Update audio renderer to REV12: Add support for splitter biquad filter (#6813)

* Update audio renderer to REV12: Add support for splitter biquad filter

* Formatting

* Official names

* Update BiquadFilterState size + other fixes

* Update tests

* Update comment for version 2

* Size test for SplitterDestinationVersion2

* Should use Volume1 if no ramp

src/Ryujinx.Audio/Renderer/Server/Splitter/SplitterDestinationVersion1.cs

@@ -0,0 +1,206 @@
+using Ryujinx.Audio.Renderer.Parameter;
+using Ryujinx.Common.Utilities;
+using System;
+using System.Diagnostics;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.Audio.Renderer.Server.Splitter
+{
+    /// <summary>
+    /// Server state for a splitter destination (version 1).
+    /// </summary>
+    [StructLayout(LayoutKind.Sequential, Size = 0xE0, Pack = Alignment)]
+    public struct SplitterDestinationVersion1
+    {
+        public const int Alignment = 0x10;
+
+        /// <summary>
+        /// The unique id of this <see cref="SplitterDestinationVersion1"/>.
+        /// </summary>
+        public int Id;
+
+        /// <summary>
+        /// The mix to output the result of the splitter.
+        /// </summary>
+        public int DestinationId;
+
+        /// <summary>
+        /// Mix buffer volumes storage.
+        /// </summary>
+        private MixArray _mix;
+        private MixArray _previousMix;
+
+        /// <summary>
+        /// Pointer to the next linked element.
+        /// </summary>
+        private unsafe SplitterDestinationVersion1* _next;
+
+        /// <summary>
+        /// Set to true if in use.
+        /// </summary>
+        [MarshalAs(UnmanagedType.I1)]
+        public bool IsUsed;
+
+        /// <summary>
+        /// Set to true if the internal state need to be updated.
+        /// </summary>
+        [MarshalAs(UnmanagedType.I1)]
+        public bool NeedToUpdateInternalState;
+
+        [StructLayout(LayoutKind.Sequential, Size = sizeof(float) * Constants.MixBufferCountMax, Pack = 1)]
+        private struct MixArray { }
+
+        /// <summary>
+        /// Mix buffer volumes.
+        /// </summary>
+        /// <remarks>Used when a splitter id is specified in the mix.</remarks>
+        public Span<float> MixBufferVolume => SpanHelpers.AsSpan<MixArray, float>(ref _mix);
+
+        /// <summary>
+        /// Previous mix buffer volumes.
+        /// </summary>
+        /// <remarks>Used when a splitter id is specified in the mix.</remarks>
+        public Span<float> PreviousMixBufferVolume => SpanHelpers.AsSpan<MixArray, float>(ref _previousMix);
+
+        /// <summary>
+        /// Get the reference of the next element or null if not present.
+        /// </summary>
+        public readonly ref SplitterDestinationVersion1 Next
+        {
+            get
+            {
+                unsafe
+                {
+                    return ref Unsafe.AsRef<SplitterDestinationVersion1>(_next);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Create a new <see cref="SplitterDestinationVersion1"/>.
+        /// </summary>
+        /// <param name="id">The unique id of this <see cref="SplitterDestinationVersion1"/>.</param>
+        public SplitterDestinationVersion1(int id) : this()
+        {
+            Id = id;
+            DestinationId = Constants.UnusedMixId;
+
+            ClearVolumes();
+        }
+
+        /// <summary>
+        /// Update the <see cref="SplitterDestinationVersion1"/> from user parameter.
+        /// </summary>
+        /// <param name="parameter">The user parameter.</param>
+        public void Update<T>(in T parameter) where T : ISplitterDestinationInParameter
+        {
+            Debug.Assert(Id == parameter.Id);
+
+            if (parameter.IsMagicValid() && Id == parameter.Id)
+            {
+                DestinationId = parameter.DestinationId;
+
+                parameter.MixBufferVolume.CopyTo(MixBufferVolume);
+
+                if (!IsUsed && parameter.IsUsed)
+                {
+                    MixBufferVolume.CopyTo(PreviousMixBufferVolume);
+
+                    NeedToUpdateInternalState = false;
+                }
+
+                IsUsed = parameter.IsUsed;
+            }
+        }
+
+        /// <summary>
+        /// Update the internal state of the instance.
+        /// </summary>
+        public void UpdateInternalState()
+        {
+            if (IsUsed && NeedToUpdateInternalState)
+            {
+                MixBufferVolume.CopyTo(PreviousMixBufferVolume);
+            }
+
+            NeedToUpdateInternalState = false;
+        }
+
+        /// <summary>
+        /// Set the update internal state marker.
+        /// </summary>
+        public void MarkAsNeedToUpdateInternalState()
+        {
+            NeedToUpdateInternalState = true;
+        }
+
+        /// <summary>
+        /// Return true if the <see cref="SplitterDestinationVersion1"/> is used and has a destination.
+        /// </summary>
+        /// <returns>True if the <see cref="SplitterDestinationVersion1"/> is used and has a destination.</returns>
+        public readonly bool IsConfigured()
+        {
+            return IsUsed && DestinationId != Constants.UnusedMixId;
+        }
+
+        /// <summary>
+        /// Get the volume for a given destination.
+        /// </summary>
+        /// <param name="destinationIndex">The destination index to use.</param>
+        /// <returns>The volume for the given destination.</returns>
+        public float GetMixVolume(int destinationIndex)
+        {
+            Debug.Assert(destinationIndex >= 0 && destinationIndex < Constants.MixBufferCountMax);
+
+            return MixBufferVolume[destinationIndex];
+        }
+
+        /// <summary>
+        /// Get the previous volume for a given destination.
+        /// </summary>
+        /// <param name="destinationIndex">The destination index to use.</param>
+        /// <returns>The volume for the given destination.</returns>
+        public float GetMixVolumePrev(int destinationIndex)
+        {
+            Debug.Assert(destinationIndex >= 0 && destinationIndex < Constants.MixBufferCountMax);
+
+            return PreviousMixBufferVolume[destinationIndex];
+        }
+
+        /// <summary>
+        /// Clear the volumes.
+        /// </summary>
+        public void ClearVolumes()
+        {
+            MixBufferVolume.Clear();
+            PreviousMixBufferVolume.Clear();
+        }
+
+        /// <summary>
+        /// Link the next element to the given <see cref="SplitterDestinationVersion1"/>.
+        /// </summary>
+        /// <param name="next">The given <see cref="SplitterDestinationVersion1"/> to link.</param>
+        public void Link(ref SplitterDestinationVersion1 next)
+        {
+            unsafe
+            {
+                fixed (SplitterDestinationVersion1* nextPtr = &next)
+                {
+                    _next = nextPtr;
+                }
+            }
+        }
+
+        /// <summary>
+        /// Remove the link to the next element.
+        /// </summary>
+        public void Unlink()
+        {
+            unsafe
+            {
+                _next = null;
+            }
+        }
+    }
+}