// Removes any regions that are outside of the given viewport,
// and clips the regions that are intersecting it so that
// all regions remaining are fully contained inside of the viewport.
func (vr *ViewRegions) Cull(viewport text.Region) {
pe := util.Prof.Enter("render.vr.Cull")
defer pe.Exit()
nr := []text.Region{}
for _, r := range vr.Regions.Regions() {
if viewport.Intersects(r) {
in := viewport.Intersection(r)
if in.Size() != 0 {
nr = append(nr, in)
}
}
}
vr.Regions.Clear()
vr.Regions.AddAll(nr)
}
