refactor into projects

MshLib/Msh0x01.cs

@@ -0,0 +1,191 @@
+using System.Buffers.Binary;
+using NResLib;
+
+namespace MshLib;
+
+/// <summary>
+/// MSH-компонент 0x01: таблица узлов модели.
+/// Для обычного AniMesh node имеет size 0x26.
+/// У ландшафта metadata/magic1 может иметь другой смысл, например grid_x_count.
+/// </summary>
+public static class Msh0x01
+{
+    public const int NormalElementSize = 0x26;
+    public const int StateCount = 3;
+    public const int MaxLodCount = 5;
+    public const int SlotCount = StateCount * MaxLodCount;
+
+    public static Msh0x01Component ReadComponent(FileStream mshFs, NResArchive archive)
+    {
+        var entry = archive.Files.FirstOrDefault(x => x.FileType == "01 00 00 00");
+
+        if (entry is null)
+        {
+            throw new Exception("Archive doesn't contain node table component (0x01)");
+        }
+
+        if (entry.ElementSize <= 0)
+        {
+            throw new Exception("Node table component (0x01) has invalid element size");
+        }
+
+        if (entry.FileLength % entry.ElementSize != 0)
+        {
+            throw new Exception("Node table component (0x01) payload size is not divisible by element size");
+        }
+
+        if (entry.ElementSize < 8)
+        {
+            throw new Exception("Node table component (0x01) element size is too small");
+        }
+
+        var elementCount = entry.FileLength / entry.ElementSize;
+        var data = new byte[entry.FileLength];
+
+        mshFs.Seek(entry.OffsetInFile, SeekOrigin.Begin);
+        mshFs.ReadExactly(data, 0, data.Length);
+
+        var dataSpan = data.AsSpan();
+
+        var nodes = new List<Node>(elementCount);
+
+        for (var i = 0; i < elementCount; i++)
+        {
+            var baseOffset = i * entry.ElementSize;
+            var elementSpan = dataSpan.Slice(baseOffset, entry.ElementSize);
+
+            var rawBytes = elementSpan.ToArray();
+
+            var slotIndices = new ushort[SlotCount];
+            Array.Fill(slotIndices, ushort.MaxValue);
+
+            var slotWordCount = Math.Min(
+                slotIndices.Length,
+                Math.Max(0, (entry.ElementSize - 8) / 2));
+
+            for (var slotIndex = 0; slotIndex < slotWordCount; slotIndex++)
+            {
+                slotIndices[slotIndex] =
+                    BinaryPrimitives.ReadUInt16LittleEndian(elementSpan.Slice(0x08 + slotIndex * 2, 2));
+            }
+
+            nodes.Add(new Node(
+                RawBytes: rawBytes,
+                Flags: (NodeFlags)BinaryPrimitives.ReadUInt16LittleEndian(elementSpan.Slice(0x00, 2)),
+                ParentIndexOrLink: BinaryPrimitives.ReadUInt16LittleEndian(elementSpan.Slice(0x02, 2)),
+                AnimMapStart0x13: BinaryPrimitives.ReadUInt16LittleEndian(elementSpan.Slice(0x04, 2)),
+                FallbackKey0x08: BinaryPrimitives.ReadUInt16LittleEndian(elementSpan.Slice(0x06, 2)),
+                Msh02SlotIndicesByStateAndLOD: slotIndices));
+        }
+
+        return new Msh0x01Component(entry.ElementSize, nodes);
+    }
+
+    /// <summary>Результат чтения MSH-компонента 0x01.</summary>
+    /// <param name="ElementSize">Размер node entry из NRes metadata.</param>
+    /// <param name="Nodes">Узлы компонента 0x01.</param>
+    public sealed record Msh0x01Component(
+        int ElementSize,
+        List<Node> Nodes)
+    {
+        public bool IsNormalAniMeshNodeTable => ElementSize == NormalElementSize;
+    }
+
+    /// <summary>Узел MSH 0x01.</summary>
+    /// <param name="RawBytes">Сырые байты узла. Нужны для copy-through нестандартных вариантов.</param>
+    /// <param name="Flags">[0x00..0x02] Флаги узла.</param>
+    /// <param name="ParentIndexOrLink">[0x02..0x04] Parent node index. 0xFFFF обычно значит root/no parent.</param>
+    /// <param name="AnimMapStart0x13">[0x04..0x06] Начало блока в MSH 0x13 animation map или 0xFFFF.</param>
+    /// <param name="FallbackKey0x08">[0x06..0x08] Fallback key / index в MSH 0x08.</param>
+    /// <param name="Msh02SlotIndicesByStateAndLOD">
+    /// [0x08..0x26] Индексы geometry slot в MSH 0x02.
+    /// Формула: slot = lod * 5 + group. 0xFFFF значит отсутствует.
+    /// </param>
+    public sealed record Node(
+        byte[] RawBytes,
+        NodeFlags Flags,
+        ushort ParentIndexOrLink,
+        ushort AnimMapStart0x13,
+        ushort FallbackKey0x08,
+        ushort[] Msh02SlotIndicesByStateAndLOD)
+    {
+        public bool IsRoot => ParentIndexOrLink == ushort.MaxValue;
+
+        public int ParentIndexOrMinusOne =>
+            ParentIndexOrLink == ushort.MaxValue ? -1 : ParentIndexOrLink;
+
+        public ushort ResolveSlotIndex(int state, int lod = 0)
+        {
+            
+            // MODEL_STATE_DEFAULT	    -1
+            // MODEL_STATE_REGULAR	    0
+            // MODEL_STATE_COLLAPSED	1
+            // _MODEL_STATE_UNKNOWN_2	2
+            
+            // LOD_LEVEL_MAX_0	    0
+            // LOD_LEVEL_MINUS_1	1
+            // LOD_LEVEL_MINUS_2	2
+            // LOD_LEVEL_MINUS_3	3
+            // LOD_LEVEL_MINUS_4	4
+            
+            var index = state * MaxLodCount + lod;
+
+            return index >= 0 && index < Msh02SlotIndicesByStateAndLOD.Length
+                ? Msh02SlotIndicesByStateAndLOD[index]
+                : ushort.MaxValue;
+        }
+
+        public bool HasGeometrySlot(int lod, int group = 0) =>
+            ResolveSlotIndex(lod, group) != ushort.MaxValue;
+
+        public int CountLodsForGroup(int group = 0)
+        {
+            var count = 0;
+
+            for (var lod = 0; lod < StateCount; lod++)
+            {
+                if (!HasGeometrySlot(lod, group))
+                {
+                    break;
+                }
+
+                count++;
+            }
+
+            return count;
+        }
+    }
+}
+
+[Flags]
+public enum NodeFlags : ushort
+{
+    None = 0,
+
+    /// <summary>
+    /// Still uncertain. In recursive bounds/intersection paths this can suppress/alter child recursion.
+    /// Seen as child_node.flags &amp; 0x04.
+    /// </summary>
+    MSH01_BOUNDS_MODE0_STOP = 0x0004,
+
+    /// <summary>
+    /// Stops recursive traversal into children for bounds/render/intersection helpers.
+    /// </summary>
+    MSH01_STOP_CHILD_BOUNDS_TRAVERSAL = 0x0010,
+
+    /// <summary>
+    /// Special lod-4 mode bit. In lod 4, selects alternate piece render mode.
+    /// </summary>
+    MSH01_HAS_SPECIAL_LOD_4 = 0x0020,
+
+    /// <summary>
+    /// Exclude from shadow / no shadow. CAniMesh tracks has_any_shadow_casting_piece when this bit is absent.
+    /// </summary>
+    MSH01_NO_SHADOW = 0x0040,
+
+    /// <summary>
+    /// Used during attached MSH load: if parent/root description contains "central", piece gets hidden/excluded flag.
+    /// Exact semantic name still provisional.
+    /// </summary>
+    MSH01_CHECK_PARENT_DESCRIPTION_CENTRAL = 0x0800,
+}