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 some small updates to the ground cache.
- Remove the usage of dynamic_cast where it is known that the result will be
non null.
- Renormalize the surface normal in double precision.
- Place the groundcaches center at the point it was requested not at the
scenery center. This fixes the problems with JSBSim's trimming together with
the ground cache. Now I am ready to commit JSBSim's ground cache usage.
have a "property" mode as well as the original "binary" mode. The property mode
will allow the remote module to request any set of properties, and it will send
those properties each frame. The remote module can reply with a list of arbitrary
property name/value pairs to update on the FlightGear side.
This is a first stab, so it's not the cleanest, most well concieved code, but it
allows an external module (communicating via a pipe) to have a huge amount of
flexibility in the data in can access and update.
popping up and crashing when the B-29 model is in use. This isn't the
right solution; we should fine the NaN condition. But it's harmless
and allows development with the B-29 to continue.
back, but forgot to put the same fix into the runtime code. Also
added some comments so I don't get confused again the next time I come
through here. :)
I still work on getting the YASim models see the detailed environment
especially the carrier.
I have *forgotten* to initialize and to destruct the ground cache object!
Oooopppss!
currently just returns a lagged normalized value in the range of 0-1 that
is proportional to N1. It's up to the engine gauge to scale to the right
range. This is for lack of a real model of these items so we can have
something to drive the engine gauges.
I have now split out the ground cache functions into src/FDM/groundcache.[ch]xx
Attached are the two files and the patch to integrate that cache into
FGInterface.
The code is nowhere used at the moment, the fdm's need to be updated to use
that ground cache. The JSBSim-dropin.tar.gz from Martins ftp server does this
for example.
The carrier's scenegraph is not yet processed to be visible for ground
intersection testing. So the only benefit up to now is that the api is set
up. Using this I can put the changes to make JSBSim work with that into
JSBSim's cvs. Also I aim to provide Andy a patch to make use of that with
YASim.
I've added two new debug log types for the instrumentation and systems. They
used to use the autopilot debug log, because I couldn't figure out how to
make new log types. Well, now I have figured it out. ;-)
As I had reported on 2004/8/4 00:02:56 ("yasim + bo105 + vrp + @#%$#@ == argh!")
there must be a bug somewhere in YASim, which is responsible for the Bo105
turning around the FDM origin (nose tip) rather than the CG. Some people assumed
that I was just another victim of the "view offset" illusion, but this wasn't
and isn't the case.
Maik Justus (the rotor man) has now supposedly found the bug in YASim[1].
Look at this code in FDM/YASim/Integrator.cpp:35--66:
Stub in hooks for Propeller feathering controls and the turbo prop "condition"
lever.
I added a line in FGFDM.cpp to force control properties to exist if they
don't already. This way you can specify anything you want and find them
in the property browser, otherwise no one else may create them and you are
stuck.
In PropEngine::solve() the code original sets _running = true at the
beginning and then sets running = false at the end. I changed this to
save the current value at the start, set to true, solve(), and then
restore the original value at the end. That way if we start off with
_running = true, we don't have to hack up the calc() routine which wasn't
using the value anyway.
Finally I added some very initial support to shut down a turbine engine
(_running = false) when the condition lever goes to zero.
I have 3 issues that are fixed by this set of patches.
1. In extensions.cxx
#else if !defined( WIN32 ) must be changed by
#elif !defined( WIN32 ) because the text after #else
seems to be ignored
2. banner is not available on windows, only cygwin
3. ANSI escape sequences are not interpreted on the
windows console. We just have garbage that is hard
to read.
the 30 seconds that Maik had originally intended, according to the comment.
This is important for the pending sound and rotor disc changes (and of course
for realism).
