From 630a56bd9c61d9d5fcc2ac7ee6768e42b1dcdf8e Mon Sep 17 00:00:00 2001
From: Dan Balasescu <smoogipoo@smgi.me>
Date: Wed, 1 May 2024 20:24:11 +0900
Subject: [PATCH] Fix D3D regression causing broken buffer updates

---
 src/Veldrid/D3D11/D3D11CommandList.cs | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/Veldrid/D3D11/D3D11CommandList.cs b/src/Veldrid/D3D11/D3D11CommandList.cs
index da80d4f37..e97c431c2 100644
--- a/src/Veldrid/D3D11/D3D11CommandList.cs
+++ b/src/Veldrid/D3D11/D3D11CommandList.cs
@@ -1009,16 +1009,16 @@ private void bindSampler(D3D11Sampler sampler, int slot, ShaderStages stages)
         private unsafe void UpdateSubresource_Workaround(
             ID3D11Resource resource,
             int subresource,
-            Box region,
+            Box? region,
             IntPtr data)
         {
             bool needWorkaround = !gd.SupportsCommandLists;
             var pAdjustedSrcData = data.ToPointer();
 
-            if (needWorkaround)
+            if (needWorkaround && region is Box dstRegion)
             {
-                Debug.Assert(region.Top == 0 && region.Front == 0);
-                pAdjustedSrcData = (byte*)data - region.Left;
+                Debug.Assert(dstRegion.Top == 0 && dstRegion.Front == 0);
+                pAdjustedSrcData = (byte*)data - dstRegion.Left;
             }
 
             DeviceContext.UpdateSubresource(resource, subresource, region, (IntPtr)pAdjustedSrcData, 0, 0);
@@ -1215,10 +1215,10 @@ private protected override unsafe void UpdateBufferCore(DeviceBuffer buffer, uin
 
             if (useUpdateSubresource)
             {
-                Box subregion = new Box((int)bufferOffsetInBytes, 0, 0, (int)(sizeInBytes + bufferOffsetInBytes), 1, 1);
+                Box? subregion = new Box((int)bufferOffsetInBytes, 0, 0, (int)(sizeInBytes + bufferOffsetInBytes), 1, 1);
 
                 if (isUniformBuffer)
-                    subregion = default;
+                    subregion = null;
 
                 if (bufferOffsetInBytes == 0)
                     DeviceContext.UpdateSubresource(d3dBuffer.Buffer, 0, subregion, source, 0, 0);