Translation and rotation of MDX (2)

Yesterday I sent a translation of an article, it is said that there are existing algorithms exist, yes, I would like to remind, I am not a highly skilled scholar, or a so-and-so researcher, then my algorithm how to come, some people said that the world article a big copy, see you will copy will not copy, do not know whether you have been to those papers site , did not go there to find any papers, anyway, I often go, you go to you will find that many of their algorithms are others have done, have written.

I also just think of a reminder of the role, to say let me think of a sophisticated algorithm, I believe that there is no such level.

First of all, in MDX, the mouse rotation is known, the mouse is not moving in a plane, but in a hemisphere moving.

　

As in the previous figure, the point from a to B is moving according to the trajectory of the circle, not the line from A to B.

Rotation of all called rotation that must have the rotation axis and rotation angle, the rotation axis is the plane of the normal vector of the OAB, the plane of the normal vector formula can be asked, the rotation angle as well as the formula can be asked:

N=oaxob

Α=acos (OA*OB)/(| oa|*| ob|))

The rotation angle (alpha) in the program can be set to twice times so that if you click on the left Middle edge of the view, and then drag to the right middle edge of the view, you can implement the model with the y-axis axis of 360 rotation, which is a week.

Now the problem is to find the A,b two point of the coordinates of the problem, then the two points of the coordinates of how to determine, note that there are two situations: