EXPERIMENTAL: Metal backend (#441)

This is not a continuation of the Metal backend; this is simply bringing
the branch up to date and merging it as-is behind an experiment.

---------

Co-authored-by: Isaac Marovitz <isaacryu@icloud.com>
Co-authored-by: Samuliak <samuliak77@gmail.com>
Co-authored-by: SamoZ256 <96914946+SamoZ256@users.noreply.github.com>
Co-authored-by: Isaac Marovitz <42140194+IsaacMarovitz@users.noreply.github.com>
Co-authored-by: riperiperi <rhy3756547@hotmail.com>
Co-authored-by: Gabriel A <gab.dark.100@gmail.com>

src/Ryujinx.Graphics.Metal/TextureBuffer.cs

@@ -0,0 +1,132 @@
+using Ryujinx.Common.Memory;
+using Ryujinx.Graphics.GAL;
+using SharpMetal.Metal;
+using System;
+using System.Runtime.Versioning;
+
+namespace Ryujinx.Graphics.Metal
+{
+    [SupportedOSPlatform("macos")]
+    class TextureBuffer : TextureBase, ITexture
+    {
+        private MTLTextureDescriptor _descriptor;
+        private BufferHandle _bufferHandle;
+        private int _offset;
+        private int _size;
+
+        private int _bufferCount;
+        private Auto<DisposableBuffer> _buffer;
+
+        public TextureBuffer(MTLDevice device, MetalRenderer renderer, Pipeline pipeline, TextureCreateInfo info) : base(device, renderer, pipeline, info)
+        {
+            MTLPixelFormat pixelFormat = FormatTable.GetFormat(Info.Format);
+
+            _descriptor = new MTLTextureDescriptor
+            {
+                PixelFormat = pixelFormat,
+                Usage = MTLTextureUsage.Unknown,
+                TextureType = MTLTextureType.TextureBuffer,
+                Width = (ulong)Info.Width,
+                Height = (ulong)Info.Height,
+            };
+
+            MtlFormat = pixelFormat;
+        }
+
+        public void RebuildStorage(bool write)
+        {
+            if (MtlTexture != IntPtr.Zero)
+            {
+                MtlTexture.Dispose();
+            }
+
+            if (_buffer == null)
+            {
+                MtlTexture = default;
+            }
+            else
+            {
+                DisposableBuffer buffer = _buffer.Get(Pipeline.Cbs, _offset, _size, write);
+
+                _descriptor.Width = (uint)(_size / Info.BytesPerPixel);
+                MtlTexture = buffer.Value.NewTexture(_descriptor, (ulong)_offset, (ulong)_size);
+            }
+        }
+
+        public void CopyTo(ITexture destination, int firstLayer, int firstLevel)
+        {
+            throw new NotSupportedException();
+        }
+
+        public void CopyTo(ITexture destination, int srcLayer, int dstLayer, int srcLevel, int dstLevel)
+        {
+            throw new NotSupportedException();
+        }
+
+        public void CopyTo(ITexture destination, Extents2D srcRegion, Extents2D dstRegion, bool linearFilter)
+        {
+            throw new NotSupportedException();
+        }
+
+        public ITexture CreateView(TextureCreateInfo info, int firstLayer, int firstLevel)
+        {
+            throw new NotSupportedException();
+        }
+
+        public PinnedSpan<byte> GetData()
+        {
+            return Renderer.GetBufferData(_bufferHandle, _offset, _size);
+        }
+
+        public PinnedSpan<byte> GetData(int layer, int level)
+        {
+            return GetData();
+        }
+
+        public void CopyTo(BufferRange range, int layer, int level, int stride)
+        {
+            throw new NotImplementedException();
+        }
+
+        public void SetData(MemoryOwner<byte> data)
+        {
+            Renderer.SetBufferData(_bufferHandle, _offset, data.Memory.Span);
+            data.Dispose();
+        }
+
+        public void SetData(MemoryOwner<byte> data, int layer, int level)
+        {
+            throw new NotSupportedException();
+        }
+
+        public void SetData(MemoryOwner<byte> data, int layer, int level, Rectangle<int> region)
+        {
+            throw new NotSupportedException();
+        }
+
+        public void SetStorage(BufferRange buffer)
+        {
+            if (_bufferHandle == buffer.Handle &&
+                _offset == buffer.Offset &&
+                _size == buffer.Size &&
+                _bufferCount == Renderer.BufferManager.BufferCount)
+            {
+                return;
+            }
+
+            _bufferHandle = buffer.Handle;
+            _offset = buffer.Offset;
+            _size = buffer.Size;
+            _bufferCount = Renderer.BufferManager.BufferCount;
+
+            _buffer = Renderer.BufferManager.GetBuffer(_bufferHandle, false);
+        }
+
+        public override void Release()
+        {
+            _descriptor.Dispose();
+
+            base.Release();
+        }
+    }
+}