IEnumerator DrawLineToMouse(float range)
{

    RayCastHit hit;
    Vector3 endPos;
    float rangeSquared = Mathf.Sqrt(range);

    while (Input.GetButton("Fire1"))
    {

        if (Physics.Raycast(Camera.main.ScreenPointToRay(Input.mousePosition), out hit, 2000))
        {

            endPos = (hit.point - startPos).normalized * rangeSquared; // startPos is the starting point of the line to be drawn

            Debug.DrawLine(startPos, hit.point, Color.green, Time.deltaTime);
            Debug.DrawLine(startPos, endPos, Color.red, Time.deltaTime);

        }

        yield return null;
    }

}

endPos = startPos + (hit.point - startPos).normalized * rangeSquared;