Re: [osg-users] Compute Terrain Intersection for .flt databases[SEC=UNCLASSIFIED]
Thanks Robert/Shayne, turns out I was computing HAT correctly but was using wrong texture filtering ( I store the positions in a texture ). thus the computed heights were displayed incorrectly in the vert shader. Thanks again. On 09/08/2010 12:27 AM, Tueller, Shayne R Civ USAF AFMC 519 SMXS/MXDEC wrote: > Paul, > > For HAT, you only need one point. LOS requires a start and end point. Both > require that the points be specified in the database coordinates (i.e. > geocentric Cartesian coordinates for round earth databases). > > I haven't worked with .flt databases but the osgSim methods appear to work > for paged databases built by VPB... > > -Shayne > > -Original Message- > From: osg-users-boun...@lists.openscenegraph.org > [mailto:osg-users-boun...@lists.openscenegraph.org] On Behalf Of Paul Pocock > Sent: Thursday, September 02, 2010 11:06 PM > To: osg-users@lists.openscenegraph.org > Subject: [osg-users] Compute Terrain Intersection for .flt > databases[SEC=UNCLASSIFIED] > > Hi - Whats the best way to get the z down intersect point onto a paged > database. I'm getting what looks like loss of precision errors. I am not > sure if it is because I am using osgUtil::IntersectVisitor (Which I > believe is deprecated?) or my lack of knowledge of > osgSim::HeightAboveTerrain. Is it my proper understanding that I provide > two points x,y,z (beginning and end) for HAT? Even doing this gives some > very strange results... Is there a very basic example out there to > achieve this? Is it a trivial problem? > > Regards > Paul > > > > IMPORTANT: This email remains the property of the Department of Defence and > is subject to the jurisdiction of section 70 of the Crimes Act 1914. If you > have received this email in error, you are requested to contact the sender > and delete the email. > ___ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > > > ___ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Compute Terrain Intersection for .flt databases[SEC=UNCLASSIFIED]
Paul, For HAT, you only need one point. LOS requires a start and end point. Both require that the points be specified in the database coordinates (i.e. geocentric Cartesian coordinates for round earth databases). I haven't worked with .flt databases but the osgSim methods appear to work for paged databases built by VPB... -Shayne -Original Message- From: osg-users-boun...@lists.openscenegraph.org [mailto:osg-users-boun...@lists.openscenegraph.org] On Behalf Of Paul Pocock Sent: Thursday, September 02, 2010 11:06 PM To: osg-users@lists.openscenegraph.org Subject: [osg-users] Compute Terrain Intersection for .flt databases[SEC=UNCLASSIFIED] Hi - Whats the best way to get the z down intersect point onto a paged database. I'm getting what looks like loss of precision errors. I am not sure if it is because I am using osgUtil::IntersectVisitor (Which I believe is deprecated?) or my lack of knowledge of osgSim::HeightAboveTerrain. Is it my proper understanding that I provide two points x,y,z (beginning and end) for HAT? Even doing this gives some very strange results... Is there a very basic example out there to achieve this? Is it a trivial problem? Regards Paul IMPORTANT: This email remains the property of the Department of Defence and is subject to the jurisdiction of section 70 of the Crimes Act 1914. If you have received this email in error, you are requested to contact the sender and delete the email. ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org smime.p7s Description: S/MIME cryptographic signature ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Compute Terrain Intersection for .flt databases [SEC=UNCLASSIFIED]
Hi Paul, osgUtil::IntersectVisitor is deprecated. osgUtil::IntersectionVisitor coupled with LineSegmentIntersector is more flexible and has the support for using KdTree to improve performance significantly - you'll need to enable the build of KdTree's in the DatabasePager to use them. This topic has been discussed several times so have a look through the archives. osgSim::HeightAboveTerrain provides a simpler interface ontop of IntersectionVisitor and also adds support for automatically loaded high levels of details. The loaded is done synchronously though so if the intersection traversal it does needs to load external tiles it will take significantly longer to do the query. There is a cache of tiles to help reduce this cost on subsequent queries. The osgintersection example provides code that illustrates the various intersection routines in action. Robert. On Fri, Sep 3, 2010 at 6:06 AM, Paul Pocock wrote: > Hi - Whats the best way to get the z down intersect point onto a paged > database. I'm getting what looks like loss of precision errors. I am not > sure if it is because I am using  osgUtil::IntersectVisitor (Which I > believe is deprecated?) or my lack of knowledge of > osgSim::HeightAboveTerrain. Is it my proper understanding that I provide > two points x,y,z (beginning and end) for HAT? Even doing this gives some > very strange results... Is there a very basic example out there to > achieve this? Is it a trivial problem? > > Regards > Paul > > > > IMPORTANT: This email remains the property of the Department of Defence and > is subject to the jurisdiction of section 70 of the Crimes Act 1914. If you > have received this email in error, you are requested to contact the sender > and delete the email. > ___ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
