For those not yet aware, Dare Protoplay is a showcase of games created during the Dare to be Digital competition. It’s running from the 13th-15th August at the EICC (Edinburgh) and entrance is free.

Two students from my CGT class are taking part this year, Andrew Glass and Iain Fergus, as part of the team Shark on a Bike so make sure to say hi to them! their promo video is here:

You can check out all of the other fantastic teams and games on the Dare website, and hopefully play them in person at the weekend.

Anyway, here’s a brief update just to list a few things I’ve been up to since I last posted:

• I graduated from Abertay! With first class honours! Wooh!
• I came second in Aardvark Swift’s Search for a Star competition, following a day trip to Brighton. From Dundee. By Train. The competition was a really great learning experience (the three rounds involved a programming test, modifying and expanding upon an existing game with a few added bugs and then an interview) even if the travelling itself wasn’t so much fun.
• I’m currently an intern at Tag Games over the summer, which hopefully explains both how I’ve coped without my laptop and why I haven’t had much time to blog.

So, there you have it. Expect more posts, but not necessarily right away.

The larger square shows the total area of the small virtual world. Each smaller square represents a microcell, an area of the world to be assigned to and updated by a single worker node. The worker nodes are shown by the three colours in the images below, which are each viewed from the central server. The simulation was run for a number of minutes, with cells being redistributed dynamically between nodes. Numbers at the bottom right indicate the number of minutes the system had been active for when the screenshot was captured.

This image shows the view from a worker node, each blue dot represents a single entity following a path. This node is completely under-loaded just so that the entities can be seen clearly, when thousands are processed it can be hard to pick out individuals.

This shows the use of varying microcell sizes. The use of different sizes didn’t actually make a difference to average load, maximum load or load disparity between worker nodes except when particularly small cells were used. This caused a great deal of load for the central server, a huge increase in the number of transfers required and as the images show prevent the world from being re-partitioned in a reasonable period of time.

Finally, this image shows the cell distribution between worker nodes when the number used was scaled to match the problem size. As the number of entities was increased and then decreased, the number of computers used was scaled similarly.

That’s all for now, I’ll do my best to go over some details when my laptop has been repaired.

Additionally, the framework now supports both hexagons and quads as cells. Hexagons have the advantage that only 3 cells meet at any corner, limiting the maximum number of nodes which might be involved should an event take place there. Here’s some images of the view from the server with the most basic (block) distribution of cells:

While last year many blogs covered technical superstars, this year I’d like to write about someone a little closer to home: my mum, Karin McKendrick. As well as being an insane long distance runner, she’s also a programmer and systems analyst; suffice to say I wouldn’t be where I am today without her influence.

Perhaps surprisingly, my mum originally studied Classics at university. I don’t know when she first started programming (a number of older computers and gaming systems still lurk around our house), but she returned to work after the birth of my brother and I in time to work on Millennium Bug related problems. During her break from employment (not that I think you could class raising children as “taking a break”) she completed Open University degrees in mechatronics and product design. I didn’t see much significance in basing our holidays conveniently at summer school locations as a child, but as a student myself now I really admire and appreciate the commitment that completing self-study courses must involve.

In high school, I guess a lot of the need to encourage women in technical fields confused me (one of the most shocking times was when a particularly intelligent friend suddenly decided she was terrible at maths overnight), because I was never given any reason why my gender should affect my abilities or aims. Now, I feel hugely fortunate to be where I am.

Hope that wasn’t too cheesy!

A major part of the project involves distributing microcells (fixed areas of the world) between a series of worker nodes both statically and dynamically. In order to test methods of achieving this, I created a small testbed application which simulates the task without networking. It is capable of using various methods to distribute cells, both at the start of the application and as it runs, both controlled by a central server and initiated by worker nodes and gives graphical and numerical feedback.

The images below were taken with a greatly reduced number of cells, and the work involved in processing each cell is artificial: there are no pathfinding characters yet. However hopefully it demonstrates to some extent how division of the world takes place, and allows me to easily test distribution methods before using them in the proper simulation.

Coloured by number of characters per cell.

Initial block distribution.

Random distribution for comparison.

Block distribution with dynamic passing after time.

As the actual application I am working on is written in C#, I used XNA to create the images here. As it is possible to render XNA frames to a windows form application with little difficulty, this is also the approach I will employ for visualising the complete project.

Although the first round was taking place on the day before an exam, myself and two other students from Abertay took part. This round involved answering ten programming questions: 9 based on the C++ language and a final question focussing more on object oriented design.

I wasn’t sure what to expect beforehand (other than a vague notion that reversing a string in place might be involved) but found actually sitting the test to be quite a relief! Although I wasn’t 100% sure all my answers were spot on, there weren’t any concepts which I was unfamiliar with. It certainly increased my confidence (or at least reduced my sheer terror) concerning programming tests I might face when applying for a job.

I was pleasantly surprised to be told that I was one of the eleven programmers who had reached the second round, a more open-ended programming task. For this we were given an uncompleted and incorrect Asteroids like game, and tasked with fixing and improving it within seven days. Working with someone else’s code was an interesting exercise, and I aimed to uphold their programming style and standards as much as possible. I hadn’t touched DirectX or DirectInput in some time, but I didn’t find it hard to get back into; nothing in the codebase was particularly surprising or unfamiliar.

The only downside of the problem was the short timespan, as I also had coursework deadlines and continued work with Digital Colony and on my dissertation to contend with. I successfully submitted a corrected and improved application, however it would have been nice to dedicate more of my time. I’m still waiting on the results of this stage, so I will of course update the blog when I hear back. Since I worked on someone else’s codebase I’m unsure whether posting screenshots of the application is acceptable, however I may also follow up with those at a later date after seeking permission.

Image used under Creative Commons license from Computer Science Geek.

The most useful thing I can share is the class diagram this was based on. It’s rough, it doesn’t detail methods or member data, and it’s far from beautiful, but perfection is an easy trap to fall into. I thought it was better to have a functioning library and an ugly diagram than a work of art demonstrating a library which I then would have no time to create.

The current phase of the project is far more interesting in my opinion, and thankfully should result in something slightly more visually interesting. It concerns the division of the world, hierarchically, into microcells. This spatial partitioning, and more importantly the assignment of work to specific processors is fast becoming the major focus of the project, and I hope to follow up with more on that topic shortly.

EDIT: I have replaced the original diagram with a still-ugly but slightly more descriptive update (if you actually view it at a decent size, that is). The majority of member data and functions are still missing, but hopefully the few I’ve added will make my intentions slightly clearer.