//! tests whether boxes intersect and returns boolean as mask of all 1s or 0s.if one box is whole world, and the other is inverse full (empty) - returns non-intersection
//! tests whether boxes intersect and returns boolean (0 or non-0). if one box is whole world, and the other is inverse full (empty) - returns non-intersection
/// return zero if not visible in frustum or if bbox screen size is smaller, than threshold. 1, if all vertex are in front of near plane, -1 (and fullscreen rect) otherwise
/// also, screen_box is minX, maxX, minY, maxY - in clipspace coordinates (-1, -1) .. (1,1), minmax_w is wWwW (minw, maxw, minw, maxw)