Fix D3D multi-layer texture fallback upload alignment

src/gpu/d3d12/SDL_gpu_d3d12.c

@@ -6007,7 +6007,11 @@ static void D3D12_UploadToTexture(
         needsPlacementCopy = source->offset % D3D12_TEXTURE_DATA_PLACEMENT_ALIGNMENT != 0;
     }
 
-    alignedBytesPerSlice = alignedRowPitch * destination->h;
+    alignedBytesPerSlice = alignedRowPitch * blockHeight;
+    if (!renderer->UnrestrictedBufferTextureCopyPitchSupported && destination->d > 1 && alignedBytesPerSlice % D3D12_TEXTURE_DATA_PLACEMENT_ALIGNMENT != 0) {
+        needsRealignment = true;
+        alignedBytesPerSlice = D3D12_INTERNAL_Align(alignedBytesPerSlice, D3D12_TEXTURE_DATA_PLACEMENT_ALIGNMENT);
+    }
 
     sourceLocation.Type = D3D12_TEXTURE_COPY_TYPE_PLACED_FOOTPRINT;
     sourceLocation.PlacedFootprint.Footprint.Format = SDLToD3D12_TextureFormat[textureContainer->header.info.format];
@@ -6021,7 +6025,7 @@ static void D3D12_UploadToTexture(
         temporaryBuffer = D3D12_INTERNAL_CreateBuffer(
             d3d12CommandBuffer->renderer,
             0,
-            alignedRowPitch * blockHeight * destination->d,
+            alignedBytesPerSlice * destination->d,
             D3D12_BUFFER_TYPE_UPLOAD,
             NULL);