s0rg/grid

package grid

import "image"

type path struct {
    Parent *path
    Point  image.Point
    length int
    Cost   float64
}

func (p *path) Len() (rv int) {
    return p.length
}

func (p *path) Last() (v image.Point) {
    return p.Point
}

func (p *path) Points() (rv []image.Point) {
    rv = make([]image.Point, p.length)

    for i := p.length - 1; i > 0; i-- {
        rv[i], p = p.Point, p.Parent
    }

    return rv
}

func (p *path) Fork(pt image.Point, dist float64) (rv *path) {
    rv = &path{
        Point:  pt,
        Cost:   dist,
        length: 1,
    }

    if p == nil {
        return
    }

    rv.Parent = p
    rv.Cost += p.Cost
    rv.length += p.length

    return rv
}