2011 Khronos Group
dFdx, dFdy 3G
dFdx, dFdy return the partial derivative of an argument with respect to x or y

## Declaration

genType `dFdx` genType p genType `dFdy` genType p

## Parameters

p

  Specifies the expression of which to take the partial derivative.

## Description

Available only in the fragment shader, `dFdx` and `dFdy` return the partial derivative of expression p in x and y, respectively. Deviatives are calculated using local differencing. Expressions that imply higher order derivatives such as `dFdx(dFdx(n))` have undefined results, as do mixed-order derivatives such as `dFdx(dFdy(n))`. It is assumed that the expression p is continuous and therefore, expressions evaluated via non-uniform control flow may be undefined.

## Version Support

#VARTABLECOLS#
#FUNCTABLEHEADER#
dFdx#newin11#
dFdy#newin11#

## See Also

fwidth

## Copyright

Copyright 2011 Khronos Group. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. http://opencontent.org/openpub/.