1 files changed, 67 insertions, 0 deletions
diff --git a/src/Ryujinx.Audio/Renderer/Dsp/State/DelayState.cs b/src/Ryujinx.Audio/Renderer/Dsp/State/DelayState.cs
new file mode 100644
index 00000000..2a1e7f83
--- /dev/null
+++ b/src/Ryujinx.Audio/Renderer/Dsp/State/DelayState.cs
@@ -0,0 +1,67 @@
+using Ryujinx.Audio.Renderer.Dsp.Effect;
+using Ryujinx.Audio.Renderer.Parameter.Effect;
+using System.Runtime.CompilerServices;
+
+namespace Ryujinx.Audio.Renderer.Dsp.State
+{
+    public class DelayState
+    {
+        public DelayLine[] DelayLines { get; }
+        public float[] LowPassZ { get; set; }
+        public float FeedbackGain { get; private set; }
+        public float DelayFeedbackBaseGain { get; private set; }
+        public float DelayFeedbackCrossGain { get; private set; }
+        public float LowPassFeedbackGain { get; private set; }
+        public float LowPassBaseGain { get; private set; }
+
+        private const int FixedPointPrecision = 14;
+
+        public DelayState(ref DelayParameter parameter, ulong workBuffer)
+        {
+            DelayLines = new DelayLine[parameter.ChannelCount];
+            LowPassZ = new float[parameter.ChannelCount];
+
+            uint sampleRate = (uint)FixedPointHelper.ToInt(parameter.SampleRate, FixedPointPrecision) / 1000;
+
+            for (int i = 0; i < DelayLines.Length; i++)
+            {
+                DelayLines[i] = new DelayLine(sampleRate, parameter.DelayTimeMax);
+                DelayLines[i].SetDelay(parameter.DelayTime);
+            }
+
+            UpdateParameter(ref parameter);
+        }
+
+        public void UpdateParameter(ref DelayParameter parameter)
+        {
+            FeedbackGain = FixedPointHelper.ToFloat(parameter.FeedbackGain, FixedPointPrecision) * 0.98f;
+
+            float channelSpread = FixedPointHelper.ToFloat(parameter.ChannelSpread, FixedPointPrecision);
+
+            DelayFeedbackBaseGain = (1.0f - channelSpread) * FeedbackGain;
+
+            if (parameter.ChannelCount == 4 || parameter.ChannelCount == 6)
+            {
+                DelayFeedbackCrossGain = channelSpread * 0.5f * FeedbackGain;
+            }
+            else
+            {
+                DelayFeedbackCrossGain = channelSpread * FeedbackGain;
+            }
+
+            LowPassFeedbackGain = 0.95f * FixedPointHelper.ToFloat(parameter.LowPassAmount, FixedPointPrecision);
+            LowPassBaseGain = 1.0f - LowPassFeedbackGain;
+        }
+
+        public void UpdateLowPassFilter(ref float tempRawRef, uint channelCount)
+        {
+            for (int i = 0; i < channelCount; i++)
+            {
+                float lowPassResult = LowPassFeedbackGain * LowPassZ[i] + Unsafe.Add(ref tempRawRef, i) * LowPassBaseGain;
+
+                LowPassZ[i] = lowPassResult;
+                DelayLines[i].Update(lowPassResult);
+            }
+        }
+    }
+}
+\ No newline at end of file