ASTC optimizations (#845)

* ASTC optimizations

* Move code to Ryujinx.Common

* Support 3D textures

* Address feedback

* Remove ASTC logging

* Use stackalloc instead of a Buffer20 struct

* Code style and cleanup

* Respond to feedback

* Rearrange public/private property ordering

1 files changed, 23 insertions, 0 deletions

diff --git a/Ryujinx.Graphics.Texture/Astc/EndPointSet.cs b/Ryujinx.Graphics.Texture/Astc/EndPointSet.cs
new file mode 100644
index 00000000..45e61ca2
--- /dev/null
+++ b/Ryujinx.Graphics.Texture/Astc/EndPointSet.cs
@@ -0,0 +1,23 @@
+using System;
+using System.Diagnostics;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.Graphics.Texture.Astc
+{
+    [StructLayout(LayoutKind.Sequential, Size = AstcPixel.StructSize * 8)]
+    internal struct EndPointSet
+    {
+        private AstcPixel _start;
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public Span<AstcPixel> Get(int index)
+        {
+            Debug.Assert(index < 4);
+
+            ref AstcPixel start = ref Unsafe.Add(ref _start, index * 2);
+
+            return MemoryMarshal.CreateSpan(ref start, 2);
+        }
+    }
+}