Interface SahTree

[minX, minY, minZ, maxX, maxY, maxZ] around everything.

Levels of nodes on the longest root-to-leaf path (a lone root counts as 1). Bounds the traversal stack use.

nodeCount nodes in the layout from gpu-layout.ts. Child indices are relative to this tree.

order[i] is the input primitive that must be stored at position i. A leaf's index and count refer to positions in this order.

Parent node of every node; the root has NO_PARENT. Only the refit pass reads this.