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.
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.
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.
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.
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
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
is 9 not 8.) Note that the initial altitude setting was placing us way below
the ground, but as it doesn't seem to have caused us problems, it's probably
redundant!
FGOptions is history, and the modules are (starting) to use the property
manager directly. Let me know if I left any files out.
Inevitably, there will be some problems with broken options, etc.,
that I haven't found in my tests, but I'll try to fix them quickly.
We also need to stress that the property names currently in use are
not stable -- we need to reorganize them a bit for clarity.
- removed Toggle Clouds menu item
src/Main/options.cxx:
- (minor) added some code to sync up options with properties
src/Main/bfi.[ch]xx:
- removed (get|set)Clouds(ASL)?
- removed setSpeedNorth, setSpeedEast, and setSpeedDown -- these are
all read-only now
- added setAirspeed (for calibrated kt)
- extensive rewrite to support Tony's FDM changes
- rearranged everything in bfi.hxx to mess up Curt's ediff examination
- added properties for setting initial panel position
src/Main/save.cxx:
- reinit the tile cache after restore
LaRCsim c172 on-ground and in-air starts, reset: all work
UIUC Cessna172 on-ground and in-air starts work as expected, reset
results in an aircraft that is upside down but does not crash FG. I
don't know what it was like before, so it may well be no change.
JSBSim c172 and X15 in-air starts work fine, resets now work (and are
trimmed), on-ground starts do not -- the c172 ends up on its back. I
suspect this is no worse than before.
I did not test:
Balloon (the weather code returns nan's for the atmosphere data --this
is in the weather module and apparently is a linux only bug)
ADA (don't know how)
MagicCarpet (needs work yet)
External (don't know how)
known to be broken:
LaRCsim c172 on-ground starts with a negative terrain altitude (this
happens at KPAO when the scenery is not present). The FDM inits to
about 50 feet AGL and the model falls to the ground. It does stay
upright, however, and seems to be fine once it settles out, FWIW.
To do:
--implement set_Model on the bus
--bring Christian's weather data into JSBSim
-- add default method to bus for updating things like the sin and cos of
latitude (for Balloon, MagicCarpet)
-- lots of cleanup
The files:
src/FDM/flight.cxx
src/FDM/flight.hxx
-- all data members now declared protected instead of private.
-- eliminated all but a small set of 'setters', no change to getters.
-- that small set is declared virtual, the default implementation
provided preserves the old behavior
-- all of the vector data members are now initialized.
-- added busdump() method -- FG_LOG's all the bus data when called,
useful for diagnostics.
src/FDM/ADA.cxx
-- bus data members now directly assigned to
src/FDM/Balloon.cxx
-- bus data members now directly assigned to
-- changed V_equiv_kts to V_calibrated_kts
src/FDM/JSBSim.cxx
src/FDM/JSBSim.hxx
-- bus data members now directly assigned to
-- implemented the FGInterface virtual setters with JSBSim specific
logic
-- changed the static FDMExec to a dynamic fdmex (needed so that the
JSBSim object can be deleted when a model change is called for)
-- implemented constructor and destructor, moved some of the logic
formerly in init() to constructor
-- added logic to bring up FGEngInterface objects and set the RPM and
throttle values.
src/FDM/LaRCsim.cxx
src/FDM/LaRCsim.hxx
-- bus data members now directly assigned to
-- implemented the FGInterface virtual setters with LaRCsim specific
logic, uses LaRCsimIC
-- implemented constructor and destructor, moved some of the logic
formerly in init() to constructor
-- moved default inertias to here from fg_init.cxx
-- eliminated the climb rate calculation. The equivalent, climb_rate =
-1*vdown, is now in copy_from_LaRCsim().
src/FDM/LaRCsimIC.cxx
src/FDM/LaRCsimIC.hxx
-- similar to FGInitialCondition, this class has all the logic needed to
turn data like Vc and Mach into the more fundamental quantities LaRCsim
needs to initialize.
-- put it in src/FDM since it is a class
src/FDM/MagicCarpet.cxx
-- bus data members now directly assigned to
src/FDM/Makefile.am
-- adds LaRCsimIC.hxx and cxx
src/FDM/JSBSim/FGAtmosphere.h
src/FDM/JSBSim/FGDefs.h
src/FDM/JSBSim/FGInitialCondition.cpp
src/FDM/JSBSim/FGInitialCondition.h
src/FDM/JSBSim/JSBSim.cpp
-- changes to accomodate the new bus
src/FDM/LaRCsim/atmos_62.h
src/FDM/LaRCsim/ls_geodesy.h
-- surrounded prototypes with #ifdef __cplusplus ... #endif , functions
here are needed in LaRCsimIC
src/FDM/LaRCsim/c172_main.c
src/FDM/LaRCsim/cherokee_aero.c
src/FDM/LaRCsim/ls_aux.c
src/FDM/LaRCsim/ls_constants.h
src/FDM/LaRCsim/ls_geodesy.c
src/FDM/LaRCsim/ls_geodesy.h
src/FDM/LaRCsim/ls_step.c
src/FDM/UIUCModel/uiuc_betaprobe.cpp
-- changed PI to LS_PI, eliminates preprocessor naming conflict with
weather module
src/FDM/LaRCsim/ls_interface.c
src/FDM/LaRCsim/ls_interface.h
-- added function ls_set_model_dt()
src/Main/bfi.cxx
-- eliminated calls that set the NED speeds to body components. They
are no longer needed and confuse the new bus.
src/Main/fg_init.cxx
-- eliminated calls that just brought the bus data up-to-date (e.g.
set_sin_cos_latitude). or set default values. The bus now handles the
defaults and updates itself when the setters are called (for LaRCsim and
JSBSim). A default method for doing this needs to be added to the bus.
-- added fgVelocityInit() to set the speed the user asked for. Both
JSBSim and LaRCsim can now be initialized using any of:
vc,mach, NED components, UVW components.
src/Main/main.cxx
--eliminated call to fgFDMSetGroundElevation, this data is now 'pulled'
onto the bus every update()
src/Main/options.cxx
src/Main/options.hxx
-- added enum to keep track of the speed requested by the user
-- eliminated calls to set NED velocity properties to body speeds, they
are no longer needed.
-- added options for the NED components.
src/Network/garmin.cxx
src/Network/nmea.cxx
--eliminated calls that just brought the bus data up-to-date (e.g.
set_sin_cos_latitude). The bus now updates itself when the setters are
called (for LaRCsim and JSBSim). A default method for doing this needs
to be added to the bus.
-- changed set_V_equiv_kts to set_V_calibrated_kts. set_V_equiv_kts no
longer exists ( get_V_equiv_kts still does, though)
src/WeatherCM/FGLocalWeatherDatabase.cpp
-- commented out the code to put the weather data on the bus, a
different scheme for this is needed.
ing features:
a) ADA Flight model - ADA.cxx, ADA.hxx, flight.hxx
b) Fighter a/c HUD - flight.hxx, hud.hxx, hud.cxx, cockpit.cxx, hud_ladr.c
xx, hud_card.cxx
c) 3-window display - options.hxx, options.cxx, viewer.cxx
d) Moving objects (ship) - main.cxx
e) Patches - main.cxx
ADA.cxx, ADA.hxx
--------------------------
Interface to the external ADA flight dynamics package.
flight.hxx
----------
Included prototypes for accepting additional data fron the External flight
model for fighter aircraft HUD
Hud.hxx
-------
Included prototypes for accepting additional data for fighter HUD from Exernal F
light model.
Defined FIGHTER_HUD pre-processor directive to enable compilation of fighter hud
code.
hud.cxx, cockpit.cxx, hud_ladr.cxx, hud_card.cxx
---------------------------------------
Included code to initialise additional reticles/text for fighter HUD which is co
nditionally
compiled if FIGHTER_HUD is defined.
options.hxx
-----------
Added window_offset, and function to retrieve its value for 3 windows
options.cxx
-----------
Changed few options to suit ADA/CEF projection system/screens and checks for win
dow offset.
views.cxx
---------
Added code to retrieve view offset for window.
Main.cxx
--------
Added code to load and move an aircraft carrier.
Patch to enable clouds from command line until Curtis fixes it. By default cloud
s are disabled.
- /engines/engine0/rpm changed to read-only
- /engines/engine0/egt added (read-only)
- /controls/mixture added
- /controls/propellor-pitch added (not used for C172)
BFI:
- getEGT() added
- getMixture() and setMixture() added
- getPropAdvance() and setPropAdvance() added (= pitch)
- cleaned up reinit function a bit
- force reinit only when values are actually changed; for example,
setting the flight model to the current flight model will not cause
a reinit
LaRCSim:
- hook up mixture and pitch to FGControls (they were hard-coded
before)
Cleaned a bit of cruft out of gui.[ch]xx
Cleaned up win_ratio() and fov code to make more sense and be a bit more
consistant and robust and less buggy and less susceptible to screw ups.
Panel is activated now by default, HUD is off by default.
This set of changes cleans up my previous ones quite a bit:
[tony@valkyrie FlightGear]$ tar -ztf tp_changes.tgz
src/Controls/controls.cxx
src/Controls/controls.hxx
src/FDM/JSBsim.cxx
src/Main/fg_init.cxx
src/Main/options.cxx
src/Main/options.hxx
src/Joystick/joystick.cxx
controls.[ch]xx: removed the trimmed_throttle stuff. This undoes the
changes I submitted last time.
JSBsim.cxx: updates for the removal of the trimmed_throttle stuff
fg_init.cxx: removed the autothrottle logic. The autothrottle is now
off
by default.
options.[ch]xx: Sets trim_mode to false by default. It is enabled only
when --notrim is not used and JSBsim is the FDM.
joystick.cxx: Added logic for syncing the throttle lever. This is
only enabled when trim_mode is enabled. The way I
did it is, I hope, a good way of going about it.
I tested:
fgfs --fdm=larcsim
fgfs --fdm=jsb --aircraft=c172 --vc=100 --altitude=500
fgfs --notrim --fdm=jsb --aircraft=c172 --vc=100 --altitude=500
All work as intended, at least for me.
Make sure your joystick is calibrated and give:
fgfs --fdm=jsb --aircraft=c172 --vc=100 --altitude=500
a try, I think you just might be impressed.
I am. ;-)
Tony submitted:
JSBsim:
Added trimming routine, it is longitudinal & in-air only at this point
Added support for taking wind & weather data from external source
Added support for flaps.
Added independently settable pitch trim
Added alphamin and max to config file, stall modeling and warning to
follow
c172.cfg:
Flaps!
Adjusted Cmo, model should be speed stable now
FG:
Hooked up Christian's weather code, should be using it soon.
Hooked up the trimming routine. Note that the X-15 will not trim.
This is not a model or trimming routine deficiency, just the
nature of the X-15
The trimming routine sets the pitch trim and and throttle at startup.
The throttle is set using Norman's code for the autothrottle so the
autothrottle is on by default. --notrim will turn it off.
Added --vc, --mach, and --notrim switches
(vc is airspeed in knots)
uBody, vBody, and wBody are still supported, last one entered
on the command line counts, i.e. you can set vc or mach or u,v,
and w but any combination will be ignored.
- knobs now continue to rotate when you hold down the mouse
- the middle mouse button makes knobs rotate much faster
- there are NAV1, NAV2, and ADF radios that can be tuned using the mouse
- there are standby frequencies for NAV1 and NAV2, and buttons to swap
- there is a crude, rather silly-looking DME, hard-wired to NAV1
- there is a crude, rather silly-looking autopilot that can lock
the heading (to the bug on the gyro), can lock to NAV1, and can lock
the current altitude
- the knobs for changing the radials on NAV1 and NAV2 look much better
and are in the right place
- tuning into an ILS frequency doesn't change the displayed radial for
NAV1
Code
- I've created a new module, sp_panel.[ch]xx, that constructs the
default single-prop panel; this works entirely outside of FGPanel,
so it is possible to construct similar modules for other sorts of
panels; all code specific to the default panel has been removed from
panel.cxx
- current_panel is now a pointer
- radiostack.[ch]xx keeps track both of the actual radial and of the
selected radial (they will differ with ILS); the NAV gauges should
not spin around automatically to show the actual radial (we need to
do something similar with the autopilot)
- the panel is initialized fairly early
- make sure that standby frequencies also get initialized
- I've started combining and clipping small textures to save texture
memory; there's a lot more to do, but at least I've made a start
