void aabox_union(struct aabox *res, struct aabox *a, struct aabox *b);
float aabox_surf_area(struct aabox *box);
float surf_area(float dx, float dy, float dz);
void aabox_union(struct aabox *res, struct aabox *a, struct aabox *b);
float aabox_surf_area(struct aabox *box);
float surf_area(float dx, float dy, float dz);