Author Topic: sf::View culling (Read 3209 times)

Elusive · « **on:** September 25, 2011, 04:28:08 am »

Hi,

Is there a simple way of culling invisible items in the scene using sf::View? Is there some method of checking wether a boundary box is intersecting with the visible region?

-Elusive

Laurent · « **Reply #1 on:** September 25, 2011, 08:58:52 am »

Build the view's rectangle (from its size and position), the entities' bounding rects, and use rect1.Intersect(rect2) to find out if they intersect.

Elusive · « **Reply #2 on:** September 25, 2011, 01:09:27 pm »

That was my first guess, but what about the view rotation?

Laurent · « **Reply #3 on:** September 25, 2011, 01:52:43 pm »

If you have a rotation it becomes more complicated. You must use the separate axis theorem to compute the intersection between two non-aligned rectangles.

Elusive · « **Reply #4 on:** September 25, 2011, 01:59:36 pm »

That is not part of SFML, right? I'll look into that. Thanks!

Nexus · « **Reply #5 on:** September 25, 2011, 02:06:30 pm »

Here you find a tutorial that explains the Separate Axis Theorem.

Elusive · « **Reply #6 on:** September 25, 2011, 02:08:04 pm »

Awesome! Thanks a lot!