how do I rotate a direction Vector3 upwards by an angle in unity-CodePudding

this is my direction vector new Vector3(target.transform.position.x - projectile.position.x, 0, target.transform.position.z - projectile.position.z).normalized

I tried multiplying it by Quaternion.AngleAxis(45, Vector3.up) but that simply doesn't work All other orientations like Vector3.left, right, etc. don't help either

The only thing I could observe is the way that the angle changes when I move the target or projectile

CodePudding user response：

You were close. Use cross product to get the axis you need, use that in AngleAxis, then finally apply that rotation to your starting direction:

Vector3 RotateTowardsUp(Vector3 start, float angle)
{
    // if you know start will always be normalized, can skip this step
    start.Normalize();

    Vector3 axis = Vector3.Cross(start, Vector3.up);

    // handle case where start is colinear with up
    if (axis == Vector3.zero) axis = Vector3.right;

    return Quaternion.AngleAxis(angle, axis) * start;
}