optimize AcquireSwapchainTexture

src/Graphics/CommandBuffer.cs

@@ -1630,13 +1630,13 @@ namespace MoonWorks.Graphics
 				return null;
 			}
 
-			return new Texture(
-				Device,
-				texturePtr,
-				window.SwapchainFormat,
-				width,
-				height
-			);
+			// Override the texture properties to avoid allocating a new texture instance!
+			window.SwapchainTexture.Handle = texturePtr;
+			window.SwapchainTexture.Width = width;
+			window.SwapchainTexture.Height = height;
+			window.SwapchainTexture.Format = window.SwapchainFormat;
+
+			return window.SwapchainTexture;
 		}
 
 		/// <summary>

src/Graphics/GraphicsDevice.cs

@@ -73,6 +73,10 @@ namespace MoonWorks.Graphics
 			{
 				window.Claimed = true;
 				window.SwapchainFormat = GetSwapchainFormat(window);
+				if (window.SwapchainTexture == null)
+				{
+					window.SwapchainTexture = new Texture(this, IntPtr.Zero, window.SwapchainFormat, 0, 0);
+				}
 			}
 
 			return success;

src/Graphics/GraphicsResource.cs

@@ -5,7 +5,7 @@ namespace MoonWorks.Graphics
 	public abstract class GraphicsResource : IDisposable
 	{
 		public GraphicsDevice Device { get; }
-		public IntPtr Handle { get; protected set; }
+		public IntPtr Handle { get; internal set; }
 
 		public bool IsDisposed { get; private set; }
 		protected abstract Action<IntPtr, IntPtr> QueueDestroyFunction { get; }

src/Graphics/Resources/Texture.cs

@@ -9,14 +9,15 @@ namespace MoonWorks.Graphics
 	/// </summary>
 	public class Texture : GraphicsResource
 	{
-		public uint Width { get; }
-		public uint Height { get; }
+		public uint Width { get; internal set; }
+		public uint Height { get; internal set; }
 		public uint Depth { get; }
-		public TextureFormat Format { get; }
+		public TextureFormat Format { get; internal set; }
 		public bool IsCube { get; }
 		public uint LevelCount { get; }
 		public TextureUsageFlags UsageFlags { get; }
 
+		// FIXME: this allocates a delegate instance
 		protected override Action<IntPtr, IntPtr> QueueDestroyFunction => Refresh.Refresh_QueueDestroyTexture;
 
 		/// <summary>

src/Window.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using MoonWorks.Graphics;
 using SDL2;
 
 namespace MoonWorks
@@ -10,6 +11,7 @@ namespace MoonWorks
 		public ScreenMode ScreenMode { get; private set; }
 		public uint Width { get; private set; }
 		public uint Height { get; private set; }
+		internal Texture SwapchainTexture { get; set; } = null;
 
 		public bool Claimed { get; internal set; }
 		public MoonWorks.Graphics.TextureFormat SwapchainFormat { get; internal set; }