Hi all,
the reflection around an arbitrary { y = x * tan angle } axis
can be get using the following matrix:
[cos 2angle, sin 2angle, sin 2angle, -cos 2angle, 0, 0]
I'm aware this could be obtained from a combination of other
transformations (although I don't know how), but I think this
operation is so common it is worth a discussion.
Ciao
--
Nicola