Interview on .Net Rocks!

About a month ago Richard Campbell asked me if I'd like to give an interview about SLARToolkit on the .Net Rocks talk show. Of course I agreed right away. .Net Rocks! is the largest .Net developer podcast out there and Carl Franklin and Richard Campbell always have great guests. It's a real honor for me to have been on show #564.
We mainly talked about the Silverlight Augmented Reality Toolkit (SLARToolkit), but also about some of my other projects and articles.
You can download the podcast in various formats from here. I hope you like it. Also make sure you subscribe to .Net Rocks!

Poll Results: Do you block Google Analytics tracking in your browser?

I recently encountered a large difference between the Google Analytics statistics of my website and the server logs. This raised the question in me how reliable the Google Analytics data really is and I asked you to take part in a small survey: Do you block Google Analytics tracking in your browser?. The poll is closed now and here are the results.

The poll got 267 votes total and 68 people voted "Yes, I block Google Analytics." 199 voted for "No, I don't block Google Analytics." This means 25.47% of the participants block Google Analytics in their browser. 

You can now use a simple formula to get the real world Google Analytics statistics (at least for my visitors - the best of all). :-)

GAreal = GAreport * 1.25468164794007490636704119850187


Big thanks to all that helped me and took part in the survey!

Do you block Google Analytics tracking in your browser?

Recently I checked the server logs for my website and compared the statistics with the Google Analytics data for the timespan. I expected that the page views and visits won't be the same, but I haven't expected such a large difference I encountered.
Just to make it clear, I don't use Google Analytics for evil, I'm not Google and I'm not interested in advertising or web marketing, I'm just curious what my visitors (you) are looking for and what caught the interest, so I can provide more content in this field.
I know some people that block Analytics tracking in their browser because of the Google octopus, or disabled Java Script at all.

The difference between the Google Analytics statistics and the server logs raised the question in me how reliable the Google Analytics data is when several people block it in their browser. I started to search for some block statistics, but couldn't find any useful information and I also think the actual blocking-rate does crucially depend on the website's audience and used technology. That's why I created a little poll at twtpoll.com and asked my Twitter friends to vote. Big thanks to all that already voted, but not all of you are on Twitter, so I like to ask here too:

Do you block Google Analytics tracking in your browser?

I will publish the results here on my blog after the poll is over on Feb 28, 2010. Thanks for taking your time.

Update 03-10-2010
The results are now available.

Summer Silverlight Coding Competition

ComponentArt is hosting the "Summer Silverlight Coding Competition" from June 22nd to Semptember 22nd:

ComponentArt is excited to host the 2009 Summer Silverlight Coding Competition and award $10,000 USD to the author of the best application as selected by our expert panel and the community. Authors of the two runner-up applications will each receive ComponentArt licenses (a $1,299 USD value).

I submitted my Silverlight website and I am very happy that it was published yesterday. The community voting is now open. If you like my Silverlight real-time physics website it would be nice if you vote for it here. Unfortunately you need a ComponentArt.com account to cast your vote, but the registration is quickly done.

Silverlight 2 Real-time Physics Website

It's been 5 years since I developed my previous website in 2004 with Macromedia (Adobe) Flash. A couple of months ago I decided to work on a makeover, which was long overdue. As a media & computer scientist and .Net developer it was a matter of course to give Microsoft's Silverlight 2 a try. I love the ability to write the code in my favorite language C# and having most functionality of the .Net library at hand.

Lightning it up

However, the first Show Stopper was the lack of basic HTML or rich text support in Silverlight 2. I was quite surprised and disappointed that Silverlight Text controls don't provide basic HTML formatting or at least WPF's Inline Hyperlink. I think a lot of people need such a feature. Some guys on Twitter told me that there isn't really a demand for this and it could be done with other techniques, but sometimes performance does matter and an overlayed DIV using Silverlight's windowless mode is just terribly slow.

HTML Link support is essential for this project, because the HTML formatted text is stored in XML files and loaded asynchronously by the ContentPages and then deserialized to POCOs. The controls in turn use Silverlight's great Data Binding mechanism to present the data and load the images.

This XML-based approach gives me the ability to change the content of my site without any recompilation. I also have a fallback solution for non-Silverlight visitors and all that without a redundand information storage. Non-Silverlight visitors could use the POH (Plain Old HTML) version, which is simply the XSL transformation of the underlying XML data. And there's another advantage: If I ever decide to store the data in a database, I just need to change the internal functionality of the data assembly and integrate an ORM framework like NHibernate. The domain models and therefore the DataBinding won't be touched.

My Silverlight website uses the Dependency Injection framework NInject. The whole project, including the physics engine, is developed keeping a contract first design in mind. The usage of the DI pattern and a appropriate framework helps a lot to separate the concerns and produce code with a high maintainability.

Extended Silverlight LinkLabel Control

As I mentioned earlier I was really annoyed by the lack of HTML support in Silverlight and it forced me to extend the Silverlight LinkLabel Control so it supports HTML tags. I was also able to improve the performance of it. TextBlock's performance is still bad, but that's not the fault of the LinkLabel control.

Here is how it works: The original LinkLabel control "parses" the input text and creates a HyperlinkButton for each of the links it founds. The rest of the text is splitted into single words and for each word (!) a TextBlock is created. These many controls are then all added to a WrapPanel, which provides the word wrapping functionality.

I measured the LinkLabel control and encountered that the high number of TextBlocks are killing the performance. Therefore I extended the LinkLabel control by a word grouping functionality. Single words are now grouped to n words and assigned to one TextBlock. This modification reduced the number of TextBlocks and in turn increased the performance significantly. However, a lot of text has still a huge negative impact on the performance. So please Microsoft, implement WPF's Inline Hyperlink into Silverlight. WPF is a desktop technology and has the Inline Hyperlink, but Silverlight as a subset of WPF and RIA platform doesn't come with Inline Hyperlink?! I don't get it.

Soft Body Physics Engine

With my passion for computer graphics and physical simulations it was also a must that my new website simulates real-time physics. That's why I developed a flexible Silverlight soft body physics engine and a simple Renderer. The soft body physic is based on a Newtonian mass-spring system and also implements the Pressure Soft Body Model by Maciej Matyka. The resulting differential equations are solved numerically with a Verlet integration. The engine is flexible designed and could easily be extended. It comes with a constraint system, various types of bodies and force generators, basic collision detection and so on.

The work on the engine is in progress and there's still a lot to be done, but if you want to see it in action, just go to my website click near the balloon and throw it around or grab a corner of the content element. If I find the time, I will continue my work on the engine, hack some demos, release it as open source and blog about it. But I demand high standards of myself and I currently have other projects in the queue, so don't expect a release soon. Especaillay the implemented collision detection is just basic and the development of a proper collision detection system takes some time.

Conclusion

It was a long and tricky task for my first Silverlight and XAML project, but mostly it was a lot of fun and Silverlight 2 is an awesome step in the right direction. I don't regret that decision. Silverlight is definitely now my favorite platform.


Update 08-07-2009

I submitted my website to the Summer Silverlight Coding Competition. Feel free to vote for it here.