The SetConvolutionKernelMono function defines the resolution and weights of the kernel filter, which is used when the D3DTEXF_CONVOLUTIONMONO texture filtering mode is set.


PFND3DDDI_SETCONVOLUTIONKERNELMONO Pfnd3dddiSetconvolutionkernelmono;

HRESULT Pfnd3dddiSetconvolutionkernelmono(
  HANDLE hDevice,



A handle to the display device (graphics context).


pData [in]

A pointer to a D3DDDIARG_SETCONVOLUTIONKERNELMONO structure that describes parameters for setting the monochrome convolution kernel.

Return Value

SetConvolutionKernelMono returns one of the following values:

Return code Description
S_OK The monochrome convolution kernel is successfully set.
E_OUTOFMEMORY SetConvolutionKernelMono could not allocate the required memory for it to complete.


D3DTEXF_CONVOLUTIONMONO is a texture filter mode that is used for sampling monochrome textures (that is, textures that are formatted as one bit per pixel (D3DDDIFMT_A1)). In the Direct3D 9.L runtime, the convolution filter is a two-dimensional box filter (that is, all weights = 1.0). However, the SetConvolutionKernelMono function is defined to support a more general filter. When D3DTEXF_CONVOLUTIONMONO is set to a texture sampler, the texture sampler states D3DTSS_MIPFILTER, D3DTSS_MINFILTER and D3DTSS_MAGFILTER are ignored. The texture address D3DTADDRESS_BORDER with border color 0 should be applied in this filtering mode. The user-mode display driver should return an error or ignore the rendered primitive if this filtering mode is used with a non-monochrome texture.

The following formula is used to perform the convolution:

Result = Sum(i=0, i <Nv)[ (Ri*(1 - alpha) + Ri+1*alpha) * S)]

Rₖ = Sum(j=0, j <Nu)[Tk,j*(1 - beta) + Tk,j+1*beta], where 0 < k < Nv

S = 1 / (Nu * Nv)

Nu and Nv are the width and height of the filter kernel.

Ti,j are texture samples from a monochrome texture at location (i, j).

The precision of the filter operations must be at least 6 bits.

The interpolated texture coordinate values (U, V) at a pixel center are the coordinates of the center of the filter kernel.

The coordinates of the upper left filter kernel sample (Uf,Vf) are computed as:

Uf = U * TextureWidth - Nu * 0.5

Vf = V * TextureHeight - Nv * 0.5


beta = Uf - truncate(Uf)

alpha = Vf - truncate(Vf)


Minimum supported client Available in Windows Vista and later versions of the Windows operating systems.
Target Platform Desktop
Header d3dumddi.h (include D3dumddi.h)

See Also