Method Add

path_intersection.go:1398–1430

(x float64, event *SweepPoint, refNode *SweepNode)

}

func (squares *toleranceSquares) Add(x float64, event *SweepPoint, refNode *SweepNode) {
	// refNode is always the node itself for left-endpoints, and otherwise the previous node (ie.
	// the node below) of a right-endpoint, or the next (ie. above) node if the previous is nil.
	// It may be inside or outside the right edge of the square. If outside, it is the first such
	// segment going upwards/downwards from the square (and not just any segment).
	y := snap(event.Y, BentleyOttmannEpsilon)
	if idx, ok := squares.find(x, y); !ok {
		// create new tolerance square
		square := boSquarePool.Get().(*toleranceSquare)
		*square = toleranceSquare{
			X:      x,
			Y:      y,
			Events: []*SweepPoint{event},
			Node:   refNode,
		}
		*squares = append((*squares)[:idx], append(toleranceSquares{square}, (*squares)[idx:]...)...)
	} else {
		// insert into existing tolerance square
		(*squares)[idx].Node = refNode
		(*squares)[idx].Events = append((*squares)[idx].Events, event)
	}

	// (nearly) vertical segments may still be used as the reference segment for squares around
	// in that case, replace with the new reference node (above or below that segment)
	if !event.left {
		orig := event.other.node
		for i := len(*squares) - 1; 0 <= i && (*squares)[i].X == x; i-- {
			if (*squares)[i].Node == orig {
				(*squares)[i].Node = refNode
			}
		}
	}
}

//func (event *SweepPoint) insertIntoSortedH(events *[]*SweepPoint) {
//	// O(log n)