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Windows Driver Kit DDI reference (nc-d3dumddi-pfnd3dddi_composerects)

PFND3DDDI_COMPOSERECTS callback function

Description

The ComposeRects function composes two-dimensional areas from a source surface to a destination surface.

Parameters

`hDevice`

A handle to the display device (graphics context).

`unnamedParam2`

pData [in]

A pointer to a D3DDDIARG_COMPOSERECTS structure that specifies the parameters that are used to compose rectangular areas.

Return value

ComposeRects returns one of the following values:

Return code	Description
S_OK	The rectangular areas were successfully composed.
E_OUTOFMEMORY	ComposeRects could not allocate the required memory for it to complete.

Remarks

The following constraints and validations apply to the ComposeRects function:

The driver should ignore the source rectangular areas that are not completely inside the source surface.
The destination rectangular areas--after applying offsets--can be partially or completely outside the destination surface. The destination rectangular areas are clipped if partially outside and rejected or completely clipped if completely outside.
The same surface cannot be specified for the source and the destination.
Surfaces and vertex buffers that are used with ComposeRects should not be locked.
The source and destination surfaces are formatted as one bit per pixel (D3DDDIFMT_A1) when they are created.
In the debug build, the Microsoft Direct3D runtime validates that a source rectangular area description exists for each index in the destination rectangular area description. In the retail build, ComposeRects returns an error if an invalid index exists.
The number of rectangular areas should be less than 0xFFFF to prevent internal overflow during math operations.
Surfaces and vertex buffers should be created by using the same display device (graphics context).
Local display memory should be specified for the destination surface.

The following example code shows an operation that ComposeRects performs:

for (UINT i=0; i < COMPOSERECTS.NumDstRects; i++) {
   if (i >= Size(VertexBuffer(hDstRectDescsVB)) / sizeof(D3DCOMPOSERECTDSTDESC))
      Ignore the rectangle;
   if (VertexBuffer(hDstRectDescsVB)[i].RectDescIndex >= Size(VertexBuffer(hSrcRectDescsVB)) / sizeof(D3DCOMPOSERECTSRCDESC))
      Ignore the rectangle;
   SourceRectangle = VertexBuffer(hSrcResource)[VertexBuffer(hDstRectDescsVB)[i].RectDescIndex];
   DestinationRectangle.X = {VertexBuffer(hDstRectDescsVB)[i].X + COMPOSERECTS.Xoffset;
   DestinationRectangle.Y = {VertexBuffer(hDstRectDescsVB)[i].Y + COMPOSERECTS.Yoffset;
   DestinationRectangle.Width = SourceRectangle.Width;
   DestinationRectangle.Height = SourceRectangle.Height;
   Perform COMPOSERECTS.Operation for each pixel;
}

PFND3DDDI_COMPOSERECTS - NtDoc