ddy

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

ret ddy(x)

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

This function is only supported in pixel shaders.

Parameters

Item Description
x
[in] The specified value.

Return Value

The partial derivative of the x parameter.

Type Description

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

Minimum Shader Model

This function is supported in the following shader models.

Shader Model Supported
Shader Model 5 and higher shader models yes
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:

Vertex Hull Domain Geometry Pixel Compute
x

See also

Intrinsic Functions (DirectX HLSL)