问题
I'm trying to obtain the camera rotation on various axis in OpenGL (but using Java, LWJGL, and jME specifically). The camera object allows me to get the direction as a Vector3f, but this doesn't seem to work to get the componentised rotation; each axis appears tied to another axis. I found that toAngleAxis with the angle component with offset was a quick hack, but doesn't work properly in most situations. I'm not so good at maths unfortunately, otherwise I may have been able to work out this problem :) Again, I just need the X, Y and Z axes componentised and in radians, from 0 radians to 2 PI radians.
Can anyone help?
Cheers and thanks in advance, Chris
回答1:
Obtaining the rotation angels requires just transforming the view vector given in cartesian coordinates into spherical coordinates. You can find the formulas in wikipedia.
viewvector = <x, y, z>
r = sqrt(x² + y² + z²)
phi = arctan2(y, x)
theta = arccos(z / r)
Note that you can only obtain two rotation angels form the view vector. Obtaining the third rotation angle requires knowing the projection plane x or y axis.
回答2:
I'd recommend reading about Euler Angles, yaw/pitch/roll, and quaternion orientation. These topics will help you understand everything involved. If I understand correctly, you're trying to construct Euler angles from a specified orientation.
See this code for some algorithms for working with Euler angles. In particular, I believe what you want is the setDirection method.
This will give you a yaw and pitch from a directional vector. Note that you only need 2 rotations, though, since "roll" would require a rotation about the directional vector (or your direction specified as a single quaternion rotation).
来源：https://stackoverflow.com/questions/993332/obtaining-the-camera-rotation-in-radians-on-the-x-y-and-z-axis-in-opengl