gradient3d VEX function
Returns the gradient of a single channel texture image at the position specified by P.
vector gradient3d(string filename, string channel, vector P)
Returns the gradient of a single channel texture image at the position specified by P. If P is outside of the bounding box of the image, the value returned will be 0. If the channel specified contains more values than the return type (i.e. a vector channel when a float return type is desired), the gradient of the first component of the vector will be returned.
You can pass additional arguments to control the evaluation (see colormap):
||Specifies the filter for evaluation.|
||Specifies the filter width for evaluation.|