If you want to experiment with Physically Based Rendering, PBRT is the tool to use. Unfortunately, the latest builds (>1.03) have some incomplete instructions on how to build PBRT on your own machine. I’ve built it on Ubuntu 9.10 and 10.04 using the following instructions:

  • PBRT needs the OpenEXR libraries, but unlike it mentions in its makefile, just installing openexr and libopenexr-dev is not enough. The full apt-get install line should read:
    sudo apt-get install openexr openexr-viewers libopenexr-dev libilmbase-dev.
  • The makefile looks for EXR libraries in /usr/local/*, while ubuntu installs them in /usr/lib. The following lines in the makefile should be changed:
    EXRINCLUDE = -I/usr/local/include/OpenEXR to EXRINCLUDE = -I/usr/include/OpenEXR
    EXRLIBDIR = -L/usr/local/lib
    to EXRLIBDIR = -L/usr/lib
  • PBRT should compile now, by running make in the source directory.
  • Before you can render scenes, you should set the PBRT_SEARCHPATH environment variable. In a terminal, type:
    export PBRT_SEARCHPATH = /location/to/pbrt/bin
    (the bin folder was created in the make process)

Well, I hope this is a timesaver! :)

ubuntuIt’s that time of the year again. The 10th month means lots of things: start of spring,  silly birthdays and a new and shiny Ubuntu release. And it wouldn’t be the same without me recklessly updating to the beta a couple of weeks before release.

What’s fixed? What’s broken? And what about the rest? Read it after the cut.

Continue reading »

WICDThere are lots of things to like about the GNOME desktop environment. It’s free, it’s highly consistent and backup up with excellent development ethics and a wide range of supported applications. It comes as no surprise that it is the default desktop in a lot of Linux distributions (Ubuntu, Fedora, …). There’s one thing that’s been bothering me for a few years now: the default network manager. It had to go.

Continue reading »

ubuntuSince a lot of people seem to be struggling with this issue (getting good performance out of Intel Mobile Graphics chips on Ubunty Jaunty), I’ll give a quick heads-up on my findings again. I’m on an 945GM chip myself, so although this issue probably effects the whole range of chips using the xorg-intel driver, keep in mind that results may vary.

Last time I explained how I installed the xserver-xorg-video-intel driver from the X.org SWAT Launchpad PPA. This resulted in a performance increase and a fix for the swap-hogging problem. Behold, I was wrong about that last bit. Mock me behind the cut. Continue reading »

ubuntuA couple of weeks ago, I reported about a fix for Intel driver performance regression in Ubuntu 9.04 (Jaunty Jackalope). The fix solved the overal responsiveness of the interface (especially for composite-enabled desktops), but introduced a new problem which wasn’t visible at first: a memory leak slowly filling up swap space.

Over the course of 2 or 3 hours, my UXA-enabled driver would start to fill swap space with unrecoverable junk blocks. The only solution was to restart X before it grinded to a halt. This was not optimal, but I preferred restarting X over the clunky EXA method.

I’ve experimented with a new solution – read more behind the cut. Continue reading »

ubuntuAfter upgrading from Intrepid (8.10) to Jaunty (9.04) I noticed a noticeable performance hit, in 2d and 3d applications on my Ubuntu system, running a (rather crappy) Intel 945GM mobile graphics chip. After poking around on the Ubuntu forums I found this thread. The problem seems to be the switch between EXA and UXA in the new intel driver.

More tech talk and a solution behind the cut.

Continue reading »

ubuntuYesterday, I decided to upgrade my Ubuntu installation from Intrepid Impatient Ibex (8.10) to Jaunty Jackalope (9.04). I recklessly went update-manager -d and just let it run. Backups are for wimps, real men save their data the moment the shit hits the fan. Even when there’s still 12 days of public beta in the can ;)

Remarks behind the cut.

Continue reading »

Dvb-T Receiver

Dvb-T Receiver (patent pending)

I recently bought a Pinnacle PCTV DVB-T Stick Solo 72e (bonus points for Pinnacle’s over-the-top naming scheme), because the public TV services in Belgium switched to digital broadcasting. It was the €40 pricetag which turned me. The box contains the USB 2.0 stick and an antenna. I advise on attaching this antenna to a metal object (the attach point is magnetic).  I attached it to my desk lamp. I can’t light it and watch TV, but that’s a setback I can live with. No issue.

What’s the real issue then? More behind the cut.

Continue reading »

Every six months, it’s that time again … upgrading to the newest Ubuntu release. I don’t know which department is in charge of the release branding, but with the label for release 8.04 (The year 2008, fourth month) they have outdone themselves: Hardy Heron. I really hope Mark Shuttleworth opens an Ubuntu Zoo out there in South Africa. Screw PETA, it would be horribly nice of him. The man’s been into space, is there anything he can’t afford ? A couple of drakes, fawns and herons would do the trick.

Back to the dist-upgrading then. The great thing about Unix is that all of your settings are stored in a central place: the Home folder (trademark). Backing up your system is a simple matter of backing up one directory. Even if it all goes bottoms up, it’s just a matter of an hour (I/O wait time, mostly) to get your system back into the exact state it was.

After the obligatory reboot – yes, the only necessary reboot is when your kernel has changed – all seemed to work, except for a few Gnome panels. I’m 23 days early, the release is still in beta, so I was expecting some trouble either way.

Let’s go quickly over the big changes in this release:

  • Firefox 3 beta: A huge improvement. The overall feel is a lot smoother, pages render blazingly fast, regardless of how many flash elements, poorly structured chunks of HTML or high-resolution pictures the page holds. The interface (and the download dialog) had a necessary cleanup, and the bookmarks system is a lot clearer now.
  • Gnome 2.22: Simple, yet elegant, Gnome remains my favorite desktop manager, although I’m going to check out the spectacular-looking KDE4 too. The most noticable improvement probably is the bundling of file transfer dialogs. When you’re moving a lot of files between disks, the task bar used to get cluttered with “copying files” or “moving files” dialogs. Now, they are all bundled into one convenient dialog. It’s a detail, but it sure makes a difference.
  • CFS (Completely Fair Scheduler): Since kernel 2.6.23, the standard Linux schedular has switched to CFS mode, which is an intelligent way of distributing processor time over several processes. It improves desktop reaction time, and makes the overall experience of working with GUI’s feel smoother. You can read the (nerdy at first glance, extremely interesting at a second look) lengthy discussion Mr. Torvalds had with the other kernel developers here.

I’m very satisfied with the new release overall ! Also, very interesting for windows users: you can try out Ubuntu from within windows now, thanks to the new Wubi installation system !

(warning: next section is extremely boring if you don’t have an Intel Proset Wireless chipset in your laptop, if any :) )

And now, on to the slightly bad news: this update bricked my wireless connectivity, partially. Since the 2.6.24 kernel version, ubuntu has switched from ipw3945 to ilw3945 as kernel module for Intel Proset Wireless interfaces. This new module seems to have several quirks, which hopefully will be ironed out before Hardy goes out of beta. Here’s a couple of things you can do if you’re experiencing troubles with given card:

  • Launchpad #204709: Solution for network interface wlan0 changing to wlan0_rename and useless activation of eth1 after performing an upgrade.
  • This thread offers a solution which is connected to a broken CAPA implementation, but that seems to be resolved in the latest Network-Manager updates.
  • Launchpad: #210005: My bugreport about the issue

In my never-ending quest to make life even lazier than it is, I decided to fiddle around a bit with my Bluetooth-enabled phone. I have a Nokia 6600, which only downside I’ve found so far is it’s clunky size and weight. Then again, the weight has its upsides too. Within a 10-yard radius, I’m deadly with this phone.

Back to the Bluetooth-goodness then. Although it was hyped up by the telecom sector around the year 2000, it’s most common use field today is still in the business section. You’ve seen them, those fancy headsets. Have a look at the advert on the left. It’s hard to neglect the pure joy of wearing a headset, even when you’re a businesswoman with curly hair. Most people have Bluetooth-enabled phones nowadays, but don’t realize the tremendous fun and excitement it brings.

For instance, I was at a concert once, and a guy in front of me was trying to capture the whole experience using his cell phone. I fail to see how much joy he would have afterwards when watching the blurry VGA 30-second clip, bundled with the sound equivalent of farts in a box, but hey, who am I to judge. He was, however, blocking my view with the desperate cell-phone waving.

So I flipped out my mobile, scanned for Bluetooth devices, and found his gadget. When I sent him the Bluetooth connection invitation, the video recording application on his phone quit. He spent the next 10 minutes figuring out what the hell happened, and I was the concert hero. Well, not exactly, at least I could see the stage again.

Today, I managed to control my Linux music player using my cell phone. Using Remuco, an open-source server/client(java) bundle, I’m now capable of switching tracks, changing the volume and rating tracks, all without leaving the chair.

And that, my friends, is holy.

Code is poetry. Please, Suffusion WordPress theme by Sayontan Sinha