Draw a line with collision

Currently I am creating a line using linerenderer This is based on user input via mouse or touch. However, I want to add collision physics to this line. Basically, I want the user to be able to draw a line with their finger and for the player game object to be able to walk on this line.

My idea was to use ray-cast however, I don't know how to implement the code.

Thanks for the help!

Here is my current code: (in C#)

using UnityEngine; using System.Collections; using System.Collections.Generic;

public class DrawLineMouse : MonoBehaviour
{

 public Material newMaterialRef;
 private LineRenderer line;  
 private bool isMousePressed;     
 private List<Vector3> pointsList;     
 private Vector3 mousePos;     
 public GameObject player;
 public int lineNumber; // set in inspector, used to keep track of multiple gameObjects using same C# file
 int counter = 1;        // Keep track of how many times you're touching the screen and building a line.
 // Structure for line points   
 
 struct myLine //I don't think I need this if I'm not using the intersect code. (but whatever)
 { 
     public Vector3 StartPoint;         
     public Vector3 EndPoint;     
 };     
 
 //    -----------------------------------         
 void Awake()     
 {         
     // Create line renderer component and set its property         
     line = gameObject.AddComponent<LineRenderer>();         
     line.material =  new Material(newMaterialRef);  //    Shader.Find("Particles/Additive"   
     line.SetVertexCount(0);         
     line.SetWidth(0.5f,0.5f);         
     line.SetColors(Color.white, Color.white);         
     line.useWorldSpace = true;             
     isMousePressed = false;         
     pointsList = new List<Vector3>();  
 }     
 //    -----------------------------------         
 
 void Update ()      
 {         

     //if (Input.touchCount > 0) {
     //    var touch = Input.GetTouch (0);
             
     if (Input.GetKey (KeyCode.Z)) //delete all lines with button press
     {
         line.SetVertexCount (0);             
         pointsList.RemoveRange (0, pointsList.Count);             
         line.SetColors (Color.white, Color.white);    
     }
     
         if (Input.GetMouseButtonUp (0)) { //every time the user touches screen (mouse) and releases counter goes up (user just create another line)
         counter++;
     }
     if (counter == 11) { //if user makes so many lines, we go back to the original game object, this line (up to 10) will be redrawn.
         counter = 1;
     }

     // If mouse button down, remove old line and set its color to green         
     if (counter == lineNumber) {
         
         if (Input.GetMouseButtonDown (0) ) {             
             isMousePressed = true;             
             line.SetVertexCount (0);             
             pointsList.RemoveRange (0, pointsList.Count);             
             line.SetColors (Color.white, Color.white);    
         } else if (Input.GetMouseButtonUp (0) ) { //touch.phase == TouchPhase.Ended             
             isMousePressed = false; 
         }         
         // Drawing line when mouse is moving(presses)         
         if (isMousePressed) {             
             mousePos = Camera.main.ScreenToWorldPoint (Input.mousePosition); //changed from Input.mousePosition to touch.position        
             mousePos.z = 0;             
             if (!pointsList.Contains (mousePos)) {

                 pointsList.Add (mousePos);                 
                 line.SetVertexCount (pointsList.Count);  
                 line.SetPosition (pointsList.Count - 1, (Vector3)pointsList [pointsList.Count - 1]); 

                 //Instantiate (drawBox, mousePos, rotation.rotation);
                 //Instantiate (drawEdge, mousePos, rotation.rotation);

                 //if (isLineCollide () || isLineCollidedWithOtherObject()) {  //don't end up using this.  
                 //if( OnCollisionEnter() ){

                 if (isLineCollidedWithOtherObject()) {
                     isMousePressed = false;
                     line.SetColors (Color.red, Color.red);                 
                 }             
             } 
             
         } 
         
     }

 } //end update  
 //    -----------------------------------         
 //  Following method checks is currentLine(line drawn by last two points) collided with line      
 //    -----------------------------------         
 
 private bool isLineCollide()     
 {         
     return false; //temp to disable this part of the code
     if (pointsList.Count < 2)            
         return false;        
         int TotalLines = pointsList.Count - 1;        
         myLine[] lines = new myLine[TotalLines];        
         if (TotalLines > 1)          
         {            
             for (int i=0; i<TotalLines; i++)              
             {                
             lines [i].StartPoint = (Vector3)pointsList [i];                 lines [i].EndPoint = (Vector3)pointsList [i + 1];             }        
         }        
         for (int i=0; i<TotalLines-1; i++)          
         {            
             myLine currentLine;            
             currentLine.StartPoint = (Vector3)pointsList [pointsList.Count - 2];            
             currentLine.EndPoint = (Vector3)pointsList [pointsList.Count - 1];            
             if (isLinesIntersect (lines [i], currentLine))                  
             return true;        
         }        
     return false;    
 }
 
 //    -----------------------------------         
 //    Following method checks whether given two points are same or not     
 //    -----------------------------------         
 private bool checkPoints (Vector3 pointA, Vector3 pointB)     
 {         
     return (pointA.x == pointB.x && pointA.y == pointB.y);     
 }     
 //    -----------------------------------         
 //    Following method checks whether given two line intersect or not     
 //    -----------------------------------         
 private bool isLinesIntersect (myLine L1, myLine L2)     
 {         
     if (checkPoints (L1.StartPoint, L2.StartPoint) ||             checkPoints (L1.StartPoint, L2.EndPoint) || checkPoints (L1.EndPoint, L2.StartPoint) || checkPoints (L1.EndPoint, L2.EndPoint))             
         return false;         
     return((Mathf.Max (L1.StartPoint.x, L1.EndPoint.x) >= Mathf.Min (L2.StartPoint.x, L2.EndPoint.x)) &&(Mathf.Max (L2.StartPoint.x, L2.EndPoint.x) >= Mathf.Min (L1.StartPoint.x, L1.EndPoint.x)) && (Mathf.Max (L1.StartPoint.y, L1.EndPoint.y) >= Mathf.Min (L2.StartPoint.y, L2.EndPoint.y)) &&(Mathf.Max (L2.StartPoint.y, L2.EndPoint.y) >= Mathf.Min (L1.StartPoint.y, L1.EndPoint.y)));     
 } 
 

 private bool isLineCollidedWithOtherObject()
 {
     RaycastHit hit;
     Ray ray = Camera.main.ScreenPointToRay(Camera.main.WorldToScreenPoint(pointsList[pointsList.Count-1]));
     if(Physics.Raycast(ray,out hit))
     {
         if(hit.collider)
             return true;
     }

     return false;
 }

}//end public class

/* if (Input.touchCount > 0) { var touch = Input.GetTouch (0); Vector3 touchDeltaPosition = new Vector3 (Input.GetTouch(0).position.x, Input.GetTouch(0).position.y, 0);

 if (Input.GetTouch (0).phase == TouchPhase.Began) {  


     mousePos = Camera.main.ScreenToWorldPoint (touchDeltaPosition);

*/