under some circumstances. The history of this patch is somewhat unclear,
but was brought to my attention by Martin Spott, while preparing for the
Lelystad FSWeekend show. See also my posting on FlightGear devel, on
November 22, 2007 "(Multiplayer Local Echo Patch)", but wasn't committed
then because I/we assumed that had been superseded by other code
modifications. The local echo problem still persists, however, albeit
under specific circumstances. The current patch reportedly prevents this
from happening.
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
Instead of just reporting that the magic number, length, etc. of a
multiplayer packet is invalid, abort processing this packet. Also,
check if enough space remains to send a property string.
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.
This patch removes some useless indirection when creating AIModels. It
obsolets AIScenario*.
AIEntities are just an intermediate copy of an other intermediate copy of an
xml file on the way from the ai scenario configuration file to the AIModels.
As such the AImodels can now be created directly from the property tree read
from the scenario file.
This reduces the amount of work needed to add an other AIModel and reduces the
amount of copy operations done during initialization.
It also moves internal knowledge of special AI models into these special AI
models class instead of spreading that into the whole AIModel subdirectory
which in turn enables to use carrier internal data structures for carrier
internal data ...
Also some unused variables are removed from the AIModel classes.
I believe that there are still more of them, but that is what I stumbled
accross ...
Tested, like the other splitouts these days in a seperate tree and using the
autopilot for some time, and in this case with a carrier start ...
This patch is a combined effort by Gregor Richards, Oliver Schroeder, and
Vivian Meazza (and code cleanups and improvements by Erik Hofman). It corrects
the bug in which a Multiplayer model responds to local inputs, and the view
number bug which caused certain aircraft to appear as cockpit only models. It
passes remote properties over the net, and all major control surfaces and gear
are now animated correctly, providing that the local ~model.xml file contains
no leading "/" in the <property></property> data entries. MP objects
are now extrapolated using 1st and 2nd derivatives to make their movement
appear more smooth. The sim is now halted while a new client joins the net.
Known problems with MP are non-display of the remote client under certain
circumstances of starting/resetting, and a freeze on starting. These bugs are
long standing, and are not addressed by this patch.
Special thanks must go to AJ Macleod for his patient testing of this patch over many evenings.
We have also moved part of multiplayer into AIModels as part of the ongoing
development of MP.
This was the reason why some people (especially SuSE10.0/gcc 4.0.2
users) couldn't see others in MP. I don't even know why I'm committing
that. It's less important than taxi lights ...
there was the situation where four directories contained jst two files,
of which three directories were aircraft related, and one directory contained
test code from Curt that might be better of in SimGear anyhow.
This is just a patch to move a bunch of files to new locations. In case of
local changes to any of them you can do the following:
move replay.[ch]xx from src/Replay to src/Aircraft
move control.[ch]xx from src/Control to src/Aircraft
move ssgEntityArray.[ch]xx from src/Objects to simgear/screen
In addition it has been decided only to use .[ch]xx files in all directories
unless it's contained within an FDM specific directory, in which case the
author is free to do whatever (s)he wants.
In this repspect the following files have been renamed in src/Multiplayer:
tiny_xdr.[ch]pp has become tiny_xdr.[ch]xx
multiplaymgr.[ch]pp has become multiplaymgr.[ch]xx
I have prepared a new patch for multiplayer, which fixes endianess issues with
multiplayer code. It's basically identical to the patch I sent before my
vacation, but contains minor fixes.
Multiplayer should now be working under all unix-like environments and windows
native. The basic trick is to let configure check for endianess of the host
system.
It will not work on system not using configure in the build process (excluding
windows), ie. possibly MACOS. For those system we should provide #ifdefs in
tiny_xdr.hpp.
Erik:
I've updated the patch to use the Plib utils package for endian swapping an
used a preprocessor directive to detect endianess.
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
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 ;
I have now included a patch to the multiplyer protocoll which does:
1. place the 3d model into the scenery using a placement transform which can
dynamically change its scenry center.
2. Transmits unique position and orientation data for the 3d model.
3. Thus breaks protocol compatibility.
Oliver Schroeder:
With help from Norman I fixed the alignment in the used headers.
But this patch again fixes only symtoms, not the problems. I suggest to
put it into cvs anyway, as it will enable the majority to get experience
with the multiplayer mode.
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.
scene management code and organizing it within simgear. My strategy is
to identify the code I want to move, and break it's direct flightgear
dependencies. Then it will be free to move over into the simgear package.
- Moved some property specific code into simgear/props/
- Split out the condition code from fgfs/src/Main/fg_props and put it
in it's own source file in simgear/props/
- Created a scene subdirectory for scenery, model, and material property
related code.
- Moved location.[ch]xx into simgear/scene/model/
- The location and condition code had dependencies on flightgear's global
state (all the globals-> stuff, the flightgear property tree, etc.) SimGear
code can't depend on it so that data has to be passed as parameters to the
functions/methods/constructors.
- This need to pass data as function parameters had a dramatic cascading
effect throughout the FlightGear code.
