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Some stereo separation theorie (Part I)

Last Updated on Friday, 06 November 2009 22:54 Friday, 06 November 2009 00:00

Well, after I have discussed, how you should combine your headtracking stuff with OpenGL I will show you, how you can generate some 3D stereo mode for your OpenGL applications. The eye separation will work with Direct3D in the same way, but I tend to use OpenGL as it is a portable graphics library and works great under linux. As not everyone of you might own a NVIDIA Quadro-Card and a stereo display, I will show, how you create anaglyph 3D pictures and extend it on quadbuffered cards afterwards.

I will also show you how you can archieve the effekt of objects appearing in front of your display. This is an effect that is very difficult to archieve as there are many things that can destroy the illusion.


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Read It Linewise

Last Updated on Thursday, 31 December 2009 00:31 Thursday, 05 November 2009 13:29

Ever been in the need to read a text file linewise using a bash script?

I mostly perform line operations using awk or sed but from time to time there are some problems I have to solve that are to hard to solve using this tools. For this, there is a simple way to read a file linewise using a simple bash script:

# get one filename
FILENAME="Just A Filename"

# backup the old ifs and set it to newline

for LINE in $(cat "$FILENAME"); do
# process your lines here

# reset the ifs variable

The IFS-variable changes the behaviour of the for-loop an whitespaces. Normally the for loop would use any whitespace (tabulator, space, linebreak) as token delimiter. By setting the IFS to \n we only use the newline token as token delimiter and we can read our file linewise.



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Window To A Different World

Last Updated on Wednesday, 28 October 2009 17:20 Wednesday, 28 October 2009 17:13

You probably have heard about Jhonny Chung Lee (, the man who connected a wiimote to his computer to use it as a "touch"  Device for a beamer projected. An other project of him was using the wiimote ad a headtracking device. He developed an application that used the position of

his head and used the tracking information within a program showing a simple 3D scene. With this he archieved the illusion of looking through a window as you are able to look around other objects that are near to the screen surface.

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GPshell and GlobalPlatform On Gentoo

Last Updated on Thursday, 31 December 2009 00:32 Saturday, 03 October 2009 13:56

As I will start with SmartCard development the next weeks, I was in the need to install gpshell and globalplatform on my gentoo box today. As I could not find any ebuilds in the official portage, I started googling around and found this bug report:

I decided to copy both ebuilds to my layman overlay. I changed the directory of app-crypt/gpshell to dev-util/gpshell as it fits there much better and added the debug-use flag to globalplatform, as it might be useful as well ;).

To install the ebuilds on your system, just use layman to add my overlay and unmask both packages with your system keywords. Afterwards, just execute emerge -av dev-util/gpshell und hope, that it works for you as well.

For usage instructions for the overlay, just take a look at this page:

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My Pidgin Talkes To Me

Last Updated on Wednesday, 30 September 2009 13:19 Tuesday, 29 September 2009 09:59

I recently played aroud with the festival TTS (text-to-speech) plugin for pidgin. All in all, it is a nice idea but has a little problem:

It uses festival which currently only contains language support for english languages. As I am a german speaker, I tried to find a way to combine pidgin with a german TTS. After some minutes of googleing, I foudn a TTS system supporting several languages like german, french, english and many other languages. it is called eSpeak Text To Speech. The TTS engine is developed under GPL. As I was not able to find any existing for eSpeak integration in Pidgin out there, I decided to develop my own solution and created a small perl plugin. It is not some well planned solution but a little (hackish) perl script just calling the eSpeak executeable. As eSpeak itself is not able to play any sound on my system, I added support for pipeing the wave-output provided by eSpeak into aplay (of the alsa-utilities package).


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What time is it, please?

Friday, 25 September 2009 09:57

Reading the current time since 01/01/1970 in milliseconds (or even microseconds) is something, most operating systems provide by system calls. One of the most unpleasent things about it is, that every operating system provides other methods (or at least method names) to read this value. This is not really a problem, if you use higher level languages like Java or something like this, but if you try to develop portable applications using C/C++ you might dislike this.

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