I studied matrix algebra over 15 years ago, and a) I didn't really get it, and b) it wasn't presented as having anything to do with image distortions or such. So, where could I go to get a little hand-holding on *why* a certain matrix operation rotates or shears or does something else, and how I would approach making my own operations? Is there a web site or book someone could recommend? PB documentation seems to assume I already know all this.
The Wikipedia article on Transformation matrix will give you an idea
about the raw math (this type of matrix performs this type of
Each transform matrix also has a link to more detailed article about
how the translation takes place.
Thanks, I'd seen the page and I think maybe I need something a step or two back - I think I can grasp why the rotation and sharing matrices look the way they do, the others are a little much at the moment.
In the end I want to be able to generate my own for a particular transform I have in mind. Trying to understand how to get there.
You may want to check out John Vince's book, "Mathematics for Computer Graphics." It's a good book and covers transformations.
one easy way to understand what matrix does is to look at its columns - they are vectors that this matrix turns unit vectors into. e.g., this matrix
will turn vector (1, 0) into (A, B) and (0, 1) into (C, D) - thus you can see easily rotation and shearing it does.