D3D10_MAPPED_TEXTURE2D structure (d3d10.h)

Provides access to subresource data in a 2D texture.

Syntax

typedef struct D3D10_MAPPED_TEXTURE2D {
  void *pData;
  UINT RowPitch;
} D3D10_MAPPED_TEXTURE2D;

Members

pData

Type: void*

Pointer to the data.

RowPitch

Type: UINT

The pitch, or width, or physical size (in bytes), of one row of an uncompressed texture. A block-compressed texture is encoded in 4x4 blocks (see virtual size vs physical size) ; therefore, RowPitch is the number of bytes in a block of 4x4 texels.

Remarks

This structure is used in a call to Map.

To illustrate the row pitch, assume an uncompressed 2D texture with mipmap levels, as shown in the following illustration.

Visualize the top-level texture drawn in a single plane like the following illustration.

However, the actual layout of each element in memory looks more like the following illustration.

For this example, the row pitch encompasses 5 elements (one row), whose size would be five times the number of bytes per element.

Use row pitch to advance a pointer between rows within a single 2D texture plane.

Example

To access data in, say, the third mipmap level, you must cast the pData pointer as demonstrated in the following example for a floating-point texture.

D3D10_MAPPED_TEXTURE2D mappedTexture;
if( SUCCEEDED( pTexture->Map( D3D10CalcSubresource(2, 0, 3), D3D10_MAP_WRITE_DISCARD, 0, &mappedTexture )))
{
    D3D10_TEXTURE2D_DESC desc;
    pTexture->GetDesc( &desc );
	
    // Compute the width and height of the third mipmap level
    const UINT WIDTH = desc.Width >> 2;
    const UINT HEIGHT = desc.Height >> 2;
	
    FLOAT* pTexels = (FLOAT*)mappedTexture.pData;
    for( UINT row = 0; row < HEIGHT; row++ )
    {
      UINT rowStart = row * mappedTexture.RowPitch/4;
      for( UINT col = 0; col < WIDTH; col++ )
      {
        pTexels[rowStart + col*4 + 0]; // Red
        pTexels[rowStart + col*4 + 1]; // Green
        pTexels[rowStart + col*4 + 2]; // Blue
        pTexels[rowStart + col*4 + 3]; // Alpha
      }
    }

    pTexture->Unmap(D3D10CalcSubresource(2, 0, 3));
}

Requirements

Requirement	Value
Header	d3d10.h

See also

Resource Structures