BDC cell sweep

[rland93]

Right now, each node of the Reeb Graph generated by bdc.py's line sweep (R called on line 175 of bdc.py) has an attribute called cellpts that stores the affine polygon produced by the boustrophedon decomposition of the shape.

We need to "lawnmower sweep" each of these cells as we traverse the reeb graph, skipping over cells that have already been swept.

Down the line, a sweep algorithm would optimize sweeping from starting exit/entry points and sweeping in order. Or, if the cell is strictly convex in multiple directions, we can choose an optimal direction for the line sweep. Or, we can solve an optimization problem to determine the mixture of exit/entry points, sweep direction, etc.

[rland93]

Starting work on this. It's been about a year since I touched this code

To do

• refactor bdc to have OO interface similar to planner
  • polygon
  • bdc
• test coverage
• fix polygon skeleton to either use shapely or a similarly high-quality library
• lawnmower cell sweep
• make API compatible with planner