// This should maybe be a plane method.
func PlaneIntersectionAt(plane *Plane, line *Line, target vec.Vector) float64 {
dist := (plane.anchorDotNormal - vec.Dot(line.Anchor, plane.Normal)) /
vec.Dot(line.Normal, plane.Normal)
if target == nil {
return dist
}
line.Normal.ScaleAt(dist, target)
vec.AddAt(line.Anchor, target, target)
return dist
}
func NewPlane(anchor, normal vec.Vector) *Plane {
if len(anchor) != len(normal) {
panic("")
}
plane := new(Plane)
plane.Anchor = make([]float64, len(anchor))
copy(plane.Anchor, anchor)
plane.Normal = normal.Normalize()
plane.anchorDotNormal = vec.Dot(plane.Anchor, plane.Normal)
return plane
}