What is this rotation behavior in XNA?

Question

I am just starting out in XNA and have a question about rotation. When you multiply a vector by a rotation matrix in XNA, it goes counter-clockwise. This I understand.

Answer 1

Since you are new to XNA, allow me to introduce a library that will greatly help you out while you learn. It is called XNA Debug Terminal and is an open source project that allows you to run arbitrary code during runtime. So you can see if your variables have the value you expect. All this happens in a terminal display on top of your game and without pausing your game. It can be downloaded at http://www.protohacks.net/xna_debug_terminal It is free and very easy to setup so you really have nothing to lose.