dx-graphics-hlsl-ddy.md

title	description	ms.assetid	keywords	topic_type	api_name	api_type	ms.topic	ms.date	api_location
ddy	Returns the partial derivative of the specified value with respect to the screen-space y-coordinate.	1c88804f-a13f-4714-a3ef-466307afbc1b	ddy HLSL	apiref	ddy	NA	reference	05/31/2018

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)