[osg-users] Camera control in osgvisual

[Vijeesh Theningaledathil]

Hi,

I' new to the osg. I generated a terrain using osgdem. now Iwant to render it and I should be able to fly around. I downloaded osgVisual and in configuration file a selected the terrain which i created. But while executing the camera goes to some lat/lon . How can I control the camera manually from an external application. I also doesnt understand the concept of cluster, slave, stand alone etc in the osgvisual . Can somebody help me to place the camera so that Ican view my terrain. Please help me
Thank you!

Thanks,
Vijeesh

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[Torben Dannhauer]

Hi Vijeesh,

If you just want to view your terrain you can also use the plain osgviewer.

The benefit of osgVisual is that it allows to attach visible objects to external datasources and that you can use it across multiple rendering channels.

To your problem:
In your start command, do you specify an xml configuration file like "osgvisual -c yourconfig.xml"?
The SVN contains a complete xml example file. I haven't written the wiki page because I'm currently cleaning up the code, xml support is quite new.

osgVisual supports the standard OSG camera manipulators like
trackball,
terrain,
flight,
nodetracker
animationpath.
The animationpath controls where your simulation starts. The animationpath file you can specify in the osgVisual XML configuration file.

Additionally you can use osgVisual like camera manipulator:
1. You can use 3DConnexion Spacenavigator (http://www.3dconnexion.com/products/spacenavigator.html) for free 3D manipulation of camera.
2. A Spacenavigator based node tracker.
3. A cameramanipulator with a fix offset to a visual_object (A entity which contains info about position, attitude, geometry to display, label etc.)
4. A Cameramanipulator which coordinates are controlled via the extternal Link (extLink)

Definition of extLink:
The visual system needs a simulation host which decides how the scene should be visualized (position of objects, time, weather etc). The link from the visual system to the external simulation host is called extLink.
There is an extLink baseclass you can subclass for implementing your own connection between visual system and your proprietary simulation host.
I have a working extLink implementation (extLinkVCL), but it is based on proprietary software of a funding partner, so you have to implement your own extLink, for example based on boost::asio.

Additionally osgVisual supports distributed rendering to allow to use large screens with more than one video projector seamless. Each video projector can be driven of a seperate rendering machine ("A channel")

The software module called "cluster" is the module which transports the rendering info to each rendering machine.
The rendering machine which holds the external link to the simulation host is called master, the rendering machines which are in the cluster and are not directly connected to the simulation host but only to the cluster are slaves.
The master gets the info from the extLink and passes it to its own rendering part and tells all slaves what they should render to provide a seamless scene across all channels.

If you want just one channel with only one rendering machine, then you do not need the cluster functionality and you can use "standalone" to bypass all cluster code.

I you have further questions don't hesitate to contact me.

Cheers,
Torben

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[Vijeesh Theningaledathil]

Hi Torben

Thanks for the reply. I want to develop a flight simulation visuals. That'ts why I can't use osgviewer. I modified the xml configuration file that is included in the download so that my terrain is loaded. (section pointing to terrain filename). and I removed the animation because I want to control the camera using external application(simulation host). But how can I specify the initial position of camera, so that the terrain is visible as soon as the application is loaded.

Thank you!

With Regards,
Vijeesh

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[Torben Dannhauer]

Hi vijeesh,

I personally use the animationpath ( I recorded it for 1 second while hovering on the destination location) so it immediately strts at that position and as soon as I want to use another camera manipulator, I use that. So I use th animationpath not for playing a real animation but to start at my desired location.

You said you want to use a simulation host. Then you have to subclass extLink to use any network technique to transport lat, lon, alt, and rot_x, rot_y and rot_z from your simultion host to the visual system. You can look into extLinkVCL for inspiration.

If you have a running simulation host which provides the correct lat/lon coordinates for your aircraft, then the visual system will immediately retrieve that values over your extLink and will position the camera accordingly.

Cheers,
Torben

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[Vijeesh Theningaledathil]

Hi,
I want to interface with a simulation host. but before going to the interface part, I want to see the terrain. is there any API in osg through which the camera can be set. If there any, can you please tell me how to use it. I have a test program. I'll try in that. I'm just starting the osg SDK. That's why. If you can give me a sample program that'll be great.

Thank you!

With Regards
Vijeesh

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[Torben Dannhauer]

Hi,

Thats quite easy: You can manipulate the camera with so called "camera manipulators" :)

Please ask google or this forum for details

One reference could be:

http://www.openscenegraph.org/projects/osg/wiki/Support/Tutorials

Section : control camera

Thank you!

Cheers,
Torben

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[Tueller, Shayne R Civ USAF AFMC 519 SMXS/MXDEC]

This is an interesting thread of discussion.

In terms of communicating with a simulation host, are there any plans to
support CIGI for communicating between the host and osgVisual? I would think
that would be a good thing to support...

-Shayne

[Torben Dannhauer]

Hi S2LR,

Yes, there were plans to create a CIGI implementation of extLink. Unfortunately for more than one year the project is not funded so all developments are competetive to my job. Therefore I can't spend as many hours as I would like to and CIGI support ist not on top of my todo stack..

But I would like to support any development in the direction of CIGI! It would be an improvement because currently only my proprietary extLink implementation is available.

Thank you!

Cheers,
Torben

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[Tueller, Shayne R Civ USAF AFMC 519 SMXS/MXDEC]

Torben,

Thanks for the information. I ask this because I'm currently working on
doing a CIGI tie-in to an OSG-based IG backend I've been developing. I'm not
a proponent for reinventing the wheel so to speak so I'm always on the
lookout for other options in this regard.

osgVisual would be something I would seriously consider using if it
supported CIGI. Unfortunately our hosts talk CIGI so we need this support.

By way of interest, I have found another OSG-based IG solution called
SubrScene that does talk CIGI but it appears to be using a pretty old
version of OSG. I'm not sure it's OpenSource so updating it to the current
OSG might not be an option. SubrScene is included with the distribution of
OpenEaagles which is OpenSource.

I will still play with osgVisual to see what it has to offer...:)

Regards,
-Shayne

-----Original Message-----
From: osg-user...@lists.openscenegraph.org
[mailto:osg-user...@lists.openscenegraph.org] On Behalf Of Torben
Dannhauer
Sent: Friday, February 04, 2011 12:06 AM
To: osg-...@lists.openscenegraph.org
Subject: Re: [osg-users] Camera control in osgvisual

[ted morris]

this indeed has caught my eye as well. But I am not familiar with the CIGI standard.

Would this include the ability to manage object motions and behaviors across the

cluster? (e.g., not only camera positioning).

thnx,

t

[Torben Dannhauer]

Hi Tedzini,

I'm not very familiar with CIGI, but it seem to be a communication library for communication with the sim-host.

I'm quite sure you can use CIGI not only for managing the camera but also for managing objects you want to display.

Currently osgVisuals "cluster" module is used to transport objects or camera modifications from the master to all slaves, but maybe that UDP implementation could be replaced by CIGI - it mainly depends on the performance.

Cheers,
Torben

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[ted morris]

yes... I'll have to have a closer look at this when I have some time. Thanks for spending to the to

develop an interface for this functionality; I think it will be very useful.

-t

[Philip Taylor]

Last time I downloaded the CIGI source code it came with an OSG application …….. MPV aka Multi-Purpose Viewer

 

http://cigi.sourceforge.net/

 

Looking at the WIKI page at the above site, it states that it requires OSG 2.4 but will work with 2.6 – that makes it quite an old implementation but MPV is only supposed to be an example, with limited functionality. It would be real cool to have an updated version …..

 

PhilT

 

From: osg-user...@lists.openscenegraph.org [mailto:osg-user...@lists.openscenegraph.org] On Behalf Of ted morris
Sent: 13 February 2011 20:14
To: osg-...@lists.openscenegraph.org
Subject: Re: [osg-users] Camera control in osgvisual

 

 

yes... I'll have to have a closer look at this when I have some time. Thanks for spending to the to

[Torben Dannhauer]

Hi Philip,

MPV ist OSG based? very interesting! That pushes CIGI a little bit closer to the top of my stack :)

Thank you!

Cheers,
Torben

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[Tueller, Shayne R Civ USAF AFMC 519 SMXS/MXDEC]

CIGI is an industry standard for controlling most aspects of an Image
Generator. This includes ownship and entity behaviors along with a lot of
other stuff. Most commercial IG vendors support CIGI.

You can learn more about the ICD by reading here...
http://cigi.sourceforge.net/

[Tueller, Shayne R Civ USAF AFMC 519 SMXS/MXDEC]

CIGI uses UDP so updating osgVisual to use CIGI shouldn't be an issue in
terms of performance. Effectively you'd be replacing one UDP implementation
with another that uses an industry wide standard for the packet
description...a big plus IMO.

Like I stated earlier, CIGI is used by most commercial IG vendors so
performance is more than adequate.

The main advantage of CIGI is that it provides a common interface for a
simulation host so that you can run the same host on different IGs on the
back end. We just swapped out an old IG for a newer one with minimal changes
to our host software.

If osgVisual supported CIGI, I can guarantee that you would open it up to a
much wider audience of users...at least in the simulation industry for sure.
Having an OpenSource solution here would be a benefit. Right now, the
software that currently ties CIGI to OSG for multi-channel IG purposes is
proprietary in nature. VT-MAK is one such company that comes to mind...

-Shayne

-----Original Message-----
From: osg-user...@lists.openscenegraph.org
[mailto:osg-user...@lists.openscenegraph.org] On Behalf Of Torben
Dannhauer
Sent: Sunday, February 13, 2011 4:48 AM
To: osg-...@lists.openscenegraph.org
Subject: Re: [osg-users] Camera control in osgvisual

[Tueller, Shayne R Civ USAF AFMC 519 SMXS/MXDEC]

Boeing's multipurpose viewer (MPV) was designed to simply be a test harness
for the CIGI protocol. It's a far cry from it being used as a general
purpose IG.

I've downloaded MPV from the CIGI site and played with it. It does use old
OSG stuff (osgProducer). I had to modify it to use the newer osgViewer
stuff. It also does not support osgTerrain type or round earth geocentric
databases last time I checked.

Lastly, the largest deficit IMO, is that it doesn't support multi-channel
rendering with OSG...a big drawback. It does support multi-window rendering
on one machine but not true "multi-channel" (i.e. a channel per box).

In short, it would require a great deal of modification and development to
bring it up to a point that it could be used as a commercial IG.

One might get closer to the goal by making osgVisual talk CIGI...

-Shayne

-----Original Message-----
From: osg-user...@lists.openscenegraph.org
[mailto:osg-user...@lists.openscenegraph.org] On Behalf Of Philip
Taylor
Sent: Sunday, February 13, 2011 6:49 PM
To: 'OpenSceneGraph Users'
Subject: Re: [osg-users] Camera control in osgvisual

Last time I downloaded the CIGI source code it came with an OSG application

.... MPV aka Multi-Purpose Viewer

http://cigi.sourceforge.net/

Looking at the WIKI page at the above site, it states that it requires OSG

2.4 but will work with 2.6 - that makes it quite an old implementation but

MPV is only supposed to be an example, with limited functionality. It would

be real cool to have an updated version ...

[Torben Dannhauer]

Hi Shayne,

I totally agree to you, but as I said I have to take care on my regular job (medical research and doctorate student in medical science), so it will take a littel bit to accomplish it.

Today eent I plan to tag osgVisual 0.6 and i hope to finish the documentation/wiki to the new features till the end of the week.

The next task I have to solve is terrain modification (flattening terrain and/or curting wholes in it) to allow to insert airport models with a flat runway.

After that I would like to dive into CIGI.
I totally agree that currently osgVisual is only useful for very few people wich can use the proprietary VCL implementation. CIGI would be great there - expecially because VCL only supports doubles currently, so it is tricky to update object labels etc. ;)

Thank you!

Cheers,
Torben

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[Torben Dannhauer]

Hi Shane,

Today I spent a lot of time in reading CIGI documentation and playing with the MPV and HE. Am I right that CIGI is a framework to organize and standardize date formats and query formats, but it does not provide the final network communication functions?

Thank you!

Cheers,
Torben

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