Monday, July 24, 2006

More quadtree poking. Currently items can be dragged and dropped around the quadtree area. Actually the only items a small rectangle drawn in using GDI, it lights up yellow when the mouse moves over it.
The codes become quite unclean. Here's the most horrible thing in it at the moment:

void OnNodeWantsToChangePosition(INode n, float x, float y)
n.UnsafeSetPosition(x, y);

Not very elegant casts that really shouldn't be required. Moving through a quadtree isn't very efficent, which is cool because they're generally for static stuff (my items). So when to move something in a quad I take it out of the tree, changes it position then replace it in the tree.

Still quite busy - I'll be going to Tokyo on the 31st for five days before returning to Old Bilayati. Upon arriving I guess I'll be quite busy again for a while. And soon I'll start University doing a masters in game programming - I'm considering doing a write up of all lectures here, so that's something to look forward to.


Anonymous said...

Hey man, I read your blog every now and then and you're going about this the wrong way.

The entities need to contain a reference to the quadtree node they're in. Then when they move, you check if the node still contains them, then and only then should you replace them in the tree - or cheat a little like I do and just move them up one and let the next update reposition them further if it needs to.

That way, you don't have all these tree-searches every frame, for every single moving entity.

Dan said...

Cheers, I've stopped messing with this now and am using a different approach but I do know when I was using it I wasn't really sure if I was doing the best thing!

(I may come back to it at one point, if so than I'll definitely take your advice.)