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 (2582 downloads )

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 (2596 downloads ) 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

(1 votes, average: 5.00 out of 5)

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Posted in 3d, games, gentoo, graphics, linux | No Comments »

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: [download#43]

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: [download#72] 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

(1 votes, average: 5.00 out of 5)

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Posted in 3d, gentoo, graphics, linux | No Comments »

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 [download#59] 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 [download#58] 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

(1 votes, average: 5.00 out of 5)

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Posted in 3d, drivers, games, gentoo, linux, networking | No Comments »

I recently received my VR920 3D stereo glasses from USA. A detailed review of the device can be found here : Introducing the Vuzix iWear VR920. A photo of the VR920 can be seen below:

The device of course works flawlessly using Windows. The situation under Linux is a bit different, due to missing driver support from the manufacturer, as usual.

Stereo vision works at least with nvidia quadro boards, probably also with others. I.e. Ati FireGL should work, but I never tried this. Setting this up was easy. I only had to start a second XServer and add the line

Option “Stereo” “1″

into the screen section of its xorg.conf. With this setting you get a different image for both eyes and thus real stereo vision if your application supports quad-bufferred stereo. It is important that the screen resolution is between 640×480 and 1024×768 and the refresh rate is 60 Hz. The xorg.conf you are using for this must not use the composite extension. For disabling the Composite extension append the following to the xorg.conf:

Section “Extensions”
Option         “Composite” “Disable”
EndSection

Sadly this also prevents the use of compiz, hopefully Nvidia fixes the incompatibility between stereo and the composite extension some day.

For starting the xserver i use the following little script, which opens 2 xterms and starts the program (given as parameter with arguments) in one of them.

#!/bin/bash

/usr/X11R6/bin/X :1 -dpi 96 -xf86config ./xorg.conf.3d -auth /var/gdm/:1.Xauth vt8 &
DISPLAY=:1.0
export DISPLAY
sleep 5
icewm&
hotkeys&
xterm -fn 9×15&
xterm -fn 9×15 -e $@&

The headphone gets detected as alsa device:

usb 2-2: new full speed USB device using uhci_hcd and address 8
usb 2-2: configuration #1 chosen from 1 choice
generic-usb 0003:1BAE:0002.0002: hiddev0,hidraw1: USB HID v1.00 Device [Icuiti Corp. VR920 Video Eyewear] on usb-0000:00:1d.1-2/input3
usb 2-2: New USB device found, idVendor=1bae, idProduct=0002
usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
usb 2-2: Product: VR920 Video Eyewear
usb 2-2: Manufacturer: Icuiti Corp.
usbcore: registered new interface driver snd-usb-audio

cat /proc/asound/cards:

1 [ Eyewear ]: USB-Audio – VR920 Video Eyewear
Icuiti Corp. VR920 Video Eyewear at usb-0000:00:1d.1-2, full speed

I was able to get mplayer to play on the device by setting the output device to hw=1,0 .

Sadly the mixer does not seem to work. At least the mixer levels are not controllable. Perhaps any alsa developer has an idea for this? It is even more important since the mixer control wheel at the device freezes after three steps when using linux.

More important than having controllable sound is to get the integrated headtracking to work. There is a non-working driver at vuzix forums. At least it can read the sensor data from the device but does not seem to handle the data correctly. I will look into this soon.

Update: My VR920 headtracking driver is now available here: VR920 headtracking driver for Linux

Playing with the device I had to find out that there is no jps stereoimage viewer for linux. The only programm I found, which is able to read jps-images, is gqview (GQView3D). Sadly gqview is not able to display theese images using active quad-buffered stereo. Thus I decided to write my own jps viewer. It will be based upon OpenSceneGraph (OpenSceneGraph) since I have some experience in OpenSceneGraph development. Perhaps I can integrate headtracking into it. Would be really cool to view a sea panorama image in 3D by turning the head

Stay tuned for updates.

Jürgen

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Posted in 3d, hardware, linux | 22 Comments »