Hi fellow wiki editors!

To help newly registered users get more familiar with the wiki (and maybe older users too) there is now a {{Welcome to the wiki}} template. Have a look at it and feel free to add it to new users discussion pages (and perhaps your own).

I have tried to keep the template short, but meaningful. /Johan G

Difference between revisions of "Head-up display"

From FlightGear wiki
Jump to: navigation, search
m (added link to heliHUD)
(first stage of a complete revision)
Line 1: Line 1:
This is a short description of [[FlightGear]]'s default '''Head-up display''' ('''HUD'''), it can be (de)activated with the <tt>[h]</tt>-key. To change the brightness, press <tt>[shift]</tt>+<tt>[h]</tt>.
+
{{WIP|Article is going to be completely reworked.}}
  
There are also two so called 'minimal' HUDs available which are accessible with <tt>[shift]</tt>+<tt>[i]</tt>, to return to default HUD press <tt>[i]</tt>.  
+
The [http://en.wikipedia.org/wiki/Head-up_display '''Head-up display'''] (HUD) is an important instrument in modern, mostly military, cockpits. FlightGear provides a XML-based system to relatively easily create HUDs for aircrafts such as the [[F-14]] and [[F-16]].
  
Some of the HUDs options can be altered in the menu: <tt>View > Adjust HUD Properties</tt>
+
However, this article's focus is on FlightGear's default head-up displays. Those are available for any craft which does not include its own set. Have a look at [[#Further Information]] if you're planning to create a HUD.
  
== Features ==
+
Activate the HUD with the '''<tt>[h]</tt>'''-key. Pressing it repeatedly moves through the configured colours and turns it off again. To change the brightness, press '''<tt>[shift]</tt>+<tt>[h]</tt>'''. Press '''<tt>[shift]</tt>+<tt>[i]</tt>''' to go through the available HUD's. Press '''[i]''' to switch back to the first one at any time. Have in mind that some aircraft do assign one or more of those keys differently and therefore one or more function/s is/are missing on them.
  
=== Aileron ===
+
Some of the head-up display's options can be altered in the menu: <tt>View</tt> --> <tt>Adjust HUD Properties</tt>
[[File:HUD_aileron.jpg|thumb|200px|Aileron]]
+
Monitors the bearing of the control input on the ailerons axis.
+
:[[Aileron]]
+
  
=== Airspeed ===
 
[[File:HUD_speed.jpg|thumb|200px|Airspeed]]
 
Current speed relating to the ambient air in knot/knots (kt/kts) (1 kt = 1.852 km/h).
 
  
=== Altitude ===
+
[[File:HUD_default_overview.png|thumb|520px|Huds/default.xml]]
[[File:HUD_altitude.jpg|thumb|200px|Altitude]]
+
== Features ==
Current altitude relating to sea-level in feet (ft) (1 ft = 30.48 cm).
+
=== Control inputs ===
 +
; [[Aileron]]
 +
: Monitors the bearing of the control input on the aileron's axis. Attached along the upper side is the indicator for the trim input on that axis.
 +
: Properties: <code>/controls/flight/aileron</code> and <code>/controls/flight/aileron-trim</code>
  
=== GPS ===
+
; [[Elevator]]
The active GPS waypoint identifier is displayed, as well as the distance and bearing to it. The GPS ground track and course-deviation are also displayed - for the course deviation,
+
: Monitors the bearing of the control input on the elevator's axis. Attached to the left the trim on this axis.
the distance off-course is displayed in nautical miles (nm), with an arrow indicating the direction to fly to regain the GPS course.
+
: Properties: <code>/controls/flight/elevator</code> and <code>/controls/flight/elevator-trim</code>
  
=== Elevation ===
+
; [[Rudder]]
Current altitude above ground in feet. Relating to the location of the aircraft's radio altimeter, therefore it's not zero if the aircraft is on the ground.
+
: Monitors the bearing of the control input on the rudder's axis. Attached to the bottom the trim input.
 +
: Properties: <code>/controls/flight/rudder</code> and <code>/controls/flight/rudder-trim</code>
  
=== Elevator ===
+
; Throttle
[[File:HUD_elevator.jpg|thumb|200px|Elevator]]
+
: Monitors the throttle input axis.
Monitors the bearing of the control input on the elevators axis.
+
: Property: <code>/controls/engines/engine/throttle</code>
:[[Elevator]]
+
  
=== G-load ===
 
Displays the g-force to the pilot in g - to avoid black-/redout.
 
:The value riding on top of the [[#Airspeed|Airspeed]] indicator.
 
  
=== Heading ===
+
=== Instruments ===
[[File:HUD_heading.jpg|thumb|200px|Heading]]
+
; [[AMSL]] (Height <u>a</u>bove <u>m</u>ean <u>s</u>ea <u>l</u>evel)
Direction of the aircraft relating to the geographical North pole in degree (360 degree scale).
+
: Current altitude relative to sea level in feet (ft) (1 ft = 30.48 cm).
:[[Avionics and Instruments#Compass|Compass]]
+
: Property: <code>/position/altitude-ft</code>
  
=== Location ===
+
; g-load
[[File:HUD_location.jpg|thumb|200px|Location]]
+
: The [http://en.wikipedia.org/wiki/G-force g-force] appealing to the pilot - to avoid black-/redout.
To change the coordinates-system, go to <tt>Autopilot > Set Lat/Lon-format</tt>.
+
: Property: <code>/accelerations/pilot/z-accel-fps_sec</code> with factor <tt>-0.03108095</tt>
  
=== Pitch ===
+
; [[Avionics and Instruments#Directional_Gyro|Gyrocompass]]
Like set with <tt>[Home]</tt>/<tt>[End]</tt>.
+
: This is an ideal version of a gyrocompass without the drawbacks of a real one. It shows heading of the aircraft relative to the geographical North Pole (true north) in degree (360 degree scale).
:It's the left marker of the [[#Elevator|Elevator]] indicator.  
+
: Property: <code>/orientation/heading-deg</code>
  
=== Pitch ladder ===
+
; [[KIAS]] (<u>K</u>nots <u>I</u>ndicated <u>A</u>ir<u>s</u>peed)
Displays the aircraft's pitch relating to the grounds level/horizontal in degree. It's used as an artificial horizon.
+
: Current speed relating to the ambient air in knot/knots (kt/kts) (1 kt = 1.151 mph = 1.852 km/h).
:The big ladder like looking indicator at the HUDs centre.  
+
: Property: <code>/velocities/airspeed-kt</code>
:[[Avionics and Instruments#Attitude Indicator|Attitude indicator]]
+
  
=== Rudder ===
+
; Latitude / Longitude
[[File:HUD_rudder.jpg|thumb|200px|Rudder]]
+
: Current location according to the [http://en.wikipedia.org/wiki/Geographic_coordinate_system geographic coordinate system].
Monitors the bearing of the control input on the rudders axis.
+
: To change the format of the displayed coordinates, go to <tt>Autopilot</tt> --> <tt>Set Lat/Lon-format</tt>.
:[[Rudder]]
+
: Properties: <code>/position/latitude-string</code> and <code>/position/longitude-string</code>
  
=== Thrust ===
+
; Pitch ladder
[[File:HUD_thrust.jpg|thumb|200px|Thrust]]
+
: Displays the aircraft's pitch and roll relative to the ground's level/horizontal in degree. It's used as an artificial horizon ([[Avionics and Instruments#Attitude Indicator|Attitude indicator]]).
Monitors the thrust on airplanes or the collective of helicopters.
+
: Properties: <code>/orientation/roll-deg</code> and <code>/orientation/pitch-deg</code>
  
=== Turn-bank-indicator ===
+
; Radio altimeter
:[[Avionics and Instruments#Turn Coordinator|Turn Coordinator]]
+
: Shows current altitude [[above ground level]] (AGL) in feet. Relating to the location of the aircraft's radio altimeter, it's not zero if the aircraft is on the ground.
 +
: Property: <code>/position/altitude-agl-ft</code>
 +
 
 +
; Turn-bank-indicator
 +
: [[Avionics and Instruments#Turn Coordinator|Turn Coordinator]]
 +
: Properties: <code>/orientation/roll-deg</code> and <code>/orientation/side-slip-deg</code>
  
[[File:HUD_default_autopilot.jpg|thumb|200px|HUD autopilot]]
 
[[File:HUD_default_overview.png|thumb|200px|HUD overview]]
 
  
 
== Further Information ==
 
== Further Information ==
The basic setup of the above described default HUD is defined at <tt>[[$FG ROOT]]/Huds/Default/default.xml</tt>. There is also a 'Runway projection' available which is, because of some issues, disabled by default.
+
The setup of the default HUD is defined at <tt>[[$FG_ROOT]]/Huds/default.xml</tt>.
 
+
Documentation can be found at: <tt>[[$FG ROOT]]/Docs/README.xmlhud</tt>
+
 
+
Since FlightGear 0.9.10 there is ''also'' a newer and more flexibly HUD-system available. An example can be found at <tt>[[$FG ROOT]]/Huds/NTPS.xml</tt> and documentation at <tt>[[$FG ROOT]]/Docs/README.hud</tt>.
+
Also have a look at <tt>$FG_ROOT/Huds/README</tt>.
+
 
+
== preferences.xml ==
+
While the instruments and their behaviour are set in the Huds-directory, the basic settings and the look regarding to any HUD are set in <tt>[[$FG ROOT]]/preferences.xml</tt>. Search the file for <tt><hud></tt> and you will find a list of properties. For a short description of those have a look at [[#Property_tree|property tree]]. But I'll give some of them a closer look:
+
 
+
=== Colour ===
+
The preferred thing one would like to customize is, I guess, the HUDs colour.
+
 
+
Discover your own settings is quite easy: Access the property tree via the Menu <tt>File > Browse Internal Properties</tt> (<tt>[/]</tt>-character) '''or''' via the [[Property Tree#Property server|Property server]] and your browser. Go to sim/hud/color, e.g. http://localhost:5500/sim/hud/color, edit a value and watch the result in FlightGears window instantly.
+
 
+
Once the decision is made head back to preferences.xml, copy the <color n="0">-tag and paste it on top of the colours within the <palette>-tag. Rename the existing tags in numeric order and finally put your discovered values in the new one. It should look like this, except your own values, of course:
+
    <current-color type="int">0</current-color>
+
    <palette>
+
    <color n="0">
+
      <transparent type="bool">true</transparent>
+
      <antialiased type="bool">false</antialiased>
+
      <brightness type="float">1</brightness>
+
      <alpha type="float">0.67</alpha>
+
      <red type="float">0.1</red>
+
      <green type="float">1.0</green>
+
      <blue type="float">0.3</blue>
+
    </color>
+
    <color n="1"><nowiki><!-- day --></nowiki>
+
      ...
+
    </color>
+
    <color n="2"><nowiki><!-- night --></nowiki>
+
      ...
+
    </color>
+
    </palette>
+
 
+
=== Font ===
+
 
+
    <nowiki><font></nowiki>
+
    <name type="string">Helvetica.txf</name>
+
    <size type="float">8</size>
+
    <nowiki></font></nowiki>
+
 
+
To change font just enter another name out of the ones in <tt>[[$FG ROOT]]/Fonts</tt> (case sensitive!). For more information about those fonts and on .txf format peruse $FG_ROOT/Fonts/README.
+
 
+
Since the size is type 'float' values like '7.449' are allowed, too.
+
 
+
=== Path ===
+
/!\ Just a draft and maybe not correct.
+
 
+
  <path>Huds/Default/default.xml</path>
+
  <path>Huds/NTPS.xml</path>          <nowiki> <!-- new HUD --></nowiki>
+
The first one is the default HUD mentioned above. It is for the old HUD only.
+
The second is the first one of the 'minimal HUD's and it is for the new HUD only. The other 'minimal' one is called by the code (I guess), its path is Huds/Minimal/default.xml.
+
 
+
For each <path> are some more HUDs available, a complete list (except aircraft specific):
+
 
+
old HUD:
+
Huds/Custom/default.xml
+
Huds/Default/default.xml
+
Huds/Engineering/default.xml
+
Huds/Minimal/default.xml
+
 
+
new HUD:
+
Huds/NTPS.xml
+
Huds/default.xml
+
 
+
  
== Property tree ==
+
Documentation can be found at [http://mapserver.flightgear.org/git/?p=fgdata;a=blob_plain;f=Docs/README.hud;hb=HEAD <tt>$FG_ROOT/Docs/README.hud</tt>].
More information about FlightGear's property tree and on how to access it can be found at its page: [[Property Tree]].
+
  
Paths starting with '[[$FG ROOT]]/' apply to the file system, the others are intra-property tree.
+
HUD's may be replaced or added by changing or adding their path(s) to preferences.xml (<hud> tag) or by setting the paths as command line options. To change the order of the existing ones the options would be: <code>--prop:/sim/hud/path[1]=Huds/minimal.xml</code> <code>--prop:/sim/hud/path[2]=Huds/default.xml</code> <code>--prop:/sim/hud/path[3]=Huds/NTPS.xml</code>
  /sim/hud
+
  current-color  (0|1|2...)    int    One out of /sim/hud/palette
+
  enable3d        (false|true)  bool    hud n=0 3D off|on
+
  enable3d[1]     (false|true)  bool    hud n=1 3D off|on
+
  frame-stat-type (tris|???)            ???
+
  path            (Huds/...)            Path to hud n=0
+
  path[1]        (Huds/...)            Path to hud n=1
+
  visibility      (false|true)  bool    hud n=0 hidden|visible
+
  visibility[1]  (false|true)  bool    hud n=1 hidden|visible
+
/sim/hud/color/          Contains settings of current-color
+
    alpha        (0...1)      float  0=invisible, 1=nontransparent
+
    alpha-clamp  (???)                ???
+
    antialiased  (false|true)  bool    Antialiasing off|on
+
    blue          (0...1)      float
+
    brightness    (0...1)      float  0=dark/black
+
    green        (0...1)      float
+
    red          (0...1)      float
+
    transparent  (false|true)  bool    Transparency off|on
+
/sim/hud/font/
+
    name          (*.txf)      string  One out of $FG_ROOT/Fonts
+
    size          (8)          float  Size of font
+
/sim/hud/palette/
+
/sim/hud/palette/color/        Settings of predefined colours, nearly
+
/sim/hud/palette/color[n]/     the same options as in /sim/hud/color.
+
  
  
== Additional HUD's ==
+
== Additional HUDs ==
 
; HeliHUD
 
; HeliHUD
: Designed to fly helicopters in Helicopter View it is also handy for any craft with a not yet finished cockpit. The [http://janodesbois.free.fr/D-HUND/helihud_0.2.tar.bz2 download] contains instructions and specs.
+
: Designed to fly helicopters in Helicopter View it is also handy for any craft with a not yet finished cockpit. It also contains a minimalistic HUD only showing some navigation informations such as compass and GPS. The [http://janodesbois.free.fr/D-HUND/helihud_0.2.tar.bz2 download] contains instructions and specs.
  
  
 
[[Category:FlightGear feature]]
 
[[Category:FlightGear feature]]
 
[[Category:Menubar]]
 
[[Category:Menubar]]

Revision as of 14:30, 27 January 2013

WIP.png Work in progress
This article or section will be worked on in the upcoming hours or days.
Note: Article is going to be completely reworked.
See history for the latest developments.

The Head-up display (HUD) is an important instrument in modern, mostly military, cockpits. FlightGear provides a XML-based system to relatively easily create HUDs for aircrafts such as the F-14 and F-16.

However, this article's focus is on FlightGear's default head-up displays. Those are available for any craft which does not include its own set. Have a look at #Further Information if you're planning to create a HUD.

Activate the HUD with the [h]-key. Pressing it repeatedly moves through the configured colours and turns it off again. To change the brightness, press [shift]+[h]. Press [shift]+[i] to go through the available HUD's. Press [i] to switch back to the first one at any time. Have in mind that some aircraft do assign one or more of those keys differently and therefore one or more function/s is/are missing on them.

Some of the head-up display's options can be altered in the menu: View --> Adjust HUD Properties


Huds/default.xml

Features

Control inputs

Aileron
Monitors the bearing of the control input on the aileron's axis. Attached along the upper side is the indicator for the trim input on that axis.
Properties: /controls/flight/aileron and /controls/flight/aileron-trim
Elevator
Monitors the bearing of the control input on the elevator's axis. Attached to the left the trim on this axis.
Properties: /controls/flight/elevator and /controls/flight/elevator-trim
Rudder
Monitors the bearing of the control input on the rudder's axis. Attached to the bottom the trim input.
Properties: /controls/flight/rudder and /controls/flight/rudder-trim
Throttle
Monitors the throttle input axis.
Property: /controls/engines/engine/throttle


Instruments

AMSL (Height above mean sea level)
Current altitude relative to sea level in feet (ft) (1 ft = 30.48 cm).
Property: /position/altitude-ft
g-load
The g-force appealing to the pilot - to avoid black-/redout.
Property: /accelerations/pilot/z-accel-fps_sec with factor -0.03108095
Gyrocompass
This is an ideal version of a gyrocompass without the drawbacks of a real one. It shows heading of the aircraft relative to the geographical North Pole (true north) in degree (360 degree scale).
Property: /orientation/heading-deg
KIAS (Knots Indicated Airspeed)
Current speed relating to the ambient air in knot/knots (kt/kts) (1 kt = 1.151 mph = 1.852 km/h).
Property: /velocities/airspeed-kt
Latitude / Longitude
Current location according to the geographic coordinate system.
To change the format of the displayed coordinates, go to Autopilot --> Set Lat/Lon-format.
Properties: /position/latitude-string and /position/longitude-string
Pitch ladder
Displays the aircraft's pitch and roll relative to the ground's level/horizontal in degree. It's used as an artificial horizon (Attitude indicator).
Properties: /orientation/roll-deg and /orientation/pitch-deg
Radio altimeter
Shows current altitude above ground level (AGL) in feet. Relating to the location of the aircraft's radio altimeter, it's not zero if the aircraft is on the ground.
Property: /position/altitude-agl-ft
Turn-bank-indicator
Turn Coordinator
Properties: /orientation/roll-deg and /orientation/side-slip-deg


Further Information

The setup of the default HUD is defined at $FG_ROOT/Huds/default.xml.

Documentation can be found at $FG_ROOT/Docs/README.hud.

HUD's may be replaced or added by changing or adding their path(s) to preferences.xml (<hud> tag) or by setting the paths as command line options. To change the order of the existing ones the options would be: --prop:/sim/hud/path[1]=Huds/minimal.xml --prop:/sim/hud/path[2]=Huds/default.xml --prop:/sim/hud/path[3]=Huds/NTPS.xml


Additional HUDs

HeliHUD
Designed to fly helicopters in Helicopter View it is also handy for any craft with a not yet finished cockpit. It also contains a minimalistic HUD only showing some navigation informations such as compass and GPS. The download contains instructions and specs.