The bottom ray facing away from the splitting plane

Sec. 4.4]	Kd-Tree Accelerator	169

Figure 4.13: The position of the origin of the ray with respect to the splitting plane can be used to determine which of the node’s children should be processed first. If a ray like r1 is “below” side of the splitting plane, we should process the “below”chilld before the “above” child, and vice versa.

	Primitives and Intersection Acceleration	[Ch. 4

KdToDo::node KdToDo::tmax KdToDo::tmin	168 168 168	Figure 4.14: Two cases where both children of a node don’t need to be processed
		because the ray doesn’t overlap them. On the left, the top ray intersects the splitting
		plane beyond the ray’s tmax position and thus doesn’t enter the far child. The bottom ray is facing away from the splitting plane, indicated by a negative tsplit value. On the right, the ray intersects the plane before the ray’s tmin value, indicating that the near plane doesn’t need processing.
		Otherwise, the else clause handles the case of both children needing processing;