Initial commit — WPF guitar note name tutor using FFT frequency detection

2026-05-09 03:17:07 +00:00
commit 99b73f710a
30 changed files with 1637 additions and 0 deletions
@@ -0,0 +1,156 @@
+using System;
+using System.Diagnostics;
+using System.Windows;
+using System.Collections.Generic;
+using System.Windows.Threading;
+using FrequencyDetection;
+using SoundCapture;
+
+namespace GuitarNoteNameTutor
+{
+	/// <summary>
+	/// Interaction logic for Window1.xaml
+	/// </summary>
+	public partial class Window
+	{
+		private bool IsListenning { get; set; }
+
+		private static readonly Dictionary<int, string> HalfNoteSharpNames =
+			new Dictionary<int, string>
+				{
+					{0, "A"},
+					{1, "A\u266F"},
+					{2, "B"},
+					{3, "C"},
+					{4, "C\u266F"},
+					{5, "D"},
+					{6, "D\u266F"},
+					{7, "E"},
+					{8, "F"},
+					{9, "F\u266F"},
+					{10, "G"},
+					{11, "G\u266F"},
+				};
+
+		private static readonly Dictionary<int, string> HalfNoteFlatNames =
+			new Dictionary<int, string>
+				{
+					{0, "A"},
+					{1, "B\u266D"},
+					{2, "B"},
+					{3, "C"},
+					{4, "D\u266D"},
+					{5, "D"},
+					{6, "E\u266D"},
+					{7, "E"},
+					{8, "F"},
+					{9, "G\u266D"},
+					{10, "G"},
+					{11, "A\u266D"},
+				};
+
+		static readonly double ToneStep = Math.Pow(2, 1.0 / 12);
+
+		private readonly Random _rand = new Random();
+
+		FrequencyInfoSource _frequencyInfoSource;
+
+		public Window()
+		{
+			InitializeComponent();
+
+			//timer = new DispatcherTimer {Interval = TimeSpan.FromSeconds(2)};
+			//timer.Tick += timer_Tick;
+			//timer.Start();
+		}
+
+		private void StopListenning()
+		{
+			IsListenning = false;
+			_frequencyInfoSource.FrequencyDetected -= FrequencyInfoSource_FrequencyDetected;
+			_frequencyInfoSource.Stop();
+			_frequencyInfoSource = null;
+		}
+
+		private void StartListenning(SoundCaptureDevice device)
+		{
+			IsListenning = true;
+			_frequencyInfoSource = new SoundFrequencyInfoSource(device);
+			_frequencyInfoSource.FrequencyDetected += FrequencyInfoSource_FrequencyDetected;
+			_frequencyInfoSource.Listen();
+		}
+
+		void FrequencyInfoSource_FrequencyDetected(object sender, FrequencyDetectedEventArgs e)
+		{
+			if (!Dispatcher.CheckAccess())
+			{
+				Dispatcher.BeginInvoke(
+					new EventHandler<FrequencyDetectedEventArgs>(FrequencyInfoSource_FrequencyDetected), sender, e);
+			}
+			else
+			{
+				if (e.Frequency <= 0)
+				{
+					unknownFreqLabel.Visibility = Visibility.Visible;
+					frequencyLabel.Content = "?";
+					return;
+				}
+				unknownFreqLabel.Visibility = Visibility.Hidden;
+
+				NoteFrequency closestNote = FindClosestNote(e.Frequency);
+				label.Content = HalfNoteSharpNames[closestNote.HalfStepsFromA];
+				frequencyLabel.Content = string.Format("{0:0.0}Hz", e.Frequency);
+			}
+		}
+
+		private class NoteFrequency
+		{
+			public int HalfStepsFromA;
+			public double Frequency;
+		}
+
+		private static NoteFrequency FindClosestNote(double frequency)
+		{
+			const double aFrequency = 440.0;
+			const int toneIndexOffsetToPositives = 120;
+
+			int toneIndex = (int)Math.Round(Math.Log(frequency / aFrequency, ToneStep));
+			int toneHalfStep = (toneIndexOffsetToPositives + toneIndex) % HalfNoteSharpNames.Count;
+			Debug.WriteLine(string.Format("{0}, {1}", toneIndexOffsetToPositives + toneIndex, (toneIndexOffsetToPositives + toneIndex) / 12 - 7));
+			NoteFrequency noteFrequency = new NoteFrequency
+          	{
+				HalfStepsFromA = toneHalfStep,
+          		Frequency = Math.Pow(ToneStep, toneIndex)*aFrequency,
+          	};
+
+			return noteFrequency;
+		}
+
+		private DispatcherTimer timer;
+
+		private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
+		{
+			if (IsListenning)
+			{
+				StopListenning();
+			}
+		}
+
+		private void startButton_Click(object sender, RoutedEventArgs e)
+		{
+			SoundCaptureDevice device = null;
+			SelectDevice form = new SelectDevice {Owner = this};
+			bool? dialogResponse = form.ShowDialog();
+			if (dialogResponse.HasValue && dialogResponse == true)
+			{
+				device = form.SelectedDevice;
+			}
+
+			if (device != null)
+			{
+				label.Content = string.Empty;
+				StartListenning(device);
+			}
+		}
+	}
+}