Improve the filters by storing them persistently instead of constantl…

…y creating new ones
Xlinka · Nov 25, 2024 · eeedcd6 · eeedcd6
1 parent 9052f1c
commit eeedcd6
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Showing 2 changed files with 46 additions and 13 deletions.
diff --git a/ProjectObsidian/Components/Audio/BandPassFilter.cs b/ProjectObsidian/Components/Audio/BandPassFilter.cs
@@ -22,6 +22,9 @@ public class BandPassFilter : Component, IAudioSource, IWorldElement
 
         private double lastTime;
 
+        private object lowFilter = null;
+        private object highFilter = null;
+
         public bool IsActive
         {
             get => Source.Target != null && Source.Target.IsActive;
@@ -40,13 +43,22 @@ public void Read<S>(Span<S> buffer) where S : unmanaged, IAudioSample<S>
             tempBuffer = buffer;
             Source.Target.Read(tempBuffer);
 
-            var LowPass = new ButterworthFilter.FilterButterworth<S>(HighFrequency, (int)(tempBuffer.Length / (Engine.Current.AudioSystem.DSPTime - lastTime)), ButterworthFilter.FilterButterworth<S>.PassType.Lowpass, Resonance);
-            var HighPass = new ButterworthFilter.FilterButterworth<S>(LowFrequency, (int)(tempBuffer.Length / (Engine.Current.AudioSystem.DSPTime - lastTime)), ButterworthFilter.FilterButterworth<S>.PassType.Highpass, Resonance);
+            if (lowFilter == null)
+            {
+                lowFilter = new ButterworthFilter.FilterButterworth<S>();
+            }
+            if (highFilter == null)
+            {
+                highFilter = new ButterworthFilter.FilterButterworth<S>();
+            }
+
+            ((ButterworthFilter.FilterButterworth<S>)lowFilter).UpdateCoefficients(HighFrequency, (int)(tempBuffer.Length / (Engine.Current.AudioSystem.DSPTime - lastTime)), ButterworthFilter.FilterButterworth<S>.PassType.Lowpass, Resonance);
+            ((ButterworthFilter.FilterButterworth<S>)highFilter).UpdateCoefficients(LowFrequency, (int)(tempBuffer.Length / (Engine.Current.AudioSystem.DSPTime - lastTime)), ButterworthFilter.FilterButterworth<S>.PassType.Highpass, Resonance);
 
             for (int i = 0; i < tempBuffer.Length; i++)
             {
-                LowPass.Update(ref tempBuffer[i]);
-                HighPass.Update(ref tempBuffer[i]);
+                ((ButterworthFilter.FilterButterworth<S>)lowFilter).Update(ref tempBuffer[i]);
+                ((ButterworthFilter.FilterButterworth<S>)highFilter).Update(ref tempBuffer[i]);
             }
 
             lastTime = Engine.Current.AudioSystem.DSPTime;
@@ -60,5 +72,15 @@ protected override void OnAwake()
             HighFrequency.Value = 20000f;
             lastTime = Engine.Current.AudioSystem.DSPTime;
         }
+
+        protected override void OnChanges()
+        {
+            base.OnChanges();
+            if (Source.GetWasChangedAndClear())
+            {
+                lowFilter = null;
+                highFilter = null;
+            }
+        }
     }
 }
diff --git a/ProjectObsidian/Components/Audio/ButterworthFilter.cs b/ProjectObsidian/Components/Audio/ButterworthFilter.cs
@@ -19,6 +19,8 @@ public class ButterworthFilter : Component, IAudioSource, IWorldElement
 
     private double lastTime;
 
+    private object filter = null;
+
     public bool IsActive
     {
         get
@@ -35,6 +37,15 @@ protected override void OnAwake()
         Resonance.Value = 1.41f;
     }
 
+    protected override void OnChanges()
+    {
+        base.OnChanges();
+        if (Source.GetWasChangedAndClear())
+        {
+            filter = null;
+        }
+    }
+
     public int ChannelCount => Source.Target?.ChannelCount ?? 0;
 
     public void Read<S>(Span<S> buffer) where S : unmanaged, IAudioSample<S>
@@ -50,11 +61,16 @@ public void Read<S>(Span<S> buffer) where S : unmanaged, IAudioSample<S>
 
         Source.Target.Read(span);
 
-        var filter = new FilterButterworth<S>(Frequency, (int)(span.Length / (Engine.Current.AudioSystem.DSPTime - lastTime)), LowPass ? FilterButterworth<S>.PassType.Lowpass : FilterButterworth<S>.PassType.Highpass, Resonance);
+        if (filter == null)
+        {
+            filter = new FilterButterworth<S>();
+        }
+
+        ((FilterButterworth<S>)filter).UpdateCoefficients(Frequency, (int)(span.Length / (Engine.Current.AudioSystem.DSPTime - lastTime)), LowPass ? FilterButterworth<S>.PassType.Lowpass : FilterButterworth<S>.PassType.Highpass, Resonance);
 
         for (int i = 0; i < span.Length; i++)
         {
-            filter.Update(ref span[i]);
+            ((FilterButterworth<S>)filter).Update(ref span[i]);
         }
 
         lastTime = Engine.Current.AudioSystem.DSPTime;
@@ -71,7 +87,7 @@ public class FilterButterworth<S> where S: unmanaged, IAudioSample<S>
         private readonly int sampleRate;
         private readonly PassType passType;
 
-        private readonly float c, a1, a2, a3, b1, b2;
+        private float c, a1, a2, a3, b1, b2;
 
         /// <summary>
         /// Array of input values, latest are in front
@@ -83,13 +99,8 @@ public class FilterButterworth<S> where S: unmanaged, IAudioSample<S>
         /// </summary>
         private S[] outputHistory = new S[3];
 
-        public FilterButterworth(float frequency, int sampleRate, PassType passType, float resonance)
+        public void UpdateCoefficients(float frequency, int sampleRate, PassType passType, float resonance)
         {
-            this.resonance = resonance;
-            this.frequency = frequency;
-            this.sampleRate = sampleRate;
-            this.passType = passType;
-
             switch (passType)
             {
                 case PassType.Lowpass: