Norman,
Thanks. I get the point.
Well writing separate code is precisely what I wanted to avoid. But it looks like I have no choice.
On the Timezone problem (remember you sent the entire timezone sub-directory from your installation), I did a base package fresh update using cvs instead of WinCVS and it worked. Looks like I need to set something in WinCVS to recognise my binary mounted drive of Cygwin. Dont bother about this anymore, I'll use only cvs from now on.Thanks again.
Regards
Ranga
----- Original Message -----
From: Norman Vine
To: flightgear-devel@lists.sourceforge.net
Sent: Saturday, July 28, 2001 7:35 PM
Subject: RE: [Flightgear-devel] Height over objects in scene

VS Renganathan  writes: 
 
I am unable to crack this and could do with some help. 
I load saratoga.obj thro FGLoadDCS() in main.cxx and set(SSGTRAV_HOT)  
and also add the node to the terrain branch.  
I find that hit_list.Intersect() does not detect the presence of this object. 
What else do I have to do so that I can obtain the correct Height  
 over Terrain when on the deck. 
 
Hi Ranga
 
Your are loading your objects with global coordinates.
The hit_list works with a scenery_center + tile coordinate based system
 
see the prep_nodes function in the tile_manager and tile_entry.cxx
 
See my WorldCoordinate() function for determining the tile coordinates
at load time.
 
I think that you will have to attached your object to the appropriate
tile_transform node inorder fo this to work.
 
Another approach might be to use the built in SSG HOT terrain functions
( SSGTRAV_HOT) and build a separate scene graph for your carrier.
This would have the added benefit of being a REAL FAST test as if you
were above the carrier or not.and give you both the height over water
and the height over the flight deck.  The only tricky part in doing this that
I see would be building the transforms for the intersection in global rather
then a 'scenery centered' based coordinate system. 
 
I would have to think abiut this some to get the 'best' method of doing this.
But I think that you can get the global plane position and the global transform
directly out of the viewer.  Tou would then have to write a new function
similar to fgCurrentElev()  to work witth this scenegraph. 
< fgCurrentElev is hardwired for our tile based approach >
 
Cheers
 
Norman