Return the partial derivative of an argument with respect to x or y.
||-||Specifies the expression of which to take the partial derivative.|
Available only in the fragment shader, these functions return the partial derivative of expression
p with respect to the window [math]x[/math] coordinate (for
dFdx* ) and [math]y[/math] coordinate (for
dFdyFine calculate derivatives using local differencing based on the value of
p for the current fragment and its immediate neighbor(s).
dFdyCoarse calculate derivatives using local differencing based on the value of
p for the current fragment's neighbors, and will possibly, but not necessarily, include the value for the current fragment. That is, over a given area, the implementation can compute derivatives in fewer unique locations than would be allowed for the corresponding
dFdx returns either
dFdy returns either
dFdyFine . The implementation may choose which calculation to perform based upon factors such as performance or the value of the API
Expressions that imply higher order derivatives such asdFdx(dFdx(n))have undefined results, as do mixed-order derivatives such asdFdx(dFdy(n)). It is assumed that the expression
p is continuous and therefore, expressions evaluated via non-uniform control flow may be undefined.
|dFdxCoarse, dFdxFine, dFdyCoarse, dFdyFine||4.5+|
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