I believe I understood most of this chapter and the linear algebra side of things. I was able to do the suggested exercise, panning and zooming. But I don’t feel like I have a full understanding of why certain things are happening with the projection matrix. It’s bugging me and I don’t feel like carrying on until I fully understand it! Please help me out!
First of all, in the projection matrix there are lots of little fractions. What is the significance of 2 as the numerator? Is this because normalized coordinates are in the range of -1 and 1?
In OrthoM() when I add the 1 (or any other number) to bottom, top and/or left, right it allows me to pan up and then to the right. Is this because the clipping plane has been changed?
In OrthoM() when I make left more left, right more right, bottom more lower and top more higher - it zooms out. I don’t understand why changing the near and far has no effect on zooming.
Lastly (I think) I don’t understand why the aspect ratio is calculated and used for left, right ONLY then top, bottom ONLY.