278
   408
    /* check availability */
icculus@10274
   409
    const int available = EM_ASM_INT_V({
icculus@9278
   410
        if (typeof(AudioContext) !== 'undefined') {
icculus@9278
   411
            return 1;
icculus@9278
   412
        } else if (typeof(webkitAudioContext) !== 'undefined') {
icculus@9278
   413
            return 1;
icculus@9278
   414
        }
icculus@9278
   415
        return 0;
icculus@9278
   416
    });
icculus@9278
   417
philipp@9831
   418
    if (!available) {
philipp@9831
   419
        SDL_SetError("No audio context available");
philipp@9831
   420
    }
philipp@9831
   421
icculus@10274
   422
    const int capture_available = available && EM_ASM_INT_V({
icculus@10274
   423
        if ((typeof(navigator.mediaDevices) !== 'undefined') && (typeof(navigator.mediaDevices.getUserMedia) !== 'undefined')) {
icculus@10274
   424
            return 1;
icculus@10274
   425
        } else if (typeof(navigator.webkitGetUserMedia) !== 'undefined') {
icculus@10274
   426
            return 1;
icculus@10274
   427
        }
icculus@10274
   428
        return 0;
icculus@10274
   429
    });
icculus@10274
   430
icculus@10274
   431
    impl->HasCaptureSupport = capture_available ? SDL_TRUE : SDL_FALSE;
icculus@10274
   432
    impl->OnlyHasDefaultCaptureDevice = capture_available ? SDL_TRUE : SDL_FALSE;
icculus@10274
   433
icculus@9278
   434
    return available;
icculus@9278
   435
}
icculus@9278
   436
icculus@10281
   437
AudioBootStrap EMSCRIPTENAUDIO_bootstrap = {
icculus@10281
   438
    "emscripten", "SDL emscripten audio driver", EMSCRIPTENAUDIO_Init, 0
icculus@9278
   439
};
icculus@9278
   440
icculus@9278
   441
#endif /* SDL_AUDIO_DRIVER_EMSCRIPTEN */
icculus@9278
   442
icculus@9278
   443
/* vi: set ts=4 sw=4 expandtab: */