refactored PlaceOnPlane, conformed to naming conventions

Assets/Scenes/SampleScene.unity

   m_Script: {fileID: 11500000, guid: 7d5359d5f13250e4485741ed685a32be, type: 3}
   m_Name: 
   m_EditorClassIdentifier: 
-  PlacedPrefab: {fileID: 1934569588295450, guid: b34b6c8f1206a6844b983e23b9da0441,
+  placedPrefab: {fileID: 1934569588295450, guid: b34b6c8f1206a6844b983e23b9da0441,
     type: 2}

Assets/Scripts/PlaceOnPlane.cs

 public class PlaceOnPlane : MonoBehaviour
 {
     [SerializeField] [Tooltip("Instantiates this prefab on a plane at the touch location.")]
-    public GameObject PlacedPrefab;
+    public GameObject placedPrefab;
-    private List<ARRaycastHit> hits;
-    private bool spawnedPrefab = false;
-    private GameObject spawnedObject;
-    private ARSessionOrigin sessionOrigin;
+    List<ARRaycastHit> m_Hits;
+    GameObject m_SpawnedObject;
+    ARSessionOrigin m_SessionOrigin;
-        sessionOrigin = GetComponent<ARSessionOrigin>();
-        hits = new List<ARRaycastHit>();
+        m_SessionOrigin = GetComponent<ARSessionOrigin>();
+        m_Hits = new List<ARRaycastHit>();
     }
 
     void Update()
             Touch touch = Input.GetTouch(0);
 
-            if (!spawnedPrefab)
+            if (m_SessionOrigin.Raycast(touch.position, m_Hits, TrackableType.PlaneWithinPolygon))
-                if (touch.phase == TouchPhase.Began)
+                Pose hitPose = m_Hits[0].pose;
+
+                if (m_SpawnedObject == null)
-                    if (sessionOrigin.Raycast(touch.position, hits, TrackableType.PlaneWithinPolygon))
+                    if (touch.phase == TouchPhase.Began)
-                        Pose hitPose = hits[0].pose;
-                       
-                        spawnedObject = Instantiate(PlacedPrefab, hitPose.position, hitPose.rotation);
-                        spawnedPrefab = true;                    
+                        m_SpawnedObject = Instantiate(placedPrefab, hitPose.position, hitPose.rotation);
-            }
-            else
-            {
-                if (sessionOrigin.Raycast(touch.position, hits, TrackableType.PlaneWithinPolygon))
+                else
-                    Pose hitPose = hits[0].pose;
-                    spawnedObject.transform.position = hitPose.position;                 
+                    m_SpawnedObject.transform.position = hitPose.position;
                 }
             }
         }