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dConstructing Augmented Reality

08.09.2011 15:45 | 0 comments | 0 pingbacks | , , , , ,

One of the events that kicked off Brighton Digital Festival was dConstruct, the always thought provoking conference run by clearleft.

As usual I found most of the sessions interesting, but not always relevant as there’s a heavy design rather than development focus. The most relevant talk this year was Kevin Slavin’s final talk, Reality is Plenty, which argued that augmented reality is not the next big thing, just as it wasn’t in 2005.

Despite Kevin having a dig at Second Life and having spent a lot of time working on Augmented Reality with Blast Theory while at Nottingham University, I mostly agreed. While there are definitely use cases which benefit from augmented reality (fighter pilot navigation systems and things like Carbon Goggles which are all about making invisible aspects of objects visible) and virtual reality (simulation and virtual meeting spaces) there are plenty of others which are better served by other interfaces. Environments like Second Life are particularly exciting as they allow people to quickly prototype systems to discover which applications work and which don’t.

With both AR and VR it’s tempting to argue that they allow for intuitive interfaces as they model or overlay the real world: people know how to navigate a 3D space so they know how to use a 3D environment and they know how to use AR as they can see. Anyone who has done their time climbing the Second Life learning curve or trying to use AR to find their way around will know this clearly isn’t true. Apparently more abstract interfaces like maps, which talk to the mind rather than the senses are often much easier to use.

There’s a lot of work to be done to make both AR and VR as easy to use as 2D interfaces, let alone as natural as using real world senses. Now that the huge technical problems around networking virtual environments and tracking real world objects with mobile devices are starting to be solved, it is mostly UI work that needs to be done to make these technologies more widely used.

Even if the UX issues are solved there will still be many cases where speaking to the mind is much better than speaking to the senses.

Introspecting Python Decorators

25.08.2011 17:05 | 0 comments | 0 pingbacks | , , , ,

Over the last couple of years I’ve found myself using python decorators to annotate handlers for web requests more and more, both when using Django and with micro-frameworks like mnml and newf.

Where the same functionality is required for all handlers, or the required functionality can be determined from standard request or response headers, using WSGI or Django middleware is fine, but where the required functionality is varies based on the handler its much cleaner to use a parameterised decorator than poluting the environment or response objects just to control the middleware. Functionality can be added to a framework as a suite of decorators and plugged together in an aspect oriented way like lego to easily build up sophisticated behaviours.

Unlike other mechanisms for implementing macros, templating or aspect orientation that introduce a new language, python decorators are pure syntactic sugar that under the hood are simply rewritten as python expressions:

@requires_oauth_scope("email")
def notify_friends(request):
    pass

Is simply shorthand for:

def notify_friends(request):
    pass

notify_friends = requires_oauth_scope("email")(notify_friends)

This simplicity is powerful as it allows decorators to also be used as normal functions, for example to build up higher level decorators that bundle common decorator configurations, but it also means that decorators potentially interact badly with another powerful Python feature: introspection.

In the above example the undecorated notify_friends function has the __name__ “notify_friends”, but the decorated function has the __name__ “requires_oauth_scope”. When decorators are used extensively, this can seriously impact the usefulness of introspection for debugging or generating documentation.

Decorating your decorators with the functools @wraps decorator, which copies the __name__ of the wrapped function over to the wrapping function solves this introspection problem, but introduces another: the decorators now become invisible to introspection. In the example above the __name__ of the decorated function would now be “notify_friends” as in the undecorated case, but we wouldn’t know that the function had been decorated or not.

A potential solution to this new problem is to store the details about the decoration in another attribute that can be inspected at runtime. In addition to copying over the __name__ attribute, functools.wraps also copies over the target __dict__ by default, allowing it to be used to store information about the decoration and be correctly copied over when decorators are chained:

from functools import wraps

def requires_oauth_scope(scope):

    def decorator(target):

        target.__dict__["my_project_requires_oauth_scope"] = scope

        @wraps(target)
        def wrapper(*args, **kwargs):
            # return target(*args, **kwargs) or FORBIDDEN if token does not have required scope

        return wrapper
    return decorator

By constructing decorators in this way we get the benefits of python decorators and more declarative C# style attributes that are visible to introspection.

Meaningful Choices

27.09.2010 17:23 | 0 comments | 0 pingbacks | , , , , ,

On Friday I jumped on the train to London to attend Playful 2010, a one day conference put on by mudlark of World of Love fame. Despite billing itself as a day of cross “disciplinary frolicking” and featuring designers, podcasts, discussions of narrative, iphone augmented paper games and Disco Snake the thing that stood out for me was a thread running through the talks that addressed a fundamental of game design: meaningful choices.

Jonathan Smith talked about the dangers of giving people too much freedom in his talk about the Lego Games. Lego is almost a shorthand for freedom: the easy to understand system of knobs and anti-knobs that allows 2 4x2 blocks to be combined in 9 million ways an ultimate sandbox aspired to by games and virtual worlds like Second Life. This open, free system led Travellers Tales to add lots of open, free features to it’s early Lego games that were largely ignored by players who need boundaries and feedback from the game to determine ‘what I want versus what’s expected of me’. Choosing freedom and rebellion is more meaningful when it is clear that I am exercising my freedom and not doing the expected.

Margaret Robertson talked about and in the current sandbox game du jour, Minecraft, which has enough terror and threat in its horror filled night to make the choices made during the day meaningful and to reward mastery of it’s sandbox — a sandbox that compelled Margaret to stay up until early in the morning carving her slides out of earth, building them out of wood and animating them with flowing water and flames burning down the assertion that “games = points”.

It was this misguided assertion that Sebastien Deterding talked about in his look at the ‘gamification’ of the world around us. When all that gamified web sites like foursquare do is allow the accumulation of points and badges there are no meaningful choices, no mastery, no way to rebel against expectations, no play and no fun. Gamification results in loyalty schemes that are no more meaningful than Progress Quest.

The importance of being able to rebel against expectations was echoed by Alexis Kennedy’s talk about delicious misery in Echo Bazaar, a social game that would be another meaningless progression to inevitable success if it weren’t for contrarian missions that allow players to opt-in to getting their characters exiled for scandal or driven insane by demons. These missions inflict real harm on characters, but when properly signposted are the most enjoyed and shared missions: allowing players to be badass. When a game makes success inevitable, misery and failure is play and meaningful escape.

Pat Kane, formerly of Hue and Cry and more recently author of The Play Ethic gave a fascinating talk about wordplay, humour and his journey from disillusionment at the comedy industry, to fascination with humour through the Old Jews Telling Jokes’ stories of Jews laughing in the face of persecution. When misery and failure is inevitable, humour and play is rebellion. An ultimate, meaningful demonstration of freedom and humanity when all hope of victory is gone.

HTML 5 multimedia

07.06.2010 23:14 | 0 comments | 2 pingbacks | , , ,

I’ve been morbidly fascinated by the Rich Internet Application technology blood bath for a while now: Whirled,Metaplace and others tried to stuff virtual worlds in to web pages using Flash, Second Life stuffed Flash in to virtual worlds via Webkit, Unity stuffed Mono in to a 3D engine and then took on the world and Silverlight and Moonlight stuffed the CLR in to web browsers and Erik Meijer stuffed a CIL interpreter straight in to Javascript.

All good fun and there are fortunes to be won and lost to be sure, but the smart money seemed to be on waiting for the dust to settle and then using the winning technology. Recently, however, amazing technologies like V8, Node.js and the resulting browser Javascript arms race have been adding weight to the Google viewpoint that all you need is Javascript: a philosophy made more pragmatic by Apple’s decree that all you get is Javascript.

A week or so ago I decided to test the hypothesis by building a drum machine using only HTML 5 and Javascript. My first discovery was that while the canvas element is perfectly capable, it’s a very low level API, even for building something as rudimentary as a step sequencer interface. After looking at a number of drawing libraries I settled on processing.js as a higher level drawing API, something I’ve been meaning to play with since we used it to build SLorpedo at Hack Day a few years ago. Processing.js is a neat hack, that despite an incomplete API and some subtleties around casting does a great job of running processing sketches within a browser without a plugin. It also uses a sloppy parser enabling you to drop arbitrary Javascript in to your processing sketch, which makes it easy to just create Audio() objects within the sketch to playback audio. Unfortunately while it was easy to add audio playback, the playback itself was pretty disappointing: Firefox just spluttered and belched sadly while Safari did a decent job of playing beats for a couple of minutes before its timing went to hell and then the browser crashed. The shiny future may yet be HTML 5 and Javascript, especially when the experimental extensions to Firefox become widely supported, but we’re not there yet.

To experiment for yourself, click on the squares on the grid below to add beats to the sequence. To see the code, view source.

@scalecamp

07.12.2009 15:49 | 0 comments | 1 pingback | , , ,

On Friday I jumped on the train to London to attend the first scalecampuk, an unconference about scalability, at the Guardian offices.

The sessions were all very interesting and mostly very relevant. I learned new things about XSS and CSRF and Django’s defences against them from Simon Willison, new things about messaging, pubsub, queues and data stores (process 1 message at a time, use message hospitals, send URLs to unavailable data that can be polled for with JavaScript and that just check memcache entries) lots about Varnish ) and it’s use at Wikia from Artur Bergman (Wikia runs off 18 apaches and 8 varnishes with 60GB of RAM and SSDs to serve 25 million pages and 950Mbps at peak, Varnish is generally better than squid ), but you need a modern kernel).

Lots of the talks were about moving storage, caching and queuing out of the application and just writing a small piece of business logic to tie them together. Against this background Alex Evans’ talk about the back end for Media Molecule’s Little Big Planet stood out like a sore thumb. Having not enjoyed using a Java web stack, Alex has just rewritten the whole of the back end as proprietary technology as a single binary in order to know the code from end to end. While it may be true that having custom physics or rendering middleware might distinguish Little Big Planet from other games, I can’t believe that custom technology to serve HTTP requests is going to be a competitive advantage. I hope Alex’s good ideas become Redis contributions rather than a maintenance nightmare and barrier to agility.

The lightning talks were also very good. Simon’s “ScaleFail” talk about the Guardian MP expenses app was hilarious (lesson: do load testing) and Gareth’s talk about Dumbo (a Python Hadoop client) was very useful.

At times it felt like the talks were suited to an ops audience, but “Dev’s should know about this!” was a regular refrain. Don’t worry: I listened and learned a lot. Thanks to everyone who made it a great day.

Like Second Life

23.10.2008 12:26 | 1 comment | 1 pingback | , , , , ,

Was without a doubt the phrase I heard most often yesterday, especially if you include variants like “Not Like Second Life”, “A bit like Second Life” and “Unlike Second Life”. Whatever else it’s achieved, Second Life has definitely become the frame of reference for the small and somewhat myopic crowd that made up the delegates at the sparsely populated Virtual Worlds Conference in London yesterday.

Vastpark is not like Second Life because it works in a web browser. Everyone on the web integration panel seemed to agree that virtual worlds in a browser is the next step, so I was glad to be there to question the TechCrunch consensus. How does having a world in a browser help? What does back and forward mean to a virtual world? What does it mean for presence to have 10 tabs open looking in to different parts of the same virtual world? Why would you want your view further constained by extra web browser widgets? Isn’t 3D in the browser going to be a blood bath for the next few years? Aren’t you really just using the browser as a download path? I suggested that the final question was the real reason that developers are pushing virtual worlds on the web and that the integration that most people want is to be able to use existing web and 2D media while using virtual worlds and use web services as a universal data bus between virtual worlds and other web aware platforms.

MPEG-V is not like Second Life because it’s a standard defined by 35 companies which is much better than the emerging Linden led standard according to Dr. Yesha Sivan in what was the worst talk I’ve heard in a long time. Not only did he make the standardisation process sound like a 3 year political bun-fight by people who didn’t know much about virtual worlds and who might come up with a bad standard, he managed to spell MPEG and Google incorrectly, called Sun’s Darkstar, Blackstar and attributed a Ugotrade quote to Philip Rosedale amongst other clangers. He was roundly rebutted by a large part of the audience including Tara5 Oh who questioned the need for old fashioned standards processes in the web era. Thank goodness for rough consensus and running code.

Most of the virtual worlds talked about in the investment panel were not like Second Life, but were nearly all Club Penguin clones. This copy the big exit attitude was called out by one of the audience as it seemed to be at odds with a lot of the talk about wanting to back the first in a market, but at least one of the panel is still looking for a successful 18+ social world play. The panel ended with a show of hands from people wanting money and people wanting to invest, but the economic climate made the whole affair very muted with lots of the panelists saying that they are slowing down rates of investment as it’s difficult to get existing companies off their books.

As with Virtual Policy 08 and the Virtual Worlds Forum the most valuable parts of the conference were the spaces between sessions. I had another very worthwhile discussion with Adam Frisby of OpenSim about C# script compatibility between OpenSim and Second Life. The straw man design we talked about was to have an idiomatic .NET interface for event handling that can be used by C# scripts and adapted for LSL scripts and a set of static library methods for manipulating the world that would be used directly by LSL scripts and wrapped by user created libraries to provide an idiomatic object oriented interface. Adam was particularly interested in the idea of user created wrapper libraries as it would allow the creation of an OpenSim interface library that could be ported to Second Life and implemented in terms of the ll* static methods. OpenSim could then agree to support the common behaviour of this library in Second Life and OpenSim instead of having to support the gamut of ll* methods some of which don’t map well to OpenSim internals. As well as defining a common set of events and ll* static methods that are supported on both platforms there would need to be a way of extending the interface with new events and library methods. In addition Adam was interested in making the event propogation configurable so that a single script could respond to events on many objects in a scene. This would effectively add a script interest management layer to OpenSim’s scripting interface. Where platforms provide differing interfaces to scripts we would also need to decide how scripts query the available interfaces or how they behave when interfaces are not available.

Overall a worthwhile trip, but not because of the conference. This Friday I’ll be talking at the online head conference about conferencing in Second Life which has the advantage of requiring no travel making marginal conferences like the Virtual Worlds Conference less risky to attend while allowing all of the serendipitous networking opportunities that make real life conferences worthwhile.

dConstructing dConstruct

18.09.2008 12:03 | 0 comments | 0 pingbacks | , , , , ,

A couple of weeks ago the great and the good of web development descended on Brighton for the wonderful clearleft produced dconstruct conference and once again I’m glad I went along.

Steven Johnson kicked off with a talk about how Dr. John Snow’s innovative data visualization of a cholera epidemic and the wisdom of dead crowds helped convince people of the water borne nature of the disease. It was an interesting story, but it mostly ended up being a plug for his book and geoblogging aggregator outside.in.

Next up, Aleks Krotoski talked about how games had spent decades creating incredibly compelling user experiences in silos without much contact with each other the academic HCI community or the web. Meanwhile the web is very interested in creating similarly sticky experiences using virtual rewards to encourage participation. Aleks’ conclusion was that the two communities should talk and I agree.

Daniel Burka talked about similar themes in his talk about the evolution of Digg. The most interesting anecdotes where about how top diggers started off as a good incentive, but became a disincentive when new users saw how unachievable the scores had become and how the recommendation engine is now a good way to encourage some of Digg’s passive audience to get involved.

Matt Jones and Matt Bidaulph talked about their successful Silicon Roundabout startup dopplr. Jones talked about visual design and delighters which sounded a lot like Alek’s virtual rewards in games. SL uber-hacker Bidaulph talked made another gaming analogy, talking about how embedding dopplr in other sites and vice versa achieves a similar seamless experience to streaming maps in games: removing the load screens and jumps that used to bedevil console games and still are the normal experience when using the web. He also talked about the importance of using message queues and asynchronicity in services like dopplr which pull information from across the web.

Joshua Porter‘s talk on Leveraging Cognitive Bias in Social Design was the stand out talk for me. He talked about exploiting people’s tendency to pattern match to generalise isolated positive case studies on web sites and on framing account creation as something to do to avoid losing features rather than something that gains features as a way to play on the tendency to value losses greater than gains. His description of the how the 9x mismatch between customers (who over value the application they already have by 3 times) and developers (who over value the application they have developed by 3 times) creates a huge barrier to application adoption was particularly interesting.

Tantek Celik‘s talk about using hCard and rel=me links to create portable, auto-updating social network profiles and data to reduce the fatigue induced by inviting all of your friends to many social networks was the most practical session of the day. I’m going to try playing around with rel=me links and Google’s social graph API here soon.

Jeremy Keith gave a grandiose talk to end the day which wove together psychohistory from Asimov’s Foundation Series with Critical Mass and The Wisdom of Crowds to talk about how network effects and power law distributions cause some social software to explode in popularity while others wither, but that despite The Tipping Point being sold in business sections as a how-to book, it is fundamentally a retrospective and that predicting or engineering tipping points or network effects is notoriously hard. It was a great talk and the conclusion that social software is more of a lottery than a science is valid, but still: you have to be [in it to win it] (http://secondlife.com).

Hello World

01.07.2008 9:21 | 14 comments | 0 pingbacks | , , , ,

Well, not exactly. Having blogged previously on [Terra Nova] (http://terranova.blogs.com “Terra Nova”), the original [Creation Engine] (http://secondlife.blogs.com/babbage/ “The Creation Engine”) and currently on the [Official Second Life Blog] (http://blog.secondlife.com/author/babbagelinden “Official Second Life Blog”), I’m not exactly stumbling blinking in to the blinding light of the blogosphere. Recently a number of things have come up that I’ve wanted to write more than 140 words about, but that wouldn’t fit on the Official Second Life Blog [any] (http://blog.secondlife.com/2006/08/15/last-sound-system/ “Last Sound System”) [more] (http://blog.secondlife.com/2007/06/18/slorpedo/ “SLorpedo”), so I’ve finally stopped mooching off other people and set up my own blog.

One reason I hadn’t got around to it sooner is that I’ve been torn between platforms. Although it’s been tempting to throw up a [WordPress] (http://wordpress.org/ “WordPress”) blog every time I’ve had something to talk about, I really wanted to build a blog in [Django] (http://www.djangoproject.com/ “Django”) that I could tinker and experiment with. Although it’s just a matter of [plugging bits together] (http://www.b-list.org/weblog/2007/nov/29/django-blog/ “Where is Django’s blog application?”), it still takes a few hours to get a basic Django blog up and running and longer to add all the bells and whistles. I finally managed to break the impasse last week when I came across this [list of Django blog engines] (http://paltman.com/2008/02/02/i-want-to-move-my-blog-to-django/ “Django Blog Engines”) and after some routing around decided to go with [byteflow] (http://byteflow.su/ “Byteflow”) which has all the bells and whistles but is made of standard Django bits and is eminently tinkerable.

So, that’s what you see here: a default byteflow blog running on [Django trunk] (http://code.djangoproject.com/svn/django/trunk/ “Django Trunk”) running in [mod_python] (www.modpython.org “mod_python”) as a virtual host (alongside the [slateit.org] (http://slateit.org “SLateIt”) and [carbongoggles.org] (http://carbongoggles.org “Carbon Goggles”) Django apps) inside [apache2] (http://httpd.apache.org/ “Apache HTTPD”) running on ubuntu dapper on a virtual machine hosted by [bytemark] (http://www.bytemark.co.uk “Bytemark hosting”). It took long enough to get round to, but once I’d found byteflow it only took an hour to set up. I’ll be kicking the wheels and tinkering over the coming weeks, but if you find anything broken, please let me know.