using UnityEngine;
using System.Collections;

public class UILogic : MonoBehaviour {

    public LockOnScript lockOnScript;

    private Camera actorCamera;
    private Transform lockOnTarget;

    void OnGUI()
    {
        actorCamera = GetComponentInChildren<Camera>();
        lockOnTarget = lockOnScript.LockOnTarget;

        //position of target on screen using viewport (0.0-1.0, 0.0-1.0) coordinates
        //(0.0, 0.0) is top left corner of screen
        Vector3 markerCoords = actorCamera.WorldToViewportPoint(lockOnTarget.position);
        //z coordinate of markerCoords is distance of target from camera
        float depthFactor = 200.0f / markerCoords.z;

        if(lockOnTarget != null)
        {
            //if there's a target we can lock on, draw a marker over it on the screen
            //uses viewport (0.0-1.0, 0.0-1.0) coordinates, (0.0, 0.0) is top left corner of screen
            DrawCenteredVPSpaceRect(markerCoords.x, markerCoords.y, TargetMarker, depthFactor);
        }
    }

    private void DrawCenteredVPSpaceRect(float x, float y, Texture2D tex, float scale)
    {
        int texWidth = (int)(tex.width * scale);
        int texHeight = (int)(tex.height * scale);
        int xPos = (int)(x*Screen.width);
        int yPos = (int)(y*Screen.height);
        Rect texRect = new Rect(xPos, yPos, texWidth, texHeight);
        GUI.DrawTexture(texRect, tex);
    }
}