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| 1 | +#include <assert.h> |
| 2 | +#include <string.h> |
| 3 | +#include <stdio.h> |
| 4 | + |
| 5 | +#include <emscripten/em_js.h> |
| 6 | +#include <emscripten/webaudio.h> |
| 7 | + |
| 8 | +// Tests two stereo audio inputs being copied to two stereo outputs. |
| 9 | + |
| 10 | +// This needs to be big enough for the 2x stereo outputs, 2x inputs and the worker stack |
| 11 | +#define AUDIO_STACK_SIZE 6144 |
| 12 | + |
| 13 | +// Helper for MEMORY64 to cast an audio context or type to a void* |
| 14 | +#define WA_2_VOIDP(ctx) ((void*) (intptr_t) ctx) |
| 15 | +// Helper for MEMORY64 to cast a void* to an audio context or type |
| 16 | +#define VOIDP_2_WA(ptr) ((EMSCRIPTEN_WEBAUDIO_T) (intptr_t) ptr) |
| 17 | + |
| 18 | +// Count the audio callbacks and return after 375 frames (1 second with the default 128 size) |
| 19 | +// |
| 20 | +// *** Remove this in your own code *** |
| 21 | +// |
| 22 | +volatile int audioProcessedCount = 0; |
| 23 | +bool playedAndMixed(double time, void* data) { |
| 24 | + if (audioProcessedCount >= 375) { |
| 25 | + emscripten_force_exit(0); |
| 26 | + return false; |
| 27 | + } |
| 28 | + return true; |
| 29 | +} |
| 30 | + |
| 31 | +// ID to the beat and bass loops |
| 32 | +EMSCRIPTEN_WEBAUDIO_T beatID = 0; |
| 33 | +EMSCRIPTEN_WEBAUDIO_T bassID = 0; |
| 34 | + |
| 35 | +// Creates a MediaElementAudioSourceNode with the supplied URL (which is |
| 36 | +// registered as an internal audio object and the ID returned). |
| 37 | +EM_JS(EMSCRIPTEN_WEBAUDIO_T, createTrack, (EMSCRIPTEN_WEBAUDIO_T ctxID, const char* url, bool looping), { |
| 38 | + var context = emscriptenGetAudioObject(ctxID); |
| 39 | + if (context) { |
| 40 | + var audio = document.createElement('audio'); |
| 41 | + audio.src = UTF8ToString(url); |
| 42 | + audio.loop = looping; |
| 43 | + var track = context.createMediaElementSource(audio); |
| 44 | + return emscriptenRegisterAudioObject(track); |
| 45 | + } |
| 46 | + return 0; |
| 47 | +}); |
| 48 | + |
| 49 | +// Toggles the play/pause of a MediaElementAudioSourceNode given its ID |
| 50 | +EM_JS(void, toggleTrack, (EMSCRIPTEN_WEBAUDIO_T srcID), { |
| 51 | + var source = emscriptenGetAudioObject(srcID); |
| 52 | + if (source) { |
| 53 | + var audio = source.mediaElement; |
| 54 | + if (audio) { |
| 55 | + if (audio.paused) { |
| 56 | + audio.currentTime = 0; |
| 57 | + audio.play(); |
| 58 | + } else { |
| 59 | + audio.pause(); |
| 60 | + } |
| 61 | + } |
| 62 | + } |
| 63 | +}); |
| 64 | + |
| 65 | +// Callback to process and copy the audio tracks |
| 66 | +bool process(int numInputs, const AudioSampleFrame* inputs, int numOutputs, AudioSampleFrame* outputs, int numParams, const AudioParamFrame* params, void* data) { |
| 67 | + audioProcessedCount++; |
| 68 | + |
| 69 | + // Twin stereo in and out |
| 70 | + assert(numInputs == 2 && numOutputs == 2); |
| 71 | + assert(inputs[0].numberOfChannels == 2 && inputs[1].numberOfChannels == 2); |
| 72 | + assert(outputs[0].numberOfChannels == 2 && outputs[1].numberOfChannels == 2); |
| 73 | + // All with the same number of samples |
| 74 | + assert(inputs[0].samplesPerChannel == inputs[1].samplesPerChannel); |
| 75 | + assert(inputs[0].samplesPerChannel == outputs[0].samplesPerChannel); |
| 76 | + assert(outputs[0].samplesPerChannel == outputs[1].samplesPerChannel); |
| 77 | + // Now with all known quantities we can memcpy the data |
| 78 | + int totalSamples = outputs[0].samplesPerChannel * outputs[0].numberOfChannels; |
| 79 | + memcpy(outputs[0].data, inputs[0].data, totalSamples * sizeof(float)); |
| 80 | + memcpy(outputs[1].data, inputs[1].data, totalSamples * sizeof(float)); |
| 81 | + return true; |
| 82 | +} |
| 83 | + |
| 84 | +// Registered click even to (1) enable audio playback and (2) toggle playing the tracks |
| 85 | +bool onClick(int type, const EmscriptenMouseEvent* e, void* data) { |
| 86 | + EMSCRIPTEN_WEBAUDIO_T ctx = VOIDP_2_WA(data); |
| 87 | + if (emscripten_audio_context_state(ctx) != AUDIO_CONTEXT_STATE_RUNNING) { |
| 88 | + printf("Resuming playback\n"); |
| 89 | + emscripten_resume_audio_context_sync(ctx); |
| 90 | + } |
| 91 | + printf("Toggling audio playback\n"); |
| 92 | + toggleTrack(beatID); |
| 93 | + toggleTrack(bassID); |
| 94 | + return false; |
| 95 | +} |
| 96 | + |
| 97 | +// Audio processor created, now register the audio callback |
| 98 | +void processorCreated(EMSCRIPTEN_WEBAUDIO_T context, bool success, void* data) { |
| 99 | + if (success) { |
| 100 | + printf("Audio worklet processor created\n"); |
| 101 | + printf("Click to toggle audio playback\n"); |
| 102 | + |
| 103 | + // Two stereo outputs, two inputs |
| 104 | + int outputChannelCounts[2] = { 2, 2 }; |
| 105 | + EmscriptenAudioWorkletNodeCreateOptions opts = { |
| 106 | + .numberOfInputs = 2, |
| 107 | + .numberOfOutputs = 2, |
| 108 | + .outputChannelCounts = outputChannelCounts |
| 109 | + }; |
| 110 | + EMSCRIPTEN_AUDIO_WORKLET_NODE_T worklet = emscripten_create_wasm_audio_worklet_node(context, "mixer", &opts, &process, NULL); |
| 111 | + // Both outputs connected to the context |
| 112 | + emscripten_audio_node_connect(worklet, context, 0, 0); |
| 113 | + emscripten_audio_node_connect(worklet, context, 1, 0); |
| 114 | + |
| 115 | + // Create the two stereo source nodes and connect them to the two inputs |
| 116 | + // Note: we can connect the sources to the same input and it'll get mixed for us, but that's not the point |
| 117 | + beatID = createTrack(context, "audio_files/emscripten-beat.mp3", true); |
| 118 | + if (beatID) { |
| 119 | + emscripten_audio_node_connect(beatID, worklet, 0, 0); |
| 120 | + } |
| 121 | + bassID = createTrack(context, "audio_files/emscripten-bass.mp3", true); |
| 122 | + if (bassID) { |
| 123 | + emscripten_audio_node_connect(bassID, worklet, 0, 1); |
| 124 | + } |
| 125 | + |
| 126 | + // Register a click to start playback |
| 127 | + emscripten_set_click_callback(EMSCRIPTEN_EVENT_TARGET_DOCUMENT, WA_2_VOIDP(context), false, &onClick); |
| 128 | + |
| 129 | + // Register the counter that exits the test after one second of mixing |
| 130 | + emscripten_set_timeout_loop(&playedAndMixed, 16, NULL); |
| 131 | + } else { |
| 132 | + printf("Audio worklet node creation failed\n"); |
| 133 | + } |
| 134 | +} |
| 135 | + |
| 136 | +// Worklet thread inited, now create the audio processor |
| 137 | +void initialised(EMSCRIPTEN_WEBAUDIO_T context, bool success, void* data) { |
| 138 | + if (success) { |
| 139 | + printf("Audio worklet initialised\n"); |
| 140 | + |
| 141 | + WebAudioWorkletProcessorCreateOptions opts = { |
| 142 | + .name = "mixer", |
| 143 | + }; |
| 144 | + emscripten_create_wasm_audio_worklet_processor_async(context, &opts, &processorCreated, NULL); |
| 145 | + } else { |
| 146 | + printf("Audio worklet failed to initialise\n"); |
| 147 | + } |
| 148 | +} |
| 149 | + |
| 150 | +int main() { |
| 151 | + static char workletStack[AUDIO_STACK_SIZE]; |
| 152 | + EMSCRIPTEN_WEBAUDIO_T context = emscripten_create_audio_context(NULL); |
| 153 | + emscripten_start_wasm_audio_worklet_thread_async(context, workletStack, sizeof workletStack, &initialised, NULL); |
| 154 | + emscripten_runtime_keepalive_push(); |
| 155 | + return 0; |
| 156 | +} |
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