Creating a kind of head-up radar display

Hi everyone, I've been trying for some hours to find a solution to this problem but I can't manage to...

What I want to design is a kind of head-up display : when the player approach some items (that are tagged) and has them on the screen, I want a Texture2D to appear on the screen in front of the item using the GUI.

But for now I just managed to count the items within a fixed distance that are in the screen (I don't want to care about the ones behind me for example). Now I want to add the Texture but I fail at it :(

I hope one of you may be able to find where is the problem !

Here's the script I use :

 using UnityEngine;
 using System.Collections;
 
 public class GUIRadar : MonoBehaviour
 {
     public Texture2D RadarLock;        //2D Texture of the radar square that msut go in front of the items
     public GameObject Controller;    //First person controller that gives the Horizontal rotation
     
     public float[] radarWidth;        //Radar square width and height on the GUI
     public float[] radarHeight;
     
     public float[] radarXPos;        //Radar square position on the GUI ("in front" of the items)
     public float[] radarYPos;
     
     public float xPosCoef;            //3 coefficients used to adjust the position and size of the radar square on the GUI
     public float yPosCoef;
     public float sizeCoef;
     
     public float alphaX;            //Angles between    -the player looking direction and the "0"
     public float betaX;                //                    -the player->item ray and the "0"
     public float deltaX;            //The difference between those angles
     
     public float alphaY;            //Same here for vertical axis
     public float betaY;
     public float deltaY;
     
     public float XviewingAngle;        //Allowed angles to display the radar square
     public float YviewingAngle;        //i.e. : if the player looks too far away right from the item it's useless to display the square since it's out of the screen
     
     private int itemsNumber;        //Just a count of the directly visibles items
     private string numberOfItems;    //Same but in string format
     private GameObject[] PossibleInteractionItems;    //GameObject list to get all the items in view that got tagged
     private RaycastHit hittedItem;    //To colect information of the RayCast
     private Ray ray;                //To set the direction of the ray
     
     void Awake()
     {
         itemsNumber=0;
         PossibleInteractionItems=GameObject.FindGameObjectsWithTag(Tags.interact);    //I collect every items with the wanted tag
     }
     
     private void OnGUI()
     {
         //--------------------THIS THING DOESN'T WORK
         for(int i=0;i<itemsNumber;i++)
         {
             GUI.DrawTexture(new Rect(Screen.width/2-radarWidth[i]/2,Screen.height/2-radarHeight[i]/2,radarWidth[i],radarHeight[i]),RadarLock);
         }
         //----------------------
         
         GUI.Label(new Rect(Screen.width/2+50,Screen.height/2,50,50),numberOfItems);
     }
     
     void Update()
     {
         itemsNumber=0;        //At each frame I set everything to 0
         radarWidth=null;
         radarHeight=null;
         radarXPos=null;
         radarYPos=null;
         
         foreach(GameObject item in PossibleInteractionItems)    //For each tagged item
         {
             if(Vector3.Distance(transform.position,item.transform.position) < 5f)    //if the item's distance is under 5
             {
                 ray=new Ray(transform.position,new Vector3(item.transform.position.x-transform.position.x,item.transform.position.y-transform.position.y,item.transform.position.z-transform.position.z)); //I set the Ray direction : from my player to the item
                 
                 betaX=Mathf.Abs(Mathf.Atan(ray.direction.x/ray.direction.z)/(2*Mathf.PI)*360);    //I collect every angles informations
                 if(ray.direction.x<0)
                     betaX=-1*betaX;
                 if(ray.direction.x>0 && ray.direction.z<0)
                     betaX=180-betaX;
                 if(ray.direction.x<0 && ray.direction.z<0)
                     betaX=-180-betaX;
                 
                 alphaX=Controller.transform.eulerAngles.y;
                 if(alphaX>180)
                     alphaX-=360;
                 
                 deltaX=betaX-alphaX;
                 
                 betaY=Mathf.Abs(Mathf.Atan(ray.direction.z/ray.direction.y)/(2*Mathf.PI)*360-90);
                 if(ray.direction.y>0)
                     betaY=180-betaY;
                 else
                     betaY=-1*betaY;
                 
                 alphaY=-transform.eulerAngles.x;
                 if(alphaY<-180)
                     alphaY+=360;
                 
                 deltaY=betaY-alphaY;
                 
                 if(Mathf.Abs(deltaX)<XviewingAngle && Mathf.Abs(deltaY)<YviewingAngle)        //and check if the item is in the screen
                 {
                     Debug.DrawRay (transform.position,ray.direction,Color.red,0.001f);        //for debugging purposes ^^
                     Physics.Raycast(ray, out hittedItem);
                     if(hittedItem.collider.gameObject.tag == Tags.interact)                    //If the item is in direct view (not behind another obstacle)
                     {
                         //-------------------THIS DOESN'T WORK TOO
                         radarXPos[itemsNumber]=deltaX*xPosCoef;
                         radarYPos[itemsNumber]=deltaY*yPosCoef;
                         radarWidth[itemsNumber]=(Vector3.Distance (item.transform.position,transform.position))*sizeCoef;
                         radarHeight[itemsNumber]=(Vector3.Distance (item.transform.position,transform.position))*sizeCoef;
                         //-----------------------
                         itemsNumber++;                        //But this work : I got the right amount of items in the screen with a distance under 5
                     }
                 }
             }
         }
         numberOfItems=itemsNumber.ToString();                //To display it in the OnGUI()
     }
 }