added use unce to dialogue trigger and trigger editor

Assets/Plugins/Pixel Crushers/Dialogue System/Scripts/Editor/Inspectors/Triggers/DialogueSystemTriggerEditor.cs

@@ -165,6 +165,8 @@ namespace PixelCrushers.DialogueSystem
                 questPicker.showReferenceDatabase = false;
             }
             if (newDatabase != null) EditorTools.selectedDatabase = newDatabase;
+            var fireOnceProperty = serializedObject.FindProperty("fireOnce");
+            EditorGUILayout.PropertyField(fireOnceProperty);
         }
 
         protected virtual void DrawConditions()

Assets/Plugins/Pixel Crushers/Dialogue System/Scripts/Triggers/Triggers/DialogueSystemTrigger.cs

@@ -29,7 +29,7 @@ namespace PixelCrushers.DialogueSystem
         [Tooltip("The trigger that this component listens for.")]
         [DialogueSystemTriggerEvent]
         public DialogueSystemTriggerEvent trigger = DialogueSystemTriggerEvent.OnUse;
-
+        public bool fireOnce = true;
         /// <summary>
         /// The conditions under which the trigger will fire.
         /// </summary>
@@ -363,7 +363,7 @@ namespace PixelCrushers.DialogueSystem
         protected bool didIPause = false;
         protected float preConversationTimeScale = 1;
         protected bool tryingToStart = false;
-
+        protected bool hasFired = false;
         #endregion
 
         #region Trigger Checks
@@ -609,6 +609,8 @@ namespace PixelCrushers.DialogueSystem
         public void TryStart(Transform actor, Transform interactor)
         {
             if (tryingToStart) return;
+            if (fireOnce && hasFired)
+                return;
             tryingToStart = true;
             try
             {
@@ -626,6 +628,7 @@ namespace PixelCrushers.DialogueSystem
         public void Fire(Transform actor)
         {
             if (DialogueDebug.logInfo) Debug.Log("Dialogue System: Dialogue System Trigger is firing " + trigger + ".", this);
+            hasFired = true;
             DoQuestAction();
             DoLuaAction();
             DoSequenceAction(actor);