1 files changed, 136 insertions, 0 deletions
diff --git a/src/Ryujinx.Graphics.OpenGL/PersistentBuffers.cs b/src/Ryujinx.Graphics.OpenGL/PersistentBuffers.cs
new file mode 100644
index 00000000..654e25b9
--- /dev/null
+++ b/src/Ryujinx.Graphics.OpenGL/PersistentBuffers.cs
@@ -0,0 +1,136 @@
+using OpenTK.Graphics.OpenGL;
+using Ryujinx.Common.Logging;
+using Ryujinx.Graphics.GAL;
+using Ryujinx.Graphics.OpenGL.Image;
+using System;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.Graphics.OpenGL
+{
+    class PersistentBuffers : IDisposable
+    {
+        private PersistentBuffer _main = new PersistentBuffer();
+        private PersistentBuffer _background = new PersistentBuffer();
+
+        public PersistentBuffer Default => BackgroundContextWorker.InBackground ? _background : _main;
+
+        public void Dispose()
+        {
+            _main?.Dispose();
+            _background?.Dispose();
+        }
+    }
+
+    class PersistentBuffer : IDisposable
+    {
+        private IntPtr _bufferMap;
+        private int _copyBufferHandle;
+        private int _copyBufferSize;
+
+        private byte[] _data;
+        private IntPtr _dataMap;
+
+        private void EnsureBuffer(int requiredSize)
+        {
+            if (_copyBufferSize < requiredSize && _copyBufferHandle != 0)
+            {
+                GL.DeleteBuffer(_copyBufferHandle);
+
+                _copyBufferHandle = 0;
+            }
+
+            if (_copyBufferHandle == 0)
+            {
+                _copyBufferHandle = GL.GenBuffer();
+                _copyBufferSize = requiredSize;
+
+                GL.BindBuffer(BufferTarget.CopyWriteBuffer, _copyBufferHandle);
+                GL.BufferStorage(BufferTarget.CopyWriteBuffer, requiredSize, IntPtr.Zero, BufferStorageFlags.MapReadBit | BufferStorageFlags.MapPersistentBit);
+
+                _bufferMap = GL.MapBufferRange(BufferTarget.CopyWriteBuffer, IntPtr.Zero, requiredSize, BufferAccessMask.MapReadBit | BufferAccessMask.MapPersistentBit);
+            }
+        }
+
+        public unsafe IntPtr GetHostArray(int requiredSize)
+        {
+            if (_data == null || _data.Length < requiredSize)
+            {
+                _data = GC.AllocateUninitializedArray<byte>(requiredSize, true);
+
+                _dataMap = (IntPtr)Unsafe.AsPointer(ref MemoryMarshal.GetArrayDataReference(_data));
+            }
+
+            return _dataMap;
+        }
+
+        private void Sync()
+        {
+            GL.MemoryBarrier(MemoryBarrierFlags.ClientMappedBufferBarrierBit);
+
+            IntPtr sync = GL.FenceSync(SyncCondition.SyncGpuCommandsComplete, WaitSyncFlags.None);
+            WaitSyncStatus syncResult = GL.ClientWaitSync(sync, ClientWaitSyncFlags.SyncFlushCommandsBit, 1000000000);
+
+            if (syncResult == WaitSyncStatus.TimeoutExpired)
+            {
+                Logger.Error?.PrintMsg(LogClass.Gpu, $"Failed to sync persistent buffer state within 1000ms. Continuing...");
+            }
+
+            GL.DeleteSync(sync);
+        }
+
+        public unsafe ReadOnlySpan<byte> GetTextureData(TextureView view, int size)
+        {
+            EnsureBuffer(size);
+
+            GL.BindBuffer(BufferTarget.PixelPackBuffer, _copyBufferHandle);
+
+            view.WriteToPbo(0, false);
+
+            GL.BindBuffer(BufferTarget.PixelPackBuffer, 0);
+
+            Sync();
+
+            return new ReadOnlySpan<byte>(_bufferMap.ToPointer(), size);
+        }
+
+        public unsafe ReadOnlySpan<byte> GetTextureData(TextureView view, int size, int layer, int level)
+        {
+            EnsureBuffer(size);
+
+            GL.BindBuffer(BufferTarget.PixelPackBuffer, _copyBufferHandle);
+
+            int offset = view.WriteToPbo2D(0, layer, level);
+
+            GL.BindBuffer(BufferTarget.PixelPackBuffer, 0);
+
+            Sync();
+
+            return new ReadOnlySpan<byte>(_bufferMap.ToPointer(), size).Slice(offset);
+        }
+
+        public unsafe ReadOnlySpan<byte> GetBufferData(BufferHandle buffer, int offset, int size)
+        {
+            EnsureBuffer(size);
+
+            GL.BindBuffer(BufferTarget.CopyReadBuffer, buffer.ToInt32());
+            GL.BindBuffer(BufferTarget.CopyWriteBuffer, _copyBufferHandle);
+
+            GL.CopyBufferSubData(BufferTarget.CopyReadBuffer, BufferTarget.CopyWriteBuffer, (IntPtr)offset, IntPtr.Zero, size);
+
+            GL.BindBuffer(BufferTarget.CopyWriteBuffer, 0);
+
+            Sync();
+
+            return new ReadOnlySpan<byte>(_bufferMap.ToPointer(), size);
+        }
+
+        public void Dispose()
+        {
+            if (_copyBufferHandle != 0)
+            {
+                GL.DeleteBuffer(_copyBufferHandle);
+            }
+        }
+    }
+}