PHP4/5: Object orientation and compatibility
Posted by Peter | Filed under Programming, SLOODLE
Some compatibility problems were reported following the release of SLOODLE 1.0, and they largely appear to centre around the object-oriented plugin system I developed for the Presenter module.
The idea is fairly simple. The SLOODLE core or 3rd party developers can create plugin classes to extend the functionality. These will all belong to a structured inheritance hiearchy, and will be automatically detected and loaded by the SLOODLE framework. However, it has been a big challenge maintaining compatibility for both PHP4 and PHP5, given that the object orientation of the language has changed so much in that time.
After considerable efforts, I think I’ve finally found the solution, and it’s infuriatingly inelegant.
Epidemic security flaws
Posted by Peter | Filed under Software
Automatic updating is becoming very widespread on the Windows platform at the moment, particularly with security software such as firewalls and antivirus. I will wholeheartedly agree that many users simply don’t have the time and/or inclination to learn how or why to initiate updates manually, so they are at risk without automatic updates. Additionally, the average user probably wouldn’t know or care that an update is going on. Even if a popup appears saying “update complete”, many users have tunnel vision or myopia, so they just won’t notice it.
Unfortunately, painting all users with the same brush leads to a big security flaw…
OpenGL gotcha: scale your normals!
Posted by Peter | Filed under Programming
My OpenGL blunder this evening involved forgetting to make sure my normals were scaled correctly.
I had a scene with a single point light source and several small rotating cubes. Everything looked fine. I had also written a function to draw a 1×1 plane in the scene, and that looked fine too. I then applied a scaling transformation in my plane-drawing function (using glScalef) to make it 10×10, but for some reason the plane was then totally dark.
I tried moving and rotating the plane to see if it would catch the light at some other angle, but it wouldn’t. Eventually, I spotted the flaw…
PHP quirk: shell commands breaking on Windows
Posted by Peter | Filed under Programming, SLOODLE
I’ve been wrestling with many compatibility quirks in my work on SLOODLE lately, and this one certainly takes the prize. It seems that some perfectly valid shell commands will simply not work when executed from within PHP on Windows.
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OpenGL gotcha: depth buffer distortion
Posted by Peter | Filed under Programming
While I’m on the topic of OpenGL gotchas, I thought I’d mention another which caught me out a couple of years ago. I was working on some prototypes with some friends, and you can see a screenshot on the right (click it for a full view).
Notice areas where polygons overlap — you can see a striped or checked pattern of the occluded polygon showing through. In this case, it was 2d graphics and a 3d camera (so that we could make some interesting visual effects). However, the problem manifests just as badly in full 3d.
It took quite a while to figure out the problem, and it’s one I’ll never forget.
OpenGL gotcha: mipmaps only please!
Posted by Peter | Filed under Programming
Here’s an OpenGL gotcha which caught me out for quite a while. I was writing code to load textures, but it only worked if I was using the GLU function to build mipmaps. After lots of hair-pulling, I realised that it was entirely my mistake.
Review: “Crush the Castle”
Posted by Peter | Filed under Games
It’s been a while since I reviewed some games, so here goes with another great one I found recently. “Crush the Castle” is yet another physics-oriented game (you know I love ‘em!). It seems to be a single programmer job (+ 1 artist), and the concept is absolutely great. Unfortunately, it is not an original concept… it is borrowed (with permission apparently) from “Castle Clout“. Nonetheless, I enjoyed it, so here’s my thoughts…
Information finding on Oyyy.co.uk
Posted by Peter | Filed under Interface and Usability, Websites
On a recommendation from my dad, I decided to try shopping at Oyyy.co.uk — it’s an online shop for various computing and other technological things. The experience was good and I had no trouble finding the products I wanted. However, there was an apparent lack of information in one key area.
Before I go into this, please don’t read this as any kind of criticism of the Oyyy.co.uk shop or its staff. This is simply intended as an analysis of a usability problem. As an online shop, the site is better than many I have used, so this one issue is not a big deal at all.
Staples and lessons in e-commerce
Posted by Peter | Filed under Interface and Usability, Websites
Many people are familiar with Staples — supplier of general office supplies and furniture and the like. I think they have a reasonable reputation, so I decided to order a new office chair from their website. There are some good points about the site, but unfortunately, there are also some flaws which almost made me turn to a competitor.
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SLOODLE / PhD Research - Survey Invitation
Posted by Peter | Filed under SLOODLE, Software, Virtual Worlds
SURVEY CLOSED
Thanks for your interest, but I’m afraid this survey is now closed. I will be running the next set of evaluations in the coming months, so pleased stay tuned if you’re interested.
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Hello readers!
I am plastering everywhere else on the web with this, so I thought I might as well put it on my own blog too! 
I am conducting a survey alongside the SLOODLE project and as part of my PhD work. Your participation would be greatly appreciated:
https://avid-insight.co.uk/limesurvey/index.php?sid=16321〈=en
It contains 35 questions, taking around 20 minutes to complete, and the software allows you to save your responses for later completion if you are pressed for time. All data will be handled anonymously.
The broad topic of my PhD is usability and user centred design in the context of integrating technologies such as Second Life and Moodle. This particular survey is exploratory in nature, asking for general feedback (quantitative and qualitative) on a few initial concepts for the software.
The front page of the survey provides further information if you would like to know more, and you are welcome to contact me with any questions. It will hopefully be online for 3 weeks, after which time selected data will be released here for the SLOODLE community, and to any individual participants who request it.
Many thanks,
Peter R. Bloomfield (SL: Pedro McMillan)
PhD student / Research Assistant / SLOODLE developer
Supervisor: Dr. Daniel Livingstone (SL: Buddy Sprocket)
University of the West of Scotland (School of Computing)
http://peter.avid-insight.co.uk/research
