public Quaternion normalizeLocal() {
        float n = FastMath.invSqrt(norm());
        x *= n;
        y *= n;
        z *= n;
        w *= n;
        return this;
    }
Scales the quaternion to have norm=1 and returns the (modified) current
instance. For a quaternion with norm=0, the result is undefined.

@return the (modified) current instance (for chaining)
jme3-core/src/main/java/com/jme3/math/Quaternion.java