Conservatively returns the target chunks referenced by frustum-visible BVH
leaves. A box is rejected only when all eight corners lie outside a single
clip half-space, tested on undivided clip coordinates (linear in world
space), so a box intersecting the frustum is never culled; boxes outside
the frustum but not fully outside any one plane may still be kept, which
only over-fetches.
Conservatively returns the target chunks referenced by frustum-visible BVH leaves. A box is rejected only when all eight corners lie outside a single clip half-space, tested on undivided clip coordinates (linear in world space), so a box intersecting the frustum is never culled; boxes outside the frustum but not fully outside any one plane may still be kept, which only over-fetches.