WIP: waveform visualization

Source/AudioFileAnalyzer.cs

@@ -0,0 +1,88 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using Godot;
+using NAudio.Wave;
+
+namespace AudioEditor;
+
+public partial class AudioFileAnalyzer : Node
+{
+    public static AudioFileAnalyzer Instance { get; private set; }
+
+    public override void _Ready()
+    {
+        base._Ready();
+        Instance = this;
+    }
+
+    public void AnalyzeFile(string path, out WaveformInfo waveformInfo)
+    {
+        waveformInfo = new();
+
+        if (_waveformInfoCache.ContainsKey(path))
+        {
+            waveformInfo = _waveformInfoCache[path];
+            return;
+        }
+
+        var ext = Path.GetExtension(path);
+
+        switch (ext)
+        {
+            case ".wav":
+                GD.Print("Analyzing a WAV file...");
+                AnalyzeWav(path, out waveformInfo);
+                break;
+            default:
+                GD.Print($"Format {ext} is not supported!");
+                break;
+        }
+
+        _waveformInfoCache.Add(path, waveformInfo);
+    }
+
+    public bool TryGetFromCache(string path, out WaveformInfo waveformInfo)
+    {
+        return _waveformInfoCache.TryGetValue(path, out waveformInfo);
+    }
+
+    private void AnalyzeWav(string path, out WaveformInfo waveformInfo)
+    {
+        waveformInfo = new WaveformInfo();
+        using (var reader = new WaveFileReader(path))
+        {
+            waveformInfo.Length = reader.TotalTime;
+            waveformInfo.SampleRate = reader.WaveFormat.SampleRate;
+
+            long sampleCount = reader.Length / reader.WaveFormat.BlockAlign;
+            waveformInfo.Samples = new float[sampleCount];
+
+            // Render the waveform
+            byte[] buffer = new byte[reader.WaveFormat.BlockAlign];
+            for (int i = 0; i < sampleCount; i++)
+            {
+                int sampleIndex = i * reader.WaveFormat.BlockAlign;
+                while (reader.Position < reader.Length)
+                {
+                    // Read the raw bytes for the current sample
+                    reader.Read(buffer, 0, buffer.Length);
+
+                    // Convert the byte array to a 16-bit sample (assuming 16-bit PCM)
+                    short sample = BitConverter.ToInt16(buffer, 0);  // Assuming 16-bit signed samples
+
+                    waveformInfo.Samples[sampleIndex++] = (float)sample / short.MaxValue;
+                }
+            }
+        }
+    }
+
+    private Dictionary<string, WaveformInfo> _waveformInfoCache = new();
+}
+
+public class WaveformInfo
+{
+    public int SampleRate { get; set; }
+    public TimeSpan Length { get; set; }
+    public float[] Samples { get; set; }
+}

Source/ProjectController.cs

@@ -6,21 +6,46 @@ namespace AudioEditor;
 [GlobalClass]
 public partial class ProjectController : Node
 {
-    [Signal] public delegate void AudioClipDroppedEventHandler(Vector2 atPosition, string clipName, double startTime, double endTime);
+    [Signal] public delegate void AudioClipDroppedEventHandler(Vector2 atPosition, string path, string clipName, double startTime, double endTime);
 
     public override void _Ready()
     {
         GetWindow().FilesDropped += FilesDropped;
     }
 
+    public void CreateAudioClipPreview(Control audioClip)
+    {
+        // GD.Print(audioClip.Clas());
+        var path = audioClip.Get("clip_path").AsString();
+
+        if (string.IsNullOrEmpty(path))
+        {
+            return;
+        }
+
+        if (!AudioFileAnalyzer.Instance.TryGetFromCache(path, out WaveformInfo waveformInfo))
+        {
+            return;
+        }
+
+        if (audioClip.HasNode("%Waveform"))
+        {
+            var waveform = audioClip.GetNode<Waveform>("%Waveform");
+            waveform.SetWaveformInfo(waveformInfo);
+        }
+    }
+
     private void FilesDropped(string[] files)
     {
         var mousePosition = GetViewport().GetMousePosition();
 
-        var fileName = Path.GetFileName(files[0]);
+        var path = files[0];
+        var fileName = Path.GetFileName(path);
 
-        GD.Print(fileName);
+        AudioFileAnalyzer.Instance.AnalyzeFile(path, out WaveformInfo waveformInfo);
 
-        EmitSignal(SignalName.AudioClipDropped, mousePosition, fileName, 0, 10 * 1000);
+        GD.Print(path);
+
+        EmitSignal(SignalName.AudioClipDropped, mousePosition, path, fileName, 0, waveformInfo.Length.TotalMilliseconds);
     }
 }

Source/Waveform.cs

@@ -0,0 +1,101 @@
+using Godot;
+using System;
+
+namespace AudioEditor;
+
+public partial class Waveform : Control
+{
+    private WaveformInfo _waveform;
+
+    public void SetWaveformInfo(WaveformInfo waveform)
+    {
+        _waveform = waveform;
+        QueueRedraw();
+    }
+
+    public override void _Draw()
+    {
+        if (_waveform == null) return;
+        base._Draw();
+
+        int width = (int)Size.X;
+        int height = (int)Size.Y;
+
+        // Downsample the waveform to get a reasonable number of peaks to draw
+        float[] averagePeaks = DownsampleToAveragePeaks(_waveform.Samples, width, _waveform.SampleRate);
+
+        // Begin drawing the waveform
+        for (int i = 0; i < width; i++)
+        {
+            float averagePeak = averagePeaks[i];
+
+            // Normalize the average peak to fit within the height of the control
+            int y = (int)(averagePeak * height / 2);
+
+            // Drawing the line in the positive and negative direction from the center
+            DrawLine(new Vector2(i, height / 2 - y), new Vector2(i, height / 2 + y), new Color(1, 1, 1, 0.7f));  // White with transparency
+        }
+    }
+
+    private float[] DownsampleToAveragePeaks(float[] samples, int targetWidth, int sampleRate)
+    {
+        int totalSamples = samples.Length;
+        float durationInSeconds = totalSamples / (float)sampleRate;  // Calculate the total duration in seconds
+        int stepSize = totalSamples / targetWidth;  // Larger chunks for downsampling
+
+        // If stepSize is 0 (due to rounding), default to 1 to prevent division by zero
+        if (stepSize == 0) stepSize = 1;
+
+        float[] averagePeaks = new float[targetWidth];
+
+        for (int i = 0; i < targetWidth; i++)
+        {
+            int startIndex = i * stepSize;
+            int endIndex = Math.Min(startIndex + stepSize, totalSamples);
+
+            // Calculate the average or peak for this window (you can use GetPeak if needed)
+            averagePeaks[i] = GetAverage(samples, startIndex, endIndex);
+        }
+
+        return averagePeaks;
+    }
+
+    // Get the average value of samples in the current window
+    private float GetAverage(float[] samples, int startIndex, int endIndex)
+    {
+        float sum = 0f;
+        int count = 0;
+        for (int i = startIndex; i < endIndex; i++)
+        {
+            sum += Math.Abs(samples[i]);  // Use absolute values for consistency
+            count++;
+        }
+        return count > 0 ? sum / count : 0f;
+    }
+
+    // Optional: You could use this method if you prefer showing the peak values
+    private float GetPeak(float[] samples, int startIndex, int endIndex)
+    {
+        float maxPeak = 0f;
+        for (int i = startIndex; i < endIndex; i++)
+        {
+            maxPeak = Math.Max(maxPeak, Math.Abs(samples[i]));
+        }
+        return maxPeak;
+    }
+
+    // This can be an alternative to GetAverage if you want to show average peak
+    private float GetAveragePeak(float[] samples, int startIndex, int endIndex)
+    {
+        float sum = 0f;
+        int count = 0;
+
+        for (int i = startIndex; i < endIndex; i++)
+        {
+            sum += Math.Abs(samples[i]);  // Use absolute value for a more stable peak
+            count++;
+        }
+
+        return count > 0 ? sum / count : 0f;  // Return the average
+    }
+}