Hi J-S, et. al. When you mention caching the intersect visitors, when should you use reset() and when are setStart()/setEnd() used?
In my game, I keep simplified, bounding box representations of the ships in the scene and then do line segment intersections. When I do the calculations, I start at the smaller ships, which have several "intersection points". For each point, I create a line segment for the global position of where the point was last frame and where it is this frame. I then bounce that against each ship in the scene that is larger. I also translate the "last position" for the intersection point based on how the bigger ship has moved. I do all of this to make sure I catch ships flying right through each other, because they are going fast. This has all worked out really well, but I am of course looking for any speed improvements I can get. So my first question is about how I should try to cache the intersect visitors? Should I keep one around for each large ship (node passed in to the getIntersections() function), or should I just make a single one that is used over and over? Next, how often should I call reset()? Once for each big ship, or once for each intersection check? I do not see any setStart()/setEnd() functions. Please forgive my ognorance, but where are they and what do they do? Finally, I am doing a few checks before I try the line segments to see if they are even close to the node I am checking. Is this worth the check or does the intersectVisitor do that all for me anyway? Thanks, -- Rick On Fri, Jul 11, 2008 at 8:09 PM, Jean-Sébastien Guay < [EMAIL PROTECTED]> wrote: > Hi Robert, > > To wrap, all these changes on now in SVN trunk and will be part of >> 2.5.4 and hence the up coming 2.6. If you enable the build of >> automatic KdTrees of load and use >> IntersectionVisitor/LineSegmentIntersector then you'll be able to go >> straight ahead of use KdTree intersections without lifting a further >> finger ;-) >> > > This is all very cool! I'll definitely be testing this out in the next few > days to try it out with my Masters project (which was very > intersection-heavy). I'll be setting up a little competition between your > KdTree and Adrian Egli's... Just kidding! > > I think I may be able to help a bit regarding the higher-level setup and > bookkeeping changes needed to speed things up on that regard. One thing I > noticed before is that creating a new Intersector and IntersectionVisitor > each time is costly, and instead keeping static or cached instances and > using the reset() and setStart()/setEnd() methods is faster. There may be > some other similar things that can be done too, we'll see what I can dig up. > > Thanks a lot for this work, it's a great addition, and I expect that it > will be useful in lots of different applications. > > J-S > -- > ______________________________________________________ > Jean-Sebastien Guay [EMAIL PROTECTED] > http://www.cm-labs.com/ > http://whitestar02.webhop.org/ > > _______________________________________________ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > -- >> Rick Check us out at http://fringe-online.com/
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