[osg-users] Volume Rendering and Depth Buffer

[Anna Osvin]

If you mean osgViewer::View::computeIntersections, then we tried it. For some reason it does not check intersections with volume model.

Here is raycast intersection check code:

Code:

bool pickPolygonalSceneIntersection( osgViewer::View& view, const osg::Vec2& point2d, osg::Vec3& pickedPoint )
{
    const osg::Camera* camera = view.getCamera();
    if ( camera == nullptr ) {
        Q_ASSERT_X( false, "bool pickPolygonalSceneIntersection( ... )", "View has no camera." );
        return false;
    }
    
    osgUtil::LineSegmentIntersector::Intersections intersections;

    if ( view.computeIntersections( camera, osgUtil::Intersector::CoordinateFrame::WINDOW, point2d.x(), point2d.y(), intersections ) )
    {
        for (osgUtil::LineSegmentIntersector::Intersections::iterator hitr = intersections.begin();
            hitr != intersections.end();
            ++hitr)
        {
            if (hitr->nodePath.size() > 4)
            {
                pickedPoint = hitr->getWorldIntersectPoint();
                
                return true;
            }
        }
    }

    return false;
}





Chris Hanson wrote:
> Instead of reading Z depth values, can you simply run an intersection of the click ray-vector against the model data (polygonal and volumetric) when they click to place markdown points?
> 
> On Mon, Apr 15, 2019 at 2:34 PM Anna Osvin < ()> wrote:
> 
> 
> > We are working on medical software for Dentists. We need to render CBCT and give user possibility to place some markdown points on it, for future diagnostics. Also sometimes it's required to render polygonal jaw models alongside with CBCT. As I said earlier, we nailed down the rendering and even "hit detection", but there is a nasty bag with Z Buffer values of the background being incorrect, therefore user can place points onto nothing.
> > 
> > ... 
> > 
> > Thank you!
> > 
> > Cheers,
> > Anna
> > 
> > ------------------
> > Read this topic online here:
> > http://forum.openscenegraph.org/viewtopic.php?p=75839#75839 (http://forum.openscenegraph.org/viewtopic.php?p=75839#75839)
> > 
> > 
> > 
> > 
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> 
> 
> -- 
> Chris 'Xenon' Hanson, omo sanza lettere.  http://www.alphapixel.com/ (http://www.alphapixel.com/)
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Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=75845#75845