Drawing a Line very difficult, why?

I have a top down billiard game. And on click / tap the ball moves in the clicked direction like in the image below:

https://www.dropbox.com/s/x5ktxvlefjeqf1b/img.jpg?dl=0

Now, I want a line to be drawn in the direction where the mouse is hovers or the finger is swiped, here is my update code:

void Update () {

//this should make the line, why not working?
Vector3 forward = transform.forward;
Debug.DrawRay(transform.position, forward);
Debug.DrawLine(transform.position, transform.position + forward * 10000);


if (Input.GetMouseButtonDown (0)) {

//
Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
RaycastHit hit;

if (Physics.Raycast(ray, out hit, 100.0f)){

//


//
Vector3 startPos = transform.position;
Vector3 clickPos = new Vector3(hit.point.x, hit.point.y, transform.position.z);
Vector3 direction = Direction (clickPos - startPos);

//direction
rb.velocity = new Vector3(direction.x * 5, direction.y * 5, 0);


}



}



}
I tried DrawLine, Drawray, any ideas?

 

Debug functions only work in scene view.

Look up "Unity Line Renderer"


also, please use [code ][/code ] tags when pasting code into the forums, really helps with readability. There is a sticky on them at the top of the scripting forum.