maint: added htrace ssgi

Assets/Plugins/HTraceSSGI/Scripts/Extensions/CameraHistorySystem/CameraHistorySystem.cs

@@ -0,0 +1,71 @@
+using System;
+
+namespace HTraceSSGI.Scripts.Extensions.CameraHistorySystem
+{
+    public class CameraHistorySystem<T> where T : struct, ICameraHistoryData
+    {
+        private const int MaxCameraCount = 4; // minimum 2
+
+        private int _cameraHistoryIndex;
+        private readonly T[] _cameraHistoryData = new T[MaxCameraCount];
+
+
+        public int UpdateCameraHistoryIndex(int currentCameraHash)
+        {
+            _cameraHistoryIndex = GetCameraHistoryDataIndex(currentCameraHash);
+            return _cameraHistoryIndex;
+        }
+
+        private int GetCameraHistoryDataIndex(int cameraHash)
+        {
+            // Unroll manually for MAX_CAMERA_COUNT = 4
+            if (_cameraHistoryData[0].GetHash() == cameraHash) return 0;
+            if (_cameraHistoryData[1].GetHash() == cameraHash) return 1;
+            if (_cameraHistoryData[2].GetHash() == cameraHash) return 2;
+            if (_cameraHistoryData[3].GetHash() == cameraHash) return 3;
+            return -1; // new camera
+        }
+
+        public void UpdateCameraHistoryData()
+        {
+            bool cameraHasChanged = _cameraHistoryIndex == -1;
+
+            if (cameraHasChanged)
+            {
+                const int lastIndex = MaxCameraCount - 1;
+
+                if (_cameraHistoryData[lastIndex] is IDisposable disposable)
+                    disposable.Dispose();
+
+                // Shift the camera history data back by one
+                Array.Copy(_cameraHistoryData, 0, _cameraHistoryData, 1, lastIndex);
+
+                _cameraHistoryIndex = 0;
+                _cameraHistoryData[0] = new T(); //it's critical
+            }
+        }
+
+        public ref T GetCameraData()
+        {
+            return ref _cameraHistoryData[_cameraHistoryIndex];
+        }
+
+        public T[] GetCameraDatas()
+        {
+            return _cameraHistoryData;
+        }
+
+        public void SetCameraData(T data)
+        {
+            _cameraHistoryData[_cameraHistoryIndex] = data;
+        }
+
+        public void Cleanup()
+        {
+            for (int index = 0; index < _cameraHistoryData.Length; index++)
+            {
+                _cameraHistoryData[index] = default;
+            }
+        }
+    }
+}