Method initNested

s2/polygon.go:282–300

initNested takes the set of loops in this polygon and performs the nesting computations to set the proper nesting and parent/child relationships.

()

// initNested takes the set of loops in this polygon and performs the nesting
// computations to set the proper nesting and parent/child relationships.
func (p *Polygon) initNested() {
	if len(p.loops) == 1 {
		p.initOneLoop()
		return
	}

	lm := make(loopMap)

	for _, l := range p.loops {
		lm.insertLoop(l, nil)
	}
	// The loops have all been added to the loopMap for ordering. Clear the
	// loops slice because we add all the loops in-order in initLoops.
	p.loops = nil

	// Reorder the loops in depth-first traversal order.
	p.initLoops(lm)
	p.initLoopProperties()
}

// loopMap is a map of a loop to its immediate children with respect to nesting.
// It is used to determine which loops are shells and which are holes.