You can also rasterize your points as 3D cones on a 2D surface normal to the view vector. The cones will spread out and merge together, covering the space between them, so that in empty space, you'll always hit something -- the nearest point.
On Tue, Feb 12, 2013 at 3:02 AM, Sergey Kurdakov <[email protected]>wrote: > Hi Shawl, > > >my question is that i want to select a point of the scene as the rotation > center of the trackball manipulator . i know how to pick objects , > > I will not answer your question, but will say an approach, which I can > think of > > in principle 2D to 3D an approach is described say here ( just skip this > is directx ) > > http://www.mvps.org/directx/articles/rayproj.htm > http://www.mvps.org/directx/articles/improved_ray_picking.htm > > ( there are few examples to pick objects ), but in case of cloud you most > probably will need an octree, which has all points, > > then you intersect octree cubes and in the smallest cube which is > intersected - if theris one point - select it, if there are few = select > nearest point to the intersecting line ( see somewhere point line distance ) > > > Regards > Sergey > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > -- Chris 'Xenon' Hanson, omo sanza lettere. [email protected] http://www.alphapixel.com/ Training • Consulting • Contracting 3D • Scene Graphs (Open Scene Graph/OSG) • OpenGL 2 • OpenGL 3 • OpenGL 4 • GLSL • OpenGL ES 1 • OpenGL ES 2 • OpenCL Digital Imaging • GIS • GPS • osgEarth • Terrain • Telemetry • Cryptography • Digital Audio • LIDAR • Kinect • Embedded • Mobile • iPhone/iPad/iOS • Android @alphapixel <https://twitter.com/alphapixel> facebook.com/alphapixel (775) 623-PIXL [7495]
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