Gegl graph filter can only use the active layer you're working on.
One trick is to export your bump-map layer into a file and use the gegl:load into the graph:
According to the code, there is nothing to handle a curve parameter, neither by the gegl graph filter nor the gegl binary.
There is only a support for graphs described as XML.
One trick is to export your bump-map layer into a file and use the gegl:load into the graph:
Code:
bump-map aux=[ load path="/path/to/your/bumpmapfile" ]
According to the code, there is nothing to handle a curve parameter, neither by the gegl graph filter nor the gegl binary.
There is only a support for graphs described as XML.