new MoonWorks.Graphics.Fence API

lib/RefreshCS

@@ -1 +1 @@
-Subproject commit 60a7523fac254d5e2d89185392e8c1afd8581aa9
+Subproject commit b5325e6d0329eeb35b074091a569a5f679852d28

lib/dav1dfile

@@ -1 +1 @@
-Subproject commit 859f47f6fa0dfa0f7f941dcced6664fa83736202
+Subproject commit 3dcd69ff85db80eea51481edd323b42c05993e1a

src/Graphics/FencePool.cs

@@ -0,0 +1,30 @@
+using System.Collections.Generic;
+
+namespace MoonWorks.Graphics
+{
+	internal class FencePool
+	{
+		private GraphicsDevice GraphicsDevice;
+		private Queue<Fence> Fences = new Queue<Fence>();
+
+		public FencePool(GraphicsDevice graphicsDevice)
+		{
+			GraphicsDevice = graphicsDevice;
+		}
+
+		public Fence Obtain()
+		{
+			if (Fences.Count == 0)
+			{
+				return new Fence(GraphicsDevice);
+			}
+
+			return Fences.Dequeue();
+		}
+
+		public void Return(Fence fence)
+		{
+			Fences.Enqueue(fence);
+		}
+	}
+}

src/Graphics/GraphicsDevice.cs

@@ -19,6 +19,7 @@ namespace MoonWorks.Graphics
 		public bool IsDisposed { get; private set; }
 
 		private readonly HashSet<WeakReference<GraphicsResource>> resources = new HashSet<WeakReference<GraphicsResource>>();
+		private FencePool FencePool;
 
 		public GraphicsDevice(
 			Backend preferredBackend,
@@ -72,6 +73,8 @@ namespace MoonWorks.Graphics
 					}
 				);
 			}
+
+			FencePool = new FencePool(this);
 		}
 
 		public bool ClaimWindow(Window window, PresentMode presentMode)
@@ -120,94 +123,174 @@ namespace MoonWorks.Graphics
 			return new CommandBuffer(this, Refresh.Refresh_AcquireCommandBuffer(Handle));
 		}
 
-		public unsafe void Submit(CommandBuffer commandBuffer)
+		/// <summary>
+		/// Submits a command buffer to the GPU for processing.
+		/// </summary>
+		public void Submit(CommandBuffer commandBuffer)
 		{
-			var commandBufferPtrs = stackalloc IntPtr[1];
-
-			commandBufferPtrs[0] = commandBuffer.Handle;
-
 			Refresh.Refresh_Submit(
 				Handle,
-				1,
-				(IntPtr) commandBufferPtrs
+				commandBuffer.Handle
 			);
 		}
 
-		public unsafe void Submit(
-			CommandBuffer commandBufferOne,
-			CommandBuffer commandBufferTwo
-		) {
-			var commandBufferPtrs = stackalloc IntPtr[2];
-
-			commandBufferPtrs[0] = commandBufferOne.Handle;
-			commandBufferPtrs[1] = commandBufferTwo.Handle;
-
-			Refresh.Refresh_Submit(
-				Handle,
-				2,
-				(IntPtr) commandBufferPtrs
-			);
-		}
-
-		public unsafe void Submit(
-			CommandBuffer commandBufferOne,
-			CommandBuffer commandBufferTwo,
-			CommandBuffer commandBufferThree
-		) {
-			var commandBufferPtrs = stackalloc IntPtr[3];
-
-			commandBufferPtrs[0] = commandBufferOne.Handle;
-			commandBufferPtrs[1] = commandBufferTwo.Handle;
-			commandBufferPtrs[2] = commandBufferThree.Handle;
-
-			Refresh.Refresh_Submit(
-				Handle,
-				3,
-				(IntPtr) commandBufferPtrs
-			);
-		}
-
-		public unsafe void Submit(
-			CommandBuffer commandBufferOne,
-			CommandBuffer commandBufferTwo,
-			CommandBuffer commandBufferThree,
-			CommandBuffer commandBufferFour
-		) {
-			var commandBufferPtrs = stackalloc IntPtr[4];
-
-			commandBufferPtrs[0] = commandBufferOne.Handle;
-			commandBufferPtrs[1] = commandBufferTwo.Handle;
-			commandBufferPtrs[2] = commandBufferThree.Handle;
-			commandBufferPtrs[3] = commandBufferFour.Handle;
-
-			Refresh.Refresh_Submit(
-				Handle,
-				4,
-				(IntPtr) commandBufferPtrs
-			);
-		}
-
-		public unsafe void Submit(params CommandBuffer[] commandBuffers)
+		/// <summary>
+		/// Submits a command buffer to the GPU for processing and acquires a fence associated with the submission.
+		/// </summary>
+		/// <returns></returns>
+		public Fence SubmitAndAcquireFence(CommandBuffer commandBuffer)
 		{
-			var commandBufferPtrs = stackalloc IntPtr[commandBuffers.Length];
-
-			for (var i = 0; i < commandBuffers.Length; i += 1)
-			{
-				commandBufferPtrs[i] = commandBuffers[i].Handle;
-			}
-
-			Refresh.Refresh_Submit(
+			var fenceHandle = Refresh.Refresh_SubmitAndAcquireFence(
 				Handle,
-				(uint) commandBuffers.Length,
-				(IntPtr) commandBufferPtrs
+				commandBuffer.Handle
 			);
+
+			var fence = FencePool.Obtain();
+			fence.SetHandle(fenceHandle);
+
+			return fence;
 		}
 
+		/// <summary>
+		/// Wait for the graphics device to become idle.
+		/// </summary>
 		public void Wait()
 		{
 			Refresh.Refresh_Wait(Handle);
 		}
 
+		/// <summary>
+		/// Waits for the given fence to become signaled.
+		/// </summary>
+		public unsafe void WaitForFences(Fence fence)
+		{
+			var handlePtr = stackalloc nint[1];
+			handlePtr[0] = fence.Handle;
+
+			Refresh.Refresh_WaitForFences(
+				Handle,
+				1,
+				1,
+				(nint) handlePtr
+			);
+		}
+
+		/// <summary>
+		/// Wait for one or more fences to become signaled.
+		/// </summary>
+		/// <param name="waitAll">If true, will wait for all given fences to be signaled.</param>
+		public unsafe void WaitForFences(
+			Fence fenceOne,
+			Fence fenceTwo,
+			bool waitAll
+		) {
+			var handlePtr = stackalloc nint[2];
+			handlePtr[0] = fenceOne.Handle;
+			handlePtr[1] = fenceTwo.Handle;
+
+			Refresh.Refresh_WaitForFences(
+				Handle,
+				Conversions.BoolToByte(waitAll),
+				2,
+				(nint) handlePtr
+			);
+		}
+
+		/// <summary>
+		/// Wait for one or more fences to become signaled.
+		/// </summary>
+		/// <param name="waitAll">If true, will wait for all given fences to be signaled.</param>
+		public unsafe void WaitForFences(
+			Fence fenceOne,
+			Fence fenceTwo,
+			Fence fenceThree,
+			bool waitAll
+		) {
+			var handlePtr = stackalloc nint[3];
+			handlePtr[0] = fenceOne.Handle;
+			handlePtr[1] = fenceTwo.Handle;
+			handlePtr[2] = fenceThree.Handle;
+
+			Refresh.Refresh_WaitForFences(
+				Handle,
+				Conversions.BoolToByte(waitAll),
+				3,
+				(nint) handlePtr
+			);
+		}
+
+		/// <summary>
+		/// Wait for one or more fences to become signaled.
+		/// </summary>
+		/// <param name="waitAll">If true, will wait for all given fences to be signaled.</param>
+		public unsafe void WaitForFences(
+			Fence fenceOne,
+			Fence fenceTwo,
+			Fence fenceThree,
+			Fence fenceFour,
+			bool waitAll
+		) {
+			var handlePtr = stackalloc nint[4];
+			handlePtr[0] = fenceOne.Handle;
+			handlePtr[1] = fenceTwo.Handle;
+			handlePtr[2] = fenceThree.Handle;
+			handlePtr[3] = fenceFour.Handle;
+
+			Refresh.Refresh_WaitForFences(
+				Handle,
+				Conversions.BoolToByte(waitAll),
+				4,
+				(nint) handlePtr
+			);
+		}
+
+		/// <summary>
+		/// Wait for one or more fences to become signaled.
+		/// </summary>
+		/// <param name="waitAll">If true, will wait for all given fences to be signaled.</param>
+		public unsafe void WaitForFences(Fence[] fences, bool waitAll)
+		{
+			var handlePtr = stackalloc nint[fences.Length];
+
+			for (var i = 0; i < fences.Length; i += 1)
+			{
+				handlePtr[i] = fences[i].Handle;
+			}
+
+			Refresh.Refresh_WaitForFences(
+				Handle,
+				Conversions.BoolToByte(waitAll),
+				4,
+				(nint) handlePtr
+			);
+		}
+
+		/// <summary>
+		/// Returns true if the fence is signaled, indicating that the associated command buffer has finished processing.
+		/// </summary>
+		/// <exception cref="InvalidOperationException">Throws if the fence query indicates that the graphics device has been lost.</exception>
+		public bool QueryFence(Fence fence)
+		{
+			var result = Refresh.Refresh_QueryFence(Handle, fence.Handle);
+
+			if (result < 0)
+			{
+				throw new InvalidOperationException("The graphics device has been lost.");
+			}
+
+			return result != 0;
+		}
+
+		/// <summary>
+		/// Release reference to an acquired fence, enabling it to be reused.
+		/// </summary>
+		public void ReleaseFence(Fence fence)
+		{
+			Refresh.Refresh_ReleaseFence(Handle, fence.Handle);
+			fence.Handle = IntPtr.Zero;
+			FencePool.Return(fence);
+		}
+
 		private TextureFormat GetSwapchainFormat(Window window)
 		{
 			return (TextureFormat) Refresh.Refresh_GetSwapchainFormat(Handle, window.Handle);

src/Graphics/Resources/Fence.cs

@@ -0,0 +1,36 @@
+using System;
+using RefreshCS;
+
+namespace MoonWorks.Graphics
+{
+	/// <summary>
+	/// Fences allow you to track the status of a submitted command buffer.
+	/// You should only acquire a Fence if you will need to track the command buffer.
+	/// You should make sure to call GraphicsDevice.ReleaseFence when done with a Fence to avoid memory growth.
+	///
+	/// The Fence object itself is basically just a wrapper for the Refresh_Fence.
+	/// The internal handle is replaced so that we can pool Fence objects to manage garbage.
+	/// </summary>
+	public class Fence : GraphicsResource
+	{
+		protected override Action<nint, nint> QueueDestroyFunction => Release;
+
+		internal Fence(GraphicsDevice device) : base(device, true)
+		{
+		}
+
+		internal void SetHandle(nint handle)
+		{
+			Handle = handle;
+		}
+
+		private void Release(nint deviceHandle, nint fenceHandle)
+		{
+			if (fenceHandle != IntPtr.Zero)
+			{
+				// This will only be called if the client forgot to release a handle. Oh no!
+				Refresh.Refresh_ReleaseFence(deviceHandle, fenceHandle);
+			}
+		}
+	}
+}

src/Graphics/Resources/Texture.cs

@@ -592,7 +592,7 @@ namespace MoonWorks.Graphics
 
 		/// <summary>
 		/// Asynchronously saves RGBA or BGRA pixel data to a file in PNG format.
-		/// Warning: this is expensive!
+		/// Warning: this is expensive and will block to wait for data download from GPU!
 		/// </summary>
 		public unsafe void SavePNG(string path)
 		{
@@ -608,14 +608,16 @@ namespace MoonWorks.Graphics
 			// immediately request the data copy
 			var commandBuffer = Device.AcquireCommandBuffer();
 			commandBuffer.CopyTextureToBuffer(this, buffer);
-			Device.Submit(commandBuffer);
+			var fence = Device.SubmitAndAcquireFence(commandBuffer);
 
 			var byteCount = buffer.Size;
 
 			var pixelsPtr = NativeMemory.Alloc((nuint) byteCount);
 			var pixelsSpan = new Span<byte>(pixelsPtr, (int) byteCount);
 
-			Device.Wait(); // make sure the data transfer is done...
+			Device.WaitForFences(fence); // make sure the data transfer is done...
+			Device.ReleaseFence(fence); // and then release the fence
+
 			buffer.GetData(pixelsSpan);
 
 			if (Format == TextureFormat.B8G8R8A8)