Revert "Revert the Metal Experiment (#701)"

This reverts commit fe1617ffea.

src/Ryujinx.Graphics.Metal/DepthStencilCache.cs

@@ -0,0 +1,68 @@
+using Ryujinx.Graphics.Metal.State;
+using SharpMetal.Metal;
+using System.Runtime.Versioning;
+
+namespace Ryujinx.Graphics.Metal
+{
+    [SupportedOSPlatform("macos")]
+    class DepthStencilCache : StateCache<MTLDepthStencilState, DepthStencilUid, DepthStencilUid>
+    {
+        private readonly MTLDevice _device;
+
+        public DepthStencilCache(MTLDevice device)
+        {
+            _device = device;
+        }
+
+        protected override DepthStencilUid GetHash(DepthStencilUid descriptor)
+        {
+            return descriptor;
+        }
+
+        protected override MTLDepthStencilState CreateValue(DepthStencilUid descriptor)
+        {
+            // Create descriptors
+
+            ref StencilUid frontUid = ref descriptor.FrontFace;
+
+            using MTLStencilDescriptor frontFaceStencil = new()
+            {
+                StencilFailureOperation = frontUid.StencilFailureOperation,
+                DepthFailureOperation = frontUid.DepthFailureOperation,
+                DepthStencilPassOperation = frontUid.DepthStencilPassOperation,
+                StencilCompareFunction = frontUid.StencilCompareFunction,
+                ReadMask = frontUid.ReadMask,
+                WriteMask = frontUid.WriteMask
+            };
+
+            ref StencilUid backUid = ref descriptor.BackFace;
+
+            using MTLStencilDescriptor backFaceStencil = new()
+            {
+                StencilFailureOperation = backUid.StencilFailureOperation,
+                DepthFailureOperation = backUid.DepthFailureOperation,
+                DepthStencilPassOperation = backUid.DepthStencilPassOperation,
+                StencilCompareFunction = backUid.StencilCompareFunction,
+                ReadMask = backUid.ReadMask,
+                WriteMask = backUid.WriteMask
+            };
+
+            MTLDepthStencilDescriptor mtlDescriptor = new()
+            {
+                DepthCompareFunction = descriptor.DepthCompareFunction,
+                DepthWriteEnabled = descriptor.DepthWriteEnabled
+            };
+
+            if (descriptor.StencilTestEnabled)
+            {
+                mtlDescriptor.BackFaceStencil = backFaceStencil;
+                mtlDescriptor.FrontFaceStencil = frontFaceStencil;
+            }
+
+            using (mtlDescriptor)
+            {
+                return _device.NewDepthStencilState(mtlDescriptor);
+            }
+        }
+    }
+}