feat: apply different offsets to publishers to distribute the update load.

Author: Bob-Eric

Packages/UnitySensorsROS/Runtime/Scripts/Publishers/RosMsgPublisher.cs

@@ -16,11 +16,13 @@ namespace UnitySensors.ROS.Publisher
 
         [SerializeField]
         protected T _serializer;
+        private static int _publisher_count = 0;
 
         private ROSConnection _ros;
         private float _dt;
         private float _frequency_inv;
         private RosTopicState _topicState;
+        private int _publisher_id;
 
         public string topicName { get => _topicName; set => _topicName = value; }
         public float frequency
@@ -30,16 +32,39 @@ public float frequency
             {
                 _frequency = Mathf.Max(value, 0);
                 _frequency_inv = 1.0f / _frequency;
+                InitializePublisherOffset();
             }
         }
-
-        protected virtual void Start()
+        private void Awake()
         {
-            _dt = 0.0f;
             _frequency_inv = 1.0f / _frequency;
+            _publisher_id = _publisher_count;
+            _publisher_count++;
 
-            _ros = ROSConnection.GetOrCreateInstance();
+            InitializePublisherOffset();
+        }
+
+        private void InitializePublisherOffset()
+        {
+            string publisherType = GetType().Name;
+            int typeHash = publisherType.GetHashCode();
+
+            // Combine publisher ID and type to create a more dispersed value
+            // Use coprime numbers and operations to increase dispersion
+            float seed = (_publisher_id * 16777619 + typeHash) * 0.618033988749895f;
 
+            // Ensure the offset is in [0, 1)
+            float normalizedOffset = seed % 1.0f;
+            if (normalizedOffset < 0) normalizedOffset += 1.0f; // Ensure non-negative
+
+            _dt = normalizedOffset * _frequency_inv;
+
+            Debug.Log($"Publisher {GetType().Name} ID:{_publisher_id} initialized with offset {normalizedOffset:F3} ({_dt:F3}s)");
+        }
+
+        protected virtual void Start()
+        {
+            _ros = ROSConnection.GetOrCreateInstance();
             _serializer.Init();
         }