Some quite extensive changes to the AIModel code:
1. Mathias has made major changes to the AICarrier code to provide better
alignment of an aircraft on deck with the carrier - this feature is a major
improvement on the existing, but has a bug which might cause it to fail when
the computer carries out other tasks - changing window size is a known
example. This bug is outwith this code.
2. I have made significant changes to the AIShip code to enable a ship the
turn and roll smoothly.
3. I have added some simple AI which enables the carrier to remain within,
or return to, an operating box.
4. An automated turn into wind for flying operations.
5. A simplistic implementation of TACAN within AICarrier. I am in the course
of implementing this as a generic instrument, but this is some time off
completion.
I have introduced the posibility to start directly on the carrier.
With that patch you will have a --carrrier=id argument where id can either be
the pennant number configured in the nimitz scenario or the carriers name
also configured in the carriers scenario.
Additionaly you can use --parkpos=id to select different positions on the
carrier. They are also configured in the scenario file.
That includes the switch of the whole FGInterface class to make use of the
groundcache.
That means that an aircraft no longer uses the current elevation value from
the scenery class. It rather has its own local cache of the aircrafts
environment which is setup in the common_init method of FGInterface and
updated either manually by calling
FGInterface::get_groundlevel_m(lat, lon, alt_m);
or implicitly by calling the above method in the
FGInterface::_updateGeo*Position(lat, lon, alt);
methods.
A call get_groundlevel_m rebuilds the groundcache if the request is outside
the range of the cache.
Note that for the real usage of the groundcache including the correct
information about the movement of objects and the velocity information, you
still need to set up the groundcache in the usual way like YASim and JSBSim
currently does.
If you use the native interface, you will get only static objects correctly.
But for FDM's only using one single ground level for a whole step this is IMO
sufficient.
The AIManager gets a way to return the location of a object which is placed
wrt an AI Object. At the moment it only honours AICarriers for that.
That method is a static one, which loads the scenario file for that reason and
throws it away afterwards. This looked like the aprioriate way, because the
AIManager is initialized much later in flightgears bootstrap, and I did not
find an easy way to reorder that for my needs. Since this additional load is
very small and does only happen if such a relative location is required, I
think that this is ok.
Note that moving on the carrier will only work correctly for JSBSim and YASim,
but you should now be able to start and move on every not itself moving
object with any FDM.
I added an AIStatic object to my OV-10 sim for use in putting city signs,
vehicles, or anything else that will be static, but that I don't want to put
in the scenery files. It's inexpensive. Before, I was making such things
from AIShip.
I also added the ability to set flight plans to repeat, so that when an
airplane reaches the end it just starts over at the beginning. This is
useful for my OV-10 sim. I have C-141 and KC-135 traffic flying approaches
to Ramstein, and I only have to define two AI objects to do this.
Also, I found an inefficiency in AIBase, where every AI object was calculating
Mach number at every dt. Now only AIBallistic objects do this.
1) The AIStorm sets the properties:
/environment/turbulence/magnitude-norm
/environment/turbulence/rate-hz
The actual turbulence effects are handled by the FDM.
If the effects are deemed unrealistic, then that will
have to be fixed in the FDM(s).
2) The zone of turbulence is cylindrical, and is centered
at the AIStorm's lat/lon. The diameter is set with
<diameter-ft>, the top with <height-msl>, the bottom is
assumed to be at <altitude> minus 1000 feet.
3) Note that the zone of turbulence may not match well with
the visual model of the storm. In this case I had to
x-offset the storm model by 4700 meters to match the zone
of turbulence. (i.e. the storm model is 4700m off center).
4) While I was in there I also increased the speed of the
lightning flashes to look more realistic.
I have done some cleanup where I moved some values out of classes where they
do not belong and such stuff.
Also the fols offsets are now named in the carrier xml file with a more
verbose name (flols-pos/offset-*) than before (only offset-*).
There is a little preparation for definitions of parking positions on the
carrier which should later be used for starting flightgear directly on the
carrier.
I just heard from John Wojnaroski that you and he are going to work on getting
a flightgear demo machine up for the linux expo thursday and Friday. John
indicated that he would very much like to get a CVS version with the new
traffic code up and running before the expo.
This is a sub-system which can be added to any carrier.
These files add a functioning Fresnel Lens Optical Landing System (FLOLS).
The orange/red 'source' lights are illuminated according to the position of
the pilot's eye above/below the 3.5 deg glide slope. The apparent position
of the source light relative to the fixed green datum lights allow the pilot
to 'fly the meatball'. The green 'cut' lights flash when the pilot's eye is
below the coverage of the lowest (red) source light.
TODO - add rules for the operation of the wave-off lights.
Okay, here's the latest update to the tarffic manager/AI Manager. AITraffic
can now fly multiple routes and be initialized while sitting statically at
airports.
Here are files to get automated contrails working. I've set up contrails for
the 737, using my simple, untextured contrail model. Vivian has made another
contrail model, but I'm still trying to get his to work. I'm hoping others
will try to make contrail models also.
Here's some code that defines a top to thermals. When the top of a thermal is
reached the strength is phased-out linearly over the next 100 feet of
altitude. At first I tried just capping the thermal at the top, but the
change in thermal strength was too fast for the FDM to handle well.
Included is a new version of the thermal scenario that includes a top
(height-msl) to the thermal. The default value is 5000 feet.
As a result of recent requests, I've implemented the ability to switch off
aerodynamic stabilisation:
This has to be added to the submodel.xml files:
<aero-stabilised>false</aero-stabilised>
When false the submodel retains the pitch given at instantiation.
It defaults to true.
The calculation of submodel mass from weight has been moved from AIBallistic
to Submodel so that it is calculated only once, rather than on every
iteration as a present. The parameter <contents> has been added, primarily
so that droptanks will have the proper mass. It is the path to an
appropriate property containing a weight in lbs.
Care has to be taken with the use of <contents> because after a reset there
appears to be a delay in submodel instantiation (dt not properly reset???)
and the weight property is not always picked up before it is set to zero in
the key bindings. Slightly hard to explain. It works fine if FGFS has not
been reset though. There is a partial solution which involves the rejigging
of the fuel and gui nasal scripts, but there is still the visible delay in
instantiation to be resolved. I've nearly done the nasal fixes, which will
form part of an update to the Hunter only. I'll probably complete those
later today.
The value of rho (air density) varies with height. (Including the upper
stratosphere, ust in case someone wants to model ICBMs.) The standard
atmosphere is used (based on a sea-level temperature of 15 deg C.).
Erik Hofman:
I moved this code over the AIBase::update() so all AIModels can make
use of rho, temperature, pressure, etc.
I have added <Cd> and <weight> to the input parameters in the submodels.xml
script. Raw data may be used, thus avoiding the need to guestimate <eda>.
Eda remains, but should now be used to enter the proper cross-sectional
area.
Here's some new AI stuff.
1) AI objects must now be defined in a scenario file, not in preferences.xml
or a *-set file. (Of course this doesn't prevent objects from being created
dynamically, as with Durk's traffic manager).
2) A new demo_scenario file is attached. It creates 3 aircraft, a sailboat,
and a thunderstorm.
3) Objects without flightplans live forever.
4) FGAIShip::ProcessFlightplan() is not yet implemented.
5) preferences.xml should now define only <enabled> and <scenario>
1. Removed aircraft roll on ground.
2. Decreased descent pitch angle.
3. Updated flightplans to include <on-ground>
4. Fixed property indexing, so all AI aircraft have their own property branch
The default value of <on-ground> is false, so you only need to specify it when
on the ground. For takeoff you need to specify <on-ground>true</on-ground>
for the first waypoint, and for the acceleration waypoint. For landing you
need to specify it for the touchdown point and any taxi points.
One problem. WARNING **** There is a bug in the way the property system
works, which causes a segfault, but I don't know if the problem is in the
property code, or in how I'm using it. After an AI object terminates, if you
access the property tree through the property browser the sim will segfault.
I added some things to the AI stuff to improve the AIThermal processing.
Before, all the thermals were processed in order, and the last one overwrote
the prior one. Now, only the data from the nearest thermal is kept. This
way a tile can be populated with many thermals, and (as long as they have the
same diameter) the one nearest the airplane correctly takes effect. This
will make us ready for the next step, "auto-thermaling", where FlightGear's
tile manager can cover a tile with thermals, and set the thermal strength
based on land-use type.
I moved the enumerated object_type to the base class. When an AI object is
created it now sets the _otype variable in the base class. This lets the AI
manager find out what kind of AI object it is dealing with, using the base
pointer. I also added a function isa() to the base class, so the manager can
process objects differently based on their type.
The AI manager now sends AIThermal processing to a different function, where
only the data from the nearest thermal is kept. After the manager processes
all the AI objects, then the results from the nearest thermal are applied to
wind-from-down.
Here's a new batch of AI code which includes a working radar instrument.
I put the radar calculations into the existing AIAircraft class. It was
easier that way, and it can always be migrated out later if we have to.
Every tenth sim cycle the AIManager makes a copy of the current user state
information. When the AIAircraft updates it uses this information to
calculate the radar numbers. It calculates:
1) bearing from user to target
2) range to target in nautical miles
3) "horizontal offset" to target. This is the angle from the nose to the
target, in degrees, from -180 to 180. This will be useful later for a HUD.
4) elevation, in degrees (vertical angle from user's position to target
position)
5) vertical offset, in degrees (this is elevation corrected for user's pitch)
6) rdot (range rate in knots, note: not working yet, so I commented it out)
and three items used by the radar instrument to place the "blip"
7) y_shift, in nautical miles
8) x_shift, in nautical miles
9) rotation, in degrees
The radar instrument uses the above three items, and applies a scale factor to
the x-shift and y-shift in order to match the instrument's scale. Changing
the display scale can be done entirely in the XML code for the instrument.
Right now it's set up only to display a 40 mile scale.
The radar is an AWACS view, which is not very realistic, but it is useful and
demonstrates the technology. With just a little more work I can get a HUD
marker. All I need to do there is make a bank angle adjustment to the
current values.
I went through the AI code to put the "bank" node back into the config file,
so the models can fly circles. While I was in there I made some other
changes.
*) Moved the initialization of roll, tgt-roll, pitch ... etc, from init()
into the constructor, so it wouldn't over-write the config settings.
*) Changed the altitude getter to remove the meters-to-feet conversion. The
altitude is kept internally in feet. Only the scenery code needs meters.
*) Added "bank" item for config file (for type=aircraft). Left bank is
negative.
*) Added "rudder" item for config file (for type=ship). Left rudder is
negative. Internally this is stored in the "roll" variable, but the ship
model doesn't roll. It uses the "roll" variable for turning though.
The following puts a tanker at 3000 feet, 6 nm northwest of KSFO. On takeoff,
the tanker is visible over the hanger building at one-o'clock.
<entry>
<type>aircraft</type>
<class>jet_transport</class>
<path>Aircraft/737/Models/boeing733.xml</path>
<speed-KTAS type="double">320.0</speed-KTAS>
<altitude-ft type="double">3000.0</altitude-ft>
<longitude type="double">-122.455</longitude>
<latitude type="double">37.69667</latitude>
<heading type="double">200.0</heading>
<bank type="double">-15.0</bank>
</entry>
