在两个轴上计算方向的更有效方法？

Question

I have a Vector3 defined like so {x,y,z};

I want to get the angles of the point relative to the y axis and the origin.

I do:

  float tilt = atan2( point.z(), point.y() );
  float pan = atan2( point.x(), point.y() ); 

Now, I need the directions so the dot product is not interesting.

Is there a better way to get those values in one go?

Thanks

Answer 1

Expression

angle = acos(x / length(x,y,z))

gives angle between vector and OX axis. Range is 0..Pi .

Perhaps you want -Pi/2..Pi/2 range between OYZ plane and vector - in this case use Pi/2-angle