pathplan - Man Page

The function Pshortestpath  finds a shortest path between two points in a simple polygon. The polygon is specified by a list of its vertices,  in either clockwise or counterclockwise order. You pass endpoints interior to the polygon boundary. A shortest path connecting the points that remains in the polygon is returned in output_route.  If either endpoint does not lie in the polygon, -1 is returned; otherwise, 0 is returned on success. The array of points in output_route is static to the library. It should not be freed, and should be used before another call to Pshortestpath.

These functions find a shortest path between two points in the plane that contains polygonal obstacles (holes). Pobsopen creates a configuration (an opaque struct of type vconfig_t) on a set of obstacles.  The n_obstacles obstacles are given in the array obstacles;  the points of each polygon should be in clockwise order. The function Pobsclose frees the data allocated in Pobsopen.

Pobspath finds a shortest path between the endpoints that remains outside the obstacles.  If the endpoints are known to lie inside obstacles, poly0 or poly1 should be set to the index in the obstacles array.  If an endpoint is definitely not inside an obstacle, then POLYID_NONE should be passed.  If the caller has not checked, then POLYID_UNKNOWN should be passed, and the path library will perform the test. The resulting shortest path is returned in output_route. Note that this function does not provide for a boundary polygon. The array of points stored in output_route are allocated by the library, but should be freed by the user.

This function fits a cubic B-spline curve to a polyline path.  The curve is constructed to avoid a set of n_barriers barrier line segments  specified in the array barriers. If you start with polygonal obstacles, you can supply each polygon's edges as part of the barrier list. The polyline input_route provides a template for the final path; it is usually the output_route of one of the shortest path finders, but it can be any simple path that doesn't cross any barrier segment.  The input also allows the specification of desired  slopes at the endpoints via endpoint_slopes. These are specified as vectors. For example, to have an angle of T at an endpoing, one could use  (cos(T),sin(T)). A vector (0,0) means unconstrained slope.   The output is returned in output_route and consists of the control points of the B-spline. The function return 0 on success; a return value of -1 indicates failure. The array of points in output_route is static to the library. It should not be freed, and should be used before another call to Proutespline.

This is a utility function that converts an input list of polygons into an output list of barrier segments. The array of points in barriers is static to the library. It should not be freed, and should be used before another call to Ppolybarriers. The function returns 1 on success.