Rotate a vector
- by marc wellman
I want my first-person camera to smoothly change its viewing direction from direction d1 to direction d2. The latter direction is indicated by a target position t2.
So far I have implemented a rotation that works fine but the speed of the rotation slows down the closer the current direction gets to the desired one. This is what I want to avoid.
Here are the two very simple methods I have written so far:
// this method initiates the direction change and sets the parameter
public void LookAt(Vector3 target) {
_desiredDirection = target - _cameraPosition;
_desiredDirection.Normalize();
_rotation = new Matrix();
_rotationAxis = Vector3.Cross(Direction, _desiredDirection);
_isLooking = true;
}
// this method gets execute by the Update()-method if _isLooking flag is up.
private void _lookingAt() {
dist = Vector3.Distance(Direction, _desiredDirection);
// check whether the current direction has reached the desired one.
if (dist >= 0.00001f) {
_rotationAxis = Vector3.Cross(Direction, _desiredDirection);
_rotation = Matrix.CreateFromAxisAngle(_rotationAxis, MathHelper.ToRadians(1));
Direction = Vector3.TransformNormal(Direction, _rotation);
} else {
_onDirectionReached();
_isLooking = false;
}
}
Again, rotation works fine; camera reaches its desired direction. But the speed is not equal over the course of movement - it slows down.
How to achieve a rotation with constant speed ?
