Back from Qt Dev Days (Munich)

· by Steve · Read in about 5 min · (1025 Words)

qtBefore 2009, I’d never set foot in Germany before; not for any particular reason, I just hadn’t gotten around to it yet. However, thanks to gracious invitations to conferences I’ve now been twice. πŸ˜€In May I went to Stuttgart for FMX, and last week I went to Munich for Qt Developer Days.

It was an enjoyable conference, as always the best part is just meeting other delegates, the sessions themselves are merely the icing on the cake. I shared my presenting slot (in which I showed a couple of applications that use Qt and Ogre together) with two other open source veterans from projects which I have a huge amount of respect for: Bill Hoffman, CTO at Kitware and the founder of CMake (which of course we use in Ogre now, so it was great that I had chance to have quite a few discussions with Bill), and Jean-Baptiste Kempf, Chairman of VideoLAN which is of course in charge of the excellent VLC.

It was also nice (not to mention flattering and somewhat humbling) to have random people I’ve never met before spontaneously say nice things about Ogre. One of the major curiosities of open source is that you never really know quite how many people have encountered & used your software; you get a sampling of that through your community forums etc, but it’s also clear that that only represents a portion of your user base. On the day I was wearing my Ogre T-shirt I had a number of people who were more peripherally involved in the community but who had had a good experience with Ogre, and were more than happy to tell me about it. Definitely a good feeling.

Perhaps most surprising of all though was getting a sizable donation to Ogre in person from a community member while I was there (I won’t mention who just in case he’d rather not be identified, he can post in the comments if he’s happy to). We had what I thought was a theoretical discussion at one of the dinners about how much we get charged by PayPal for donations, and I’d said that although it’s undesirable, any kind of electronic payment mechanism has a cost (merchant accounts, bank transfers all come with some kind of charge). I jokingly said that the way you’d avoid the most charges would be mailing cash in an envelope, although that had it’s own risks. I thought nothing more of it, until I saw him the next day when he presented me with an envelope with a donation in it! Way more than I expected too, enough to push him straight to a Platinum sponsor. Turns out he’d just got his deposit back on a flat he had been renting, and decided to donate that to us in the absence of any code contributions, since Ogre had helped him at university and subsequently in getting a job. I have to admit, I was a little lost for words at that! His donation will definitely help cover the server running costs in the coming few months.

Back to the conference subject, Qt, the conference reinforced my opinion that it’s the best cross-platform UI system out there for C++ developers. It was great to see the range of applications that were being developed on it these days, including a coffee machine which was serving custom beverages in the dining area via a Qt interface. Obviously the Nokia acquisition has meant that they’re keen to move into more dynamic, touch-based interfaces too now, which will obviously power new phones in more interesting ways, but it was clear that they remained committed to a huge range of application targets. Well, except iPhone anyway, that was definitely the elephant in the room - occasionally mentioned but mostly avoided πŸ˜‰

Obviously Qt’s switch to LGPL this year will have a huge impact on adoption rates. One of the things that had concerned me though is that there’s a clause in the commercial license for Qt that requires you to decide between using the commercial license and the LGPL before you start developing. The reason given for this is that Qt is licensed on a per-developer basis, so if you could wait until deployment to choose the commercial license, you could scale back your team and pay less than you really should have done, which is why you have to decide up-front. I could understand this argument, but in my experience, perfect foresight is impractical and conditions can often change, so making a once-and-for-all choice before a line of code is written did not seem realistic in some cases. Also since the principle was that the entire team must use the same license, I was wondering about the practical implications of say, a commercial outfit leveraging some pre-written code by people using the LGPL version (such as QtOgre). Qt want to encourage greater community involvement (which was the reason for me being invited to the conference after all), so not allowing this seemed to go against the kind of broader adoption they were chasing.

To try to answer these questions, I went to the legal presentation and put this question to the speaker afterwards. Luckily, she mostly allayed my fears on these two issues. On the ‘circumstances change’ issue, the principle must remain that, because of the per-developer licensing, you should make your decision up-front, but if for whatever reason, and in good faith, conditions change (such as suddenly having to target a platform where LGPL is not practical), then some kind of agreement can be reached, such as by paying commercial fees for all developers historically on that project so it comes out the same as if you had opted for the commercial license originally. In addition, she didn’t think there would be a problem with community code re-use for commercial licensees provided this was mentioned during the commercial licensing process; she accepted that greater adoption is what they want, and community development inherently complicates the previous assumption that one team will be responsible for absolutely every aspect end-to-end.

So, a good conference overall. Now, I’m back to continue work on Ogre 1.7.