Flightgear-2.8.0 with quad buffered stereo

In the article Flightgear with quad buffered stereo I have written about how to get quad buffered stereo to work with the famous flight simulator FlightGear. Recently FlightGear-2.8.0 has been released. The problem with quad buffered stereo still persists with FlightGear-2.8.0 .

One expects to enable stereoscopic mode in FlightGear starting it with the following line:

export OSG_STEREO_MODE=QUAD_BUFFER;export OSG_STEREO=ON; fgfs

When starting flightgear this way, one gets the following console output and no stereoscopic view:

Warning: detected OpenGL error ‘invalid operation’ after RenderBin::draw(,)

Getting FlightGear to work with quad-buffered stereo

The reason for the above error message and the resulting broken stereo mode is, that the stereo context does not get initialized properly. The details are described here: Flightgear with quad buffered stereo. Unfortunately the patch I proposed in the mentioned post does not work for flightgear-2.8.0. However, the good news is, it only required a slight modification, the WindowBuilder.cxx file no longer is in src/Main, but in the src/Viewer directory. You can download the new patch from here: flightgear-2.8.0-stereoscopic.patch (1658)

Hopefully the patch finds its way into the next flightgear release.

As usual for quad buffered stereo, you have to use a professional graphics board that supports quad buffered stereo, like a NVIDIA Quadro FX or a Ati FireGL and proper display hardware, like shutter glasses, a HMD or a stereoscopic projection system, to benefit from it. To use the quad buffered stereo mode start flightgear with the environment variables mentioned above. Afterwards you probably have to enable quad buffered stereo mode by selecting the Stereoscopic View Options Item in the the View menu.

The Gentoo way

For gentoo users I have created an overlay. Like the previous one it contains patches and modified ebuilds for flightgear with working quad buffer support. You may get the overlay from here: flightgear-2.8.0 overlay (1699) Download the overlay and extract it in /usr/local/portage. Be sure to include the following line in your /etc/make.conf:

PORTDIR_OVERLAY=”/usr/local/portage”

Then emerge flightgear and enjoy it in three dimensions.

Have fun

Jürgen

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Flightgear-2.4.0 with quad buffered stereo

In the post Flightgear with quad buffered stereo I have written about how to get quad buffered stereo to work with the famous flight simulator FlightGear.  Recently FlightGear-2.4.0 has been released. The problem with quad buffered stereo still persists with FlightGear-2.4.0 .

One expects to enable stereoscopic mode in FlightGear starting it with the following line:

export OSG_STEREO_MODE=QUAD_BUFFER;export OSG_STEREO=ON; fgfs

When starting flightgear this way, one gets the following console output and no stereoscopic view:

Warning: detected OpenGL error ‘invalid operation’ after RenderBin::draw(,)

Getting FlightGear to work with quad-buffered stereo

The reason for the above error message and the resulting broken stereo mode is, that the stereo context does not get initialized properly.  The details are described here: Flightgear with quad buffered stereo. However, the  good news is, that the patch I proposed in the mentioned post, still works with FlightGear-2.4.0. You can download the patch from here: flightgear-2.0.0-stereoscopic.patch (1281)

As usual for quad buffered stereo, you have to use a professional graphics board that supports quad buffered stereo, like a NVIDIA Quadro FX or a Ati FireGL and proper display hardware, like shutter glasses, a HMD or a stereoscopic projection system, to benefit from it. To use the quad buffered stereo mode start flightgear with the environment variables mentioned above. Afterwards you probably have to enable quad buffered stereo mode by selecting the Stereoscopic View Options Item in the the View menu.

With the previous version, when using the quad buffered stereo mode in flightgear, there occurred some graphics errors. Some cockpit controls and other scene details contained yellow lines, like a wireframe, which were not there when starting FlightGear in “normal” display mode. These problems seem to be gone with Flightgear-2.4.0. At least I did not notice them  anymore.

The Gentoo way

For gentoo users I have created an overlay. Like the previous one it contains patches and modified ebuilds for flightgear with working quad buffer support.  You may get the overlay from here: flightgear-2.4.0 overlay (831) Download the overlay and extract it in /usr/local/portage. Be sure to include the following line in your /etc/make.conf:

PORTDIR_OVERLAY=”/usr/local/portage”

Then emerge flightgear and enjoy it in three dimensions.

Have fun

Jürgen

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Flightgear with VR920 headtracking

Recently I basically got Flightgear to work with quad buffered stereo. The only thing that was still missing for having the Vusix VR920 head mounted display fully supported in the flight simulator was headtracking.

However, with my new headtracking driver, VR920 headtracking in Flightgear is possible at last. A good part of the work has been done by Anders Gidenstam who provided the original Nasal module, the headtracking protocol description and usage instructions for his webcam based headtracking solution for Flightgear.

Download and copy the protocol description headtrack.xml (959) to $FG_ROOT/Protocol. For me (gentoo system) this location is /usr/share/games/FlightGear/Protocol/, probably for many others it is /usr/share/FlightGear/Protocol/

Afterwards download unzip the modified Nasal module headtracking.nas (1015) to ~/.fgfs/Nasal. It is important to use your home directory and NOT i.e. /usr/share/games/FlightGear/Nasal/.

Then make sure that the vr920 headtracking driver runs in UDP mode. If running Flightgear on the same machine as the headtracking driver, which should be the usual case, just use 127.0.0.1 as destionation IP for the driver and use 4242 as destination port. These are the default settings of the driver.

Finally run Flightgear with these options: –generic=socket,in,<hz>,,<port>,udp,headtrack –prop:/sim/headtracking/enabled=1

If you also want to have quad buffered stereo with it (you need an nvidia quadro board, with assumably a pre G80 Chip or probably an ATI FireGL, never tried that, and a stereo enabled xserver) use the patch from FlightGear with quad buffered stereo. For instructions on how to get the xserver to work in stereoscopic mode see: Vuzix VR920 with Linux and active 3D stereo

For the described configuration you can use the following little startup script:

export OSG_STEREO_MODE=QUAD_BUFFER
export OSG_STEREO=ON
fgfs –generic=socket,in,25,,4242,udp,headtrack –prop:/sim/headtracking/enabled=1

Now have much fun and enjoy a new experience with your VR920 and Flightgear in stereo with headtracking.

best regards

Jürgen

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VRTrack 1.0 – headtracking driver for the vr920 HMD

As I promised in New version of the vr920 headtracking driver coming soon here is the new version of my headtracking driver for the Vuzix VR920 iwear for Linux. It calculates yaw, pitch and roll from the accelerometer and magnetometer data (The device has got three of each). This makes a 3DOF tracking possible and allows you to look around in a 3D Scene.  In example you can use the driver with my stereoscopic image viewer SIV. The driver averages the sensor readings with an improved algorithm, which gives a far smoother experience than with the initial driver version. The driver package consists of a daemon which can be run in the background and for convenience a basic control application that enables one to easily tweak the various driver settings and to callibrate the device. For general Information on how to use the device with Linux see: Vuzix VR920 with Linux and active 3D stereo.

The driver provides the trackingdata in different formats to the application using it. It always writes the data to /dev/headtracking. A line read from /dev/vrtrack consists of six floats that correspond a sensor reading in this format:

yaw pitch roll x y z

Yaw, pitch and roll are angles from 0 to 360 degrees. X, y and z are always zero for the vr920, since it only supports three degrees of freedom. These values are reserved for future devices which may support six degrees of freedom, in the hope to propose a standard for tracking devices.

The driver can scale the readings and invert the axes independantly to get the needed value range for the used application and a pleasant experience.

For maximum compatibility with existing applications there are four other modes of operation available that can be enabled separately:

  • Joystick emulation
    The driver emulates a joystick device /dev/input/jsX. The readings for yaw, pitch and roll are the X,Y and Z axis of the emulated joystick. This may be used to enable basic headtracking support in games that do not natively support headtracking.
  • Mouse emulation
    The driver emulates a joystick device /dev/input/mouseX. The readings for yaw and pitch are being translated to X and Y of the mouse device, so when you look right the mouse pointer moves to the right and when you look up the pointer moves upwards and vice versa.  This may also be used to enable basic headtracking support in games that do not natively support headtracking. It can also be used to just control the mouse pointer of the window system. Controlling the viewport of the window system can also be a resonable purpose. With the new MPX extension in xorg this may be possible.
  • UDP – network
    In UDP mode the driver sends the tracking data via network as UDP unicast. The approach to send the data out via network makes the language used for writing the application independant from the language used for developing the driver. The packet sent to the clients contains the three angles, yaw, pitch and roll and x,y and z as 32 bit fixed point in Q16.16 format. This mode may i.e. used to control flightgear.
  • Multicast – network
    In multicast mode the driver sends the tracking data via network as UDP multicast, thus many clients may read the data, which makes parallelization more possible, i.e. one could use one machine for rendering and another machine for calculations. In addition to this, the approach to send the data out via network makes the language used for writing the application independant from the language used for developing the driver. The tracking data sent to the clients contains the three angles, yaw, pitch and roll and for easy usage a viewmatrix, one can directly use with scenegraph libraries. If you intend to develop an application using the headtracking of the VR920 see the file democlient.cpp included in the download for details on how to get the data into your application. This mode is used by the stereoscopic image viewer SIV.
Below is a screenshot of the control application during callibration of a vr920 device:
control_appvrtrack driver during calibration ( screenshot)

Important note: During calibration make sure that the display of the device is displaying something. Since the displays not only showing a blue screen influences the sensor data (at least with my device) you’ll end with wrong calibration else. You may use i.e. nvidia-settings to ensure this. For detailed usage instructions see the readme included in the download.

Download:

I decided to publish the driver under the creative common noncommercial license. You may download the full source from here: vrtrack-1.0.tar.gz (1278), an x86_64 binary from here: vrtrack-1.0-x86_64.tar.gz (1162) , or an i686 binary from here: vrtrack-1.0-x86.tar.gz (1135). An Archlinux PKGBUILD provided by Feilen is available here: aur.archlinux.org More binary/distribution specific formats may be available in the future. The x86_64 binary has been build on an up to date gentoo system, the i686 binary on ubuntu hardy. For the i686 binary you may install libconfig++ i.e. libconfig++8_1.3.2-2 from here: libconfig++ If none of the binaries works for you, you may have to build from source…

You need to have libusb, libconfig++, libfuse and libcurses installed on your system. For ubuntu users I included the small shell script ubuntu_install_deps.sh that installs the dependencies. Maybe it works also for for other Debian-based distributions. Gentoo users just have to make sure that  libusb, ncurses, fuse, and libconfig have been emerged. Your kernel version has to be at least 2.6.31 and you must have cuse enabled in your kernel.

Footnote:

If you like the driver, feel free to link to www.mygnu.de. If you developed an application using the tracking data provided by the driver please leave a comment, because then I can review the application and eventually write about it. To request commercial licenses contact us at info(at)mygnu.de. Well, if you just want to support our work on MyGNU.de use the donate button 😉

best regards

Jürgen

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SIV 1.1 released

I am proud to present a new version of SIV, the stereoscopic image viewer for Linux I published on MyGNU.de. It should be compilable also on MacOS and Windows, but I have never tested this. SIV is  capable of displaying JPS stereo images and MPO stereo images in different stereo modes. It is tested in fullscreen/windowed mode with anaglyphic and quad buffered stereo mode. Different output devices I tested were my Vuzix VR920 and relevator shutter glasses  on Nvidia Quadro FX 350M and FX 3700.

siv-1.1_screenshot
siv-1.1 the stereoscopic image viewer

Key Features

  • support for side by side JPS stereo images
  • support for MPO stereo images (used by Fujifilm Finepix Real 3D cameras)
  • many display modes, including quad buffered stereo
  • headtracking support for the Vuzix VR920 HMD (driver available on mygnu.de)
  • black-white and sepia filter
  • controls for gamma, brightness, contrast and parallax
  • on screen display

Basic usage
You may supply one or multiple .jps or .mpo files at the command line.  I.e.  siv *.jps will display all JPS files in the current folder. Once the first image of the list is being displayed you may use CURSOR_UP/DOWN or the mouse wheel to select a different image for being displayed. You can enable/disable the slideshow mode by pressing the [Enter] key. When displaying an image the filename of the image is displayed in the lower left corner for a few seconds. Using the number keys one may select different ways to zoom/navigate in the image. In VR920 mode or normal trackball mode use the right mouse button together with mouse movements to zoom the image. You can use the middle mouse button together with movements to pan the image. While displaying an image you may alter gamma, brightness, contrast and parallax for the best viewing experience. Some images may look better in black-white or sepia mode. By pressing the [t] key you may toggle these filters. The filters and controls use shaders on the GPU, so if you experience problems with these options you may disable them with the –disable-shaders commandline switch. At present the shader code is only tested on Nvidia hardware. If you have tested it on Intel/ATI please leave a comment.

Important keybindings are:

+/- increase/decrease parallax
HOME/END display first/last image
UP/DOWN display next/previous image
SHIFT+UP/DOWN jump 10 images forward/backward
F1/F2 decrease/increase brightness
F3/F4 decrease/increase contrast
F5/F6 decrease/increase gamma
F5/F6 decrease/increase slideshow delay
t toggle filter (normal/bw/sepia)
[Enter] toggle slideshow on/off
h Help

Press h to get the full list of keybindings.

Headtracking
If you want to try out the VR920 headtracking, enable the headtracking support with the “–vr920” option. You may want to specify the distance to the image with the “-d” option. Values between 0.25 and 0.5 seem to have a nice effect when using the headtracking. When headtracking is active you may press [z] to set the zero view so that with your current head position you will see the center of the image. If you want to manipulate the view manually press the left or mittle mouse button as described above and move the mouse. The “-m” and “-p” options allow to set IP-address and port for the connection to the headtracking driver.

Commandline Usage

siv [options] stereofile(s)

Options:
–CullDrawThreadPerContext                 Select CullDrawThreadPerContext
threading model for viewer.
–CullThreadPerCameraDrawThreadPerContext  Select
CullThreadPerCameraDrawThreadPerCo-
ntext threading model for viewer.
–DrawThreadPerContext                     Select DrawThreadPerContext
threading model for viewer.
–SingleThreaded                           Select SingleThreaded threading
model for viewer.
–accum-rgb                                Request a rgb accumulator buffer
visual
–accum-rgba                               Request a rgb accumulator buffer
visual
–cc                                       Request use of compile contexts and
threads
–clear-color <color>                      Set the background color of the
viewer in the form “r,g,b[,a]”.
–disable-shaders                          disable shaders for unsupported
graphics boards
–display <type>                           MONITOR | POWERWALL |
REALITY_CENTER |
HEAD_MOUNTED_DISPLAY
–filter=[bw|sepia]                        enable filter on startup
–rgba                                     Request a RGBA color buffer visual
–samples <num>                            Request a multisample visual
–screen <num>                             Set the screen to use when multiple
screens are present.
–serialize-draw <mode>                    OFF | ON – set the serialization of
draw dispatch
–stencil                                  Request a stencil buffer visual
–stereo                                   Use default stereo mode which is
QUAD_BUFFER if not overriden by
environmental variable
–stereo <mode>                            ANAGLYPHIC | QUAD_BUFFER |
HORIZONTAL_SPLIT | VERTICAL_SPLIT |
LEFT_EYE | RIGHT_EYE |
HORIZONTAL_INTERLACE |
VERTICAL_INTERLACE | CHECKERBOARD |
ON | OFF
–vr920                                    enable headtracking support for the
vuzix vr920 hmd
–window <x y w h>                         Set the position (x,y) and size
(w,h) of the viewer window.
-O <option_string>                         Provide an option string to
reader/writers used to load
databases
-d                                         distance (values between 0.0 and
1.0 are senseful)
-e <extension>                             Load the plugin associated with
handling files with specified
extension
-h or –help                               Display this information
-l <library>                               Load the plugin
-m                                         non default multicast ip
-p                                         non default multicast port
-s                                         start in slideshow mode
-t                                         delay for slideshow mode, defaults
to 15 sec

You may notice that most of the options come from osgViewer, which is the base class for the viewer. This gives the advantage, that one can use the “normal” osgViewer controls such as flying around the scene. Try to press [f] for toggling fullscreen mode or press [s] for toggling the onscreen stats (fps, etc.) display.

Download      

I decided to publish the viewer under the creative common noncommercial license. Make sure you have the OpenSceneGraph library installed before trying to compile or run the viewer. You may download the full source (Eclipse Project) from here: SIV-1.1 source (1548) or an x86_64 binary from here: SIV-1.1 x86_64 binary (1607). More binary formats may be available in the future. Fore the x86_64 binary you’ll need OpenSceneGraph-2.8.2.
Binaries of the OpenSceneGraph library for most linux distributions can be downloaded from www.openscenegraph.org.  On gentoo one can just emerge openscenegraph.

Building from source
For building from source unpack the zip and cd to siv/Release and run make.

Possible Problems
As default SIV starts in fullscreen quad buffered stereo mode. Thus if your graphics hardware does not support this mode, the viewer will exit with the following error:

Error: Not able to create requested visual.
GraphicsWindow has not been created successfully.
Viewer::realize() – failed to set up any windows

In this case try anaglyphic mode or the apropiate 3D mode for your hardware (see the –stereo option). For instructions on how to get the xserver to work in stereoscopic mode see: Vuzix VR920 with Linux and active 3D stereo

History
SIV-1.1
-support for the new MPO file format
-black-white and sepia filter
-controls for gamma, brightness, contrast and parallax
-improved OSD
-manual controls in vr920 headtracking mode

SIV-1.0
-slideshow mode
-vr920 headtracking

SIV – first version
-initial realease with support for jps files, quad buffered stereo and various other display modes

Footnote
If you like the viewer, feel free to link to www.mygnu.de. To request commercial licenses contact us at info(at)mygnu.de. Well, if you just want to support our work on MyGNU.de use the donate button 😉

have fun, enjoy the 3rd dimension and have a merry Christmas

Jürgen

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New version of SIV – the Stereoscopic Image Viewer ahead

Last year I published the first release of my stereoscopic image viewer, SIV here. At the time it was the first viewer for Linux supporting jps files and quad buffered stereo. As far as I know it is still the only one with support for the headtracking of the VR920 head mounted display. Currently I am working on a new and better version which will have the following additional features:

  • native support for the MPO file format (used by Fujifilm stereo cameras)
  • adjustments for
    -parallax
    -brightness
    -contrast
    -gamma
  • Improved OSD
  • Filters
    -black/white
    -sepia

In the current development stage most of the features are basically working so expect the new version of the viewer to be released soon. I hope to get it ready for Christmas, for those of you who have their new 3D camera under the Christmas tree.

Stay tuned for updates

Jürgen

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FlightGear with quad buffered stereo

With my upcoming new headtracking driver for the vusix vr920 hmd it is likely that I manage to get the famous flight simulator FlightGear to work with it. This led me again to the problem that FlightGear does not work in quad buffered stereo, as  I described in my comment to FlightGEAR 2.0.0 on GENTOO.

One expects to enable stereoscopic mode in FlightGear starting it with the following line:

export OSG_STEREO_MODE=QUAD_BUFFER;export OSG_STEREO=ON; fgfs

When starting flightgear this way, one gets the following console output and no stereoscopic view:

Warning: detected OpenGL error ‘invalid operation’ after RenderBin::draw(,)

Getting FlightGear to work with quad-buffered stereo

Doing some code analysis in OpenSceneGraph-2.8.0 I discovered the following lines of code in View.cpp:

osg::DisplaySettings* ds = osg::DisplaySettings::instance();
if (ds->getStereo())
{
switch(ds->getStereoMode())
{
case(osg::DisplaySettings::QUAD_BUFFER): traits->quadBufferStereo = true; break;
case(osg::DisplaySettings::VERTICAL_INTERLACE):
case(osg::DisplaySettings::CHECKERBOARD):
case(osg::DisplaySettings::HORIZONTAL_INTERLACE): traits->stencil = 8; break;
default: break;
}
}

It seems that the stereo context in FlightGear does not get initialized properly in WindowBuilder::makeDefaultTraits(bool stencil). Thus these lines have to be added to WindowBuilder.cxx. For convenience here is the patch against  FlightGear-2.0.0: flightgear-2.0.0-stereoscopic.patch (1281)

Perhaps some nice FlightGear developer can include this into upstream code. You have to use a professional graphics board that supports quad buffered stereo, like a NVIDIA Quadro FX or a Ati FireGL and proper display hardware, like shutter glasses, a HMD or a stereoscopic projection system, to benefit from it.

Problems remaining

When using the quad buffered stereo mode in flightgear there occur some graphics errors. These are not very annoying, but they are there. Some cockpit controls and other scene details contain yellow lines, like a wireframe,  which are not there when starting FlightGear in “normal” display mode. I suspect this to be another bug in FlightGear, which has still to be located. See the screenshots below for details. The problematic parts of the scenes are marked red. Especially the night pictures show the problem. This problem does not only exist in quad buffered stereo mode, but also in other stereo modes like HORIZONTAL_SPLIT.

flightgear_1

FlightGear by day, quad-buffered stereo, with errors

flightgear_2

FlightGgear by day, no stereo, without errors

flightgear_3

FlightGear by night, quad-buffered stereo, with errors

flightgear_4

FlightGear by night, no stereo, without errors

The Gentoo way

For gentoo users here is my overlay including the modified ebuild: flightgear-2.0.0-stereoscopic_overlay.tar.gz (1141) Download the modified overlay (including the patches) and extract it in /usr/local/portage. Be sure to include the following line in your /etc/make.conf:

PORTDIR_OVERLAY=”/usr/local/portage”

Then emerge flightgear and enjoy it in three dimensions.

Have fun

Jürgen

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