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Detect channel count, mix rate, and buffer length in HTML5 audio driver

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Refactor WebAudio driver.
This commit is contained in:
Leon Krause 2017-11-05 23:48:13 +01:00
parent f2d669f5d3
commit 8d3ca2c137
2 changed files with 88 additions and 74 deletions
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151
platform/javascript/audio_driver_javascript.cpp
View file

@ -32,113 +32,134 @@
#include <emscripten.h>
AudioDriverJavaScript *AudioDriverJavaScript::singleton_js = NULL;
AudioDriverJavaScript *AudioDriverJavaScript::singleton = NULL;
const char *AudioDriverJavaScript::get_name() const {
return "JavaScript";
}
extern "C" EMSCRIPTEN_KEEPALIVE void js_audio_driver_mix_function(int p_frames) {
extern "C" EMSCRIPTEN_KEEPALIVE void audio_driver_js_mix() {
//print_line("MIXI! "+itos(p_frames));
AudioDriverJavaScript::singleton_js->mix_to_js(p_frames);
AudioDriverJavaScript::singleton->mix_to_js();
}
void AudioDriverJavaScript::mix_to_js(int p_frames) {
void AudioDriverJavaScript::mix_to_js() {
int todo = p_frames;
int offset = 0;
while (todo) {
int tomix = MIN(todo, INTERNAL_BUFFER_SIZE);
audio_server_process(p_frames, stream_buffer);
for (int i = 0; i < tomix * internal_buffer_channels; i++) {
internal_buffer[i] = float(stream_buffer[i] >> 16) / 32768.0;
}
/* clang-format off */
EM_ASM_ARGS({
var data = HEAPF32.subarray($0 / 4, $0 / 4 + $2 * 2);
for (var channel = 0; channel < _as_output_buffer.numberOfChannels; channel++) {
var outputData = _as_output_buffer.getChannelData(channel);
// Loop through samples
for (var sample = 0; sample < $2; sample++) {
// make output equal to the same as the input
outputData[sample + $1] = data[sample * 2 + channel];
}
}
}, internal_buffer, offset, tomix);
/* clang-format on */
todo -= tomix;
offset += tomix;
int channel_count = get_total_channels_by_speaker_mode(get_speaker_mode());
int sample_count = memarr_len(internal_buffer) / channel_count;
int32_t *stream_buffer = reinterpret_cast<int32_t *>(internal_buffer);
audio_server_process(sample_count, stream_buffer);
for (int i = 0; i < sample_count * channel_count; i++) {
internal_buffer[i] = float(stream_buffer[i] >> 16) / 32768.0;
}
}
Error AudioDriverJavaScript::init() {
return OK;
/* clang-format off */
EM_ASM({
_audioDriver_audioContext = new (window.AudioContext || window.webkitAudioContext);
_audioDriver_scriptNode = null;
});
/* clang-format on */
int channel_count = get_total_channels_by_speaker_mode(get_speaker_mode());
/* clang-format off */
int buffer_length = EM_ASM_INT({
var CHANNEL_COUNT = $0;
var channelCount = _audioDriver_audioContext.destination.channelCount;
try {
// Try letting the browser recommend a buffer length.
_audioDriver_scriptNode = _audioDriver_audioContext.createScriptProcessor(0, 0, channelCount);
} catch (e) {
// ...otherwise, default to 4096.
_audioDriver_scriptNode = _audioDriver_audioContext.createScriptProcessor(4096, 0, channelCount);
}
_audioDriver_scriptNode.connect(_audioDriver_audioContext.destination);
return _audioDriver_scriptNode.bufferSize;
}, channel_count);
/* clang-format on */
if (!buffer_length) {
return FAILED;
}
if (!internal_buffer || memarr_len(internal_buffer) != buffer_length * channel_count) {
if (internal_buffer)
memdelete_arr(internal_buffer);
internal_buffer = memnew_arr(float, buffer_length *channel_count);
}
return internal_buffer ? OK : ERR_OUT_OF_MEMORY;
}
void AudioDriverJavaScript::start() {
internal_buffer = memnew_arr(float, INTERNAL_BUFFER_SIZE *internal_buffer_channels);
stream_buffer = memnew_arr(int32_t, INTERNAL_BUFFER_SIZE * 4); //max 4 channels
/* clang-format off */
mix_rate = EM_ASM_INT({
_as_audioctx = new (window.AudioContext || window.webkitAudioContext);
_as_script_node = _as_audioctx.createScriptProcessor($0, 0, $1);
_as_script_node.connect(_as_audioctx.destination);
console.log(_as_script_node.bufferSize);
var jsAudioDriverMixFunction = cwrap('js_audio_driver_mix_function', null, ['number']);
EM_ASM({
var INTERNAL_BUFFER_PTR = $0;
_as_script_node.onaudioprocess = function(audioProcessingEvent) {
// The output buffer contains the samples that will be modified and played
_as_output_buffer = audioProcessingEvent.outputBuffer;
jsAudioDriverMixFunction([_as_output_buffer.getChannelData(0).length]);
var audioDriverMixFunction = cwrap('audio_driver_js_mix');
_audioDriver_scriptNode.onaudioprocess = function(audioProcessingEvent) {
audioDriverMixFunction();
// The output buffer contains the samples that will be modified and played.
var output = audioProcessingEvent.outputBuffer;
var input = HEAPF32.subarray(
INTERNAL_BUFFER_PTR / HEAPF32.BYTES_PER_ELEMENT,
INTERNAL_BUFFER_PTR / HEAPF32.BYTES_PER_ELEMENT + output.length * output.numberOfChannels);
for (var channel = 0; channel < output.numberOfChannels; channel++) {
var outputData = output.getChannelData(channel);
// Loop through samples.
for (var sample = 0; sample < outputData.length; sample++) {
// Set output equal to input.
outputData[sample] = input[sample * output.numberOfChannels + channel];
}
}
};
return _as_audioctx.sampleRate;
}, INTERNAL_BUFFER_SIZE, internal_buffer_channels);
}, internal_buffer);
/* clang-format on */
}
int AudioDriverJavaScript::get_mix_rate() const {
return mix_rate;
/* clang-format off */
return EM_ASM_INT_V({
return _audioDriver_audioContext.sampleRate;
});
/* clang-format on */
}
AudioDriver::SpeakerMode AudioDriverJavaScript::get_speaker_mode() const {
return SPEAKER_MODE_STEREO;
/* clang-format off */
return get_speaker_mode_by_total_channels(EM_ASM_INT_V({
return _audioDriver_audioContext.destination.channelCount;
}));
/* clang-format on */
}
// No locking, as threads are not supported.
void AudioDriverJavaScript::lock() {
/*no locking, as threads are not supported
if (active && mutex)
mutex->lock();
*/
}
void AudioDriverJavaScript::unlock() {
/*no locking, as threads are not supported
if (active && mutex)
mutex->unlock();
*/
}
void AudioDriverJavaScript::finish() {
/* clang-format off */
EM_ASM({
_audioDriver_audioContext = null;
_audioDriver_scriptNode = null;
});
/* clang-format on */
memdelete_arr(internal_buffer);
internal_buffer = NULL;
}
AudioDriverJavaScript::AudioDriverJavaScript() {
internal_buffer_channels = 2;
mix_rate = DEFAULT_MIX_RATE;
singleton_js = this;
singleton = this;
}

11
platform/javascript/audio_driver_javascript.h
View file

@ -35,18 +35,11 @@
class AudioDriverJavaScript : public AudioDriver {
enum {
INTERNAL_BUFFER_SIZE = 4096,
};
int mix_rate;
float *internal_buffer;
int internal_buffer_channels;
int32_t *stream_buffer;
public:
void mix_to_js(int p_frames);
static AudioDriverJavaScript *singleton_js;
void mix_to_js();
static AudioDriverJavaScript *singleton;
virtual const char *get_name() const;