Vulkan: Use staging buffer for temporary constants (#6168)

* Vulkan: Use staging buffer for temporary constants

Helper shaders and post processing effects typically need some parameters to tell them what to do, which we pass via constant buffers that are created and destroyed each time.

This can vary in cost between different Vulkan drivers. It shows up on profiles on mesa and MoltenVK, so it's worth avoiding. Some games only do it once (BlitColor for present), others multiple times. It's also done for post processing filters and FSR upscaling, which creates two buffers.

For mirrors, I added the ability to reserve a range on the staging buffer for use as any type of binding. This PR allows these constant buffers to be instead temporarily allocated on the staging buffer, skipping allocation and buffer management costs entirely.

Two temporary allocations do remain:
- DrawTexture, because it doesn't have access to the command buffer scope
- Index buffer indirect conversion, because one of them is a storage buffer and thus is a little more complicated.

There's a small cost in that the uniform buffer takes up more space due to alignment requirements. At worst that's 256 bytes (on a GTX 1070) but more modern GPUs should have a better time.

Worth testing across different games and post effects to make sure they still work.

* Use temporary buffer for ConvertIndexBufferIndirect

* Simplify alignment passing for now

* Fix shader params length for CopyIncompatibleFormats

* Set data for helpershaders without overlap checks

The data is in the staging buffer, so its usage range is guarded using that.

src/Ryujinx.Graphics.Vulkan/BufferManager.cs

@@ -9,6 +9,36 @@ using VkFormat = Silk.NET.Vulkan.Format;
 
 namespace Ryujinx.Graphics.Vulkan
 {
+    readonly struct ScopedTemporaryBuffer : IDisposable
+    {
+        private readonly BufferManager _bufferManager;
+        private readonly bool _isReserved;
+
+        public readonly BufferRange Range;
+        public readonly BufferHolder Holder;
+
+        public BufferHandle Handle => Range.Handle;
+        public int Offset => Range.Offset;
+
+        public ScopedTemporaryBuffer(BufferManager bufferManager, BufferHolder holder, BufferHandle handle, int offset, int size, bool isReserved)
+        {
+            _bufferManager = bufferManager;
+
+            Range = new BufferRange(handle, offset, size);
+            Holder = holder;
+
+            _isReserved = isReserved;
+        }
+
+        public void Dispose()
+        {
+            if (!_isReserved)
+            {
+                _bufferManager.Delete(Range.Handle);
+            }
+        }
+    }
+
     class BufferManager : IDisposable
     {
         public const MemoryPropertyFlags DefaultBufferMemoryFlags =
@@ -238,6 +268,23 @@ namespace Ryujinx.Graphics.Vulkan
             return Unsafe.As<ulong, BufferHandle>(ref handle64);
         }
 
+        public ScopedTemporaryBuffer ReserveOrCreate(VulkanRenderer gd, CommandBufferScoped cbs, int size)
+        {
+            StagingBufferReserved? result = StagingBuffer.TryReserveData(cbs, size);
+
+            if (result.HasValue)
+            {
+                return new ScopedTemporaryBuffer(this, result.Value.Buffer, StagingBuffer.Handle, result.Value.Offset, result.Value.Size, true);
+            }
+            else
+            {
+                // Create a temporary buffer.
+                BufferHandle handle = CreateWithHandle(gd, size, out BufferHolder holder);
+
+                return new ScopedTemporaryBuffer(this, holder, handle, 0, size, false);
+            }
+        }
+
         public unsafe MemoryRequirements GetHostImportedUsageRequirements(VulkanRenderer gd)
         {
             var usage = HostImportedBufferUsageFlags;
@@ -635,13 +682,14 @@ namespace Ryujinx.Graphics.Vulkan
         {
             if (disposing)
             {
+                StagingBuffer.Dispose();
+
                 foreach (BufferHolder buffer in _buffers)
                 {
                     buffer.Dispose();
                 }
 
                 _buffers.Clear();
-                StagingBuffer.Dispose();
             }
         }