> ## Documentation Index
> Fetch the complete documentation index at: https://devdocs.xbox.com/llms.txt
> Use this file to discover all available pages before exploring further.

# CopyBufferRegion

> CopyBufferRegion (Direct3D 12 on XBOX) — Copies a region of a buffer from one resource to another. Direct3D 12 graphics API reference for XBOX game development.

Copies a region of a buffer from one resource to another.

## Syntax

```cpp theme={null}
void CopyBufferRegion(
    ID3D12Resource  pDstBuffer,
    UINT64 DstOffset,
    ID3D12Resource  pSrcBuffer,
    UINT64 SrcOffset,
    UINT64 NumBytes
)
```

### Parameters

*pDstBuffer \[in]*<br />Type: ID3D12Resource \*

Specifies the destination [ID3D12Resource](/reference/graphics/d3d12_xs/interfaces/ID3D12Resource/id3d12resource_xs).

*DstOffset*<br />Type: UINT64

Specifies a UINT64 offset (in bytes) into the destination resource.

*pSrcBuffer \[in]*<br />Type: ID3D12Resource \*

Specifies the source  [ID3D12Resource](/reference/graphics/d3d12_xs/interfaces/ID3D12Resource/id3d12resource_xs).

*SrcOffset*<br />Type: UINT64

Specifies a UINT64 offset (in bytes) into the source resource, to start the copy from.

*NumBytes*<br />Type: UINT64

Specifies the number of bytes to copy.

### Return value

Type: void

None.

## Remarks

Consider using the [CopyResource](https://learn.microsoft.com/en-us/windows/win32/api/d3d12/nf-d3d12-id3d12graphicscommandlist-copyresource) method when copying an entire resource, and use this method for copying regions of a resource.

**CopyBufferRegion** may be used to initialize resources which alias the same heap memory. See [CreatePlacedResource](/reference/graphics/d3d12/interfaces/id3d12device/methods/id3d12device_createplacedresource_public) for more details.

#### Examples

The [D3D12HelloTriangle](https://learn.microsoft.com/en-us/windows/desktop/direct3d12/working-samples) sample uses **ID3D12GraphicsCommandList::CopyBufferRegion** as follows:

```cpp theme={null}
inline UINT64 UpdateSubresources(
_In_ ID3D12GraphicsCommandList* pCmdList,
_In_ ID3D12Resource* pDestinationResource,
_In_ ID3D12Resource* pIntermediate,
_In_range_(0,D3D12_REQ_SUBRESOURCES) UINT FirstSubresource,
_In_range_(0,D3D12_REQ_SUBRESOURCES-FirstSubresource) UINT NumSubresources,
UINT64 RequiredSize,
_In_reads_(NumSubresources) const D3D12_PLACED_SUBRESOURCE_FOOTPRINT* pLayouts,
_In_reads_(NumSubresources) const UINT* pNumRows,
_In_reads_(NumSubresources) const UINT64* pRowSizesInBytes,
_In_reads_(NumSubresources) const D3D12_SUBRESOURCE_DATA* pSrcData)
{
// Minor validation
D3D12_RESOURCE_DESC IntermediateDesc = pIntermediate->GetDesc();
D3D12_RESOURCE_DESC DestinationDesc = pDestinationResource->GetDesc();
if (IntermediateDesc.Dimension != D3D12_RESOURCE_DIMENSION_BUFFER ||
IntermediateDesc.Width < RequiredSize + pLayouts[0].Offset ||
RequiredSize > (SIZE_T)-1 ||
(DestinationDesc.Dimension == D3D12_RESOURCE_DIMENSION_BUFFER &&
(FirstSubresource != 0 || NumSubresources != 1)))
{
return 0;
}

BYTE* pData;
HRESULT hr = pIntermediate->Map(0, NULL, reinterpret_cast<void**>(&pData));
if (FAILED(hr))
{
return 0;
}

for (UINT i = 0; i < NumSubresources; ++i)
{
if (pRowSizesInBytes[i] > (SIZE_T)-1) return 0;
D3D12_MEMCPY_DEST DestData = { pData + pLayouts[i].Offset, pLayouts[i].Footprint.RowPitch, pLayouts[i].Footprint.RowPitch * pNumRows[i] };
MemcpySubresource(&DestData, &pSrcData[i], (SIZE_T)pRowSizesInBytes[i], pNumRows[i], pLayouts[i].Footprint.Depth);
}
pIntermediate->Unmap(0, NULL);

if (DestinationDesc.Dimension == D3D12_RESOURCE_DIMENSION_BUFFER)
{
CD3DX12_BOX SrcBox( UINT( pLayouts[0].Offset ), UINT( pLayouts[0].Offset + pLayouts[0].Footprint.Width ) );
pCmdList->CopyBufferRegion(
pDestinationResource, 0, pIntermediate, pLayouts[0].Offset, pLayouts[0].Footprint.Width);
}
else
{
for (UINT i = 0; i < NumSubresources; ++i)
{
CD3DX12_TEXTURE_COPY_LOCATION Dst(pDestinationResource, i + FirstSubresource);
CD3DX12_TEXTURE_COPY_LOCATION Src(pIntermediate, pLayouts[i]);
pCmdList->CopyTextureRegion(&Dst, 0, 0, 0, &Src, nullptr);
}
}
return RequiredSize;
}
```

See [Example Code in the D3D12 Reference](https://learn.microsoft.com/en-us/windows/desktop/direct3d12/notes-on-example-code).

<div class="code" />

## Requirements

**Header:** d3d12\_xs.h or d3d12\_x.h<br />**Library:** d3d12\_xs.lib or d3d12\_x.lib<br />**Supported Platforms**: XBOX Series consoles and XBOX One family

## See Also

[CopyTextureRegion](/reference/graphics/d3d12/interfaces/id3d12graphicscommandlist/methods/id3d12graphicscommandlist_copytextureregion_public)

[ID3D12GraphicsCommandList](/reference/graphics/d3d12_xs/interfaces/ID3D12GraphicsCommandList/id3d12graphicscommandlist_xs)


## Related topics

- [CreatePlacedResource](/reference/graphics/d3d12/interfaces/id3d12device/methods/id3d12device_createplacedresource_public.md)
- [D3D12_CROSS_NODE_SHARING_TIER](/reference/graphics/d3d12/enums/d3d12_cross_node_sharing_tier_public.md)
- [NDA topic directory - live Microsoft Learn links](/nda/nda-topic-directory.md)
- [CopyTiles](/reference/graphics/d3d12/interfaces/id3d12graphicscommandlist/methods/id3d12graphicscommandlist_copytiles_public.md)
- [D3D12_TILE_COPY_FLAGS](/reference/graphics/d3d12/enums/d3d12_tile_copy_flags_public.md)