Holds all viable gradient provider types.

using discrete solution of the Eikonal equation, like with Fast Marching

using continuous solution with Euklidean distance to targets

using continuous solution with Euklidean distance to targets, mollified so that the gradient is continuous

obstacle "forces", continuous

uses PEDESTRIAN_CONTINUOUS, but enables the user to define two teleporter lines where the pedestrians are set back to the respective other line.