RE: [Flightgear-devel] Jitterbug pinpointed

2002-07-09 Thread Jim Wilson
Norman Vine [EMAIL PROTECTED] said: Andy Ross writes: Just adding an offset to the camera is what's already being done, and it runs into precision problems. The trick is to make sure that the camera is *never* moved to the scenery centroid before rendering the model. Right --- So

RE: [Flightgear-devel] Jitterbug pinpointed

2002-07-09 Thread Norman Vine
Jim Wilson writes: Norman Vine [EMAIL PROTECTED] said: Andy Ross writes: Just adding an offset to the camera is what's already being done, and it runs into precision problems. The trick is to make sure that the camera is *never* moved to the scenery centroid before rendering the

RE: [Flightgear-devel] Jitterbug pinpointed

2002-07-08 Thread Norman Vine
Andy Ross writes: Jim Wilson wrote: I can see what you are saying...but the aircraft (in the cockpit view) is actually a different scene graph. But it's under the same camera (oddly, ssg puts the global camera outside the graph, when it's logically the top-level node of the graph), and has

Re: [Flightgear-devel] Jitterbug pinpointed

2002-07-08 Thread Andy Ross
Norman Vine wrote: Following is IMHO a good explanation as to why having the camera a node in the scene-graph is not 'necessarily' a 'good idea' Which is a good point in theory. Their basic idea is that the scene graph specifies data, and you interpret that data via a camera. These are two

Re: [Flightgear-devel] Jitterbug pinpointed

2002-07-08 Thread Curtis L. Olson
Andy Ross writes: Which is a good point in theory. Their basic idea is that the scene graph specifies data, and you interpret that data via a camera. These are two well-defined and separate areas, and should be kept separate in code. The problem is that this leads naturally to precision

Re: [Flightgear-devel] Jitterbug pinpointed

2002-07-08 Thread Andy Ross
Curtis L. Olson wrote: I haven't been following this thread as closely as I should have been, but there should be no reason why we'd need to have the camera in the scene graph. I think we just need to be smarter about how we structure the transforms. That was my original suggestion: put the

RE: [Flightgear-devel] Jitterbug pinpointed

2002-07-08 Thread Norman Vine
Andy Ross writes The right solution (ignoring orientation, which is fine as-is) is this: Move 0m in the camera Move +1000m Draw the terrain Move ~1m to the aircraft origin Draw the cockpit Indeed ... which is why I pointed out 'where' in the code it was easiest to do this To

Re: [Flightgear-devel] Jitterbug pinpointed

2002-07-08 Thread Andy Ross
Norman Vine wrote: I guess I wrongly assumed that everyone would read this as just add the appropriate offset to move the camera to the origin :-) Unless I'm still not understanding you, I think you misunderstand the issue. Just adding an offset to the camera is what's already being done, and

RE: [Flightgear-devel] Jitterbug pinpointed

2002-07-08 Thread Norman Vine
Andy Ross writes: Norman Vine wrote: I guess I wrongly assumed that everyone would read this as just add the appropriate offset to move the camera to the origin :-) Unless I'm still not understanding you, we do seem to have a communication gap :-) not-all-M$oft-users-use-the-gui'ly yours

Re: [Flightgear-devel] Jitterbug pinpointed

2002-07-08 Thread David Megginson
Andy Ross writes: Unless I'm still not understanding you, I think you misunderstand the issue. Just adding an offset to the camera is what's already being done, and it runs into precision problems. The trick is to make sure that the camera is *never* moved to the scenery centroid

RE: [Flightgear-devel] Jitterbug pinpointed

2002-07-08 Thread Norman Vine
Andy Ross writes: Just adding an offset to the camera is what's already being done, and it runs into precision problems. The trick is to make sure that the camera is *never* moved to the scenery centroid before rendering the model. Right --- So why not leave the camera at 0,0,0 and add an

RE: [Flightgear-devel] Jitterbug pinpointed

2002-07-08 Thread Norman Vine
David Megginson writes: Andy Ross writes: Unless I'm still not understanding you, I think you misunderstand the issue. Just adding an offset to the camera is what's already being done, and it runs into precision problems. The trick is to make sure that the camera is *never* moved to

Re: [Flightgear-devel] Jitterbug pinpointed

2002-07-02 Thread Andy Ross
Jim Wilson wrote: I can see what you are saying...but the aircraft (in the cockpit view) is actually a different scene graph. But it's under the same camera (oddly, ssg puts the global camera outside the graph, when it's logically the top-level node of the graph), and has the same

Re: [Flightgear-devel] Jitterbug pinpointed

2002-07-02 Thread Andy Ross
Norman Vine wrote: To experiment I believe all you should have todo is change the value for 'center' in prep_ssg_nodes( vis, up, center ); in tilemngr.cxx to reflect the 'offset' you want. No, that won't work unless you can guarantee that the offset value will always be within ~100m of the

[Flightgear-devel] Jitterbug pinpointed

2002-07-01 Thread Andy Ross
I spent some time over the weekend struggling with the jitterbug (sorry, couldn't resist). I haven't fixed it, but I have pinpointed the issue. In essence: yes, it's a precision problem; but no, Jim's calculations aren't the problem. The problem is actually the organization of the scene graph.

Re: [Flightgear-devel] Jitterbug pinpointed

2002-07-01 Thread Jim Wilson
Andy Ross [EMAIL PROTECTED] said: Camera (orientation only, no position change) | +-- Transform (move to terrain origin) || |+-- Terrain | +-- Transform (move to model origin, orient to model frame) | +-- Aircraft Model I got started trying to figure out how