Implement #1329: Add remove-unused-objects command (#6324)

src/openrct2/windows/EditorObjectSelection.cpp

@@ -1877,3 +1877,44 @@ bool editor_check_object_group_at_least_one_selected(sint32 checkObjectType)
     }
     return false;
 }
+
+sint32 editor_remove_unused_objects()
+{
+    bool createSelectionFlags = (_objectSelectionFlags == nullptr);
+    if (createSelectionFlags && !sub_6AB211())
+    {
+        return 0;
+    }
+
+    setup_in_use_selection_flags();
+
+    sint32 numObjects = (sint32)object_repository_get_items_count();
+    const ObjectRepositoryItem * items = object_repository_get_items();
+
+    sint32 numUnselectedObjects = 0;
+    for (sint32 i = 0; i < numObjects; i++)
+    {
+        if (!(_objectSelectionFlags[i] & OBJECT_SELECTION_FLAG_IN_USE) && !(_objectSelectionFlags[i] & OBJECT_SELECTION_FLAG_ALWAYS_REQUIRED))
+        {
+            const ObjectRepositoryItem * item = &items[i];
+            uint8 objectType = item->ObjectEntry.flags & 0xF;
+
+            if (objectType == OBJECT_TYPE_PARK_ENTRANCE || objectType == OBJECT_TYPE_SCENARIO_TEXT || objectType == OBJECT_TYPE_WATER || objectType == OBJECT_TYPE_SCENERY_SETS)
+            {
+                continue;
+            }
+
+            _numSelectedObjectsForType[objectType]--;
+            _objectSelectionFlags[i] &= ~OBJECT_SELECTION_FLAG_SELECTED;
+            numUnselectedObjects++;
+        }
+    }
+    unload_unselected_objects();
+
+    if (createSelectionFlags)
+    {
+        editor_object_flags_free();
+    }
+
+    return numUnselectedObjects;
+}