Earlier last week, on May 4th, 2009, I released version 1.0 of Elm4J on the University of Calgary’s InnoVis Lab site. Elm4J is a Java library for representing hierarchically structured data, also known as tree data structures. It makes use of generics, provided in Java 5, to enable the creation of trees of arbitrary vertex and edge types. The library also comes with a handy Newick file parser. The project is released under the GNU Lesser General Public License.

Elm4J is a Java port of an Elm, a C++ library I wrote in earlier 2008 as part of my master’s thesis project. Interestingly enough, I haven’t had the chance to release the original C++ project, though the progenitor should be released into the wild at some point in the next few months.

Today I updated Elm4J to version 1.0.3, after stamping out a bunch of bugs in the Newick file parser and extending the robustness of the tree traversal API. To this date, I’ve had one known user (thanks Darryl for the bug reports), so I’m already counting this as a win.

I’ve been scratching the last few days over a GCC error that’s been popping up in a project which I have been porting from Visual Studio 2008 to Xcode 3.0. The cryptic error message from GCC (version: i686-apple-darwin9-gcc-4.0.1 ) is:

error: expected unqualified-id before ‘OTHER’ token

After debugging it for a while, I figured it might of been caused by some incorrectly set extended attributes on the source files, as these errors were coming from files with extended attributes. I cleaned out all the extended attributes (thanks to Diego Zamboni’s script), but the error still remained. In the end the only thing that worked was to delete the erroneous files, create a new file, and paste the code back in. This solution suggests that the files were corrupted and therefore needed to be re-created.

How many time have been about to write some class, but couldn’t come up with a good name? Like the other day, I had a Line class and was working on a “two connected line segments” class which for lack of a better word I decided to call a Path. Instead of thinking and obsessing about the right name, wouldn’t it be great if there was something that could just give me a great class name?

Well there is. It’s called: ClassNamer.com

Goodbye Path, hello CryptographicScrollbarSubscriber!

I’ve just posted my first programming how to guide.  This article covers Creating a Framework in Xcode 2.5.

Changing you MAC address isn’t something you’ll be doing everyday (well maybe it is…), but from time to time it can be useful. Say, for example your machines gets blacklisted from some network. This being a erroneous blacklisting, of course. Often blacklisting is done via a machine’s MAC address, so by simply changing this address, the machine can again gain access to this proscribed network. Here’s how.

sudo ifconfig <interface> lladdr <new MAC address>

For example:

sudo ifconfig en0 lladdr 4a:74:00:b5:f8:3c:17

Flare is a visualization toolkit written in ActionScript 3 based on the Prefuse visualization toolkit which is written in Java. An alpha version of the library was released on October 22, 2007. Although there is no affiliation mentioned on the site, Jeff Heer is likely behind this one…

The folks at Griffin Technology have put out a (much needed) driver update for those the sleek blue-LED knob knows as a PowerMate. The new driver supports is widely configurable and is really what driver version 1.0 should have been.

ATI’s X1600 which is found on the MacBook Pro offers support for OpenGL 2.0, but the Architectural Review Board extension ARB_texture_non_power_of_two is not supported by this particular GPU. This has been noted elsewhere [ iDevGames ].

Developers using the X1600 can use ARB_texture_rectangle which allows non-power of two textures to be used, however with some limitations:

However, non-power-of-two sized textures have limitations that do not apply to power-of-two sized textures. NPOTS textures may not use mipmap filtering; POTS textures support both mipmapped and non-mipmapped filtering. NPOTS textures support only the GL_CLAMP, GL_CLAMP_TO_EDGE, and GL_CLAMP_TO_BORDER wrap modes; POTS textures support GL_CLAMP_TO_EDGE, GL_REPEAT, GL_CLAMP, GL_MIRRORED_REPEAT, and GL_CLAMP_TO_BORDER (and GL_MIRROR_CLAMP_ATI and GL_MIRROR_CLAMP_TO_EDGE_ATI if ATI_texture_mirror_once is supported) . NPOTS textures do not support an optional 1-texel border; POTS textures do support an optional 1-texel border.

NPOTS textures are accessed by dimension-dependent (aka non-normalized) texture coordinates. So instead of thinking of the texture image lying in a [0..1]x[0..1] range, the NPOTS texture image lies in a [0..w]x[0..h] range.

When using ARB_texture_rectangle with GLSL, textures are accessed in fragment shaders using the texture2DRect() function which returns a sampler2DRect data type.

If you’ve written shaders in Xcode, you’ll probably noticed that the .vert and .frag files don’t have syntax high lighting by default. Sure you can use the C syntax colouring for your shader files, but what about something more in tune with the syntax of GLSL or Cg?

If your in this situation, a PhD. student by the name of Alexander Taliesin Streit has just the thing: Cg & GLSL Shaders Syntax Highlighting in Xcode.