#dFdx, dFdy

return the partial derivative of an argument with respect to x or y

#Declaration

• genType dFdx(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.