Add README

src/_data/audioworklet_data.yaml

@@ -52,10 +52,10 @@
         This example demonstrates how this library can be used as a channel
         between a worker thread and AudioWorklet to send audio data.
       href: free-queue/examples/simple-passthrough/
-    - title: Hello WebAssembly
-      description: Example of using FreeQueue with WebAssembly.
-        This example uses a mp3 decoding library to play load and play song
-        from WebAssembly.
+    - title: Using FreeQueue with WebAssembly
+      description: An example demonstrates the usage of FreeQueue with 
+        WebAssembly. It includes an external C/C++ MP3 decoder library to 
+        load and play music with FreeQueue on top of AudioWorklet.
       href: free-queue/examples/hello-webassembly/
 
 - title: Migration from ScriptProcessorNode

src/_data/build_info.json

@@ -1 +1 @@
-{"version":"3.0.2","revision":"d20a9e8","lastUpdated":"2022-09-04","copyrightYear":2022}
+{"version":"3.0.2","revision":"a7e8c6d","lastUpdated":"2022-09-10","copyrightYear":2022}

src/audio-worklet/free-queue/examples/hello-webassembly/README.md

@@ -0,0 +1,35 @@
+# Using FreeQueue with WebAssembly
+
+This example demonstrates how to use FreeQueue with WebAssembly.
+It includes an external C/C++ MP3 decoder
+([dr_mp3.h](https://github.com/mackron/dr_libs/blob/master/dr_mp3.h)) 
+library to load and play music with FreeQueue on top of AudioWorklet.
+
+## Building
+
+Run `build.sh` for Linux and `build.cmd` for windows to build.
+Refer to build scripts for building instructions.
+
+### Emscripten Flags
+```
+    // To tell emscriptenm to build for worker environment
+
+    // To build and load as an ES6 module
+    -s ENVIRONMENT=worker
+    -s MODULARIZE=1 
+    -s EXPORT_NAME=ExampleModule 
+    -s EXPORT_ES6=1 
+
+    // To run main automatically after loading module.
+    -s INVOKE_RUN=1 
+
+    // To enable pthread support
+    -pthread 
+
+    -s EXPORTED_RUNTIME_METHODS="['callMain','ccall', 'cwrap']" 
+    -o build/example.js 
+
+    // Preload mp3 file
+    --preload-file moonlight.mp3
+
+```

src/audio-worklet/free-queue/examples/hello-webassembly/example.c

@@ -1,9 +1,9 @@
 #include <emscripten.h>
 
-/**
- * Include FreeQueue interface library and dr_mp3 library (For loading and
- * decodin mp3 file).
-*/
+ 
+// Include FreeQueue interface library and dr_mp3 library (For loading and
+// decodin mp3 file).
+
 #define FREE_QUEUE_IMPL
 #include "../../src/interface/free_queue.h"
 #define DR_MP3_IMPLEMENTATION
@@ -12,7 +12,7 @@
 struct FreeQueue *queue;
 drmp3 mp3;
 
-// Function we can call from JavaScript to get FreeQueue address in memory.
+// Function to get FreeQueue address in memory from JavaScript.
 EMSCRIPTEN_KEEPALIVE void *getFreeQueue()
 {
     return queue;
@@ -23,8 +23,9 @@ drmp3_uint64 framesRead = 0;
 
 #define FRAME_SIZE 4096
 
+// buffer to store interleaved PCM frames from mp3 
 float buffer[2*FRAME_SIZE];    // 2 channels so 2 * FRAME_SIZE
-// input buffer
+// input buffer to store decoded mp3 channel data.
 float* input[] = {
     (float[FRAME_SIZE]){},
     (float[FRAME_SIZE]){}
@@ -35,6 +36,7 @@ float* input[] = {
 */
 EMSCRIPTEN_KEEPALIVE bool audio_loop()
 {
+    // Here if the last FRAME read was pushed we read more frames from 
     if (lastFramePushed) {
         framesRead = drmp3_read_pcm_frames_f32(&mp3, DRMP3_COUNTOF(buffer)/mp3.channels, buffer);
         // Seperating PCM frames into 2 channels
@@ -44,6 +46,7 @@ EMSCRIPTEN_KEEPALIVE bool audio_loop()
         }
 
     }
+    // Push FRAME to queue.
     lastFramePushed = FreeQueuePush(queue, input, framesRead);
     return lastFramePushed;
 }

src/audio-worklet/free-queue/examples/hello-webassembly/index.njk

@@ -1,7 +1,7 @@
 ---
 eleventyNavigation:
   key: hello-webassembly
-  title: Hello WebAssembly
+  title: Using FreeQueue with WebAssembly
   parent: audio-worklet
 to_root_dir: ../../../../
 ---

src/audio-worklet/free-queue/examples/hello-webassembly/sink-processor.js

@@ -12,24 +12,20 @@ const RENDER_QUANTUM = 128
 class SinkProcessor extends AudioWorkletProcessor {
   constructor(options) {
     super();
-    /**
-     * Initialize the Queue.
-     * We have to set prototype of queue, because queue object is passed
-     * using structured cloning algorithm.
-     * See - 
-     * https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm
-     */
+    // Initialize the Queue.
+    // We have to set prototype of queue, because queue object is passed
+    // using structured cloning algorithm.
+    // See - 
+    // https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm
     this.queue = options.processorOptions.queue;
     Object.setPrototypeOf(this.queue, FreeQueue.prototype);
   }
 
   process(inputs, outputs) {
     const output = outputs[0];
 
-    /**
-     * Pull out render quantum frame from the queue into output.
-     * If failed, print "failed" to console.
-     */
+    // Pull out render quantum frame from the queue into output.
+    // If failed, print "failed" to console.
     const didPull = this.queue.pull(output, RENDER_QUANTUM);
     didPull ? null : console.log("failed");