Well, I did it. I got the laser to bounce through the portals properly, even the mirrors. Problem is, I don't like it at all. The reason is that it simply confusing to look at. If you have a laser beam hit a mirror, you will have four seperate laser segments - the two in the space you are in consisting of the laser from the avatar and the bounce in the mirror, and then the reflection of this. It just looks too busy to me. Perhaps I can tone it down a bit. Of course, if you have a mirror in a mirror, which was my test case, it get's really bad. But it does work - except for one thing. I only really need this when the pointer button is down and an object is selected and being manipulated. But this is precisely when I am not testing the pointer hit, presuming that I already have the object in hand that I am targeting. Further, the laser point will change, but only based on the actions of the user and the response of the target. That is, instead of the user determining the interaction, the target object does. This means that I really need to do an inverse of the steps I take to find the object in the first place. This is often impossible. For example, when the target point is moved outside of the scope of the portal. Besides, the math is at least as complex, and I don't have the energy to attack it. Given my unhappiness with how it looks, I am not even certain it is worth the effort.
Well, at least I got the math right. Now I can focus on aesthetics.