Added function to remove duplicate selections

if you select the parent and its child, then the child is removed from
the export set and all the parent's children are exported

Author: vkovec

Assets/FbxExporters/Editor/FbxExporter.cs

@@ -486,16 +486,52 @@ protected int ExportComponents (GameObject  unityGo, FbxScene fbxScene, FbxNode
             /// </summary>
             /// <returns>The object count.</returns>
             /// <param name="exportSet">Export set.</param>
-            public int GetGameObjectCount (IEnumerable<UnityEngine.Object> exportSet)
+            public int GetGameObjectCount (HashSet<GameObject> exportSet)
             {
                 int count = 0;
                 foreach (var obj in exportSet) {
+                    count += obj.transform.hierarchyCount;
+                }
+                return count;
+            }
+
+            /// <summary>
+            /// Removes objects that will already be exported anyway.
+            /// E.g. if a parent and its child are both selected, then the child
+            ///      will be removed from the export set.
+            /// </summary>
+            /// <returns>The revised export set</returns>
+            /// <param name="unityExportSet">Unity export set.</param>
+            protected HashSet<GameObject> RemoveDuplicateObjects(IEnumerable<UnityEngine.Object> unityExportSet)
+            {
+                // basically just remove the descendents from the unity export set
+                HashSet<GameObject> toExport = new HashSet<GameObject> ();
+                HashSet<UnityEngine.Object> hashedExportSet = new HashSet<Object> (unityExportSet);
+
+                Queue<UnityEngine.Object> queue = new Queue<Object> (unityExportSet);
+                while(queue.Count > 0) {
+                    var obj = queue.Dequeue();
                     var unityGo = GetGameObject (obj);
+
                     if (unityGo) {
-                        count += unityGo.transform.hierarchyCount;
+                        // if any of this nodes ancestors is already in the export set,
+                        // then ignore it, it will get exported already
+                        bool parentInSet = false;
+                        var parent = unityGo.transform.parent;
+                        while (parent != null) {
+                            if (hashedExportSet.Contains (parent.gameObject)) {
+                                parentInSet = true;
+                                break;
+                            }
+                            parent = parent.parent;
+                        }
+
+                        if (!parentInSet) {
+                            toExport.Add (unityGo);
+                        }
                     }
                 }
-                return count;
+                return toExport;
             }
 
             /// <summary>
@@ -561,16 +597,13 @@ public int ExportAll (IEnumerable<UnityEngine.Object> unityExportSet)
                         // export set of object
                         FbxNode fbxRootNode = fbxScene.GetRootNode ();
                         int i = 0;
-                        int count = GetGameObjectCount (unityExportSet);
-                        foreach (var obj in unityExportSet) {
-                            var unityGo = GetGameObject (obj);
-
-                            if (unityGo) {
-                                i = this.ExportComponents (unityGo, fbxScene, fbxRootNode, i, count);
-                                if (i < 0) {
-                                    Debug.LogWarning ("Export Cancelled");
-                                    return 0;
-                                }
+                        var revisedExportSet = RemoveDuplicateObjects(unityExportSet);
+                        int count = GetGameObjectCount (revisedExportSet);
+                        foreach (var unityGo in revisedExportSet) {
+                            i = this.ExportComponents (unityGo, fbxScene, fbxRootNode, i, count);
+                            if (i < 0) {
+                                Debug.LogWarning ("Export Cancelled");
+                                return 0;
                             }
                         }