PFND3DDDI_SETCONVOLUTIONKERNELMONO callback function (d3dumddi.h)

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

Syntax

PFND3DDDI_SETCONVOLUTIONKERNELMONO Pfnd3dddiSetconvolutionkernelmono;

HRESULT Pfnd3dddiSetconvolutionkernelmono(
  HANDLE hDevice,
  const D3DDDIARG_SETCONVOLUTIONKERNELMONO *unnamedParam2
)
{...}

Parameters

hDevice

A handle to the display device (graphics context).

unnamedParam2

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:

Remarks

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 <N_v)[ (R_i*(1 - alpha) + R_i+1*alpha) * S)]

Rₖ = Sum(j=0, j <N_u)[T_k,j*(1 - beta) + T_k,j+1*beta], where 0 < k < N_v

S = 1 / (N_u * N_v)

N_u and N_v are the width and height of the filter kernel.

T_i,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 (U_f,V_f) are computed as:

U_f = U * TextureWidth - N_u * 0.5

V_f = V * TextureHeight - N_v * 0.5

Then

beta = U_f - truncate(U_f)

alpha = V_f - truncate(V_f)

Requirements

See also

D3DDDIARG_SETCONVOLUTIONKERNELMONO

D3DDDI_DEVICEFUNCS