Make _clone() internal

docs/api/quaternion.md

 
 The magnitude of the quaternion.
 
-### clone
-
-`quaternion.clone(): Quaternion`
-
-Clone the quaternion.
-
-**Returns**
-
-A new quaternion object with the same coordinates as `this`.
-
 ### equals
 
 `quaternion.equals(q: Quaternion): boolean`

docs/api/vector2.md

 
 A new unit vector pointing to `v` from `this`.
 
-### clone
-
-`vector.clone(): Vector2`
-
-Clone the vector.
-
-**Returns**
-
-A new vector object with the same coordinates as `this`.
-
 ### equals
 
 `vector.equals(v: Vector2): boolean`

docs/api/vector3.md

 
 A new unit vector pointing to `v` from `this`.
 
-### clone
-
-`vector.clone(): Vector3`
-
-Clone the vector.
-
-**Returns**
-
-A new vector object with the same coordinates as `this`.
-
 ### cross
 
 `vector.cross(v: Vector3): Vector3`

src/geometry/quaternion.ts

     }
 
     /**
-     * Clone this quaternion
-     * @returns a clone of this quaternion
-     */
-    clone(): Quaternion
-    {
-        return new Quaternion(this._x, this._y, this._z, this._w);
-    }
-
-    /**
      * Check if this and q have the same coordinates
      * @param q a quaternion
      * @returns true if this and q have the same coordinates
 
         return this;
     }
+
+    /**
+     * Clone this quaternion
+     * @returns a clone of this quaternion
+     * @internal
+     */
+    _clone(): Quaternion
+    {
+        return new Quaternion(this._x, this._y, this._z, this._w);
+    }
 }

src/geometry/vector2.ts

      */
     directionTo(v: Vector2): Vector2
     {
-        return v.clone()._subtract(this)._normalize();
-    }
-
-    /**
-     * Clone this vector
-     * @returns a clone of this vector
-     */
-    clone(): Vector2
-    {
-        return new Vector2(this._x, this._y);
+        return v._clone()._subtract(this)._normalize();
     }
 
     /**
 
         return this;
     }
+
+    /**
+     * Clone this vector
+     * @returns a clone of this vector
+     * @internal
+     */
+    _clone(): Vector2
+    {
+        return new Vector2(this._x, this._y);
+    }
 }

src/geometry/vector3.ts

      */
     directionTo(v: Vector3): Vector3
     {
-        return v.clone()._subtract(this)._normalize();
+        return v._clone()._subtract(this)._normalize();
     }
 
     /**
     }
 
     /**
-     * Clone this vector
-     * @returns a clone of this vector
-     */
-    clone(): Vector3
-    {
-        return new Vector3(this._x, this._y, this._z);
-    }
-
-    /**
      * Check if this and v have the same coordinates
      * @param v a vector
      * @returns true if this and v have the same coordinates
 
         return this;
     }
+
+    /**
+     * Clone this vector
+     * @returns a clone of this vector
+     * @internal
+     */
+    _clone(): Vector3
+    {
+        return new Vector3(this._x, this._y, this._z);
+    }
 }

src/trackers/pointer-tracker/pointer-tracker.ts

 
             // determine the position delta
             const deltaPosition = !previous ? Vector2.ZERO :
-                                  position.clone()._subtract(previous.position);
+                                  position._clone()._subtract(previous.position);
 
             // determine the initial position
             const initialPosition = previous ? previous.initialPosition :
-                                    Object.freeze(position.clone());
+                                    Object.freeze(position._clone());
 
             // determine the velocity
-            const velocity = deltaPosition.clone()._scale(inverseDeltaTime);
+            const velocity = deltaPosition._clone()._scale(inverseDeltaTime);
 
             // determine the elapsed time since the tracking began
             const elapsedTime = previous ? previous.elapsedTime + deltaTime : 0;