Audren: Implement polyphase upsampler (#4256)

* Audren: Implement polyphase upsampler

* prefer shifting to modulo

* prefer MathF

* fix nits

* rm ResampleForUpsampler

* oop

* Array20

* nits

2 files changed, 19 insertions, 0 deletions

diff --git a/Ryujinx.Audio/Renderer/Server/Upsampler/UpsamplerBufferState.cs b/Ryujinx.Audio/Renderer/Server/Upsampler/UpsamplerBufferState.cs
new file mode 100644
index 00000000..a45fa8e5
--- /dev/null
+++ b/Ryujinx.Audio/Renderer/Server/Upsampler/UpsamplerBufferState.cs
@@ -0,0 +1,14 @@
+using Ryujinx.Common.Memory;
+
+namespace Ryujinx.Audio.Renderer.Server.Upsampler
+{
+    public struct UpsamplerBufferState
+    {
+        public const int HistoryLength = 20;
+
+        public float Scale;
+        public Array20<float> History;
+        public bool Initialized;
+        public int Phase;
+    }
+}
\ No newline at end of file
diff --git a/Ryujinx.Audio/Renderer/Server/Upsampler/UpsamplerState.cs b/Ryujinx.Audio/Renderer/Server/Upsampler/UpsamplerState.cs
index 065e4838..e508f35b 100644
--- a/Ryujinx.Audio/Renderer/Server/Upsampler/UpsamplerState.cs
+++ b/Ryujinx.Audio/Renderer/Server/Upsampler/UpsamplerState.cs
@@ -38,6 +38,11 @@ namespace Ryujinx.Audio.Renderer.Server.Upsampler
         public ushort[] InputBufferIndices;
 
         /// <summary>
+        /// State of each input buffer index kept across invocations of the upsampler.
+        /// </summary>
+        public UpsamplerBufferState[] BufferStates;
+
+        /// <summary>
         /// Create a new <see cref="UpsamplerState"/>.
         /// </summary>
         /// <param name="manager">The upsampler manager.</param>