amadeus: Add missing compressor effect from REV11 (#4010)

* amadeus: Add missing compressor effect from REV11

This was in my reversing notes but seems I completely forgot to
implement it

Also took the opportunity to simplify the Limiter effect a bit.

* Remove some outdated comment

* Address gdkchan's comments

2 files changed, 58 insertions, 6 deletions

diff --git a/Ryujinx.Audio/Renderer/Dsp/State/CompressorState.cs b/Ryujinx.Audio/Renderer/Dsp/State/CompressorState.cs
new file mode 100644
index 00000000..76aff807
--- /dev/null
+++ b/Ryujinx.Audio/Renderer/Dsp/State/CompressorState.cs
@@ -0,0 +1,51 @@
+using Ryujinx.Audio.Renderer.Dsp.Effect;
+using Ryujinx.Audio.Renderer.Parameter.Effect;
+
+namespace Ryujinx.Audio.Renderer.Dsp.State
+{
+    public class CompressorState
+    {
+        public ExponentialMovingAverage InputMovingAverage;
+        public float Unknown4;
+        public ExponentialMovingAverage CompressionGainAverage;
+        public float CompressorGainReduction;
+        public float Unknown10;
+        public float Unknown14;
+        public float PreviousCompressionEmaAlpha;
+        public float MakeupGain;
+        public float OutputGain;
+
+        public CompressorState(ref CompressorParameter parameter)
+        {
+            InputMovingAverage = new ExponentialMovingAverage(0.0f);
+            Unknown4 = 1.0f;
+            CompressionGainAverage = new ExponentialMovingAverage(1.0f);
+
+            UpdateParameter(ref parameter);
+        }
+
+        public void UpdateParameter(ref CompressorParameter parameter)
+        {
+            float threshold = parameter.Threshold;
+            float ratio = 1.0f / parameter.Ratio;
+            float attackCoefficient = parameter.AttackCoefficient;
+            float makeupGain;
+
+            if (parameter.MakeupGainEnabled)
+            {
+                makeupGain = (threshold * 0.5f * (ratio - 1.0f)) - 3.0f;
+            }
+            else
+            {
+                makeupGain = 0.0f;
+            }
+
+            PreviousCompressionEmaAlpha = attackCoefficient;
+            MakeupGain = makeupGain;
+            CompressorGainReduction = (1.0f - ratio) / Constants.ChannelCountMax;
+            Unknown10 = threshold - 1.5f;
+            Unknown14 = threshold + 1.5f;
+            OutputGain = FloatingPointHelper.DecibelToLinearExtended(parameter.OutputGain + makeupGain);
+        }
+    }
+}
diff --git a/Ryujinx.Audio/Renderer/Dsp/State/LimiterState.cs b/Ryujinx.Audio/Renderer/Dsp/State/LimiterState.cs
index 92ed13ff..0560757c 100644
--- a/Ryujinx.Audio/Renderer/Dsp/State/LimiterState.cs
+++ b/Ryujinx.Audio/Renderer/Dsp/State/LimiterState.cs
@@ -1,3 +1,4 @@
+using Ryujinx.Audio.Renderer.Dsp.Effect;
 using Ryujinx.Audio.Renderer.Parameter.Effect;
 using System;
 
@@ -5,20 +6,20 @@ namespace Ryujinx.Audio.Renderer.Dsp.State
 {
     public class LimiterState
     {
-        public float[] DectectorAverage;
-        public float[] CompressionGain;
+        public ExponentialMovingAverage[] DetectorAverage;
+        public ExponentialMovingAverage[] CompressionGainAverage;
         public float[] DelayedSampleBuffer;
         public int[] DelayedSampleBufferPosition;
 
         public LimiterState(ref LimiterParameter parameter, ulong workBuffer)
         {
-            DectectorAverage = new float[parameter.ChannelCount];
-            CompressionGain = new float[parameter.ChannelCount];
+            DetectorAverage = new ExponentialMovingAverage[parameter.ChannelCount];
+            CompressionGainAverage = new ExponentialMovingAverage[parameter.ChannelCount];
             DelayedSampleBuffer = new float[parameter.ChannelCount * parameter.DelayBufferSampleCountMax];
             DelayedSampleBufferPosition = new int[parameter.ChannelCount];
 
-            DectectorAverage.AsSpan().Fill(0.0f);
-            CompressionGain.AsSpan().Fill(1.0f);
+            DetectorAverage.AsSpan().Fill(new ExponentialMovingAverage(0.0f));
+            CompressionGainAverage.AsSpan().Fill(new ExponentialMovingAverage(1.0f));
             DelayedSampleBufferPosition.AsSpan().Fill(0);
             DelayedSampleBuffer.AsSpan().Fill(0.0f);