ddx

Returns the partial derivative of the specified value with respect to the screen-space x-coordinate.

ret ddx(x)

 

This function computes the partial derivative with respect to the screen-space x-coordinate. To compute the partial derivative with respect to the screen-space y-coordinate, use the ddy function.

This function is only supported in pixel shaders.

Parameters

ItemDescription

x

[in] The specified value.

 

Return Value

The partial derivative 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 5 and higher shader modelsyes
Shader Model 4 yes
Shader Model 3 (DirectX HLSL) yes
Shader Model 2 (DirectX HLSL) yes in ps_2_x; unsupported in ps_2_0.
Shader Model 1 (DirectX HLSL) no

 

This function is supported in the following types of shaders:

VertexHullDomainGeometryPixelCompute
x

 

See also

Intrinsic Functions (DirectX HLSL)

 

 

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