Together with previous patch, make view reference frame, view offset,
and current view visible in property tree.
Also some comments about the concepts behind these variables.
Add a view debugging functions and represent the viewer quats in the property tree for debugging.
Do a nontrivial calculation, demonstrating how to find the 12:00 orientation given the view and the view offset. it, and observe that the 12:00 direction does not change when you change the view offset, which is a nontrivial result.
Erik: This already proved to be useful since I now obserbed that the sky and fog coloring code depends on view offset rather that the view orientations. This is why those effects are out of line in some views.
/sim/view[*] that it finds. It's not only unnecessary that view definitions
have subsequent indices, but aircraft are now *requested* to use indices
100++. /sim/view[0] .. /sim/view[99] are reserved for the system. (Not
that we'd ever need that many, This is just a convention, it's nowhere
hard-coded.)
- replace the string operations for property paths by method calls & other
improvements
I have done a patch to eliminate the jitter of 3D-objects near the viewpoint
(for example 3D cockpit objects).
The problem is the roundoff accuracy of the float values used in the
scenegraph together with the transforms of the eyepoint relative to the
scenery center.
The solution will be to move the scenery center near the view point.
This way floats relative accuracy is enough to show a stable picture.
To get that right I have introduced a transform node for the scenegraph which
is responsible for that shift and uses double values as long as possible.
The scenery subsystem now has a list of all those transforms required to place
objects in the world and will tell all those transforms that the scenery
center has changed when the set_scenery_center() of the scenery subsystem is
called.
The problem was not solvable by SGModelPlacement and SGLocation, since not all
objects, especially the scenery, are placed using these classes.
The first approach was to have the scenery center exactly at the eyepoint.
This works well for the cockpit.
But then the ground jitters a bit below the aircraft. With our default views
you can't see that, but that F-18 has a camera view below the left engine
intake with the nose gear and the ground in its field of view, here I could
see that.
Having the scenery center constant will still have this roundoff problems, but
like it is now too, the roundoff error here is exactly the same in each
frame, so you will not notice any jitter.
The real solution is now to keep the scenery center constant as long as it is
in a ball of 30m radius around the view point. If the scenery center is
outside this ball, just put it at the view point.
As a sideeffect of now beeing able to switch the scenery center in the whole
scenegraph with one function call, I was able to remove a one half of a
problem when switching views, where the scenery center was far off for one or
two frames past switching from one view to the next. Also included is a fix
to the other half of this problem, where the view position was not yet copied
into a view when it is switched (at least under glut). This was responsible
for the 'Error: ...' messages of the cloud subsystem when views were
switched.
I have added a --aspect-ratio-multiplier=x.xx option to give some end user
control over the aspect ratio. (This may seem a little strange, but it's a
building block towards the capability of doing asymmetric view frustums in
FlightGear.)
The jitter is most likely caused by the irregular frame rate and CPU clock dependent intervals. There's no easy way around that. I tried some fancy interpolation and all that -- to no avail.
The current chase view respects heading but ignores roll & pitch. And it follows heading without delay, which makes the viewer behave quite strange. This change makes the chase view feel more natural. You aren't fixed behind the plane, but follow all its movements with a delay.
Erik Hofman:
I've decided not to add the patch to preferences.xml in the base package because something feels funny with that. I think there needs to be some more discussion about it.
04Feb. Actually been running since the beginning of January with these
patches. All changes work without crashing with the current base package cvs,
but there are some visual problems with the views (other than pilot view)
without changes to the base package.
As soon as you can build test and commit I can add in those base package
updates that will make it all work nicely. I will also go through all the 3D
Aircraft configs to make sure the change in the "pitch-offset" for cockpit
views (see below) are made to maintain current behavior.
Here are the files (changes listed below):
http://www.spiderbark.com/fgfs/viewerupdate.diffs.gzhttp://www.spiderbark.com/fgfs/viewerupdate.tar.gz
Make locally-used strings local instead of global. (The safety and
cleanliness benefit outweights the slight performance hit. If
performance is an issue, the way these strings are used should be
optimised.) Use existing defined constant instead of a literal
number.
- changed FGSubsystem::update(int) to
FGSubsystem::update(delta_time_sec); the argument is now delta time
in seconds rather than milliseconds
- added FGSubsystem::suspend(), FGSubsystem::suspend(bool),
FGSubsystem::resume(), and FGSubsystem::is_suspended(), all with
default implementations; is_suspended takes account of the master
freeze as well as the subsystem's individual suspended state
- the FDMs now use the delta time argument the same as the rest of
FlightGear; formerly, main.cxx made a special case and passed a
multiloop argument
- FDMs now calculate multiloop internally instead of relying on
main.cxx
There are probably some problems -- I've done basic testing with the
major FDMs and subsystems, but we'll probably need a few weeks to
sniff out bugs.
