This is just a port of an old 3D HUD patch to the new view code.
This pans the HUD with the view, by pasting it onto a quad fixed in front of the viewer. It also fixes the awful, arbitrary scaling problems the HUD code has. The old HUD only looks right when viewed at 1024x768 and 55 degree FOV. This works the scale out magically so that it looks right in all views. It also redefines the "<compression-factor>" tag in the ladder to (1) mean compression instead of expansion and (2) have non-psychopathic units (now "1" means 1 degree per degree). Fix this in your existing HUD ladder files before reporting bugs. It's definitely a cosmetic win -- the velocity vector points at the right thing and the horizon lines up properly.
Norman wrote:
I have created a modified version of Andy's patch that implements the 3D HUD as the 'normal' and the 2D HUD as the 'minimal' HUD. < i > and < shift I > keys
I've fixed a bug in FGRunways::search(aptid, tgt_hdg) which wasn't working properly for airports with multiple parallel runways. I've also firmed up and pulled out into it's own function the GetReverseRunwayNo code, and done some input checking.
As a result of fixing the above in runways.cxx, I've pulled out the
parallel implementation in the functions that set position by airport and
heading/runway number in fg_init.cxx and called the runways functions
instead.
earlier, before fgInitSubsystems().
Modify fgInitPos() so that the plane is not automatically aligned with
a runway when an airport is the reference point unless (a) a runway
was explicitly requested, or (b) the plane is on the ground with no
offset distance specified. To set up the plane lined up on an
approach to a runway, use something like
fgfs --airport=CYOW --runway=32 --altitude=300 --offset-distance=0.5
This way, it's possible to specify a starting position relative to an
airport without getting snapped onto a runway approach (unless you
want to be).
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
All logs and log entries are now disabled by default, unless
explicitly enabled by an 'enabled' property. This works much more
intuitively with the GUI dialog.
if the station is too far away. Instead, simply return the closest station.
All the code that searches navaids does it's own range checking anyway.
This will make the navlist query functions a bit more useful for other
types of functionality where you may need to lookup a station without
consideration of range (i.e. presetting your position relative to a navaid.)
(I thought I'd slip this in along with David's change to the default menu
configure option. I believe that will cause a new config.h to be generated
which will cause a near complete rebuild of FG (as will this globals.hxx
change) so it shouldn't cause additional grief to have these happen at the
same time.)
input bindings. They will work only with the latest CVS; otherwise,
./configure will disable them. There is a new command, 'script',
which takes a single argument, also called 'script', containing PSL
code (currently PSL requires a main() function).
Erik Hofman has written some more elaborate code for triggering PSL
code from drop-down menus and scheduling events; I will look at
integrating that next.
and property-multiply:
Firstly, change back to wrapping modulo the interval, with "min <= x <
max" semantics. I believe the previous implementation did that. The
inline function that Norman mentioned also does that.
Secondly, make it snap to the nearest value (min + N*resolution) when a
"resolution" tag is present, taking special care of floating-point
precision. Or perhaps specify "number of divisions in the interval" as
an integer, instead of "resolution" by which I meant a floating-point
"size of a division".
[also fixed]
While working on this file I noticed some potentially serious warnings:
fg_commands.cxx: In function `bool do_property_adjust(const
SGPropertyNode*)':
fg_commands.cxx:435: warning: control reaches end of non-void function
fg_commands.cxx: In function `bool do_property_multiply(const
SGPropertyNode*)':
fg_commands.cxx:465: warning: control reaches end of non-void function
/usr/local/include/simgear/misc/props.hxx: At top level:
fg_commands.cxx:600: warning: `bool do_presets_commit(const
SGPropertyNode*)' defined but not used
Some more cmall changes to the SimGear header files and removed the
SG_HAVE_NATIVE_SGI_COMPILERS dependancies from FlightGear.
I've added a seperate JSBSim patch for the JSBSim source tree.
experimental lighting rendering (which is very expensive on my
machine, for example). To use distance attenuation,
/sim/rendering/distance-attenuation must also be true.
It adds a command line options to enable/disbale distance attenuation
using a property rather than using a #define inside the code. It also
adds a small change for systems that don't support the OpenGL extension,
so that the lights *do* fade away as they get furher away but they don't
get smaller in size.
property-adjust.
Modified property-adjust and property-multiply so that they always
work with double values, to simplify the code.
Factored out some common code.
Added a 'mask' argument to the property-adjust and property-multiply
commands. If mask is set to "all" (the default), then the command
works as before; if mask is set to "integer", it works only to the
left of the decimal point; and if mask is set to "decimal", it works
only to the right of the decimal place. This functionality is useful
for tuning VHF COM and NAV radios.
- dialog-open
- dialog-close
- dialog-update
- dialog-apply
The last two can copy a value from a property to a GUI field or
vice-versa either individually or across the whole dialog.
I have updated the lighting code to use fog to try to fade the runway lights
in smoothly, but still keep them from being visible until you are about 7-10
miles out, and then only have them be very faint at first. I think what I
have is a bit nicer than before since it completely avoids the "popping" effect,
but I've very open to tweaking the actual ranges based on people's real
world experiences.
option to specify a starting airport + specific runway. If you don't specify
a runway, you get the one that's closest to your specified (or default)
heading.
The general idea is to help clean up some aspects of the FDM init and be
able to provide startup conditions in a less ambiguous manner.
Previously, things like positions, orientations, and velocites were set on
"the bus". These had to be read by the FDMs which then were supposed to
initialized themselves to those values and turn write around and start
modifying those values. It was messy and cumbersome.
Now, all the initial fdm conditions are written to a sub-[property-]tree
under /sim/presets/
The values in /sim/presets/ always stay set to what the user has specified.
The user can change these at his/her liesure, and then request a "reset"
which will reset to the new conditions. I don't even want to say how this
worked before. :-)
Now, an script, or gui interface can stage a set of initial conditions while
the sim is running (without disrupting it), and then call "reset" to commit
the change.
People who should worry about all this are FDM writters, and a small few
others who care about over all program structure and flow.
The biggest and coolest patch adds mouse sensitivity to the 3D
cockpits, so we can finally work the radios. This ended up requiring
significant modifications outside of the 3D cockpit code. Stuff folks
will want to look at:
+ The list of all "3D" cockpits is stored statically in the
panelnode.cxx file. This is clumsy, and won't migrate well to a
multiple-aircraft feature. Really, there should be a per-model list
of 3D panels, but I couldn't find a clean place to put this. The
only handle you get back after parsing a model is a generic ssg
node, to which I obviously can't add panel-specific methods.
+ The aircraft model is parsed *very* early in the initialization
order. Earlier, in fact, than the static list of allowable command
bindings is built in fgInitCommands(). This is bad, as it means
that mouse bindings on the instruments can't work yet. I moved the
call to fgInitCommands, but someone should look carefully to see
that I picked the right place. There's a lot of initialization
code, and I got a little lost in there... :)
+ I added yet another "update" hook to the fgRenderFrame routine to
hook the updates for the 3D panels. This is only required for
"mouse press delay", and it's a fairly clumsy mechanism based on
frame rate instead of real time. There appears to be delay handling
already in place in the Input stuff, and there's a discussion going
on about different mouse behavior right now. Maybe this is a good
time to unify these two (now three) approaches?
Now the options can be localized as well. This adds a slight problem for
the --language options, but not that much (worst case, the strings are
loaded twice consuming some more memory). I tried to be as accurate as
posiible when copying the options texts, but there might be some
mostakes left.
This adds supports for a language specific font, defined in locale.xml
I've also moved the fgInitLocale() routine from main.cxx to fg_init.cxx
to prevent an ungly extern definition in options.cxx.
are now working. A runway light is defined by a point and a direction. The
point and direction are combined with the local up vector to create a small
triangle orthogonal to the direction. The two ficticous corners of the
triangle are given an alpha value of zero, the orignal corner is given an
alpha of one. The triangle is drawn in glPolygonMode(GL_FRONT, GL_POINT)
mode which means only the corner points are drawn, and since two have alpha=0
only the original point is drawn. This is a long way to go to draw a point,
but it ensures that the point is only visible within 90 degrees of the light
direction, behind the light it is not visible. This is still a long way
to get to drawing a point, but we use an environement map, with the direction
vector as the normal to mimic a light that is brightest when viewed head
on and dimmest when viewed perpendicularly or disappears when viewed from
behind.
- warning, there is a bug in how the current runway light direction vector
is calculated which will adversely effect runway lighting. The airports
should be regenerated in order to fix this problem.
The FGGlobals constructor does not initialise the locale pointer.
Under MSVC, uninitialized pointer have a value of 0xcdcdcdcd, not
0, so a test in mainLoop fails and the program segfault.
This patch set un initial value to locale.
This patch fixes some bugs for correctly reporting un-updated
configuration files, and adds support for a --language=<code>
commandline option, overriding the language specified by the OS.
jump whenever you cross a tile, but there are currently a lot of other
positioning problems as well, so this doesn't really detract too much and
means you can play with 3d clouds from just about any starting point.
I removed some pending random code and I also fixed a
small cosmetic glitch where dt_play was cleared before it was printed.
Curt: Erik changed the sound update intervale and I further I tweaked it.
The issue is that if we put too much into the sound buffer, then we can't react
quick enough to sounds like tire squeek that need to be synced with the visuals
and the action. We put too little into the sound buffer and we risk the
audio dropping out for moment if a frame takes longer to draw than the amount
of audio in the buffer.
I've modified the code to display a brief help message instead of the
whole bunch of options. To get the complete message -v or --verbose has
to be added to the command line.
Here is a FGIO class derived from FGSubsystem that replaces the fgIOInit()
and fgIOProcess() functions. The FGIO::update(double delta) doesn't use the
delta argument yet. I suspect it could be used as a replacement for the
calculated interval value but I'm not familiar enough with that piece of code
just yet.
I've also added two "command properties" to fg_commands.cxx that select the
next or previous view. Writing any value to these properties triggers the
corresponding action. As an example I modified my keyboard.xml:
<key n="118">
<name>v</name>
<desc>Next view</desc>
<binding>
<command>property-assign</command>
<property>/command/view/next</property>
<value type="bool">true</value>
</binding>
</key>
<key n="86">
<name>V</name>
<desc>Prev view</desc>
<binding>
<command>property-assign</command>
<property>/command/view/prev</property>
<value type="bool">true</value>
</binding>
</key>
And of course these actions can also be triggered from external scripts via
the props server.
- Removed some old cruft.
- Removed some support for older versions of automake which technically was
correct, but caused the newer automakes to squawk warnings during an
initial sanity check (which isn't done very intelligently.)
NOTE: this fix is technically not correct for older version of automake.
These older version use the variable "INCLUDES" internally and could have
them already set to an important value. That is why we were appending
our values to them. However, newer versions of automake don't set this
value themselves so it is an error to append to a non-existant variable.
We seem to "get away" with overwriting the value on older versions of
automake, but if you have problems, consider upgrading to at least
automake-1.5.
Animations are now contained within the scene graph itself and are
updated whenever the graph is traversed -- that saves time by not
updating animations not currently in sight, and it allows animations
to be used for static objects and random objects as well.
Added new FGModelLoader and FGTextureLoader classes. These are intern
tables for models, to guarantee (mostly) that no model is loaded more
than once. FGTextureLoader is not yet used anywhere, but
FGModelLoader is now in place everywhere that ssgLoad* used to be
used (thus adding the ability to use animations).
In the future, FGModelLoader will add some interesting functionality,
including the ability to reload 3D models on the fly.
I've merged FGProps and FGTelnet so there is just a single property server.
I've left in the --telnet=port# command line option but it could be removed
if we wanted to. The command line accepts two forms of the --props option.
The original (--props=medium,dir,hz,host,port#,style) and the shorter
--props=port#. If you accept this change then src/Network/telnet.[ch]xx
can be removed from the cvs repository.
the triangles containing the objects were out of the view Frustum,
they were never traversed by ssg (and thus, never culled). Now, every
200 frames, do a pass through the whole scene graph with cull-testing
disabled and without drawing anything; that will allow random-objects
to be collected incrementally.
The present sets of bindings result in the throttle being "squared"
about its centre, which is silly. This is because the "squared"
parameter is not set by the throttle binding, but the default is
"true". We discussed this before and I think there was general
agreement that the default should be "false" on the basis of
generality.
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.
This is the small code fix which is needed for the new options.xml file.
It is needed because otherwise the "--prop:name=value" is showed
incorrectly.
There is another problem though, when compiling with --without-logging
the help message isn't displayed at all! We *must* change that somehow.
Curt: good point, the SG_LOG()'s have been switched to cout's ...
I've updated the FIXME in the code, and fixed a typo (descr instead of
description), but the SG_LOG() functions doesn't produce any output for
me. Could you confirm it's still working for you?
Curt Olson:
I did a bit of further tweaking and it all looks good now. The tricky thing
is that SG_LOG() always appends an endl at the end of every message.
This is an enhanced version of the options patch.
It's more robust now, and gives some helpful information if something
goes wrong. Also the naming in the options.xml file has changed to the
syntax David suggested.
Since no one objected to the patch I think it is safe to included it.
contain colon-separated ranges. For examples, winds from 180 degrees
10 knots gusting 15 knots would be
--wind=180@10:15
Winds variable from 180-220 degrees 5 knots would be
--wind=180:220@5
FGEnvironment does not yet support variable-direction winds, so
nothing will yet happen in the second case.
Fetch all pending remote fdm network packets so there is not chance of
getting behind.
Add support for driving control panel lights.
Working on better modeling KX 155 tuning behavior.
This is a small fix for what turned out to be a major bug. Ground elevation
was calculated incorrectly when distant from one of the view locations. This
resulted in several problems including bizarre gear trimming, mid air
"crashes" (as in thinking we hit the ground) and so on when close to or on the
ground.
Unfortunately it does require a second ssg traversal when in tower view
(only), but the increased load isn't all that noticable. For the time being
this really is the best solution. In a future update I will be eliminating
the unecessary per frame traversals for the static views (without having to
maintain multiple ssgRoots).
When we go to multiple FDM instances we will perhaps need to put the ssg
traversal and ground elevation queries for the FDMs into an event timer that
updates the FDMs ground elevation in a round robin fashion (maybe every 1/n
seconds where n is the number of FDM instances running).
This is a new improved patch for the previous tile manager fixes.
Rather than building dependencies between FGlocation or the viewer or fdm with
tilemgr what I ended up doing was linking the pieces together in the Mainloop
in main.cxx. You'll see what I mean...it's been commented fairly well. More
than likely we should move that chunk somewhere...just not sure where yet.
The changes seem clean now. As I get more ideas there could be some further
improvement in organizing the update in tilemgr. You'll note that I left an
override in there for the tilemgr::update() function to preserve earlier
functionality if someone needs it (e.g. usage independent of an fdm or
viewer), not to mention there are a few places in flightgear that call it
directly that have not been changed to the new interface (and may not need to be).
The code has been optimized to avoid duplicate traversals and seems to run
generally quite well. Note that there can be a short delay reloading tiles
that have been dropped from static views. We could call the tile scheduler on
a view switch, but it's not a big deal and at the moment I'd like to get this
in so people can try it and comment on it as it is.
Everything has been resycned with CVS tonight and I've included the
description submitted earlier (below).
Best,
Jim
Changes synced with CVS approx 20:30EDT 2002-05-09 (after this evenings updates).
Files:
http://www.spiderbark.com/fgfs/viewer-update-20020516.tar.gz
or
http://www.spiderbark.com/fgfs/viewer-update-20020516.diffs.gz
Description:
In a nutshell, these patches begin to take what was one value for ground
elevation and calculate ground elevation values seperately for the FDM and the
viewer (eye position). Several outstanding view related bugs have been fixed.
With the introduction of the new viewer code a lot of that Flight Gear code
broke related to use of a global variable called "scenery.cur_elev".
Therefore the ground_elevation and other associated items (like the current
tile bucket) is maintained per FDM instance and per View. Each of these has a
"point" or location that can be identified. See changes to FGLocation class
and main.cxx.
Most of the problems related to the new viewer in terms of sky, ground and
runway lights, and tower views are fixed.
There are four minor problems remaining. 1) The sun/moon spins when you pan
the "lookat" tower view only (view #3). 2) Under stress (esp. magic carpet
full speed with max visibility), there is a memory leak in the tile caching
that was not introduced with these changes. 3) I have not tested these
changes or made corrections to the ADA or External FDM interfaces. 4) The
change view function doesn't call the time/light update (not a problem unless
a tower is very far away).
Details:
FDM/flight.cxx, flight.hxx - FGInterface ties to FGAircraftModel so that it's
location data can be accessed for runway (ground elevation under aircraft)
elevation.
FDM/larsim.cxx, larcsim.hxx - gets runway elevation from FGInterface now.
Commented out function that is causing a namespace conflict, hasn't been
called with recent code anyway.
FDM/JSBSim/JSBSim.cxx, YASim/YASim.cxx - gets runway elevation from
FGInterface now.
Scenery/newcache.cxx, newcache.hxx - changed caching scheme to time based
(oldest tiles discard).
Scenery/tileentry.cxx, tileentry.hxx - added place to record time, changed
rendering to reference viewer altitude in order to fix a problem with ground
and runway lights.
Scenery/tilemgr.cxx, tilemgr.hxx - Modified update() to accept values for
multiple locations. Refresh function added in order to periodically make
the tiles current for a non-moving view (like a tower).
Main/fg_init.cxx - register event for making tiles current in a non-moving
view (like a tower).
Main/location.hxx - added support for current ground elevation data.
Main/main.cxx - added second tilemgr call for fdm, fixed places where viewer
position data was required for correct sky rendering.
Main/options.cxx - fixed segfault reported by Curtis when using --view-offset
command line parameter.
Main/viewer.cxx, viewer.hxx - removed fudging of view position. Fixed numerous
bugs that were causing eye and target values to get mixed up.
Here is the new super improved telnet property interface. CVS changelog
is at the end of this message. Once this new telnet code is in and
compiles every where we can remove Network/props.[ch]xx. I've added a
--telnet=<port> command line option to invoke the new server. Later on
we could remove the --props option, or least change it to invoke the new
server. I'll let you decide.
I've added some new commands to the telnet interface:
view next Select the next view.
view prev Select the previous view.
view set <n> Select view 'n'
view get Return index of current view
I'm not sure if these same effects could be achieved through property
operations. The commands provide a convenient shortcut in any case.
I'm also planning on adding a panel command to manipulate panels and
objects contained therein (eg simulated mouse clicks). There is going
to be some commonality with the command objects so we may need to
rationalize this in the near future.
Finally, I've also included my python stuff. This is still very much a
work in progress, basically I've been using it to test the new telnet
server. I have tested it with python 2.2. Feel free to add it to the
repository if you want. I would suggest a scripts/python directory
CVS Changelog
Network/telnet.cxx: New property telnet protocol interface. It supports
the same user interface provided by the --props server. Additionally it
handles multiple simultaneous connections. Added "view" command to
manipulate viewmgr.
Network/protocol.hxx: Added protocol configuration exception.
Main/fg_io.cxx: Added new "telnet" protocol. Added protocol
configuration parse exceptions. Simplified protocol configuration
parsing.
Main/options.cxx: Added --telnet=<port> command line option and help
message.
Removed configuration option --with-new-environment and
FG_NEW_ENVIRONMENT macro.
Added configuration option --with-weathercm and FG_WEATHERCM macro.
FGEnvironment is now the default; use --with-weathercm to get the old
weather.
object rather than a pointer.
FGEnvironment now has the beginning of an atmospheric model, and will
recalculate temperature (not pressure or density, yet) based on
elevation.
FGEnvironment has a copy constructor.
- 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.
The FlightGear patch is to take account the change in the getChildren
function that now returns a vector<SGPropertyNode_ptr>. If the
removeChild functionnality is to be added in FlightGear, all those
SGPropertyNode * floating around should be changed to
SGPropertyNode_ptr.
1. If /position/longitude-deg and /position/latitude-deg are in range,
use them.
2. Otherwise, if /sim/startup/airport-id is not empty, use it.
3. Otherwise, set the lon/lat to the middle of the KSFO field.
The default used to be Globe, AZ, but that doesn't make sense since we
don't distribute that scenery by default any more.
With this change, starting from a save file seems to work properly:
fgfs myflight.sav
I have finished working the bugs out of my "Enhanced" version of the Magic
Carpet FDM. The UFO FDM works the same as the Magic Carpet with the
following exceptions:
The aircraft's pitch is determined by the Elevator setting (with a pitch
rate of 45 degrees per second).
Climb is forward velocity * sin(pitch)
Speed is forward velocity * soc(pitch)
Roll is tied to the aileron (again, with a roll rate of 45 degrees per
second)
Turn rate is sin(roll) * 45 degrees.
Yes, this does mean that turning is quite a bit more sluggish than
climbing.
If you are wondering why a UFO FDM, it is because it's best that I not
replace the existing magic carpet and this FDM does behave like a UFO (it
hovers, can spin and pitch while hovering, and does not obey the laws of
physics ;)
SGTimeStamp "-" operator returns it's result in usec's, there is an upper bound of 37.8 minutes on the maximum difference this operator can reliably report
before the math overflows. I change the global "int elapsed_time_ms" variable
to a "double sim_time_ms" and restructured how the value is calculated.
----
The practical result of the overflow bug is that a large negative dt was
passed to the event manager and the end effect was that no events would
be run until their counters caught up ... in another 37.8 minutes or so.
These are the updates for the View manager properties. Removed the last of
items (within the viewer/viewmgr) hard coded to view number. Added support
for per view configuration of ground level nearplane value. Tower views look
very nice with little or no z-buffer problem in the models. Pilot offset
dialog can be used to move eye in all views.
graph as the terrain, except for internal cockpit view. The SSG
scene-graph variables (except for the lighting root -- I'll get that
later) are now held in globals.hxx.
FGModelMgr::draw() is obsolete; I'll remove it in a future revision.
Minor fixes. Made some changes to get lighting correct for time of day
for now. MSVC compatibility fix and returned to clearing z-buffer only in
LOOKFROM (formerly pilot view).
[dpm: removed the last one, since I had already made a similar patch]
Here are the Boost-less FGEventMgr updates I promised.
Removed Boost dependencies from FGEventMgr.
Removed Boost configure check.
fgMethodCallback now handles const member functions.
I've successfully tested these changes with gcc and msvc.
Synced to CVS 19:36 EDT 2002-04-10 (after this evenings JSMsim and Base
package updates).
Description:
Added FGLocation class which is new home for calculating matrix rotations.
Viewer can now be configured to access rotations created by the model rather
than repeating the same calculations again.
Changed model initialization for the time being so that its location data is
available for the viewer (currently required by other subsystems). At some
point we can move this back to fg_init along with the viewer initialization.
Seperated the update from the draw function in the model code. The viewer
code needs the same matrix data, and moving the update portion at this time
does not increase the number of matrix math iterations.
Moved the model draw so that it always appears "in front" of lights and clouds.
Reogranized viewer update routine for using the FGLocation class and
simplified some more tasks. The routine is fairly easy to follow now, with
the steps ordered and spelled out in comments.
Viewmgr only updates the current (visible) view now, with the exception of an
old reference to "chase view" that will be corrected in forthcoming changes.
Also will be doing some work on the viewmgr outputs.
Model is now clears the z-buffer in all modes. This will be changed with the
next viewmgr update. The only side effect is that models always disappear
when over 5km distant from the eye point (can't really see them anyway:-)).
Other than a flag to indicate "internal" view I don't anticipate the
configuration interface for viewmgr/views will be changed a lot for now. It
is close to done. The next viewmgr update will however rework the outputs so
may change location.
This code will run with the previous version of preferences.xml, but will run
faster with the newer version. I am attaching a preferences.xml that should
not be commited before the code. All the changes are in the /sim/view section
and should show a simpler view configuration that references model locations.
Note that I've added a 2nd tower view in "lookfrom" mode for illustration
purposes. You can look around using the mouse. You may want to remove that or
comment it out.
I made these modifications to correct the problem of getter functions
returning pointers to local variables. Those variables are no longer
locals and become static. One should be aware that it kills reentrancy
!
This patch moves built-in Class (for now only mag-ribbon) into special
directory as you have written it in TODO: in comments of this class in
panel_io.cxx. IMHO it is good idea. I want to play with built-in
classes and OpenGC and this will be useful.
Minor patches to initial tower view code. Added calculation for "tower" at
any airport, placed a couple fractions of a degree off the center. Moved the
farplane from 100m to 5km so that "lookfrom" mode can see the model. 5km is
still in a reasonable range for a depth buffer. Note that looking at a model
anything but a small distance will cause some problems on older cards.
Temporarily changed viewer to always report elevation/lon/lat of the aircraft
in order to avoid a problem with the ground trim getting recalculated when
tower and aircraft are on different tiles.
radiostack.cxx, fg_init.cxx and main.cxx. If these changes are accepted
then you can remove Time/event.[ch]xx and Include/fg_callback.hxx from
the repository.
Tower View and viewer config is in place. Note that the interface is
still in a state of flux. A couple of the config items (namely the
offsets) are still using the old settings. The tower is hard coded
into the base package for a position off the starting runway at KSFO
and is probably not in the right place for there even. Looks pretty
cool though! Tower View is the third view. If you aren't at KSFO
you'll just see blank space in view 3. It's looking through the earth or
something like that :-). Important note: zoom in with a few
hits of the "x" key to see the plane better in tower view.
case logging is disabled). This way, when people specify a
non-existant aircraft or have an error in a custom XML file, they'll
get an error report, at least.
system. A chap from Germany called Alexander Kappes (cc'd) got
in touch with me a few weeks ago and has written the start of
Approach control. At the moment tuning in to a valid approach
frequency (Dortmund or East Midlands) should result in vectors to
a spot about 3 miles from the active runway, and a telling off if you
stray too far from the correct course, in the console window. He
seems to know what he's doing so expect this to improve rapidly!!
I've added a rudimentry AI manager and a hardwired Cessna at
KEMT on the runway - I'll remove it before the next release if I don't
have it flying by then. There seems to be an issue with framerate
which drops alarmingly when looking at it - I've a feeling that I've
possibly created several Cessnas on top of each other, but am not
sure.
and specific animation types are derived from it. This change makes
the code much easier to read, maintain, and extend.
Added a 'translate' animation type for a scaled, 3D linear translation
(such as a sliding throttle knob).
Renamed the 'offset' property to 'offset-m' or 'offset-deg' as
appropriate; ditto for 'min' and 'max' properties.
Clear frame buffer and render model after rest of 3D scene. This has a
small frame rate cost (YMV). But who thought 3D cockpit would be cheap?
If anyone has a better idea, have at it!
Just did some more careful testing and I see little or no frame rate loss
with the depth buffer clear. Also you can change the near plane to 0.1
and get rid of the "sunroof" (so I don't have to make up another set of
patches.
This patch creates a seperate scene graph for the cockpit. The near plane is
only moved up when in the interior (pilot) view. This is because with
rounding (I presume) it the visible ground is a bit up higher than it is with
the older nearplane setting. Not much, but it is enough to bury the wheels.
I suspected this might be true but spliting to two sg's confirms it. If
necessary we can adjust the model up a bit when in interior view. This might
be good so we can set the near plane even closer when in the cockpit (its
still at 0.2m).
In general this looks a lot better on my Voodoo with this patch. No
perceptibel change in frame rate on my system. In terms of future plans I'd
see the sense in making the model plug into either scene. This will be
necessary when we have multiple model instances in the frame.
The matrix doesn't define some cells, which are actually used
in the multiplication. That makes the result unpredictable.
I have no idea if 0.0 is the correct value for these, but
garbage is hardly the correct value either. Should some of them
be set to 1.0?
Think my brain is getting clogged with matrices :-). Well I've got the funky
orientation offset bug out of the model code. In the process the model.cxx
got optimized a bit. At some point we'll need to liberate model.cxx from the
viewer class, but it is no longer hard coded to access the "pilot view" to
get it's data. Instead it uses whatever the "current" view happens to be. I
may try and do that final bit of having models rotate independant of the view
tomorrow night, or start right in on the viewmgr and get a tower view up and
running. You guys have any preference? My brother's family is coming to
visit for a few days so what I don't get done tomorrow night probably won't
get done until after the weekend.
Fix FGViewer::update so that pitch offset and goal pitch offset work
together nicely (the offset was snapping to 90/-90 when only one of
the two was changed).
Viewer improvements from Jim Wilson:
These files get the 3d cockpit working and fix a few issues in the viewer
code.
XYZ offsets are now defined as follows: X -left/right+ (along wing axis), Y
-up/down+ perpendicular to the aircraft, Z is -in/out+ the aircraft's body axis.
I've also done some cleaning up of unused and mostly unusable interfaces,
added commentary to the *.hxx, combined together some duplicate code and
eliminated a couple unecessary operations. I also moved what was left of the
"protected" zone to "private" since we aren't subclassing this anymore.
(mainly in src/Input/input.cxx) will make src/GUI/mouse.cxx obsolete
and bring the mouse into the same input system as the joystick and
keyboard. This is just preliminary work allowing, covering mouse
clicks (no motion yet), and it actually crashes on a middle or right
click.
The new mouse support is disabled by default until it become stable;
to try it out, you need to configure --with-new-mouse.
Description:
This update includes the new viewer interface as proposed by David M. and
a first pass at cleaning up the viewer/view manager code by Jim W.
Note that I have dropped Main/viewer_lookat.?xx and Main/viewer_rph.?xx and
modified the Makefile.am accordingly.
Detail of work:
Overall:
The code reads a little easier. There are still some unnecessary bits in
there and I'd like to supplement the comments in the viewer.hxx with a tiny
bit on each interface group and what the groupings mean (similar but briefer
than what you emailed me the other day). I tried not to mess up the style,
but there is an occasional inconsistency. In general I wouldn't call it done
(especially since there's no tower yet! :)), but I'd like to get this out
there so others can comment, and test.
In Viewer:
The interface as you suggested has been implemented. Basically everything
seems to work as it did visually. There is no difference that I can see in
performance, although some things might be a tiny bit faster.
I've merged the lookat and rph (pilot view) code into the recalc for the
viewer. There is still some redundancy between the two, but a lot has been
removed. In some cases I've taken some code that we'd likely want to inline
anyway and left it in there in duplicate. You'll see that the code for both
looks a little cleaner. I need to take a closer look at the rotations in
particular. I've cleaned up a little there, but I suspect more can be done
to streamline this.
The external declaration to the Quat_mat in mouse.cxx has been removed. IMHO
the quat doesn't serve any intrinsic purpose in mouse.cxx, but I'm not about
to rip it out. It would seem that there more conventional ways to get
spherical data that are just as fast. In any case all the viewer was pulling
from the quat matrix was the pitch value so I modified mouse.cxx to output to
our pitchOffset input and that works fine.
I've changed the native values to degrees from radians where appropriate.
This required a conversion from degrees to radians in a couple modules that
access the interface. Perhaps we should add interface calls that do the
conversion, e.g. a getHeadingOffset_rad() to go along with the
getHeadingOffset_deg().
On the view_offset (now headingOffset) thing there are two entry points
because of the ability to instantly switch views or to scroll to a new view
angle (by hitting the numeric keys for example). This leaves an anomaly in
the interface which should be resolved by adding "goal" settings to the
interface, e.g. a setGoalHeadingOffset_deg(), setGoalPitchOffset_deg(), etc.
Other than these two issues, the next step here will be to look at some
further optimizations, and to write support code for a tower view. That
should be fairly simple at this point. I was considering creating a
"simulated tower view" or "pedestrian view" that defaulted to a position off
to the right of whereever the plane is at the moment you switch to the tower
view. This could be a fall back when we don't have an actual tower location
at hand (as would be the case with rural airports).
ViewManager:
Basically all I did here was neaten things up by ripping out excess crap and
made it compatible as is with the new interface.
The result is that viewmanager is now ready to be developed. The two
preexisting views are still hardcoded into the view manager. The next step
would be to design configuration xml (eg /sim/view[x]/config/blahblah) that
could be used to set up as many views as we want. If we want to take the easy
way out, we might want to insist that view[0] be a pilot-view and have
viewmanager check for that.
interface instead of string. This will result in a lot more
efficiency later, once I add in a simple hash table for caching
lookups, since it will avoid creating a lot of temporary string
objects. The major considerations for users will be that they cannot
use
node->getName() == "foo";
any more, and will have to use c_str() when setting a string value
from a C++ string.
inclueded in some of the files. Irix doesn't have cout in the std class,
so I changed it to "cout" and included SG_USING_NAMESPACE(std) at the
beginning of the files.
And some minor warning cleanups.
fixed this when I made the mistake the first time.
The view code wasn't properly handling the transition across tile
boundaries so we'd get a 'flash' of the scene wrongly transformed for
one frame at every tile boundary crossing. This is what
scenery.get_next_center() is for.
separate header file. This change will help integrate properties into
JSBSim.
Also, I (David Megginson) removed most of the SimGear include
statements from globals.hxx, reducing the amount of recompilation
every time SimGear changes. This required making minor changes to a
lot of files that were depending on the side-effects of the inclusions
in globals.hxx.
- implement the standard FGSubsystem interface, for consistency
- eliminate current_autopilot and add get/set_autopilot to FGGlobals,
for consistency
- use private methods rather than static functions for tying
properties
There should be no change in functionality.
is a work in progress and needs severe enhancement before it will be
useful. It provides a UDP data channel that goes both ways between
flightgear and the fdm. It also provides a TCP 'command' channel so
flightgear can 'reliably' send commands to the remote fdm (such as set
starting position, reset on ground, etc.)
This seems to pretty much correct the problem. Part of the problem is that
rotations are occuring at the firewall (model origin) which seems a little
un-natural inside the cockpit. The rest of the problem is I am just learning
how this stuff works (I know I've been saying this for a couple months
now...but hey I'm slow :-)).
created a new class, FGViewPoint (declared in viewer.hxx) that holds a
single position in FlightGear coordinates, and have used it to factor
a lot of the common code out of viewer_lookat.cxx and viewer_rph.cxx.
I don't know whether this new class will stay or not; it might just be
a temporary step, or it might end up taking over much of the current
viewer functionality. It would be a bad idea to code against it right
now.
plane to 0.2; otherwise, use the old defaults.
This is a temporary step that will allow me to work on a 3D cockpit
without breaking current behaviour; the final approach will be to put
the 3D model in its own scene graph, with different clipping plane.
and soon to be renamed) is true, FlightGear will draw the 3-D model
even in internal view. This makes sense right now only with the C310
model, since the others don't have any kind of interiors modeled and
all surfaces in all models are one-sided.
This isn't quite working yet -- the view code is very hard to
disentangle, and currently, if the view is not forward, roll and pitch
are applied incorrectly. It looks interesting (modulo a messy model)
on the ground, in level flight, or looking straight ahead under any
other flight conditions.
to 10m after takeoff, but that doesn't really make sense any more,
especially if models are going to have interior views. Is there any
real saving in pushing the near plane out anyway?
was some confusion between degrees and radians which would lead to a huge
goal_view_offset value. The display would sit and spin for a *long* time
trying to wind it's way up to this large value.
command will save *all* properties, rather than just those marked as
archivable. This feature was requested by Tony Peden to make it
easier to write documentation on the properties, but it should also be
useful for debugging. There is currently no default binding for the
command with the write-all parameter set to true.
What the attached patch does is map your panel definition onto a (non
z-buffered) quad in front of your face. You can twist the view around
and see it move in the appropriate ways.
Apply the patch (let me know if folks need help with that step), and
then set the /sim/virtual-cockpit property to true. You can do this
on the command line with --prop:/sim/virtual-cockpit=1, or via the
property picker. Bind it to a key for fast toggling if you like.
The default bindings don't allow for "panning" the view, so you'll
have to modify yours. These are the mappings to my joystick's hat
switch, for those who need hints:
<axis n="6">
<desc>View Direction</desc>
<low>
<repeatable>true</repeatable>
<binding>
<command>property-adjust</command>
<property>/sim/view/goal-offset-deg</property>
<step type="double">1.0</step>
</binding>
</low>
<high>
<repeatable>true</repeatable>
<binding>
<command>property-adjust</command>
<property>/sim/view/goal-offset-deg</property>
<step type="double">-1.0</step>
</binding>
</high>
</axis>
<axis n="7">
<desc>View Elevation</desc>
<low>
<repeatable>true</repeatable>
<binding>
<command>property-adjust</command>
<property>/sim/view/goal-tilt-deg</property>
<step type="double">1.0</step>
</binding>
</low>
<high>
<repeatable>true</repeatable>
<binding>
<command>property-adjust</command>
<property>/sim/view/goal-tilt-deg</property>
<step type="double">-1.0</step>
</binding>
</high>
</axis>
While the current implementation is happy with just plastering the
panel's notion of "screen" into the 3D world, this is actually more
general. Each panel can, in principle, have it's own coordinate
system, and you could build a cockpit out of a bunch of them. The
mapping is specified by providing a 3D coordinate for three corners of
the quad the panel should be mapped to; this should be pretty simple
to work with.
All that's needed for a perfectly general solution is a convention on
where to store the information (a cockpit xml file, or put it in the
aircraft -set file, or...), and some work on the panel's coordinate
system conventions (some of which don't coexist very nicely with a
generalized 3D environment). Combine that with a plib model for the
non-panel interior of the cockpit, and we're golden.
I'm actually really pleased with this. It worked better and more
quickly than I could have imagined, and impact on the surrounding code
is quite light -- a few property tests only. But some stuff is still
missing:
+ No equivalent work was done to the HUD, so it still displays
incorrect headings when the view changes. The use of pixel
coordinates deep in the HUD code is going to give me fits doing the
port, I sure. It's not nearly so well put together as the panel
(where I just changed the setup code -- none of the rendering code
changed at all).
+ I forgot that the panel was clickable. :) Input events still have
the screen coordinates, which essentially kills the interactivity
when in virtual cockpit mode. This won't be hard to fix; it's only
broken because I forgot the feature existed.
And one note about the implementation choice: to get away from the
inevitable near clip plane issue, the virtual cockpit renderer simply
disables the z buffer. This means that cockpits built using these
panels need to be z-sorted, which isn't too hard since they are static
geometry. It also means that no two "virtual panels" can ever be
allowed to interpenetrate. No biggie.
actually very powerful when combined with factor and offset -- for
example, on the C310 model the nose wheel can now retract completely
before the doors start closing.
subsystem to Flightgear. No more functionality is implemented
than at present (apart from an ATIS bug-fix - station wouldn't
change if the radio was switched directly from one station to
another) but it is much neater than the current hack and should be
easily extendable.
Some cruft is still probably left over in radiostack.[ch]xx such as
the bindings to the comm frequencies but I'll leave removing those
until I'm sure they're not needed there.
newauto.cxx. Basically everything is the same functionally except for a
changed in the initial altitude setting to 3000ft instead of meters (the panel
is in feet).
individual aircraft to have different sounds (and cleaning up my code
a fair bit). The most important user-visible change is the renaming
of the /sim/sound property to /sim/sound/audible.
(other than "none") is "spin", which must be tied to a property giving
a value in RPM. This gets the DC-3 propellers turning. The next type
will be "rotation", which will allow the flaps, elevators, ailerons,
and rudders to move (and even gear, eventually). Later, I'll add
"shift" for sliding things around, and will figure something out for
blinking lights.
the XML file, including the path to the 3D file.
This change obsoletes the existing /sim/model/*-offset-deg and
/sim/model/*-offset-m properties in the main property tree, and
replaces them with /offsets/*-deg and /offsets/*-m in the model
property file. The /path property in the model XML file is relative
to the XML file's location rather than FG_ROOT.
Added two new properties:
/environment/temperature-sea-level-degc
/environment/pressure-sea-level-inhg
These are now supported in FGEnvironment as well, though they always
have the same value for now. They need to be hooked up to the FDMs.
different locations, and hitched it into FGGlobals. FGEnvironmentMgr
has taken over as the subsystem, while FGEnvironment is simple the
information that it returns. I've removed current_environment
completely -- everything now uses properties or goes through
FGGlobals. FGGlobals itself has a couple of useful methods:
const FGEnvironment * get_environment ();
const FGEnvironment * get_environment (double lat, double lon, double alt);
The first one returns the environment data for the plane's current
position, while the second returns the environment data for any
arbitrary location. Currently, they both return the same information,
but that will change soon.
properties have been renamed from wind-(north|east|down)-fps to
wind-from-(north|east|down)-fps, and the FDMs modified appropriately.
No other changes should be visible unless FG_OLD_WEATHER is defined.
Attached are patches for adding the command line options to set initial
glideslope and climb rate. This was really easy to do as all the pieces
were in place. It works well with JSBSim because the trimming routine
finds the right throttle and elevator settings. It should work with
LaRCsim as well, but it has no trimming routine so there will be some
dynamics at startup. I don't know what YASim will do.
via the command line (--enable-clock-freeze / --disable-clock-freeze)
and can be toggled during a run. However this property is not currently
bound to any menu or keystroke so you have to do it via the gui property
interface or externally via the web property browser or a script.
are being driven from an external data source.)
Akso found and fixed a bug in the simgear that caused the time to go goofy
temporarily while scenery was being loaded.
max(width, height) by default (easily changeable) rather than just width.
(src/GUI/gui.cxx, src/Main/main.cxx, src/Main/viewer.cxx, src/Main/viewer.hxx)
This works on a CygWin build, and probably works on non-Cygwin builds
as well.
2. Enable FG to start even if audio is not available. (soundmgr.cxx)
Avoids the FGSoundMgr constructor crashing; the rest of FG then runs
OK without sound.
1. Enable auto-configure on more versions of auto tools. (configure.in)
2. Warnings from auto-configure tools. (src/Time/Makefile.am)
3. Typo: "the it's" -> "its". (docs-mini/README.Joystick)
4. Remove definition of FGViewer::update() that now is (or can be) pure
virtual\
. (src/Main/viewer.cxx)
5. Preferred form of function name according to comments in plib:
"not_working"\
-> "notWorking". (src/Sound/soundmgr.hxx)
/sim/freeze/master (implimented)
/sim/freeze/fuel (implimented)
/sim/freeze/position (not implimented)
/sim/freeze/time-of-day (not implimented)
/sim/freeze/master is bound to the 'p' key via keyboard.xml, however,
/sim/freeze/fuel is not bound to anything at the moment so you must
change it via the external property interface, or specify an initial
value on the command line.
properties /sim/view/view-tilt-deg and /sim/view/goal-view-tilt-deg
control the tilt. There are (temporarily) keyboard bindings in the
base package for experimentation: Ctrl-O to tilt the view down, and
Ctrl-P to tilt the view up.
FDM people. FlightGear now supports an unlimited number of fuel
tanks. Also added correct fuel-flow reporting for piston engines, and
tracked new features in SimGear property support.
other -- it is now possible to set properties at startup (such as an
autopilot altitude). The only user-visible change, other than the
fact that the properties work as they are supposed to, is that the
heading bug no longer starts at a random value.
function to allow property files as non-option parameters after the
options have finished (and added "--" to terminate options). It's now
possible to do something like
fgfs denver-am.fgd
or even
fgfs at-lax.fgd in-c310.fgd around-sunset.fgd
This works the same way as the --config option, but will be friendlier
for GUIs, where start-up situation files can now be associated easily
with FlightGear.
material-specific logic is now removed from the material library and
encapsulated in the material class itself, and materials are loaded
from $FG_ROOT/materials.xml rather than $FG_ROOT/materials. This also
removes a nasty bug in the old material-loading code that caused a
floating-point exception.
- automake-1.4 sets default values for INCLUDES which we can't
overwrite.
- automake-1.5 renames this to DEFAULT_INCLUDES and leaves INCLUDES
open for the developer to use.
Thus for automake-1.4 we are forced to 'append' to INCLUDES and in
automake-1.5 we can just set the value to whatever we like.
Unfortunately, the behaviors of the two versions are mutually
incompatible.
The solution I am committing now works for both versions but
automake-1.5 generates a lot of spurious warning messages that are
annoying, but not fatal.
(i.e. multiloop). Most subsystems currently ignore the parameter, but
eventually, it will allow all subsystems to update by time rather than
by framerate.
beginning of main() for the exceptions that can be enabled (only
divide-by-zero is enabled by default, but you can uncomment any ones
you want); eventually, FlightGear should run cleanly with all FPEs
enabled.
(i.e. multiloop). Most subsystems currently ignore the parameter, but
eventually, it will allow all subsystems to update by time rather than
by framerate.
These will log trace messages whenever a specific property value is
read or written through the property manager. They do not cause
FlightGear to poll bound values, so if a class variable that is bound
is changed directly, no trace message will be displayed.
These options are also useful in conjunction with a debugger.
--trace-read will cause the private SimGear SGPropertyNode::trace_read
method to be invoked, and --trace-write will cause the private SimGear
SGPropertyNode::trace_write method to be invoked; in a debugger
session, a user can set breakpoints on these methods then get a
backtrace to see what specific points in the code are reading or
writing properties.
works like this:
1. Parse preferences.xml, which will usually specify a default
aircraft using the /sim/aircraft property.
2. If /sim/aircraft is specified and not empty, parse the properties
in $FG_ROOT/Aircraft/{/sim/aircraft}-set.xml to set up a default
aircraft.
3. During command-line parsing, whenever the --aircraft option appears
set /sim/aircraft appropriately and parse the properties in
$FG_ROOT/Aircraft/{/sim/aircraft}-set.xml. Any --config, --prop, or
--aircraft options afterwards will take precedence.
more intuitive. We switch to an include in the preferences.xml to include
the default model, and then if the user specifies --aircraft=, that is
expanded immediately so portions can be overwritten by subsequent command
line options.
Here's an unusual patch for FlightGear -- I've created .cvsignore
files for every source directory, to make CVS output more informative.
This is especially nice when using cvs-examine from (X)Emacs to look
for changes.
a top level aircraft def file (c172-set.xml)
preferences.xml or --aircraft= or any other property setting mechanism can
be used to set the property "/sim/aircraft". After all options and config
files are parsed, the contents of /sim/aircraft is expanded into a *-set.xml
file and loaded.
- delete table in destructor
** src/FDM/flight.cxx
- bind engine properties in FGInterface::bind, and publish properties
for all engines rather than just engine 0
** src/Main/fg_props.cxx
- removed all engine properties; now bound in FGInterface::bind
** src/Sounds/fg_fx.cxx
- support multiple engine and cranking sounds
** src/Sounds/fg_fx.hxx
- support multiple engine and cranking sounds
to control logging
- /sim/logging/classes takes a value like "terrain|astro", where the
names are the macros from simgear/debug/debug_types.h with the
initial "SG_" removed and converted to lower case; for none, use
"none"
- /sim/logging/priority takes a single name like "warn", where the
name is a macro from simgear/debug/debug_types.h with the initial
"SG_" removed and converted to lower case
fix startup sequence problems where we initialize the FDM before we know
the desired starting altitude.
These changes delay fdm initialization until the local tile has been loaded
and we can do a real intersection and find the true ground elevation.
In order to do this, I depend more on the property manager as glue, rather
than the FGInterface.
There are some glitches still when switching to a new airport or reseting
the sim. I will work on addressing these, but I need to commit the changes
so far to keep in sync with other developers.
meaning of "win_ratio". I've removed win_ratio and added fov_ratio and
aspect_ratio, as it seems both are needed.
n.b. The multi-line changes in fgReshape comprise:
extracting common code,
removing an apparently arbitrary "+1" on the view height,
changing "set_win_ratio" to "set_aspect_ratio".
through the controls interface and the running and cranking flags through
the engine interface. This has no current effect on LaRCsim (other than
to make the code neater) but is necessary to add engine startup to JSBSim
which is now underway. I've also put in main.cxx which escaped getting
committed in the previous round of changes - adding this will add
the cranking sound to LaRCsim during engine startup.
one I sent yesterday. I have re-zipped all four files so you can
neglect the last lot but only io360.cxx has changed if you've
already committed. It's untested since I can't start the engine until
John has committed his update with separate properties. Should
work fine though.
- use guiErrorMessage
- added new properties /sim/view/pilot/x-offset-m,
/sim/view/pilot/y-offset-m, and /sim/view/pilot/z-offset-m to
control pilot-position offset from CG