A nicely written article on handling collision in 2D. Useful for game development or generative art.

What is sfException?

As the sfException phpDoc says:

sfException is the base class for all symfony related exceptions and provides an additional method for printing up a detailed view of an exception.

If you look at the code of sfException you’ll see that sfException has a bunch of tool to wrap an exception inside an sfException. That’s why when an exception of any kind is thrown in symfony, you see a nice html output.