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// Copyright (c) 2013 Google Inc. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
var ENVIRONMENT_IS_PTHREAD; // is set to true in pthread-main.js if we are in a worker
if(!ENVIRONMENT_IS_PTHREAD) {
(function() {
var isAudioSupported = function() {
return !!(window["AudioContext"] || window["webkitAudioContext"]);
};
var createAudioContext = function() {
if (window["AudioContext"] !== undefined) {
return new AudioContext();
} else {
return new webkitAudioContext();
}
}
// The Web Audio API currently does not allow user-specified sample rates.
var supportedSampleRate = function() {
if(isAudioSupported()) {
return createAudioContext().sampleRate;
} else {
// TODO(ncbray): should the AudioConfig interface be disabled if
// Audio is not available?
return 44100;
}
}
var createScriptNode = function(context, sample_count, channels) {
if (context.createScriptProcessor) {
return context.createScriptProcessor(sample_count, 0, channels);
} else {
// Safari has a differently named API and is buggy if there are zero input channels.
return context.createJavaScriptNode(sample_count, 1, channels);
}
}
var AudioConfig_CreateStereo16Bit = function(instance, sample_rate, sample_frame_count) {
if (sample_rate !== supportedSampleRate()) {
return 0;
}
// PP_AUDIOMINSAMPLEFRAMECOUNT = 64
// PP_AUDIOMAXSAMPLEFRAMECOUNT = 32768
if (sample_frame_count < 64 || sample_frame_count > 32768) {
return 0;
}
return resources.register(AUDIO_CONFIG_RESOURCE, {
sample_rate: sample_rate,
sample_frame_count: sample_frame_count
});
};
var AudioConfig_RecommendSampleFrameCount = function(instance, sample_rate, requested_sample_frame_count) {
// TODO(ncbray): be smarter?
return 2048;
};
var AudioConfig_IsAudioConfig = function(resource) {
return resources.is(resource, AUDIO_CONFIG_RESOURCE);
};
var AudioConfig_GetSampleRate = function(config) {
var c = resources.resolve(config, AUDIO_CONFIG_RESOURCE);
if (c === undefined) {
return 0;
}
return c.sample_rate;
};
var AudioConfig_GetSampleFrameCount = function(config) {
var c = resources.resolve(config, AUDIO_CONFIG_RESOURCE);
if (c === undefined) {
return 0;
}
return c.sample_frame_count;
};
var AudioConfig_RecommendSampleRate = function(instance) {
return supportedSampleRate();
};
registerInterface("PPB_AudioConfig;1.1", [
AudioConfig_CreateStereo16Bit,
AudioConfig_RecommendSampleFrameCount,
AudioConfig_IsAudioConfig,
AudioConfig_GetSampleRate,
AudioConfig_GetSampleFrameCount,
AudioConfig_RecommendSampleRate,
]);
registerInterface("PPB_AudioConfig;1.0", [
AudioConfig_CreateStereo16Bit,
AudioConfig_RecommendSampleFrameCount,
AudioConfig_IsAudioConfig,
AudioConfig_GetSampleRate,
AudioConfig_GetSampleFrameCount,
]);
var SetPlaybackState = function(audio, state) {
if (audio.playing === state) {
return;
}
if (state) {
audio.processor.connect(audio.context.destination);
audio.playing = true;
} else {
audio.processor.disconnect();
audio.playing = false;
}
};
var Audio_Create = function(instance, config, audio_callback, user_data) {
var config_js = resources.resolve(config, AUDIO_CONFIG_RESOURCE);
if (config_js === undefined) {
return 0;
}
// Assumes 16-bit stereo.
var buffer_bytes = config_js.sample_frame_count * 2 * 2;
var buffer = _malloc(buffer_bytes);
var context = createAudioContext();
// Note requires power-of-two buffer size.
var processor = createScriptNode(context, config_js.sample_frame_count, 2);
processor.onaudioprocess = function (e) {
Runtime.dynCall('viii', audio_callback, [buffer, buffer_bytes, user_data]);
var l = e.outputBuffer.getChannelData(0);
var r = e.outputBuffer.getChannelData(1);
var base = buffer>>1;
var offset = 0;
var scale = 1 / ((1<<15)-1);
for (var i = 0; i < e.outputBuffer.length; i++) {
l[i] = HEAP16[base + offset] * scale;
offset += 1;
r[i] = HEAP16[base + offset] * scale;
offset += 1;
}
};
// TODO(ncbray): capture and ref/unref the config?
// TODO(ncbray): destructor?
return resources.register(AUDIO_RESOURCE, {
context: context,
processor: processor,
playing: false,
audio_callback: audio_callback,
user_data: user_data,
// Assumes 16-bit stereo.
buffer: buffer
});
};
var Audio_IsAudio = function(resource) {
return resources.is(resource, AUDIO_RESOURCE);
};
var Audio_GetCurrentConfig = function(audio) {
throw "Audio_GetCurrentConfig not implemented";
};
var Audio_StartPlayback = function(audio) {
var res = resources.resolve(audio, AUDIO_RESOURCE);
if (res === undefined) {
return 0;
}
SetPlaybackState(res, true);
return 1;
};
var Audio_StopPlayback = function(audio) {
var res = resources.resolve(audio, AUDIO_RESOURCE);
if (res === undefined) {
return 0;
}
SetPlaybackState(res, false);
return 1;
};
registerInterface("PPB_Audio;1.0", [
Audio_Create,
Audio_IsAudio,
Audio_GetCurrentConfig,
Audio_StartPlayback,
Audio_StopPlayback,
], isAudioSupported);
})();
}
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