Initial commit

src/jsAudioWorkletMain/kotlin/nl/astraeus/processor/WorkletProcessor.kt

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+@file:OptIn(ExperimentalJsExport::class)
+
+package nl.astraeus.processor
+
+import org.khronos.webgl.Float64Array
+import org.w3c.dom.MessageEvent
+import org.w3c.dom.MessagePort
+
+@ExperimentalJsExport
+@JsExport
+object WorkletProcessor {
+  var port: MessagePort? = null
+
+  @JsName("setPort")
+  fun setPort(port: MessagePort) {
+    this.port = port
+    this.port?.onmessage = ::onMessage
+  }
+
+  @JsName("onMessage")
+  fun onMessage(message: MessageEvent) {
+    console.log("WorkletProcessor: Received message", message)
+
+    when (message.data) {
+      "start" -> {
+        println("Start worklet!")
+      }
+      "stop" -> {
+
+      }
+      else ->
+        console.error("Don't kow how to handle message", message)
+    }
+  }
+
+  @JsName("process")
+  fun process(samples: Int, left: Float64Array, right: Float64Array) {
+    //console.log("WorkletProcessor.process", samples)
+//    val buffer = Float64SampleBuffer(samples, left, right)
+//
+//    audioGenerator?.also { generator ->
+//      generator.fillBuffer(buffer, 0, samples, false)
+//    }
+  }
+
+}

src/jsAudioWorkletMain/resources/worklet-processor.js

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+; // make sure kotlin js code last statement is ended
+
+class WorkletProcessor extends AudioWorkletProcessor {
+
+    // Static getter to define AudioParam objects in this custom processor.
+    static get parameterDescriptors() {
+        return [{
+            name: 'volume',
+            defaultValue: 0.75
+        }];
+    }
+
+    constructor() {
+        super();
+
+        console.log("worklet-processor.constructor", this, audioWorklet);
+
+        audioWorklet.nl.astraeus.processor.WorkletProcessor.setPort(this.port);
+
+        console.log("STARTED worklet-processor.js");
+    }
+
+    process(inputs, outputs, parameters) {
+        let result = true;
+        let samplesToProcess = 0;
+
+        if (outputs.length !== 1) {
+            result = false;
+            console.log("Unexpected number of outputs!", outputs)
+        } else {
+            let channels = outputs[0].length;
+
+            if (channels !== 2) {
+                result = false;
+                console.log("Unexpected number of channels!", outputs[0]);
+            } else if (outputs[0][0].length !== outputs[0][1].length) {
+                result = false;
+                console.log("Channels have different lengths!!", outputs[0]);
+            } else {
+                samplesToProcess = outputs[0][0].length;
+
+                audioWorklet.nl.astraeus.processor.WorkletProcessor.process(
+                    samplesToProcess,
+                    outputs[0][0],
+                    outputs[0][1]
+                );
+            }
+        }
+
+        return result;
+    }
+}
+
+registerProcessor('worklet-processor', WorkletProcessor);