Jean-Sébastien Guay wrote:
> Hi all,
>
>> Any ideas?
>
> Anyone?
>
> J-S
>
> (previous message below in case you don't know what I'm talking about)
>
> Jean-Sébastien Guay wrote:
>> Hi Paul,
>>
>>> Hi J-S -- I recently wrote my own visitor to flatten transforms. To
>>> do this,
>>> I use osg::computeLocalToWorld(osg::NodePath&) to get the
>>> local-to-world
>>> matrix, and transform all vertices by that matrix.
>>
>> Yes, I've done that in the past too, and after fiddling for a while
>> with the order of operations and how to transform vectors properly
>> (as opposed to points/vertices) I got it to work too.
>>
>>> This works great for me,
>>> and what you are doing sounds like an equivalent operation, so I'm
>>> not sure
>>> why it's not working for you. Can you provide more details on the
>>> failure?
>>
>> Well, say I have this (pseudo code)
>>
>> osg::BoundingBox combinedWorldBB;
>> foreach node in selectedNodes
>> add node's BB (world-space) to combinedWorldBB
>> end
>>
>> The result I get is that when the root transform of my group of nodes
>> is identity, I get a bounding box of:
>>
>> _min = ( -1.4047172 , -0.94869113 , -1.9402435 )
>> _max = ( 2.7989883 , 0.95002991 , 0.33612174 )
>>
>> which is a bounding box of approximate size (4, 2, 2.3) centered
>> approximately at (0.6, 0, -0.8).
>>
>> If I translate the root of those nodes by -5 in Z (and they look
>> correctly transformed), I get this bounding box:
>>
>> _min = ( -1.4047172 , -0.94869113 , -11.940244 )
>> _max = ( 2.7989883 , 0.95002991 , -5.3083067 )
Interestingly enough min xseems to have been decremented by twice -5...
won't help you, but just an observation :)
Paul
>>
>> which is a bounding box of approximate size (4, 2, 6.6) centered
>> approximately at (0.6, 0, -8.6).
>>
>> So you can see, the bounding box changes much more than a simple
>> translation by -5 in Z...
>>
>>
>> My code is:
>>
>> void getWorldBounds(osg::Node* node, osg::BoundingBox& bb)
>> {
>> GetWorldCoordOfNodeVisitor worldVisitor;
>> node->accept(worldVisitor);
>> osg::Matrix localToWorld = worldVisitor.getMatrix();
>>
>> osg::ComputeBoundsVisitor cbbv;
>> node->accept(cbbv);
>> osg::BoundingBox localBB = cbbv.getBoundingBox();
>>
>> for (unsigned int i = 0; i < 8; i++)
>> {
>> bb.expandBy(localBB.corner(i) * localToWorld);
>> }
>> }
>>
>> // ... Then in a method:
>>
>> osg::BoundingBox bb;
>> foreach (osg::Node* node, selectedNodes)
>> {
>> getWorldBounds(node, bb);
>> }
>>
>> // Results inspected at this point in the debugger.
>>
>>
>> Any ideas?
>>
>> Thanks in advance,
>>
>> J-S
>
>
_______________________________________________
osg-users mailing list
osg-users@lists.openscenegraph.org
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
