Multiplayer protocol

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Revision as of 20:48, 27 August 2010 by Oschroeder (talk | contribs) (Created page with '== The Header == All messages contain XDR encoded data and have a well defined header which looks like this: |'''Magic'''|'''Version'''|'''MsgId'''|'''MsgLen'''|'''ReplyAddress…')
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The Header

All messages contain XDR encoded data and have a well defined header which looks like this:

|Magic|Version|MsgId|MsgLen|ReplyAddress|ReplyPort|Callsign|Data|

Magic: 4 bytes, always 0x46474653 ("FGFS")
Version: 4 bytes, protocol version, currently 0x00010001 (1.1)
MsgId: 4 bytes, defines what data is appended to the header.

Can be 0x00000001 for chat messages (deprecated) or
0x00000007 for position data
all other values are outdated and ignored

MsgLen: 4 bytes, the lenght of the data in bytes
ReplyAddress: 4 bytes, deprecated and ignored
ReplyPort: 4 bytes, deprecated and ignored
Callsign: 8 bytes, zero terminated array of characters representing

the user callsign


Data of a chat messages

The data for chat messages is a zero terminated array of characters. The MsgLen field in the header represents its length. The maximum length is defined to be 256 bytes.


Data of a position messages

The data of position data is more complicated and looks like this:

ModelName 96 bytes, zero terminated array of characters representing the

aircraft model used by the user

time 8 bytes, representing the time when this message was generated
lag 8 bytes, time offset for network lag
PosX 8 bytes, XDR encoded double value, X-ccordinate of users

position wrt the earth centered frame

PosY 8 bytes, XDR encoded double value, Y-ccordinate of users

position wrt the earth centered frame

PosZ 8 bytes, XDR encoded double value, z-ccordinate of users

position wrt the earth centered frame

OriX 4 bytes, XDR encoded float value, X-orientation of the user

wrt the earth centered frame, stored in the angle axis representation where the angle is coded into the axis length

OriY 4 bytes, XDR encoded float value, Y-orientation of the user

wrt the earth centered frame, stored in the angle axis representation where the angle is coded into the axis length

OriZ 4 bytes, XDR encoded float value, Z-orientation of the user

wrt the earth centered frame, stored in the angle axis representation where the angle is coded into the axis length

VelX 4 bytes, XDR encoded float value, velocity of the user in X direction

wrt the earth centered frame measured in the earth centered frame

VelY 4 bytes, XDR encoded float value, velocity of the user in Y direction

wrt the earth centered frame measured in the earth centered frame

VelZ 4 bytes, XDR encoded float value, velocity of the user in Z direction

wrt the earth centered frame measured in the earth centered frame

AV1 4 bytes, XDR encoded float value, 1. part of the three dimensional

angular velocity vector
wrt the earth centered frame measured in the earth centered frame

AV2 4 bytes, XDR encoded float value, 2. part of the three dimensional

angular velocity vector
wrt the earth centered frame measured in the earth centered frame

AV3 4 bytes, XDR encoded float value, 3. part of the three dimensional

angular velocity vector
wrt the earth centered frame measured in the earth centered frame

LA1 4 bytes, XDR encoded float value, 1. part of the three dimensional

linear accelaration vector
wrt the earth centered frame measured in the earth centered frame

LA2 4 bytes, XDR encoded float value, 2. part of the three dimensional

linear accelaration vector
wrt the earth centered frame measured in the earth centered frame

LA3 4 bytes, XDR encoded float value, 3. part of the three dimensional

linear accelaration vector
wrt the earth centered frame measured in the earth centered frame

AA1 4 bytes, XDR encoded float value, 1. part of the three dimensional

angular accelaration vector
wrt the earth centered frame measured in the earth centered frame

AA2 4 bytes, XDR encoded float value, 2. part of the three dimensional

angular accelaration vector
wrt the earth centered frame measured in the earth centered frame

AA3 4 bytes, XDR encoded float value, 3. part of the three dimensional

angular accelaration vector
wrt the earth centered frame measured in the earth centered frame

pad up to 8 bytes for padding the data to a multiple of 8 bytes

This data is followed by property-values, which are encoded in the form ID|Value
The following properties are transmitted, but not necessarily all present and not in this order:

ID Property Type(*)
100 "surface-positions/left-aileron-pos-norm" FLOAT
101 "surface-positions/right-aileron-pos-norm" FLOAT
102 "surface-positions/elevator-pos-norm" FLOAT
103 "surface-positions/rudder-pos-norm" FLOAT
104 "surface-positions/flap-pos-norm" FLOAT
105 "surface-positions/speedbrake-pos-norm" FLOAT
106 "gear/tailhook/position-norm" FLOAT
107 "gear/launchbar/position-norm" FLOAT
108 "gear/launchbar/state" STRING
109 "gear/launchbar/holdback-position-norm" FLOAT
110 "canopy/position-norm" FLOAT
111 "surface-positions/wing-pos-norm" FLOAT
112 "surface-positions/wing-fold-pos-norm" FLOAT
200 "gear/gear[0]/compression-norm" FLOAT
201 "gear/gear[0]/position-norm" FLOAT
210 "gear/gear[1]/compression-norm" FLOAT
211 "gear/gear[1]/position-norm" FLOAT
220 "gear/gear[2]/compression-norm" FLOAT
221 "gear/gear[2]/position-norm" FLOAT
230 "gear/gear[3]/compression-norm" FLOAT
231 "gear/gear[3]/position-norm" FLOAT
240 "gear/gear[4]/compression-norm" FLOAT
241 "gear/gear[4]/position-norm" FLOAT
300 "engines/engine[0]/n1" FLOAT
301 "engines/engine[0]/n2" FLOAT
302 "engines/engine[0]/rpm" FLOAT
310 "engines/engine[1]/n1" FLOAT
311 "engines/engine[1]/n2" FLOAT
312 "engines/engine[1]/rpm" FLOAT
320 "engines/engine[2]/n1" FLOAT
321 "engines/engine[2]/n2" FLOAT
322 "engines/engine[2]/rpm" FLOAT
330 "engines/engine[3]/n1" FLOAT
331 "engines/engine[3]/n2" FLOAT
332 "engines/engine[3]/rpm" FLOAT
340 "engines/engine[4]/n1" FLOAT
341 "engines/engine[4]/n2" FLOAT
342 "engines/engine[4]/rpm" FLOAT
350 "engines/engine[5]/n1" FLOAT
351 "engines/engine[5]/n2" FLOAT
352 "engines/engine[5]/rpm" FLOAT
360 "engines/engine[6]/n1" FLOAT
361 "engines/engine[6]/n2" FLOAT
362 "engines/engine[6]/rpm" FLOAT
370 "engines/engine[7]/n1" FLOAT
371 "engines/engine[7]/n2" FLOAT
372 "engines/engine[7]/rpm" FLOAT
380 "engines/engine[8]/n1" FLOAT
381 "engines/engine[8]/n2" FLOAT
382 "engines/engine[8]/rpm" FLOAT
390 "engines/engine[9]/n1" FLOAT
391 "engines/engine[9]/n2" FLOAT
392 "engines/engine[9]/rpm" FLOAT
800 "rotors/main/rpm" FLOAT
801 "rotors/tail/rpm" FLOAT
810 "rotors/main/blade[0]/position-deg" FLOAT
811 "rotors/main/blade[1]/position-deg" FLOAT
812 "rotors/main/blade[2]/position-deg" FLOAT
813 "rotors/main/blade[3]/position-deg" FLOAT
820 "rotors/main/blade[0]/flap-deg" FLOAT
821 "rotors/main/blade[1]/flap-deg" FLOAT
822 "rotors/main/blade[2]/flap-deg" FLOAT
823 "rotors/main/blade[3]/flap-deg" FLOAT
830 "rotors/tail/blade[0]/position-deg" FLOAT
831 "rotors/tail/blade[1]/position-deg" FLOAT
900 "sim/hitches/aerotow/tow/length" FLOAT
901 "sim/hitches/aerotow/tow/elastic-constant" FLOAT
902 "sim/hitches/aerotow/tow/weight-per-m-kg-m" FLOAT
903 "sim/hitches/aerotow/tow/dist" FLOAT
904 "sim/hitches/aerotow/tow/connected-to-property-node" BOOL
905 "sim/hitches/aerotow/tow/connected-to-ai-or-mp-callsign" STRING
906 "sim/hitches/aerotow/tow/brake-force" FLOAT
907 "sim/hitches/aerotow/tow/end-force-x" FLOAT
908 "sim/hitches/aerotow/tow/end-force-y" FLOAT
909 "sim/hitches/aerotow/tow/end-force-z" FLOAT
930 "sim/hitches/aerotow/is-slave" BOOL
931 "sim/hitches/aerotow/speed-in-tow-direction" FLOAT
932 "sim/hitches/aerotow/open" BOOL
933 "sim/hitches/aerotow/local-pos-x" FLOAT
934 "sim/hitches/aerotow/local-pos-y" FLOAT
935 "sim/hitches/aerotow/local-pos-z" FLOAT
1001 "controls/flight/slats" FLOAT
1002 "controls/flight/speedbrake" FLOAT
1003 "controls/flight/spoilers" FLOAT
1004 "controls/gear/gear-down" FLOAT
1005 "controls/lighting/nav-lights" FLOAT
1006 "controls/armament/station[0]/jettison-all" BOOL
1100 "sim/model/variant" INT
1101 "sim/model/livery/file" STRING
1200 "environment/wildfire/data" STRING
10001 "sim/multiplay/transmission-freq-hz" STRING
10002 "sim/multiplay/chat" STRING
10100 "sim/multiplay/generic/string[0]" STRING
10101 "sim/multiplay/generic/string[1]" STRING
10102 "sim/multiplay/generic/string[2]" STRING
10103 "sim/multiplay/generic/string[3]" STRING
10104 "sim/multiplay/generic/string[4]" STRING
10105 "sim/multiplay/generic/string[5]" STRING
10106 "sim/multiplay/generic/string[6]" STRING
10107 "sim/multiplay/generic/string[7]" STRING
10108 "sim/multiplay/generic/string[8]" STRING
10109 "sim/multiplay/generic/string[9]" STRING
10110 "sim/multiplay/generic/string[10]" STRING
10111 "sim/multiplay/generic/string[11]" STRING
10112 "sim/multiplay/generic/string[12]" STRING
10113 "sim/multiplay/generic/string[13]" STRING
10114 "sim/multiplay/generic/string[14]" STRING
10115 "sim/multiplay/generic/string[15]" STRING
10116 "sim/multiplay/generic/string[16]" STRING
10117 "sim/multiplay/generic/string[17]" STRING
10118 "sim/multiplay/generic/string[18]" STRING
10119 "sim/multiplay/generic/string[19]" STRING
10200 "sim/multiplay/generic/float[0]" FLOAT
10201 "sim/multiplay/generic/float[1]" FLOAT
10202 "sim/multiplay/generic/float[2]" FLOAT
10203 "sim/multiplay/generic/float[3]" FLOAT
10204 "sim/multiplay/generic/float[4]" FLOAT
10205 "sim/multiplay/generic/float[5]" FLOAT
10206 "sim/multiplay/generic/float[6]" FLOAT
10207 "sim/multiplay/generic/float[7]" FLOAT
10208 "sim/multiplay/generic/float[8]" FLOAT
10209 "sim/multiplay/generic/float[9]" FLOAT
10210 "sim/multiplay/generic/float[10]" FLOAT
10211 "sim/multiplay/generic/float[11]" FLOAT
10212 "sim/multiplay/generic/float[12]" FLOAT
10213 "sim/multiplay/generic/float[13]" FLOAT
10214 "sim/multiplay/generic/float[14]" FLOAT
10215 "sim/multiplay/generic/float[15]" FLOAT
10216 "sim/multiplay/generic/float[16]" FLOAT
10217 "sim/multiplay/generic/float[17]" FLOAT
10218 "sim/multiplay/generic/float[18]" FLOAT
10219 "sim/multiplay/generic/float[19]" FLOAT
10300 "sim/multiplay/generic/int[0]" INT
10301 "sim/multiplay/generic/int[1]" INT
10302 "sim/multiplay/generic/int[2]" INT
10303 "sim/multiplay/generic/int[3]" INT
10304 "sim/multiplay/generic/int[4]" INT
10305 "sim/multiplay/generic/int[5]" INT
10306 "sim/multiplay/generic/int[6]" INT
10307 "sim/multiplay/generic/int[7]" INT
10308 "sim/multiplay/generic/int[8]" INT
10309 "sim/multiplay/generic/int[9]" INT
10310 "sim/multiplay/generic/int[10]" INT
10311 "sim/multiplay/generic/int[11]" INT
10312 "sim/multiplay/generic/int[12]" INT
10313 "sim/multiplay/generic/int[13]" INT
10314 "sim/multiplay/generic/int[14]" INT
10315 "sim/multiplay/generic/int[15]" INT
10316 "sim/multiplay/generic/int[16]" INT
10317 "sim/multiplay/generic/int[17]" INT
10318 "sim/multiplay/generic/int[18]" INT
10319 "sim/multiplay/generic/int[19]" INT


(*) The types are XDR encoded as follows:

INT    4 bytes, send unconditionally


FLOAT: 4 bytes, send unconditionally


BOOL:  4 bytes, send unconditionally


STRING [LEN|STR|PAD]: send only when length > 0

LEN:    4 bytes, length of the string

STR:    n bytes, string string itself

PAD:    n bytes, padding so the overall length is a multiple of 4
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