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.
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.
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.
radiostack.cxx:703 says
bool light_on = ( outer_blink || middle_blink || inner_blink );
but none of the flags has ever been initialized when this line is first
executed.
as a follow-up of my previous message, I found that in panel.cxx, function
const char *FGTextLayer::Chunk::getValue () const, there is the use of a
member variable _buf that seems to be uninitialized.
(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.
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.
Oh yeah, I forgot to send that one along. This one is my bug, I
goofed the precedence in the fgPanelVisible() function in panel.cxx
such that the panel was *always* visible if virtual cockpit was
enabled. Here's a replacement. I've modified the style from a single
boolean expression to an if-list, since that's more readable to my
eyes for expressions this big:
Actually, I think I'm off the hook here; the problem is pre-existing.
What's happening is that the x/y offsets enter the modelview matrix at
line 346 in the current panel.cxx. But note that the same
transformation also occurs before each instrument rendered at line
403. What's happening is that the instruments are double-translated
relative to the background.
Unless I'm not understanding something, the one inside the instrument
render loop looks unnecessary. Removing it fixes the issue and
doesn't cause any bugs that I can find. It also fixes a bug where you
could scroll the instruments on top of the 3D panel, where the offsets
are supposed to be ignored. :)
Attached is a new panel.cxx which fixes that bug, and substantially
simplifies the virtual panel code (the matrix inversion that I thought
was needed wasn't, but there were some offsetting scale bugs that hid
the problem).
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.
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.
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)
- 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.
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.
- 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
Heres an update to the ATIS stuff. In brief:
The possible buffer overflow in the display with wind should
hopefully be fixed.
Temperature is taken from the global temperature property instead
of being hardwired.
The display class now includes an implementation of the member
function to change the repeating message.
The message callsign is no longer hardwired. The first message
from each station is generated with a random callsign.
Subsequent messages from the same station have the callsign
incremented every hour. A map of airport-id vs. last callsign and
transmission time is kept for each station that has transmitted for
the duration of the FlightGear session. The logic might be flaky if
FlightGear is run for more than 24 hours at a stretch between
visiting the same ATIS station though! (ie I don't check the day.)
This map is kept in the atislist class. This might not be the best
long-term place for it (in an ATC class of some sort might be
better), but it works for now.
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".
in init)
- free data structures in destructor
- ensure that interpolation tables are allocated before any searching
is done; otherwise, starting at some locations (such as CYYZ) causes
a segfault
with different modifiers (the format of the key bindings has changed
again slightly, adding a <code>..</code> element; see keyboard.xml for
details).
2. Modified FGInput to try default modifiers for ctrl, shift, and alt
when the initial bindings fail (i.e. you don't have to specify
mod-shift explicitly for upper-case 'P' any more).
3. Fixed problems with properties and panel reloading reported by
Martin Dressler and John Check.
4. Updated preferences.xml to get rid of obsolete references to
/controls/brakes/left and /controls/brakes/right (as reported by John
Check).
There were also two non-bugs reported by John Check:
(a) Differential braking doesn't work (John was using the obsolete
properties from #4 above).
(b) Duplicates show up in the property tree using the telnet interface
(the property tree doesn't show indices, and John was seeing separate
entries for each possible engine, etc.).
When you tune into a station start at a "random" point in the sequence.
Sped up the words per minute to 13 to which means one sequence per about 4 secs.
This means we get through the whole sequence in about 20 seconds leaving 10
seconds of silence.
DG heading bug initializes to a random setting.
Activating heading hold doesn't touch the DG heading bug any more.
Max autopilot decent rate is now -1000.
good as we can get" until we find a data source with actual VOR magnetic
offsets. We can use VOR offsets from some fixed date, but not all VOR's
were installed on the same day so no matter what date we pick we will be off on most of them.
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.
FlightGear subsystems -- it isolates some of the config and #ifdef
stuff in a single place.
2. Added a new FGSubsystem interface, defined in fgfs.hxx; so far,
only FGControls implements it, but if that works, we can start letting
it propagate through the system and simplify the code in main.cxx and
fg_init.cxx (which is terrifyingly complex for anyone new to the
project).
3. Added new src/Main/fgfs_props.[hc]xx files with convenience
functions for tying properties under FlightGear.
4. Experimentally modified src/Controls/controls.cxx to tie properties
directly (rather than tying to BFI functions). I'd appreciate it if
you could get this into CVS as soon as possible, so we can see if the
template stuff causes trouble for any other platforms before I add
properties to the other subsystems.
5. Miscellaneous superficial modifications to other files.
In addition, I've made a couple of further changes:
6. Modified BFI to add support for setting the view axes (i.e. with a
joystick hat).
7. Cleaned up bfi.cxx and removed all cout statements.
====================================
Cockpit.cxx
-----------
Commented #ifdef FIGHTER_HUD.
Hud.cxx
-------
Included code to read the xml file and draw the corresponding instrument.
Hud.hxx, Hud_ladr.cxx, Hud_card.cxx and Hud_labl.cxx
---------------------------------------------------
Integrated code to draw any kind of hud.
Preference.xml
---------------
Included XML file path in the sim/hud property.
ReadMe.xmlhud
-------------
The Readme.xmlhud describes the reconfigurable HUD implemented thru XML
files.
derive specific viewer classes from it. Here's what I currently have in mind:
FGViewer
|
|-> FGViewerPRH (current system with orientation specified in
| LaRCsim Euler angle convention)
|
|-> FGViewerLookAt Feed in a position, view direction, and up vector
|
|-> FGViewerHPR (similar to PRH, but using ssg hpr euler angle
| convention)
|-> others?
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.
I have a scrollable panel working (it didn't take long in the end). A
panel can now be much wider or higher than the available area, and the
user can scroll around using [Shift]F5, [Shift]F6, [Shift]F7, and
[Shift]F8. The user can also scroll the panel down to get a bigger
external view. Mouse clicks seem still to be working correctly.
To set the panel's (virtual) height and width, use the panel file's /w
and /h properties in a panel XML file; to set the initial x- and y-
offsets (untested), use the panel file's /x-offset and /y-offset
properties; to set the initial height of the external view (untested
and optional), use the panel file's /view-height property. Note that
none of these show up in the regular FGFS property manager.
Unfortunately, these patches will not affect your initialization
problems with the property manager -- I'm having a hard time tracking
them down because I cannot reproduce them.
I have also made some patches to main.cxx and views.cxx to do two
things:
1. Expand or shrink the external view as the panel moves up and down.
2. Set the window ratio correctly, so that we don't get an oval sun
and flat clouds when the panel is visible (the problem before was
integer division, so I added casts).
Unfortunately, the window ratio is not set properly at start-up --
there are too many dependencies, and I haven't figured that part out
yet. As soon as you hide and redisplay the panel or move it
vertically (i.e. force fgReshape to be called), you'll see the correct
ratio.
src/Cockpit/radiostack.cxx
- extended VOR ranges to make them slightly more usable (pending some
real radio code)
src/Cockpit/sp_panel.cxx
- fixed heading bug on gyro compass (sort-of -- the AP still doesn't
work quite as expected)
- skid ball moves the right direction
- moved whiskey compass more to the co-pilot's side, as suggested by
Alex a while back
src/Joystick/joystick.cxx
- included Norm's Windows patches
- renamed brake properties (see bfi.cxx, below)
src/Main/bfi.cxx
src/Main/bfi.hxx
- renamed getBrake and setBrake to getBrakes and setBrakes
- added getCenterBrake and setCenterBrake
- added getAPHeading (without mag correction, needed for the panel)
- renamed property /controls/brake to /controls/brakes/all
- renamed property /controls/left-brake to /controls/brakes/left (as
requested by Alex)
- renamed property /controls/right-brake to /controls/brakes/right (as
requested by Alex)
- added property /controls/brakes/center
- added property /autopilot/settings/heading
- fixed bug in setAltitude so that altitude will be property restored
from a save file
- fixed getBrakes to return the highest of the three brake settings
src/Main/save.cxx
- call FGBFI::getBrakes instead of FGBFI::getBrake
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.
1. I've modified src/Time/fg_time.cxx so that the --start-date-gmt
option works correctly, at least on my system.
2. I've modified src/Main/bfi.cxx to return the correct time from
FGBFI::getTimeGMT(), so that saving and reloading now keeps the time set
correctly again.
3. I've modified src/Main/main.cxx so that the engine still makes a
noise when it's idling (it sounded very strange when the engine simply
turned off at idle then magically turned on again with a little
throttle).
I've done some substantial reengineering of the 2D panel: except for the
radios, the whole panel is built from a large table now. I'd be
grateful if you could add these changes to the main distribution.
Since I always like to provide some eye-candy with my updates, I've
fixed the ADF gauge to be more usable by slimming the needle and adding
markings every 45 deg (you'll need to use the attached textures).
- the panel uses much, much less texture memory, and draws much
faster, at least on my hardware
- there is a wet (magnetic) compass at the top of the panel
- the gyro compass shows true heading again, but don't get used to it:
we're going to set it up to drift soon
- there are TO/FROM flags on NAV1 and NAV2 (but no GS flag yet)
- the ADF looks a little more realistic (if you can forgive the ugly
needle)
- when the HUD is not open, the framerate is moved to the right side
of the screen so that it won't be obscured by the mag compass
- 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
the NAV face, and one for a NAV needle (just a thin, slightly blurry red
line for now). I'm attaching my two new textures, together with my newest
panel.cxx (modified from Alex's to use the new textures). Obviously,
there's a lot more to do, including TO/FROM indicators, but this is a
start, and it's fun.
NAV2 is now the VOR radial 068 from MZB,
ADF is now the Compass locator on the outer marker.
This combination is more than the legally required to
fly any of KMYF-ILS-28R, KMYF-LOC-28R KMYF-NDB28.
If you don't have access to the approach plates
and would like them, let me know and I'll scan them
(and put them on the webpage area).
The approaches do work; I've checked them all out in
terms of altitude profile, centerlines and other stuff.
In real life, the radar vectoring will basically abandon you
overhead KSEE airport at 4000 ft heading 210 or so. Sometime
later you'll be turned to a heading of 260 if the controller
doesn't have too much else to do, just before you hit the
extended centerline. You can't rely on that though.
Maintain 3500ft until established, 2100 ft until the outer marker,
If non-precision, maintain 1340 until crossing the radial,
then 900 thereafter until you miss, based on time from the NDB.
The miss takes you heading 270 to intercept a radial which this
hacky implementation will not let you set up the computer for.
The hacky math implementation does not take range and/or signal
strength into account, so you can fly to San Diego from England
by following the needle indication on the ADF. It is also
fairly inaccurate math; about as accurate as the real-life signals.
When we have a _real_ radio module, I will be very happy to
throw all that code away. For now, it makes it demonstratable.
Please notice the nastiness involving the "VARY_E" constant.
This is _not_ something that will go away with the radio module.
As far as I know, we don't have a routine that calculates
magnetic variation as a function of global position.
We will need one, probably within the next two months.
Externally: added a chronometer and a control-position indicator a la
MSFS, along with dummies for the radio-nav gauges.
Internally, substantially reworked the code so that the individual gauges
can be table- (and eventually, file-) driven.
old routines from SRGP. Steve's plib/sg.h does a nice job of completely
replacing this (and since plib is already around) and is a nice clean design
so it just makes sense.
I've reorganized the code in panel.cxx and panel.hxx so that it will
be a little easier to extend the panel later if someone wants to.
It's still basically Friedemann's code at the core, but I've
repackaged it into a saner class hierarchy and encapsulated as much as
I could (there are still a couple of circular dependencies that need
swatting). If someone wants to modify it to use SSG or to add new
gauges, it should be a lot easier now.
There are no user-visible changes.
