Robert,
I think I know why things go bad in KDTree,
I'm using KDTree to "spoof" the location of some actual geometry, which is
transformed in a vertex/geometry shader.
So, I compute a bounding box for where the geometry ought to be, and create
a dummy geometry from that - I then compute the KDTree for this dummy
geometry, and assign it to the actual geometry that will be sent down the
pipe, which is at the scene origin, not its final location.
When the line-segment intersector goes to pick, it first checks to see if
the line segment intersects the bounding box of the drawable, which as far
as I can tell is computed against the actual geometry (in this case the
geometry at the origin) and not the KDTree's bounding box. When it doesn't
properly intersect, the line-segment intersector returns without hitting the
KDTree.
I think what is needed is to test against the KDTree bounding box, rather
than the geometry bounding box, if a KDTree is assigned.
Does this make any sense?
sean
On Wed, Dec 3, 2008 at 10:05 AM, Sean Spicer <[EMAIL PROTECTED]> wrote:
> Robert,
>
> I will see if I can repro the problem with osgpick and send you the osg
> file. It may take me a week or two though as I've got a lot on my plate ;-)
>
> cheers,
>
> sean
>
>
> On Wed, Dec 3, 2008 at 3:28 AM, Robert Osfield <[EMAIL PROTECTED]>wrote:
>
>> Hi Sean,
>>
>> This sounds like a bug, but without a dataset and example that
>> reproduces the problem it's next to impossible to home in on a fix.
>> Would it be possible for you to provide a problem dataset that
>> illustrates the problem? If it can be reproduced with one of the
>> existing examples like osgpick then this will make it easier to track
>> down.
>>
>> Robert.
>>
>> On Wed, Dec 3, 2008 at 12:00 AM, Sean Spicer <[EMAIL PROTECTED]>
>> wrote:
>> > Hi Gang,
>> >
>> > I'm working on improving picking performance via KDTree, but I'm hitting
>> an
>> > issue that is driving me nuts: If I pick a node from directly above
>> (e.g. +
>> > Z axis) everything works great, and picking is *very* fast. If I pick
>> at an
>> > angle, (e.g. from eye(1,1,1)) then picking is fast, but not accurate -
>> nodes
>> > to the left, right, top, or bottom get picked instead of what I'm after.
>> >
>> > Here is my KDTree Build function:
>> >
>> > #ifdef USE_KDTREE
>> >
>> > // Update the KDTree
>> > osg::KdTree::BuildOptions kdTreeBuildOptions;
>> > osg::ref_ptr<osg::KdTree> kdTree = new osg::KdTree();
>> >
>> > if(kdTree->build(kdTreeBuildOptions, geometry))
>> > {
>> > geometry->setShape(kdTree.get());
>> > }
>> > else
>> > {
>> > LOG_MSG(logERROR) << "osg::KdTree::build() unsuccessful.";
>> > }
>> > #endif
>> >
>> > Any suggestions?
>> >
>> > cheers,
>> >
>> > sean
>> >
>> > _______________________________________________
>> > osg-users mailing list
>> > [email protected]
>> >
>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
>> >
>> >
>> _______________________________________________
>> osg-users mailing list
>> [email protected]
>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
>>
>
>
_______________________________________________
osg-users mailing list
[email protected]
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
