1 files changed, 49 insertions, 0 deletions
diff --git a/testing/web-platform/tests/webaudio/the-audio-api/the-audioworklet-interface/processors/one-pole-processor.js b/testing/web-platform/tests/webaudio/the-audio-api/the-audioworklet-interface/processors/one-pole-processor.js
new file mode 100644
index 0000000000..0bcc43f6f0
--- /dev/null
+++ b/testing/web-platform/tests/webaudio/the-audio-api/the-audioworklet-interface/processors/one-pole-processor.js
@@ -0,0 +1,49 @@
+/**
+ * @class OnePoleFilter
+ * @extends AudioWorkletProcessor
+ *
+ * A simple One-pole filter.
+ */
+
+class OnePoleFilter extends AudioWorkletProcessor {
+
+  // This gets evaluated as soon as the global scope is created.
+  static get parameterDescriptors() {
+    return [{
+      name: 'frequency',
+      defaultValue: 250,
+      minValue: 0,
+      maxValue: 0.5 * sampleRate
+    }];
+  }
+
+  constructor() {
+    super();
+    this.updateCoefficientsWithFrequency_(250);
+  }
+
+  updateCoefficientsWithFrequency_(frequency) {
+    this.b1_ = Math.exp(-2 * Math.PI * frequency / sampleRate);
+    this.a0_ = 1.0 - this.b1_;
+    this.z1_ = 0;
+  }
+
+  process(inputs, outputs, parameters) {
+    let input = inputs[0];
+    let output = outputs[0];
+    let frequency = parameters.frequency;
+    for (let channel = 0; channel < output.length; ++channel) {
+      let inputChannel = input[channel];
+      let outputChannel = output[channel];
+      for (let i = 0; i < outputChannel.length; ++i) {
+        this.updateCoefficientsWithFrequency_(frequency[i]);
+        this.z1_ = inputChannel[i] * this.a0_ + this.z1_ * this.b1_;
+        outputChannel[i] = this.z1_;
+      }
+    }
+
+    return true;
+  }
+}
+
+registerProcessor('one-pole-filter', OnePoleFilter);