UnityEditor.Lightmapping.GetTerrainGIChunks C# (CSharp) Method

        public static extern void GetTerrainGIChunks(Terrain terrain, ref int numChunksX, ref int numChunksY);
        private static void Internal_CallCompletedFunctions()

        void ShowTerrainChunks(Terrain[] terrains)
        {
            if (terrains == null)
            {
                return;
            }

            int terrainChunksX = 0, terrainChunksY = 0;

            foreach (var terrain in terrains)
            {
                int tmpChunksX = 0, tmpChunksY = 0;
                Lightmapping.GetTerrainGIChunks(terrain, ref tmpChunksX, ref tmpChunksY);
                if (terrainChunksX == 0 && terrainChunksY == 0)
                {
                    terrainChunksX = tmpChunksX;
                    terrainChunksY = tmpChunksY;
                }
                else if (terrainChunksX != tmpChunksX || terrainChunksY != tmpChunksY)
                {
                    terrainChunksX = terrainChunksY = 0;
                    break;
                }
            }
            if (terrainChunksX * terrainChunksY > 1)
            {
                EditorGUILayout.HelpBox(string.Format(L10n.Tr("Terrain is chunked up into {0} instances for baking."), terrainChunksX * terrainChunksY), MessageType.None);
            }
        }