Method Intersect

ln/tree.go:40–80

(r Ray, tmin, tmax float64)

}

func (node *Node) Intersect(r Ray, tmin, tmax float64) Hit {
	var tsplit float64
	var leftFirst bool
	switch node.Axis {
	case AxisNone:
		return node.IntersectShapes(r)
	case AxisX:
		tsplit = (node.Point - r.Origin.X) / r.Direction.X
		leftFirst = (r.Origin.X < node.Point) || (r.Origin.X == node.Point && r.Direction.X <= 0)
	case AxisY:
		tsplit = (node.Point - r.Origin.Y) / r.Direction.Y
		leftFirst = (r.Origin.Y < node.Point) || (r.Origin.Y == node.Point && r.Direction.Y <= 0)
	case AxisZ:
		tsplit = (node.Point - r.Origin.Z) / r.Direction.Z
		leftFirst = (r.Origin.Z < node.Point) || (r.Origin.Z == node.Point && r.Direction.Z <= 0)
	}
	var first, second *Node
	if leftFirst {
		first = node.Left
		second = node.Right
	} else {
		first = node.Right
		second = node.Left
	}
	if tsplit > tmax || tsplit <= 0 {
		return first.Intersect(r, tmin, tmax)
	} else if tsplit < tmin {
		return second.Intersect(r, tmin, tmax)
	} else {
		h1 := first.Intersect(r, tmin, tsplit)
		if h1.T <= tsplit {
			return h1
		}
		h2 := second.Intersect(r, tsplit, math.Min(tmax, h1.T))
		if h1.T <= h2.T {
			return h1
		} else {
			return h2
		}
	}
}

func (node *Node) IntersectShapes(r Ray) Hit {
	hit := NoHit