From Till:
i started the project at the end of february with a simple idea: move all
3d-model loading to the DatabasePager-thread. my first attempts looked
promising, though they were a little too optimistic (or naive?). the patch
has evolved a lot since.
currently it does the following things:
1. revive SGModelLib, move functions for xml-model-loading there
2. replace all calls to sgLoad3dModel with calls to either
SGModelLib::loadModel() or SGModelLib::loadPagedModel()
almost all models will be loaded by the DatabasePager. the few exceptions are:
your own plane, shared models in scenery, random objects, AIBallistic models.
3. simplify mode-loading functions (avoid passing around fg_root)
4. avoid supurious MatrixTransform nodes in loaded models
5. fix some memory leaks
a crash when using the model manager from XML files (which apparently
nobody does, anyway ;-) Now those models work (again), but have no
shadows. Those placed at runtime (e.g. via ufo) still have a shadow.
implement FGNasalModelData class for execution of XML <load> and <unload>
scripts. modelLoaded() is called by the model loader, and the destructor
on branch removal.
modelmgr.cxx:
tilemgr.cxx:
tileentry.[ch]xx:
make scenery and custom objects run their Nasal scripts on loading
and unloading. Let OBJECT_STATIC object not be cached.
The new multiplayer patch with an extension to transmit some properties with
the base package. The properties are transmitted in a way that will not
immediately brake the packet format if we need new ones.
Even if the maxmimum number needs to be limited somehow, that format might
work well until we have an improoved packet format which is even more compact
and that does not require to retransmit redundant information with each
packet.
That part is relatively fresh and based on that what Oliver provides on his
multiplayer server web page.
The properties are transferred to the client and I have modified the seahawks
rudder animation property to use a relative property path to verify that it
works appart from the fact that you can see it changing in the property
browser.
The movement is still a bit jerky, but that can be fixed/tuned later without
again braking the packet format.
Changes
=======
- acmodel.cxx :
we now have an optional new property (/sim/model/texture-path) that is used
as the first path in wich aircraft textures are searched. If textures are not
found there then the usual texture path or model path is used ;
This allows to replace only needed textures for liveries ;
- options.cxx :
added a new --livery=xxx option for the user pleasure ;
this will just set the /sim/model/texture-path property with /livery/xxxx
- od_gauge.cxx, og_gauge.hxx, cockpit.cxx, cockpit.hxx,
generic-instrumentation.xml :
added an helper class that contain a rendering context for glass instrument
or any other opengl drawn instrument ;
- wxradar.cxx, instrument_mgr.cxx, wxradar.hxx :
first experimentation of a weather radar ;
There was a patch from Manuel Masing a few months ago which cleaned up
SGLocation's way depending on input values. That means that with that patch
SGLocation does no longer have calls with unneeded input arguments.
I took his patch and integrated that into flightgear and made maximum use of
that changes.
Erik Hofman:
Remove some duplicate code that was moved to simgear/compiler.h
- replay.cxx :
corrected a bug, now reinitialize the recording data when replay is
deactivated
- fgclouds.cxx :
cloud layers and weather condition are saved when choosing a weather scenario,
added a new scenario 'none' so we can switch back to standard flightgear
weather
- navradio.cxx :
force a search() on init to initialize some variables, preventing a nearly
infinite loop when delta-time == 0 on the first update()
- electrical.cxx :
uninitialized variable in apply_load() for FG_EXTERNAL supplier
- panel.cxx, panelnode.cxx :
added a property "depth-test" for 2.5D panels so that they update the depth
buffer and are no more visible from the outside of the aircraft when the
aircraft uses textures without an alpha channel
- panel.cxx :
moved the computation of the instruments diffuse color outside the
texturelayer code since this is constant during a frame, this is a big speedup
for 2D panels
I did some profiling of the code and found a few interessant things. Some corrections are obvious like the one in the multiplayer code, the fps is no more divided by 2 or 3 when another plane is on screen.
Other things like collision detection and computation of agl can not really be optimized. I changed a few things in hitlist.cxx but this only give a very low increase of fps. The groundcache eats a lot of cpu but I think that the real way to do it is to use a real collision system like OPCODE or something like that.
And I added an option to disable the recording of replay data. It takes more cpu than we can think.
Changes
=======
- panel.cxx :
moved the computation of the instruments diffuse color outside the texturelayer code
since this is constant during a frame, this is a big speedup for 2D panels ;
- hitlist.cxx :
changed the computation of the intersection between ray and triangle, optimized
the sphere culling by using a normalized direction vector. This can give a
35% speedup on the computation of elevation in some situations ;
- renderer.cxx, acmodel.cxx :
call ssgDrawAndCull with plane scene graph in external or internal view,
calling ssgDrawAndCull with the root scene graph was drawing other players plane
a second time in multiplayer mode ;
- mplayer.cxx :
removed the calls to ssgFlatten and ssgStripify because it was degenerating models,
causing a massive drop in frame rate ;
- replay.cxx :
added an option to disable the recording of the flight
- fgclouds.cxx :
changed the path of cloudlayer properties to match preferences.xml ;
set the altitude of clouds from scenarios to a more correct value if metar is not enabled ;
Changes
=======
New volumetric shadows for FlightGear.
There is now two new checkboxes in the rendering dialog to enable/disable shadows
for the user aircraft and for static scenery objects (ie those defined in the .stg files).
AI and random objects are not handled for the moment.
known bugs
==========
- ghost objects
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.
ssgSetNearFar(). This by default creates a symmetric view frustum which is
typically what an application wants.
However, to get control of the view frustum in order to build support for
asymmetric view frustums, we need to wrap these calls with a bit of our own
logic.
This set of changes wraps all calls to ssgSetFOV() and ssgSetNearFar() with
FGRenderer methods.
I also standardized how the FGRenderer class is handled in globals.[ch]xx.
This led to some cascading changes in a variety of source files.
As I was working my way through the changes, I fixed a few warnings along
the way.
Split up main.cxx into a program manegement part (which remains in
main.cxx) and a render part (the new renderer.?xx files). Also turn
the renderer into a small class of it's own. At this time not really
exctining because most of the stuff is still global, but it allows us
to slowly migrate some of the global definitions into the new class.
The FGRenderer class is now managed by globals, so to get the renderer
just call gloabals->get_renderer()
At some pijt it might be a good idea to also turn the remaining code in
main into a class of it's own. With a bit of luck we end up with a more
robust, and better maintainable code.
This patch is there to correct a problem that prevent to load static objects when specifying a relative fg-root or a different, relative, fg-scenery. It appears that there is a mix between fg-root, fg-scenery and PLIB's model-dir.
It has been reported on the list that users are not able to see the buildings, especially those running the win32 builds because they run 'runfgfs.bat' that set FG_ROOT=./DATA.
I decided not to use model-dir because it just add confusion and to build a valid path earlier.
