Re: [Flightgear-devel] Aerobatics using flight gear and JSBSim
Sorry about that, prematurely hit send. Here is the link:http://forums.x-plane.org/index.php?showtopic=13050st=0Might be interesting, or maybe even relevant to modelling things like snap rolls in JSBSim. Regards,Hugo Vincent.On 6/15/06, Hugo Vincent [EMAIL PROTECTED] wrote: I came across this discussion about adding a new open source FDM toX-Plane, using CFD methods to get really really high fidelity models.On Wed, 2006-06-14 at 20:32 -0500, Jon S. Berndt wrote: Snap roll: This is indeed the recipe for a snap roll: starting from a speed slightly above the stall, apply a sudden yaw with the rudder, apply opposite aileron, and pull back on the yoke. SNAP! --- One wing stalls and the plane rolls over. [I liked the clever use of the word, recipe with the phrase snap *roll*] This would be hard to model using lookup tables, but it might be possible using JSBSim functions and a table or tables, together. Could be fun. I need to think about this one. The first idea that comes to mind is that if the aircraft speed minus the yaw rate times some characteristic lateral length (span/2?) falls below the stall speed, then a rolling moment would be generated - maybe a yawing moment, too. Jon ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Aerobatics using flight gear and JSBSim
I came across this discussion about adding a new open source FDM to X-Plane, using CFD methods to get really really high fidelity models. On Wed, 2006-06-14 at 20:32 -0500, Jon S. Berndt wrote: Snap roll: This is indeed the recipe for a snap roll: starting from a speed slightly above the stall, apply a sudden yaw with the rudder, apply opposite aileron, and pull back on the yoke. SNAP! --- One wing stalls and the plane rolls over. [I liked the clever use of the word, recipe with the phrase snap *roll*] This would be hard to model using lookup tables, but it might be possible using JSBSim functions and a table or tables, together. Could be fun. I need to think about this one. The first idea that comes to mind is that if the aircraft speed minus the yaw rate times some characteristic lateral length (span/2?) falls below the stall speed, then a rolling moment would be generated - maybe a yawing moment, too. Jon ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] apt.dat changes ?
On 12/06/2006, at 9:37 PM, Thomas Förster wrote: snip Of course this also means that only an svg editor is not enough to fully specify an airport. In the case of Inkscape (I don't know about any of the other SVG editors), a reasonably simple plugin should suffice for editing the non-graphical aspects of the airport layout. ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Generic Protocol (generic.cxx etc) - Binary Mode
Any one had a chance to look over the patch yet?What needs to be changed/fixed/rewritten/redesigned(!) before it can be applied to the main CVS version?Hugo.On 4/25/06, Hugo Vincent [EMAIL PROTECTED] wrote: Thanks Erik,Here is the patch. Let me know what needs to be changed, fixed, orrefactored before it can go into CVS. Note that at this point, thebinary protocol is output only.Also attached is a really simple protocol to test the patch (bintest.xml). Run FGFS with:$ fgfs ... --generic=file,out,24,bintest_out,bintestAs well, there is a Python script (sorry, the script is a horribly dirtyhack) to decode and print the results. Execute it with: $ python test_decode.pyTo do list for the generic binary support:* use ntohl() etc to make the protocol independent of host endianess.* add CRC checksum as a possible packet footer* add binary input support * test thoroughlyCheers,Hugo VincentOn Mon, 2006-04-24 at 09:59 +0200, Erik Hofman wrote: Hugo Vincent wrote: I also updated OpenGC for this change and made a OpenGC.xml protocol file, but it appears the OpenGC project is more or less dead. Also, Network/opengc.cxx is a bit of a mess and seemingly unmaintained; it might be nice to get rid of it and replace it with a XML file at some stage. One approach is to directly replace opengc.cxx with an XML file that emulates the structure of the ogcFGData class, - however different compilers probably pad the variables in the class differently (for alignment/efficiency), so a patch to OpenGC does need to be made. If anyone wants the generic binary mode patch, or better yet, wants to add it into the main FlightGear repository, reply (to the list). Also, if anyone else has uses or requirements for binary protocols, let discuss them here, so that we can make generic binary support as broad and applicable as possible. I think it would be valuable, exactly for the reason mentioned above. Erik
Re: [Flightgear-devel] Generic Protocol (generic.cxx etc) - Binary Mode
Thanks Erik,
Here is the patch. Let me know what needs to be changed, fixed, or
refactored before it can go into CVS. Note that at this point, the
binary protocol is output only.
Also attached is a really simple protocol to test the patch
(bintest.xml). Run FGFS with:
$ fgfs ... --generic=file,out,24,bintest_out,bintest
As well, there is a Python script (sorry, the script is a horribly dirty
hack) to decode and print the results. Execute it with:
$ python test_decode.py
To do list for the generic binary support:
* use ntohl() etc to make the protocol independent of host endianess.
* add CRC checksum as a possible packet footer
* add binary input support
* test thoroughly
Cheers,
Hugo Vincent
On Mon, 2006-04-24 at 09:59 +0200, Erik Hofman wrote:
Hugo Vincent wrote:
I also updated OpenGC for this change and made a OpenGC.xml protocol
file, but it appears the OpenGC project is more or less dead. Also,
Network/opengc.cxx is a bit of a mess and seemingly unmaintained; it
might be nice to get rid of it and replace it with a XML file at some
stage. One approach is to directly replace opengc.cxx with an XML file
that emulates the structure of the ogcFGData class, - however different
compilers probably pad the variables in the class differently (for
alignment/efficiency), so a patch to OpenGC does need to be made.
If anyone wants the generic binary mode patch, or better yet, wants to
add it into the main FlightGear repository, reply (to the list).
Also, if anyone else has uses or requirements for binary protocols, let
discuss them here, so that we can make generic binary support as broad
and applicable as possible.
I think it would be valuable, exactly for the reason mentioned above.
Erik
bintest.xml
Description: application/xml
Index: Protocol/README.Protocol
===
RCS file: /var/cvs/FlightGear-0.9/data/Protocol/README.Protocol,v
retrieving revision 1.2
diff -u -p -r1.2 README.Protocol
--- Protocol/README.Protocol 22 Jun 2003 08:02:28 - 1.2
+++ Protocol/README.Protocol 25 Apr 2006 01:19:39 -
@@ -1,5 +1,5 @@
The generic communication protocol for FlightGear provides a powerfull way
-of adding a simple ASCII based output only protocol, just by defining an
+of adding a simple ASCII based or binary protocol, just by defining an
XML encoded configuration file.
The definition of the protocol consists of variable separators, line separators,
@@ -16,8 +16,9 @@ Each chunck defines:
%s string
%i integer (default)
%f float
+ (not used or needed in binary mode)
-factor an optionale multiplication factor which can be used for
+factor an optional multiplication factor which can be used for
unit conversion. (for example, radians to degrees).
offset an optional offset which can be used for unit conversion.
(for example, degrees Celsius to degrees Fahrenheit).
@@ -44,6 +45,16 @@ any other charachters just need to be ad
The var_separator is placed between each variable, while the line_separator is
placed at the end of each lot of variables.
+To enable binary mode, simply include a binary_modetrue/binary_mode tag in
+your XML file. The format of the binary output is tightly packed, with 1 byte for
+bool, 4 bytes for int, and 8 bytes for double. At this time, strings are not
+supported. A configurable footer at the end of each line or packet of binary
+output can be added using the binary_footer tag. Options include the length
+of the packet, a magic number to simplify decoding. Examples:
+
+ binary_footermagic,0x12345678/binary_footer
+ binary_footerlength/binary_footer
+ binary_footernone/binary_footer !-- default --
A simple protocol configuration file then could look something like the
following:
@@ -57,6 +68,7 @@ following:
output
line_separatornewline/line_separator
var_separatornewline/var_separator
+ binary_modefalse/binary_mode
chunk
namespeed/name
Index: src/Network/generic.cxx
===
RCS file: /var/cvs/FlightGear-0.9/source/src/Network/generic.cxx,v
retrieving revision 1.17
diff -u -p -r1.17 generic.cxx
--- src/Network/generic.cxx 9 Mar 2006 21:41:51 - 1.17
+++ src/Network/generic.cxx 25 Apr 2006 01:41:26 -
@@ -79,51 +79,99 @@ FGGeneric::~FGGeneric() {
// generate the message
bool FGGeneric::gen_message() {
-
string generic_sentence;
char tmp[255];
+length = 0;
double val;
for (unsigned int i = 0; i _out_message.size(); i++) {
-if (i 0)
+if (i 0 !binary_mode)
generic_sentence += var_separator;
switch (_out_message[i].type) {
case FG_INT:
val = _out_message[i].offset +
_out_message[i].prop-getIntValue() * _out_message[i].factor;
-snprintf(tmp, 255, _out_message[i].format.c_str(), (int)val);
+if (binary_mode) {
+*((int
[Flightgear-devel] Generic Protocol (generic.cxx etc) - Binary Mode
Hi everyone, I am new to FlightGear and am using it for a UAV project (yep, yet another one - see http://www.albatross-uav.org). I need FlightGear to output binary-formatted data into UDP packets to support a custom protocol used in the system (that is, to have data from FlightGear look like data coming from the UAV, to test the ground station software etc.). There has been talk on the mailing list before (e.g. here: http://www.opensubscriber.com/message/flightgear-devel@flightgear.org/1750238.html by Michael Meyers) about added binary support to the generic protocol, but it seems nothing was done about it. I added basic binary mode support to Network/generic.cxx that is enabled with a binary_modetrue/binary_mode tag in the protocol XML file. The patch is quite small, and if the binary_mode tag is not found it does not fail (meaning any existing protocol XML files continue to work). As well as supporting simple packed binary output, configurable data can be added at the end of each packet (aka line in ASCII protocols), such as a magic number, or the length of the packet. Other things like a CRC checksum of the packet could be added easily. I also updated OpenGC for this change and made a OpenGC.xml protocol file, but it appears the OpenGC project is more or less dead. Also, Network/opengc.cxx is a bit of a mess and seemingly unmaintained; it might be nice to get rid of it and replace it with a XML file at some stage. One approach is to directly replace opengc.cxx with an XML file that emulates the structure of the ogcFGData class, - however different compilers probably pad the variables in the class differently (for alignment/efficiency), so a patch to OpenGC does need to be made. If anyone wants the generic binary mode patch, or better yet, wants to add it into the main FlightGear repository, reply (to the list). Also, if anyone else has uses or requirements for binary protocols, let discuss them here, so that we can make generic binary support as broad and applicable as possible. Cheers, Hugo Vincent. --- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnkkid=120709bid=263057dat=121642 ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
