fwidth

Returns the absolute value of the partial derivatives of the specified value.

ret fwidth(x)

 

This function computes the following: abs(ddx(x)) + abs(ddy(x)).

This function is only supported in pixel shaders.

Parameters

ItemDescription

x

[in] The specified value.

 

Return Value

The absolute value of the partial derivatives of the x parameter.

Type Description

Name Template Type Component Type Size
xscalar, vector, or matrix float any
retsame as input x float same dimension(s) as input x

 

Minimum Shader Model

This function is supported in the following shader models.

Shader ModelSupported
Shader Model 3 (DirectX HLSL) and higher shader modelsyes
Shader Model 2 (DirectX HLSL) yes (ps_2_x only)
Shader Model 1 (DirectX HLSL) no

 

See also

Intrinsic Functions (DirectX HLSL)

 

 

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