September 19, 2006 – 17:12
I just finished implementing the Verhoeff checksum algorithm in PHP, you can download it as verhoeff.zip. Yes, mathematically it’s a bit more elaborate than other checksum algorithms, but with look-up tables it’s fairly simple and lightweight.
The implementation provides two functions calcsum($number) and checksum($number). The first one return a check digit for the decimal number used as argument, just append the returned digit to the number and you got yourself a checkable number. The second function checks the number (including the appended check digit) used as argument, the number is only valid if the function return zero.
I noticed a small bug due to a misplace modulus (simple PHP syntax typo), the verhoeff.php is now updated, tested and in working order. The bug only affected the calculation of check digits, not the check function.
I must say that Wings 3d are THE polygon and subdivision mesh modeler. It have been on my radar a long time, but the trouble of getting Erlang and compile everything have put me off of trying out the software before. Wings 3d came up once again during our work on K-3D’s next generation user interface when Joe Crawford told me that its user interface is regarded as the best for modeling of all 3D software out there.
Finally, a couple of weeks ago when I was in desperate need for a texture mapped polygon model I sat down with the notion of really trying to learn how to use it. I must say that there are few programs like Wings 3d where you go from total newbie to create quite good models in less than an hour. Possibly some text editors were you at the end of the hour have authored the first chapter of your new novel, if you’re creative enough to write a novel. That’s what I think Wings is, it is to a 3d artist what a text editor is to an author.
December 31, 2003 – 17:55
Oh, boy! It looks like this post is quite a popular one. Just keep in mind that I penned it in December 2003. But if you have any suggestions, modifications or updates, please, do leave a comment.
Traditionally, DVD authoring has been an expensive affair. Full-featured professional applications or hardware costs big sums of money, while low-budget products often come with severe limitations in features.
However, it’s now possible to author professional DVDs on Linux thanks to a group of open-source packages. Even if they do not yet support all features of the DVD specification new features are being added with each release.
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December 31, 2003 – 17:45
I successfully authored my first DVD on Linux today, with the mjpegtool and dvdauthor suites of commandline tools. Not that my creation is very content rich, it’s just some menus and slideshows with audio. I’ve started to compile all infomation I have into a long and detailed note regarding how to use the various tools to author a DVD. A work in progress copy can be found here of my DVD Primer.
MPEG-2 coded stereo soundtrack can be encoded with the exelent tooLAME tool, and a multi-channel 5.1 soundtrack can be created using the companion mctooLAME tool. It also looks possible to encode audio as AC-3 tracks using the Transcode utility, at least stereo, while waiting for the AC3 Project to produce some usable software.
A very well written general overview of multi-channel surround sound and its history can be found at ExtremeTech.
September 28, 2003 – 1:31
I’ve given up on implementing Python classes using C API since I couldn’t get instancing in the C API to work properly. No helpfull error messages, either segfault or “wrong arguments in Objects\classobjects.cpp line 504″, no helpfull documentation, and me to tired to even type gdb. I’m going back to write a simple module and wrap it in classes written in Python.
But that solutions annoy me because it will mean I first write a module, transfering my C++ interfaces to something similar to a C interface (object-oriented non the less in a GTK+ way), and then wrap that module into Python classes miming the original interfaces. I had hope to shorten that path. But apparently failed to do so. Oh well, oh well… There’s another day tomorrow, said Scarlett O’Hara before she logged of.
September 27, 2003 – 15:11
I finally figured out how to implement classes in Python using C API — the right way. Namely as a new type using the PyTypeObject complete with get and set attribute calls and plain members. But I tought my previous hack for building a class at runtime is still slim enough to share, especially if you just got a couple of methods that you want bundled into a class instead of a module.
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September 24, 2003 – 9:51
Ok. I haven’t posted anything in a (relative) long time. To tell the truth — there isn’t much to report.
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