GLScene/Source/File3DS.pas

//
// This unit is part of the GLScene Engine, http://glscene.org
//
{
  Implementation of an universal 3DS file reader (and writer). This is the main file of the
  3DS import library. Currently only loading of 3DS files (Mesh files  * .3ds, Project files  * .prj
  and Material files  * .mli) is supported.
  Note: Be careful when using LoadFromStream, because chunk data (in opposition to the
  chunk structure) will be loaded on demand, i.e. when it is needed. Therefore the
  passed stream must be available during load.
  LoadFromStream does not make a copy of the passed stream, but keeps a reference
  which must stay valid either during the entire lifetime of TFile3DS or at least
  'til all chunks have been read (by accessing them all once).
}
unit File3DS;

interface

{$I GLScene.inc}
{$ALIGN ON}
{$MINENUMSIZE 4}
{$RANGECHECKS OFF}

uses 
  System.Classes, 
  System.SysUtils,

  File3DSTypes;

type
  TFile3DS = class;

  TLoadProgress = procedure(StreamPos, StreamMax: Longint) of object;
  // Progress : TProgressBar;
  //
  // This allows to use something like that:
  //
  // procedure TSomeForm.CreateForm(Sender: TObject);
  // begin
  // ....
  // 3DSReader.OnProgress := LoadProgress;
  // ....
  // end;

  // procedure TSomeForm.LoadProgress(StreamPos, StreamMax : Longint);
  // begin
  // if StreamMax <> 0 then
  // Progress.MaxValue := StreamMax;
  // Progress.Position := StreamPos;
  // end;

  // ----- support classes -----
  // All structure data of a 3DS file is actually held in TFile3DS.FDatabase as a
  // tree with lots of links across the various chunks.
  // For convinience and speed the data of the chunks is collected into some
  // special structures (FMaterialList etc.) and presented to the user
  // by the following helper classes:

  TMaterialList = class
  private
    FOwner: TFile3DS;
    FLocalList: TList;
    function GetCount: Integer;
    function GetMaterial(Index: Integer): PMaterial3DS;
    function GetMaterialByName(const Name: String): PMaterial3DS;
  public
    constructor Create(AOwner: TFile3DS); virtual;
    destructor Destroy; override;
    procedure ClearList;
    property Count: Integer read GetCount;
    property Material[Index: Integer]: PMaterial3DS read GetMaterial; default;
    property MaterialByName[const Name: String]: PMaterial3DS read GetMaterialByName;
  end;

  TObjectList = class
  private
    FOwner: TFile3DS;
    FMeshList, 
	FOmniList, 
	FSpotList, 
	FCameraList: TList;
    function GetCamera(Index: Integer): PCamera3DS;
    function GetCamCount: Integer;
    function GetMeshObjectCount: Integer;
    function GetMesh(Index: Integer): PMesh3DS;
    function GetOmniCount: Integer;
    function GetOmniLight(Index: Integer): PLight3DS;
    function GetSpotCount: Integer;
    function GetSpotLight(Index: Integer): PLight3DS;
  public
    constructor Create(AOwner: TFile3DS); virtual;
    destructor Destroy; override;
    procedure ClearLists;
    property CameraCount: Integer read GetCamCount;
    property MeshCount: Integer read GetMeshObjectCount;
    property OmniLightCount: Integer read GetOmniCount;
    property SpotLightCount: Integer read GetSpotCount;
    property Mesh[Index: Integer]: PMesh3DS read GetMesh;
    property Camera[Index: Integer]: PCamera3DS read GetCamera;
    property OmniLight[Index: Integer]: PLight3DS read GetOmniLight;
    property SpotLight[Index: Integer]: PLight3DS read GetSpotLight;
  end;

  TKeyFramer = class
  private
    FOwner: TFile3DS;
    FMeshMotionList,
	FOmniMotionList, 
	FSpotMotionList, 
	FCameraMotionList: TList;
    FAmbientMotion: PKFAmbient3DS;
    function GetAmbientMotion: PKFAmbient3DS;
    function GetCameraMotion(Index: Integer): PKFCamera3DS;
    function GetCamMotionCount: Integer;
    function GetKFSets: TKFSets3DS;
    function GetMeshMotionCount: Integer;
    function GetMeshMotion(Index: Integer): PKFMesh3DS;
    function GetOmniMotionCount: Integer;
    function GetOmniLightMotion(Index: Integer): PKFOmni3DS;
    function GetSpotMotionCount: Integer;
    function GetSpotLightMotion(Index: Integer): PKFSpot3DS;
  public
    constructor Create(AOwner: TFile3DS); virtual;
    destructor Destroy; override;
    procedure ClearLists;
    property AmbientLightMotion: PKFAmbient3DS read GetAmbientMotion;
    property CameraMotionCount: Integer read GetCamMotionCount;
    property MeshMotionCount: Integer read GetMeshMotionCount;
    property OmniLightMotionCount: Integer read GetOmniMotionCount;
    property SpotLightMotionCount: Integer read GetSpotMotionCount;
    property MeshMotion[Index: Integer]: PKFMesh3DS read GetMeshMotion; default;
    property CameraMotion[Index: Integer]: PKFCamera3DS read GetCameraMotion;
    property OmniLightMotion[Index: Integer]: PKFOmni3DS read GetOmniLightMotion;
    property Settings: TKFSets3DS read GetKFSets;
    property SpotLightMotion[Index: Integer]: PKFSpot3DS read GetSpotLightMotion;
  end;

  (* The main class that supplies the user with all available data
    from a specific 3DS file. The data is currently read only, but the class might be
    finished sometime later... *)
  TFile3DS = class
  private
    FNodeList: PNodeList;
    FDatabase: TDatabase3DS;
    FStream: TStream;
    FOwnStream: Boolean;
    FMaterialList: TMaterialList;
    FObjectList: TObjectList;
    FKeyFramer: TKeyFramer;
    FFileName: String;
    FOnLoadProgress: TLoadProgress;
    function GetAtmosphereData: TAtmosphere3DS;
    function GetBackgroundData: TBackground3DS;
    function GetDatabaseType: TDBType3DS;
    function GetMeshSettings: TMeshSet3DS;
    function GetViewportData: TViewport3DS;
    function GetDatabaseRelease: TReleaseLevel;
    function GetMeshRelease: TReleaseLevel;
  protected
    procedure AddToNodeList(Chunk: PChunk3DS);
    procedure AssignParentNames;
    procedure CheckListNodeIDs;
    procedure CreateDatabase;
    function FindNodeByID(ID: SmallInt): PNodeList;
    function GetChunkNodeID(Chunk: PChunk3DS): SmallInt;
    procedure InitDatabase;
    function IsNode(Tag: Word): Boolean;
    procedure KFAddParentName(Chunk: PChunk3DS; const Name: String3DS);
    procedure MakeNode(var Node: PNodeList);
    procedure ParseDatabase;
    procedure ReadChildren(Parent: PChunk3DS);
    procedure ReadXDataEntryChildren(Parent: PChunk3DS);
    procedure ReleaseDatabase;
    procedure ReleaseNodeList;
    procedure ReleaseStream;
  public
    constructor Create; virtual;
    constructor CreateFromFile(const FileName: String); virtual;
    destructor Destroy; override;
    procedure ClearLists;
    // database methods
    procedure DumpDataBase(Strings: TStrings; DumpLevel: TDumpLevel);
    procedure LoadFromFile(const FileName: String);
    procedure LoadFromStream(const aStream: TStream);
    // basic access methods
    function ReadByte: Byte;
    function ReadCardinal: Cardinal;
    procedure ReadChunkData(Chunk: PChunk3DS);
    procedure ReadData(Size: Integer; Data: Pointer);
    function ReadDouble: Double;
    function ReadFace: TFace3DS;
    procedure ReadHeader(var ChunkType: Word; var ChunkSize: Cardinal);
    function ReadInteger: Integer;
    function ReadKeyHeader: TKeyHeader3DS;
    function ReadPoint: TPoint3DS;
    function ReadShort: SmallInt;
    function ReadSingle: Single;
    function ReadString: PChar3DS;
    function ReadTexVert: TTexVert3DS;
    function ReadTrackHeader: TTrackHeader3DS;
    function ReadWord: Word;
    procedure FinishHeader(StartPos, EndPos: Cardinal);
    function InitChunkData(Chunk: PChunk3DS): Pointer;
    procedure SeekChild(Chunk: PChunk3DS);
    procedure Skip(AValue: Integer);
    procedure WriteByte(AValue: Byte);
    procedure WriteCardinal(AValue: Cardinal);
    procedure WriteData(Size: Integer; Data: Pointer);
    procedure WriteDouble(AValue: Double);
    procedure WriteFace(const F: TFace3DS);
    procedure WriteFixedString(const AValue: String3DS; Len: Integer);
    procedure WriteHeader(ChunkType: Word; ChunkSize: Cardinal);
    procedure WriteInteger(AValue: Integer);
    procedure WriteKeyHeader(const K: TKeyHeader3DS);
    procedure WritePoint(const P: TPoint3DS);
    procedure WriteShort(AValue: SmallInt);
    procedure WriteSingle(AValue: Single);
    procedure WriteString(const AValue: String3DS);
    procedure WriteTexVertex(const T: TTexVert3DS);
    procedure WriteTrackHeader(const T: TTrackHeader3DS);
    procedure WriteWord(AValue: Word);
    property Atmosphere: TAtmosphere3DS read GetAtmosphereData;
    property Background: TBackground3DS read GetBackgroundData;
    property DatabaseRelease: TReleaseLevel read GetDatabaseRelease;
    property DatabaseType: TDBType3DS read GetDatabaseType;
    property FileName: String read FFileName;
    // this is only valid if loaded from a file
    property KeyFramer: TKeyFramer read FKeyFramer;
    property Materials: TMaterialList read FMaterialList;
    property MeshRelease: TReleaseLevel read GetMeshRelease;
    property MeshSettings: TMeshSet3DS read GetMeshSettings;
    property Objects: TObjectList read FObjectList;
    property Viewport: TViewport3DS read GetViewportData;
    property OnLoadProgress: TLoadProgress read FOnLoadProgress write FOnLoadProgress;
  end;

// ---------------------------------------------------------------------------------------------------------------------
implementation
// ---------------------------------------------------------------------------------------------------------------------

uses 
  File3DSConst,
  File3DSUtils,
  GLApplicationFileIO;

function StrPasFree(P: PChar3DS): String;
begin
  Result := string(StrPas(P));
  FreeMem(P);
end;

// ----------------- TMaterialList -------------------------------------------------------------------------------------

constructor TMaterialList.Create(AOwner: TFile3DS);

begin
  FOwner := AOwner;
  FLocalList := TList.Create;
end;

// ---------------------------------------------------------------------------------------------------------------------

destructor TMaterialList.Destroy;

begin
  ClearList;
  FLocalList.Free;
  inherited Destroy;
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TMaterialList.ClearList;

var
  I: Integer;
  Mat: PMaterial3DS;

begin
  for I := 0 to FLocalList.Count - 1 do
    if FLocalList[I] <> nil then
    begin
      Mat := FLocalList[I];
      // free structure data
      ReleaseMaterial(Mat);
    end;
  FLocalList.Count := 0;
end;

// ---------------------------------------------------------------------------------------------------------------------

function TMaterialList.GetCount: Integer;

begin
  if (FLocalList.Count = 0) and (FOwner.FDatabase.MatListDirty) then
    FLocalList.Count := GetMaterialCount(FOwner, FOwner.FDatabase);;
  Result := FLocalList.Count;
end;

// ---------------------------------------------------------------------------------------------------------------------

function TMaterialList.GetMaterial(Index: Integer): PMaterial3DS;

var
  NewEntry: PMaterial3DS;

begin
  Result := nil;
  if Count = 0 then
    Exit; // force reading the list if it was modified

  if FLocalList[Index] = nil then
  begin
    New(NewEntry);
    FillChar(NewEntry^, SizeOf(NewEntry^), 0);
    NewEntry^ := GetMaterialByIndex(FOwner, FOwner.FDatabase, Index);
    FLocalList[Index] := NewEntry;
  end;
  Result := FLocalList[Index];
end;

// ---------------------------------------------------------------------------------------------------------------------

function TMaterialList.GetMaterialByName(const Name: String): PMaterial3DS;

var
  Entry: PMaterial3DS;
  Index: Integer;

begin
  Result := nil;
  for Index := 0 to Count - 1 do
  begin
    Entry := GetMaterial(Index);
    if Entry = nil then
      Continue;
    if CompareText(string(Entry.NameStr), Name) = 0 then
    begin
      Result := Entry;
      Break;
    end;
  end;
end;

// ----------------- TObjectList ---------------------------------------------------------------------------------------

constructor TObjectList.Create(AOwner: TFile3DS);

begin
  FOwner := AOwner;
  FMeshList := TList.Create;
  FOmniList := TList.Create;
  FSpotList := TList.Create;
  FCameraList := TList.Create;
end;

// ---------------------------------------------------------------------------------------------------------------------

destructor TObjectList.Destroy;

begin
  ClearLists;
  FMeshList.Free;
  FOmniList.Free;
  FSpotList.Free;
  FCameraList.Free;
  inherited Destroy;
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TObjectList.ClearLists;

var
  I: Integer;

begin
  for I := 0 to FMeshList.Count - 1 do
    ReleaseMeshObj(FMeshList[I]);
  FMeshList.Clear;

  for I := 0 to FOmniList.Count - 1 do
    ReleaseLight(FOmniList[I]);
  FOmniList.Clear;

  for I := 0 to FSpotList.Count - 1 do
    ReleaseLight(FSpotList[I]);
  FSpotList.Clear;

  for I := 0 to FCameraList.Count - 1 do
    ReleaseCamera(FCameraList[I]);
  FCameraList.Clear;
end;

// ---------------------------------------------------------------------------------------------------------------------

function TObjectList.GetCamera(Index: Integer): PCamera3DS;

var
  NewEntry: PCamera3DS;

begin
  Result := nil;
  if CameraCount = 0 then
    Exit; // force reading the list if it was modified

  if FCameraList[Index] = nil then
  begin
    New(NewEntry);
    FillChar(NewEntry^, SizeOf(NewEntry^), 0);
    NewEntry^ := GetCameraByIndex(FOwner, FOwner.FDatabase, Index);
    FCameraList[Index] := NewEntry;
  end;
  Result := FCameraList[Index];
end;

// ---------------------------------------------------------------------------------------------------------------------

function TObjectList.GetCamCount: Integer;

begin
  if FCameraList.Count = 0 then
    FCameraList.Count := GetCameraCount(FOwner, FOwner.FDatabase);
  Result := FCameraList.Count;
end;

// ---------------------------------------------------------------------------------------------------------------------

function TObjectList.GetMeshObjectCount: Integer;

begin
  if FMeshList.Count = 0 then
    FMeshList.Count := GetMeshCount(FOwner, FOwner.FDatabase);
  Result := FMeshList.Count;
end;

// ---------------------------------------------------------------------------------------------------------------------

function TObjectList.GetMesh(Index: Integer): PMesh3DS;

var
  NewEntry: PMesh3DS;

begin
  Result := nil;
  if MeshCount = 0 then
    Exit; // force reading the list if it was modified

  if FMeshList[Index] = nil then
  begin
    New(NewEntry);
    FillChar(NewEntry^, SizeOf(NewEntry^), 0);
    NewEntry^ := GetMeshByIndex(FOwner, FOwner.FDatabase, Index);
    FMeshList[Index] := NewEntry;
  end;
  Result := FMeshList[Index];
end;

// ---------------------------------------------------------------------------------------------------------------------

function TObjectList.GetOmniCount: Integer;

begin
  if FOmniList.Count = 0 then
    FOmniList.Count := GetOmniLightCount(FOwner, FOwner.FDatabase);
  Result := FOmniList.Count;
end;

// ---------------------------------------------------------------------------------------------------------------------

function TObjectList.GetOmniLight(Index: Integer): PLight3DS;

var
  NewEntry: PLight3DS;

begin
  Result := nil;
  if OmniLightCount = 0 then
    Exit; // force reading the list if it was modified

  if FOmniList[Index] = nil then
  begin
    New(NewEntry);
    FillChar(NewEntry^, SizeOf(NewEntry^), 0);
    NewEntry^ := GetOmniLightByIndex(FOwner, FOwner.FDatabase, Index);
    FOmniList[Index] := NewEntry;
  end;
  Result := FOmniList[Index];
end;

// ---------------------------------------------------------------------------------------------------------------------

function TObjectList.GetSpotCount: Integer;

begin
  if FSpotList.Count = 0 then
    FSpotList.Count := GetSpotLightCount(FOwner, FOwner.FDatabase);
  Result := FSpotList.Count;
end;

// ---------------------------------------------------------------------------------------------------------------------

function TObjectList.GetSpotLight(Index: Integer): PLight3DS;

var
  NewEntry: PLight3DS;

begin
  Result := nil;
  if SpotLightCount = 0 then
    Exit; // force reading the list if it was modified

  if FSpotList[Index] = nil then
  begin
    New(NewEntry);
    FillChar(NewEntry^, SizeOf(NewEntry^), 0);
    NewEntry^ := GetSpotLightByIndex(FOwner, FOwner.FDatabase, Index);
    FSpotList[Index] := NewEntry;
  end;
  Result := FSpotList[Index];
end;

// ----------------- TKeyFramer ----------------------------------------------------------------------------------------

constructor TKeyFramer.Create(AOwner: TFile3DS);

begin
  FOwner := AOwner;
  FMeshMotionList := TList.Create;
  FOmniMotionList := TList.Create;
  FSpotMotionList := TList.Create;
  FCameraMotionList := TList.Create;
end;

// ---------------------------------------------------------------------------------------------------------------------

destructor TKeyFramer.Destroy;

begin
  ClearLists;
  FMeshMotionList.Free;
  FOmniMotionList.Free;
  FSpotMotionList.Free;
  FCameraMotionList.Free;
  inherited;
end;

// ---------------------------------------------------------------------------------------------------------------------

function TKeyFramer.GetAmbientMotion: PKFAmbient3DS;

begin
  if FAmbientMotion = nil then
  begin
    New(FAmbientMotion);
    FillChar(FAmbientMotion^, SizeOf(FAmbientMotion^), 0);
    FAmbientMotion^ := GetAmbientLightMotion(FOwner, FOwner.FDatabase);
  end;
  Result := FAmbientMotion;
end;

// ---------------------------------------------------------------------------------------------------------------------

function TKeyFramer.GetCameraMotion(Index: Integer): PKFCamera3DS;

var
  NewEntry: PKFCamera3DS;

begin
  Result := nil;
  if CameraMotionCount = 0 then
    Exit; // force reading the list if it was modified

  if FCameraMotionList[Index] = nil then
  begin
    New(NewEntry);
    FillChar(NewEntry^, SizeOf(NewEntry^), 0);
    NewEntry^ := GetCameraMotionByIndex(FOwner, FOwner.FDatabase, Index);
    FCameraMotionList[Index] := NewEntry;
  end;
  Result := FCameraMotionList[Index];
end;

// ---------------------------------------------------------------------------------------------------------------------

function TKeyFramer.GetCamMotionCount: Integer;

begin
  if FCameraMotionList.Count = 0 then
    FCameraMotionList.Count := GetCameraNodeCount(FOwner, FOwner.FDatabase);
  Result := FCameraMotionList.Count;
end;

// ---------------------------------------------------------------------------------------------------------------------

function TKeyFramer.GetKFSets: TKFSets3DS;

begin
  Result := GetKFSettings(FOwner, FOwner.FDatabase);
end;

// ---------------------------------------------------------------------------------------------------------------------

function TKeyFramer.GetMeshMotionCount: Integer;

begin
  if FMeshMotionList.Count = 0 then
    FMeshMotionList.Count := GetObjectNodeCount(FOwner, FOwner.FDatabase);
  Result := FMeshMotionList.Count;
end;

// ---------------------------------------------------------------------------------------------------------------------

function TKeyFramer.GetMeshMotion(Index: Integer): PKFMesh3DS;

var
  NewEntry: PKFMesh3DS;

begin
  Result := nil;
  if MeshMotionCount = 0 then
    Exit; // force reading the list if it was modified

  if FMeshMotionList[Index] = nil then
  begin
    New(NewEntry);
    FillChar(NewEntry^, SizeOf(NewEntry^), 0);
    NewEntry^ := GetObjectMotionByIndex(FOwner, FOwner.FDatabase, Index);
    FMeshMotionList[Index] := NewEntry;
  end;
  Result := FMeshMotionList[Index];
end;

// ---------------------------------------------------------------------------------------------------------------------

function TKeyFramer.GetOmniMotionCount: Integer;

begin
  if FOmniMotionList.Count = 0 then
    FOmniMotionList.Count := GetOmniLightNodeCount(FOwner, FOwner.FDatabase);
  Result := FOmniMotionList.Count;
end;

// ---------------------------------------------------------------------------------------------------------------------

function TKeyFramer.GetOmniLightMotion(Index: Integer): PKFOmni3DS;

var
  NewEntry: PKFOmni3DS;

begin
  Result := nil;
  if OmniLightMotionCount = 0 then
    Exit; // force reading the list if it was modified

  if FOmniMotionList[Index] = nil then
  begin
    New(NewEntry);
    FillChar(NewEntry^, SizeOf(NewEntry^), 0);
    NewEntry^ := GetOmniLightMotionByIndex(FOwner, FOwner.FDatabase, Index);
    FOmniMotionList[Index] := NewEntry;
  end;
  Result := FOmniMotionList[Index];
end;

// ---------------------------------------------------------------------------------------------------------------------

function TKeyFramer.GetSpotMotionCount: Integer;

begin
  if FSpotMotionList.Count = 0 then
    FSpotMotionList.Count := GetSpotLightNodeCount(FOwner, FOwner.FDatabase);
  Result := FSpotMotionList.Count;
end;

// ---------------------------------------------------------------------------------------------------------------------

function TKeyFramer.GetSpotLightMotion(Index: Integer): PKFSpot3DS;

var
  NewEntry: PKFSpot3DS;

begin
  Result := nil;
  if SpotLightMotionCount = 0 then
    Exit; // force reading the list if it was modified

  if FSpotMotionList[Index] = nil then
  begin
    New(NewEntry);
    FillChar(NewEntry^, SizeOf(NewEntry^), 0);
    NewEntry^ := GetSpotLightMotionByIndex(FOwner, FOwner.FDatabase, Index);
    FSpotMotionList[Index] := NewEntry;
  end;
  Result := FSpotMotionList[Index];
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TKeyFramer.ClearLists;

var
  I: Integer;

begin
  for I := 0 to FMeshMotionList.Count - 1 do
    ReleaseObjectMotion(FMeshMotionList[I]);
  FMeshMotionList.Clear;

  for I := 0 to FOmniMotionList.Count - 1 do
    ReleaseOmnilightMotion(FOmniMotionList[I]);
  FOmniMotionList.Clear;

  for I := 0 to FSpotMotionList.Count - 1 do
    ReleaseSpotlightMotion(FSpotMotionList[I]);
  FSpotMotionList.Clear;

  for I := 0 to FCameraMotionList.Count - 1 do
    ReleaseCameraMotion(FCameraMotionList[I]);
  FCameraMotionList.Clear;

  if assigned(FAmbientMotion) then
    ReleaseAmbientLightMotion(FAmbientMotion);
  FAmbientMotion := nil;
end;

// ----------------- TFile3DS ------------------------------------------------------------------------------------------

constructor TFile3DS.Create;

begin
  FMaterialList := TMaterialList.Create(Self);
  FObjectList := TObjectList.Create(Self);
  FKeyFramer := TKeyFramer.Create(Self);
end;

constructor TFile3DS.CreateFromFile(const FileName: String);
begin
  Create;
  FFileName := FileName;
  FStream := CreateFileStream(FileName, fmOpenRead or fmShareDenyWrite);
  InitDatabase;
  CreateDatabase;
end;

destructor TFile3DS.Destroy;
begin
  FKeyFramer.Free;
  FObjectList.Free;
  FMaterialList.Free;
  ReleaseDatabase;
  ReleaseStream;
  inherited Destroy;
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.AddToNodeList(Chunk: PChunk3DS);

// creates a node, put node in list and fill-in structure

var
  NewNode: PNodeList;
  HdrChunk, InstChunk: PChunk3DS;

begin
  MakeNode(NewNode);
  if NewNode = nil then
    Exit;

  HdrChunk := FindChunk(Chunk, NODE_HDR);
  if HdrChunk = nil then
    Exit;

  ReadChunkData(HdrChunk);
  if HdrChunk = nil then
    Exit;

  // fill in node Data
  NewNode.Name := HdrChunk.Data.NodeHdr.ObjNameStr;
  NewNode.ID := GetChunkNodeID(Chunk);
  NewNode.Tag := Chunk.Tag;
  NewNode.ParentID := HdrChunk.Data.NodeHdr.ParentIndex;
  NewNode.Next := nil;
  NewNode.InstStr := '';

  // check for instance
  if Chunk.Tag = OBJECT_NODE_TAG then
  begin
    InstChunk := FindChunk(Chunk, INSTANCE_NAME);
    if assigned(InstChunk) then
    begin
      ReadChunkData(InstChunk);
      NewNode.InstStr := string(StrPas(InstChunk.Data.InstanceName));
      FreeChunkData(InstChunk);
    end;
  end;
  HdrChunk.Data.NodeHdr.ObjNameStr := '';
  FreeChunkData(HdrChunk);
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.AssignParentNames;

// traverse keyframe data and assign parent names to its own chunk PARENT_NAME
// which is a child of NODE_HDR

var
  Chunk, KfDataChunk, HdrChunk, NameChunk, IdChunk: PChunk3DS;
  I: Integer;
  IDNode, IDParentNode: PNodeList;
  Name, Inst: String3DS;

begin
  KfDataChunk := FindChunk(FDatabase.TopChunk, KFDATA);
  if KfDataChunk = nil then
    Exit;

  // Find chunks in KFRAMER
  for I := 1 to NodeTagCount do
  begin
    Chunk := FindChunk(KfDataChunk, NodeTags[I]);
    while assigned(Chunk) do
    begin
      HdrChunk := FindChunk(Chunk, NODE_HDR);
      if assigned(HdrChunk) then
      begin
        IdChunk := FindChunk(Chunk, NODE_ID);
        if assigned(IdChunk) then
        begin
          ReadChunkData(IdChunk);
          if assigned(IdChunk.Data.KFID) then
          begin
            // Find table entry for node of interest
            IDNode := FindNodeByID(IdChunk.Data.KFID^);
            // no ID (bad) or no parent (ok)
            if assigned(IDNode) and (IDNode.ParentID <> -1) then
            begin
              // find table entry for parent
              IDParentNode := FindNodeByID(IDNode.ParentID);
              if assigned(IDParentNode) then
              begin
                Name := UTF8String(IDParentNode.Name);
                Inst := UTF8String(IDParentNode.InstStr);
              end;

              if Length(Name) > 0 then
              begin
                // concatenate names if there is an inst name
                if Length(Inst) > 0 then
                  Name := Name + '.' + Inst;

                // if PARENT chunk exists, copy into it
                NameChunk := FindChunk(HdrChunk, PARENT_NAME);
                if assigned(NameChunk) then
                begin
                  ReadChunkData(NameChunk);
                  if assigned(NameChunk.Data.InstanceName) then
                  begin
                    NameChunk.Data.InstanceName := AllocMem(Length(Name) + 1);
                    Move(Name[1], NameChunk.Data.InstanceName^,  Length(Name) + 1);
                  end;
                end
                else
                  KFAddParentName(HdrChunk, Name); // creates PARENT_NAME chunk
              end;
            end;
          end;
        end;
      end;
      Chunk := FindNextChunk(Chunk.Sibling, NodeTags[I]);
    end;
  end;
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.CheckListNodeIDs;

// Earlier versions (pre 3) of 3dStudio had no node ids, they simply used the order
// in which they came along, if so put in NODE IDs. Assuming that if one node
// has no ID the whole list get renumbered.

var
  ID: PNodeList;
  Index: SmallInt;

begin
  ID := FNodeList;

  while assigned(ID) do
  begin
    if (ID.ID = KNoID) then // if somebody has no ID renumber list
    begin
      Index := 0;
      ID := FNodeList;
      while assigned(ID) do
      begin
        ID.ID := Index;
        Inc(Index);
        ID := ID.Next;
      end;
      Break;
    end;
    ID := ID.Next;
  end;
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.FindNodeByID(ID: SmallInt): PNodeList;

begin
  Result := FNodeList;
  while assigned(Result) do
  begin
    if Result.ID = ID then
      Break;
    Result := Result.Next;
  end;
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.DumpDataBase(Strings: TStrings; DumpLevel: TDumpLevel);

// dumps entire database into the given string class

var
  OldSeparator: Char;

begin

  OldSeparator := FormatSettings.DecimalSeparator;
  FormatSettings.DecimalSeparator := '.';
  try
    if Assigned(FDatabase.TopChunk) then
      DumpChunk(Self, Strings, FDatabase.TopChunk, 0, DumpLevel);
  finally
    FormatSettings.DecimalSeparator := OldSeparator;
  end;
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.GetChunkNodeID(Chunk: PChunk3DS): SmallInt;

var
  IdChunk: PChunk3DS;

begin
  Result := KNoID;
  IdChunk := FindChunk(Chunk, NODE_ID);
  if assigned(IdChunk) then
  begin
    ReadChunkData(IdChunk);
    if assigned(IdChunk.Data.KFID) then
      Result := IdChunk.Data.KFID^;
    FreeChunkData(IdChunk);
  end;
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.IsNode(Tag: Word): Boolean;

var
  I: Integer;

begin
  Result := False;
  for I := 1 to NodeTagCount do
    if Tag = NodeTags[I] then
    begin
      Result := True;
      Break;
    end;
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.KFAddParentName(Chunk: PChunk3DS; const Name: String3DS);
var
  Temp: PChunk3DS;
begin
  InitChunk(Temp);
  Temp.Tag := PARENT_NAME;
  Temp.Data.Dummy := AllocMem(Length(Name) + 1);
  Move(Name[1], Temp.Data.Dummy^, Length(Name) + 1);
  AddChildOrdered(Chunk, Temp);
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.MakeNode(var Node: PNodeList);

// add node to linked list (uninitialized)

var
  ID: PNodeList;

begin
  ID := FNodeList;
  Node := AllocMem(SizeOf(TNodeList));
  if assigned(Node) then
  begin
    // first node ?
    if ID = nil then
      FNodeList := Node
    else // add to list
    begin
      while assigned(ID.Next) do
        ID := ID.Next;
      ID.Next := Node;
    end;
  end;
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.ParseDatabase;

var
  Chunk, KfDataChunk: PChunk3DS;

begin
  KfDataChunk := FindChunk(FDatabase.TopChunk, KFDATA);
  if assigned(KfDataChunk) then
  begin
    Chunk := KfDataChunk.Children;
    while assigned(Chunk) do
    begin
      if IsNode(Chunk.Tag) then
        AddToNodeList(Chunk);
      Chunk := Chunk.Sibling;
    end;
    CheckListNodeIDs;
  end;
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.ReadXDataEntryChildren(Parent: PChunk3DS);

var
  ParentBody: Cardinal;
  Child: PChunk3DS;

begin
  SeekChild(Parent);
  ParentBody := Parent.Position + Parent.Size;

  // satisfy the D4 compiler by castíng the (longint) position to a cardinal
  while Cardinal(FStream.Position) < ParentBody do
  begin
    Child := nil;
    InitChunk(Child);
    Child.Position := FStream.Position;
    ReadHeader(Child.Tag, Child.Size);
    // Validate the child chunk...
    // First, is it a valid header?
    case Child.Tag of
      XDATA_APPNAME, 
	  XDATA_STRING, 
	  XDATA_FLOAT, 
	  XDATA_DOUBLE, 
	  XDATA_SHORT,
      XDATA_LONG, 
	  XDATA_VOID, 
	  XDATA_GROUP, 
	  XDATA_RFU6, 
	  XDATA_RFU5, 
	  XDATA_RFU4,
      XDATA_RFU3, 
	  XDATA_RFU2, 
	  XDATA_RFU1:
        begin
          // second, does the size fit inside the XDATA_ENTRY chunk?
          if (Child.Position + Child.Size) <= ParentBody then
          begin
            // chances are its a good subchunk, so add it in
            AddChild(Parent, Child);
            ReadXDataEntryChildren(Child);
          end
          else
            ReleaseChunk(Child);
        end
    else // must not be a valid chunk, seek to the end of the parent then
      begin
        ReleaseChunk(Child);
        FStream.Position := ParentBody;
      end;
    end;
  end;
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.ReleaseNodeList;

var
  Next: PNodeList;

begin
  while assigned(FNodeList) do
  begin
    Next := FNodeList.Next;
    Dispose(FNodeList);
    FNodeList := Next;
  end;
end;

// ReleaseStream
//
procedure TFile3DS.ReleaseStream;
begin
  if FOwnStream then
    FreeAndNil(FStream)
  else
    FStream := nil;
  FOwnStream := False;
end;


// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.CreateDatabase;

begin
  with FDatabase do
  begin
    InitChunk(TopChunk);
    FStream.Position := 0;
    ReadHeader(TopChunk.Tag, TopChunk.Size);

    // test header to determine whether it is a top level chunk type
    if (TopChunk.Tag = M3DMAGIC) or (TopChunk.Tag = CMAGIC) or
      (TopChunk.Tag = MLIBMAGIC) then
    begin
      // gw: set needed max value for ProgressBar
      if assigned(FOnLoadProgress) then
        FOnLoadProgress(0, FStream.Size);
      // read database structure
      ReadChildren(TopChunk);
      ParseDatabase;
      AssignParentNames;
      ReleaseNodeList;
    end;
  end;
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.InitDatabase;

begin
  with FDatabase do
  begin
    TopChunk := nil;
    ObjListDirty := True;
    MatListDirty := True;
    NodeListDirty := True;
    ObjList := nil;
    MatList := nil;
    NodeList := nil;
  end;
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.ClearLists;

begin
  FMaterialList.ClearList;
  FObjectList.ClearLists;
  FKeyFramer.ClearLists;
  ReleaseDatabase;
end;

 
//
procedure TFile3DS.LoadFromFile(const FileName: String);
begin
  ClearLists;
  ReleaseStream;
  FFileName := FileName;
  FStream := CreateFileStream(FileName, fmOpenRead or fmShareDenyWrite);
  FOwnStream := True;
  InitDatabase;
  CreateDatabase;
end;

// LoadFromStream
//
procedure TFile3DS.LoadFromStream(const aStream: TStream);
begin
  ReleaseStream;
  ClearLists;
  FFileName := '';
  FStream := aStream;
  InitDatabase;
  CreateDatabase;
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.GetAtmosphereData: TAtmosphere3DS;

begin
  Result := GetAtmosphere(Self, FDatabase);
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.GetBackgroundData: TBackground3DS;

begin
  Result := GetBackground(Self, FDatabase);
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.GetDatabaseType: TDBType3DS;

begin
  case FDatabase.TopChunk.Tag of
    M3DMAGIC:
      Result := dbMeshFile;
    CMAGIC:
      Result := dbProjectFile;
    MLIBMAGIC:
      Result := dbMaterialFile;
  else
    Result := dbUnknown;
  end;
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.GetMeshSettings: TMeshSet3DS;

begin
  Result := GetMeshSet(Self, FDatabase);
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.GetViewportData: TViewport3DS;

begin
  Result := GetViewport(Self, FDatabase);
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.ReadChildren(Parent: PChunk3DS);

var
  ParentBody: Integer;
  Child: PChunk3DS;

begin
  SeekChild(Parent);
  ParentBody := Parent.Position + Parent.Size;
  while FStream.Position < ParentBody do
  begin
    Child := nil;
    InitChunk(Child);
    // gw: set ProgressBar current position
    if assigned(FOnLoadProgress) then
      FOnLoadProgress(FStream.Position, 0);

    Child.Position := FStream.Position;
    ReadHeader(Child.Tag, Child.Size);
    AddChild(Parent, Child);
    if Child.Tag = XDATA_ENTRY then
      ReadXDataEntryChildren(Child)
    else
      ReadChildren(Child);
  end;
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.ReleaseDatabase;

begin
  with FDatabase do
  begin
    if assigned(TopChunk) then
      ReleaseChunk(TopChunk);
    if assigned(ObjList) then
      ReleaseChunkList(ObjList);
    if assigned(MatList) then
      ReleaseChunkList(MatList);
    if assigned(NodeList) then
      ReleaseChunkList(NodeList);
  end;
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.InitChunkData(Chunk: PChunk3DS): Pointer;

begin
  case Chunk.Tag of
    COLOR_F:
      Chunk.Data.ColorF := AllocMem(SizeOf(TColorF));
    LIN_COLOR_F:
      Chunk.Data.LinColorF := AllocMem(SizeOf(TLinColorF));
    COLOR_24:
      Chunk.Data.Color24 := AllocMem(SizeOf(TColor24));
    LIN_COLOR_24:
      Chunk.Data.LinColor24 := AllocMem(SizeOf(TLinColor24));
    INT_PERCENTAGE:
      Chunk.Data.IntPercentage := AllocMem(SizeOf(TIntPercentage));
    FLOAT_PERCENTAGE:
      Chunk.Data.FloatPercentage := AllocMem(SizeOf(TFloatPercentage));
    MAT_MAPNAME:
      Chunk.Data.MatMapname := nil; // AllocMem(SizeOf(TMatMapname));
    M3D_VERSION:
      Chunk.Data.M3dVersion := AllocMem(SizeOf(TM3dVersion));
    MESH_VERSION:
      Chunk.Data.MeshVersion := AllocMem(SizeOf(TMeshVersion));
    MASTER_SCALE:
      Chunk.Data.MasterScale := AllocMem(SizeOf(TMasterScale));
    LO_SHADOW_BIAS:
      Chunk.Data.LoShadowBias := AllocMem(SizeOf(TLoShadowBias));
    SHADOW_FILTER:
      Chunk.Data.ShadowFilter := AllocMem(SizeOf(TShadowFilter));
    SHADOW_RANGE:
      Chunk.Data.ShadowRange := AllocMem(SizeOf(TShadowRange));
    HI_SHADOW_BIAS:
      Chunk.Data.HiShadowBias := AllocMem(SizeOf(THiShadowBias));
    RAY_BIAS:
      Chunk.Data.RayBias := AllocMem(SizeOf(TRayBias));
    SHADOW_MAP_SIZE:
      Chunk.Data.ShadowMapSize := AllocMem(SizeOf(TShadowMapSize));
    SHADOW_SAMPLES:
      Chunk.Data.ShadowSamples := AllocMem(SizeOf(TShadowSamples));
    O_CONSTS:
      Chunk.Data.OConsts := AllocMem(SizeOf(TOConsts));
    BIT_MAP:
      Chunk.Data.BitMapName := nil; // AllocMem(SizeOf(TBitMapName));
    V_GRADIENT:
      Chunk.Data.VGradient := AllocMem(SizeOf(TVGradient));
    FOG:
      Chunk.Data.FOG := AllocMem(SizeOf(TFog));
    LAYER_FOG:
      Chunk.Data.LayerFog := AllocMem(SizeOf(TLayerFog));
    DISTANCE_CUE:
      Chunk.Data.DistanceCue := AllocMem(SizeOf(TDistanceCue));
    VIEW_TOP, 
	VIEW_BOTTOM, 
	VIEW_LEFT, 
	VIEW_RIGHT, 
	VIEW_FRONT, 
	VIEW_BACK:
      Chunk.Data.ViewStandard := AllocMem(SizeOf(TViewStandard));
    VIEW_USER:
      Chunk.Data.ViewUser := AllocMem(SizeOf(TViewUser));
    VIEW_CAMERA:
      Chunk.Data.ViewCamera := nil; // AllocMem(SizeOf(TViewCamera));
    MAT_NAME:
      Chunk.Data.MatName := nil; // AllocMem(SizeOf(TMatName));
    MAT_SHADING:
      Chunk.Data.MatShading := AllocMem(SizeOf(TMatShading));
    MAT_ACUBIC:
      Chunk.Data.MatAcubic := AllocMem(SizeOf(TMatAcubic));
    MAT_SXP_TEXT_DATA, 
	MAT_SXP_TEXT2_DATA, 
	MAT_SXP_OPAC_DATA, 
	MAT_SXP_BUMP_DATA,
    MAT_SXP_SPEC_DATA, 
	MAT_SXP_SHIN_DATA, 
	MAT_SXP_SELFI_DATA,
    MAT_SXP_TEXT_MASKDATA, 
	MAT_SXP_TEXT2_MASKDATA, 
	MAT_SXP_OPAC_MASKDATA,
    MAT_SXP_BUMP_MASKDATA, 
	MAT_SXP_SPEC_MASKDATA, 
	MAT_SXP_SHIN_MASKDATA,
    MAT_SXP_SELFI_MASKDATA, 
	MAT_SXP_REFL_MASKDATA, 
	PROC_DATA:
      Chunk.Data.IpasData := AllocMem(SizeOf(TIpasData));
    MAT_WIRESIZE:
      Chunk.Data.MatWireSize := AllocMem(SizeOf(TMatWireSize));
    MAT_MAP_TILING:
      Chunk.Data.MatMapTiling := AllocMem(SizeOf(TMatMapTiling));
    MAT_MAP_TEXBLUR:
      Chunk.Data.MatMapTexblur := AllocMem(SizeOf(TMatMapTexblur));
    MAT_MAP_USCALE:
      Chunk.Data.MatMapUScale := AllocMem(SizeOf(TMatMapUScale));
    MAT_MAP_VSCALE:
      Chunk.Data.MatMapVScale := AllocMem(SizeOf(TMatMapVScale));
    MAT_MAP_UOFFSET:
      Chunk.Data.MatMapUOffset := AllocMem(SizeOf(TMatMapUOffset));
    MAT_MAP_VOFFSET:
      Chunk.Data.MatMapVOffset := AllocMem(SizeOf(TMatMapVOffset));
    MAT_MAP_ANG:
      Chunk.Data.MatMapAng := AllocMem(SizeOf(TMatMapAng));
    MAT_MAP_COL1:
      Chunk.Data.MatMapCol1 := AllocMem(SizeOf(TMatMapCol1));
    MAT_MAP_COL2:
      Chunk.Data.MatMapCol2 := AllocMem(SizeOf(TMatMapCol2));
    MAT_MAP_RCOL:
      Chunk.Data.MatMapRCol := AllocMem(SizeOf(TMatMapRCol));
    MAT_MAP_GCOL:
      Chunk.Data.MatMapGCol := AllocMem(SizeOf(TMatMapGCol));
    MAT_MAP_BCOL:
      Chunk.Data.MatMapBCol := AllocMem(SizeOf(TMatMapBCol));
    MAT_BUMP_PERCENT:
      Chunk.Data.MatBumpPercent := AllocMem(SizeOf(TMatBumpPercent));
    NAMED_OBJECT:
      Chunk.Data.NamedObject := nil; // AllocMem(SizeOf(TNamedObject));
    POINT_ARRAY:
      Chunk.Data.PointArray := AllocMem(SizeOf(TPointArray));
    POINT_FLAG_ARRAY:
      Chunk.Data.PointFlagArray := AllocMem(SizeOf(TPointFlagArray));
    FACE_ARRAY:
      Chunk.Data.FaceArray := AllocMem(SizeOf(TFaceArray));
    MSH_MAT_GROUP:
      Chunk.Data.MshMatGroup := AllocMem(SizeOf(TMshMatGroup));
    MSH_BOXMAP:
      Chunk.Data.MshBoxmap := AllocMem(SizeOf(TMshBoxmap));
    SMOOTH_GROUP:
      Chunk.Data.SmoothGroup := AllocMem(SizeOf(TSmoothGroup));
    TEX_VERTS:
      Chunk.Data.TexVerts := AllocMem(SizeOf(TTexVerts));
    MESH_MATRIX:
      Chunk.Data.MeshMatrix := AllocMem(SizeOf(TMeshMatrix));
    MESH_COLOR:
      Chunk.Data.MeshColor := AllocMem(SizeOf(TMeshColor));
    MESH_TEXTURE_INFO:
      Chunk.Data.MeshTextureInfo := AllocMem(SizeOf(TMeshTextureInfo));
    PROC_NAME:
      Chunk.Data.ProcName := nil; // AllocMem(SizeOf(TProcName));
    N_DIRECT_LIGHT:
      Chunk.Data.NDirectLight := AllocMem(SizeOf(TNDirectLight));
    DL_EXCLUDE:
      Chunk.Data.DlExclude := nil; // AllocMem(SizeOf(TDlExclude));
    DL_INNER_RANGE:
      Chunk.Data.DlInnerRange := AllocMem(SizeOf(TDlInnerRange));
    DL_OUTER_RANGE:
      Chunk.Data.DlOuterRange := AllocMem(SizeOf(TDlOuterRange));
    DL_MULTIPLIER:
      Chunk.Data.DlMultiplier := AllocMem(SizeOf(TDlMultiplier));
    DL_SPOTLIGHT:
      Chunk.Data.DlSpotlight := AllocMem(SizeOf(TDlSpotlight));
    DL_LOCAL_SHADOW2:
      Chunk.Data.DlLocalShadow2 := AllocMem(SizeOf(TDlLocalShadow2));
    DL_SPOT_ROLL:
      Chunk.Data.DlSpotRoll := AllocMem(SizeOf(TDlSpotRoll));
    DL_SPOT_ASPECT:
      Chunk.Data.DlSpotAspect := AllocMem(SizeOf(TDlSpotAspect));
    DL_SPOT_PROJECTOR:
      Chunk.Data.DlSpotProjector := nil; // AllocMem(SizeOf(TDlSpotProjector));
    DL_RAY_BIAS:
      Chunk.Data.DlRayBias := AllocMem(SizeOf(TDlRayBias));
    N_CAMERA:
      Chunk.Data.NCamera := AllocMem(SizeOf(TNCamera));
    CAM_RANGES:
      Chunk.Data.CamRanges := AllocMem(SizeOf(TCamRanges));
    VIEWPORT_LAYOUT:
      Chunk.Data.ViewportLayout := AllocMem(SizeOf(TViewportLayout));
    VIEWPORT_SIZE:
      Chunk.Data.ViewportSize := AllocMem(SizeOf(TViewportSize));
    VIEWPORT_DATA_3, 
	VIEWPORT_DATA:
      Chunk.Data.ViewportData := AllocMem(SizeOf(TViewportData));
    XDATA_ENTRY:
      Chunk.Data.XDataEntry := AllocMem(SizeOf(TXDataEntry));
    XDATA_APPNAME:
      Chunk.Data.XDataAppName := nil; // AllocMem(SizeOf(TXDataAppName));
    XDATA_STRING:
      Chunk.Data.XDataString := nil; // AllocMem(SizeOf(TXDataString));
    KFHDR:
      Chunk.Data.KFHDR := AllocMem(SizeOf(TKFHdr));
    KFSEG:
      Chunk.Data.KFSEG := AllocMem(SizeOf(TKFSeg));
    KFCURTIME:
      Chunk.Data.KFCURTIME := AllocMem(SizeOf(TKFCurtime));
    NODE_ID:
      Chunk.Data.KFID := AllocMem(SizeOf(TKFId));
    NODE_HDR:
      Chunk.Data.NodeHdr := AllocMem(SizeOf(TNodeHdr));
    PIVOT:
      Chunk.Data.PIVOT := AllocMem(SizeOf(TPivot));
    INSTANCE_NAME, PARENT_NAME:
      Chunk.Data.InstanceName := nil; // AllocMem(SizeOf(TInstanceName));
    MORPH_SMOOTH:
      Chunk.Data.MorphSmooth := AllocMem(SizeOf(TMorphSmooth));
    BOUNDBOX:
      Chunk.Data.BOUNDBOX := AllocMem(SizeOf(TBoundBox));
    POS_TRACK_TAG:
      Chunk.Data.PosTrackTag := AllocMem(SizeOf(TPosTrackTag));
    COL_TRACK_TAG:
      Chunk.Data.ColTrackTag := AllocMem(SizeOf(TColTrackTag));
    ROT_TRACK_TAG:
      Chunk.Data.RotTrackTag := AllocMem(SizeOf(TRotTrackTag));
    SCL_TRACK_TAG:
      Chunk.Data.ScaleTrackTag := AllocMem(SizeOf(TScaleTrackTag));
    MORPH_TRACK_TAG:
      Chunk.Data.MorphTrackTag := AllocMem(SizeOf(TMorphTrackTag));
    FOV_TRACK_TAG:
      Chunk.Data.FovTrackTag := AllocMem(SizeOf(TFovTrackTag));
    ROLL_TRACK_TAG:
      Chunk.Data.RollTrackTag := AllocMem(SizeOf(TRollTrackTag));
    HOT_TRACK_TAG:
      Chunk.Data.HotTrackTag := AllocMem(SizeOf(THotTrackTag));
    FALL_TRACK_TAG:
      Chunk.Data.FallTrackTag := AllocMem(SizeOf(TFallTrackTag));
    HIDE_TRACK_TAG:
      Chunk.Data.HideTrackTag := AllocMem(SizeOf(THideTrackTag));
    M3DMAGIC, // Chunks who consist entirely of children
    MLIBMAGIC, 
	MDATA, 
	AMBIENT_LIGHT, 
	SOLID_BGND, 
	DEFAULT_VIEW, 
	MAT_ENTRY,
    MAT_AMBIENT, 
	MAT_DIFFUSE, 
	MAT_SPECULAR, 
	MAT_SHININESS, 
	MAT_SHIN2PCT,
    MAT_SHIN3PCT, 
	MAT_TRANSPARENCY, 
	MAT_XPFALL, 
	MAT_REFBLUR, 
	MAT_SELF_ILPCT,
    MAT_TEXMAP, 
	MAT_TEXMASK, 
	MAT_TEX2MAP, 
	MAT_TEX2MASK, 
	MAT_OPACMAP,
    MAT_OPACMASK, 
	MAT_REFLMAP, 
	MAT_REFLMASK, 
	MAT_BUMPMAP, 
	MAT_BUMPMASK,
    MAT_SPECMAP, 
	MAT_SPECMASK, 
	MAT_SHINMAP, 
	MAT_SHINMASK, 
	MAT_SELFIMAP,
    MAT_SELFIMASK, 
	N_TRI_OBJECT, 
	KFDATA, 
	AMBIENT_NODE_TAG, 
	OBJECT_NODE_TAG,
    CAMERA_NODE_TAG, 
	TARGET_NODE_TAG, 
	LIGHT_NODE_TAG, 
	SPOTLIGHT_NODE_TAG,
    L_TARGET_NODE_TAG, 
	CMAGIC, 
	XDATA_SECTION, 
	XDATA_GROUP:
      Chunk.Data.Dummy := nil;
  else // A truely hideous thing to do but it helps with unknown chunks
    // Don't mess with dataless chunks
    if Chunk.Size > 6 then
      Chunk.Data.Dummy := AllocMem(Chunk.Size - 6)
    else
      Chunk.Data.Dummy := nil;
  end; // end of case
  Result := Chunk.Data.Dummy; // returns the pointer should someone want it
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.WriteByte(AValue: Byte);

begin
  FStream.WriteBuffer(AValue, 1);
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.ReadByte: Byte;

begin
  FStream.ReadBuffer(Result, 1);
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.WriteShort(AValue: SmallInt);

begin
  FStream.WriteBuffer(AValue, SizeOf(AValue));
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.ReadShort: SmallInt;

begin
  FStream.ReadBuffer(Result, SizeOf(Result));
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.ReadCardinal: Cardinal;

begin
  FStream.ReadBuffer(Result, SizeOf(Result));
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.ReadDouble: Double;

begin
  FStream.ReadBuffer(Result, SizeOf(Result));
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.ReadInteger: Integer;

begin
  FStream.ReadBuffer(Result, SizeOf(Result));
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.ReadSingle: Single;

begin
  FStream.ReadBuffer(Result, SizeOf(Result));
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.ReadWord: Word;

begin
  FStream.ReadBuffer(Result, SizeOf(Result));
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.WriteCardinal(AValue: Cardinal);

begin
  FStream.WriteBuffer(AValue, SizeOf(AValue));
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.WriteDouble(AValue: Double);

begin
  FStream.WriteBuffer(AValue, SizeOf(AValue));
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.WriteInteger(AValue: Integer);

begin
  FStream.WriteBuffer(AValue, SizeOf(AValue));
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.WriteSingle(AValue: Single);

begin
  FStream.WriteBuffer(AValue, SizeOf(AValue));
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.WriteWord(AValue: Word);

begin
  FStream.WriteBuffer(AValue, SizeOf(AValue));
end;

// WriteData
//
procedure TFile3DS.WriteData(Size: Integer; Data: Pointer);
begin
  if assigned(Data) then
    FStream.WriteBuffer(Data^, Size);
end;

// ReadData
//
procedure TFile3DS.ReadData(Size: Integer; Data: Pointer);
begin
  FStream.ReadBuffer(Data^, Size);
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.Skip(AValue: Integer);

begin
  FStream.Seek(soFromCurrent, AValue);
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.WriteString(const AValue: String3DS);

begin
  WriteData(Length(AValue), @AValue[1]);
  WriteByte(0); // Write a null on the end of the string
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.WriteFixedString(const AValue: String3DS; Len: Integer);

var
  I: Integer;

begin
  // len is the length of the target string space including null
  WriteString(AValue); // 1 null byte will also be written
  for I := 1 to Len - Length(AValue) - 1 do
    WriteByte(0); // fill the remaining space with nulls
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.ReadString: PChar3DS;
var
  Len, LB: Integer;
  Buffer: String3DS;
begin
  Len := 0;
  LB := 0;
  repeat
    if Len >= LB then
    begin
      Inc(LB, 50);
      SetLength(Buffer, LB);
    end;
    Inc(Len);
    FStream.Read(Buffer[Len], 1);
  until Buffer[Len] = #0;
  Result := AllocMem(Len);
  Move(Buffer[1], Result^, Len);
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.WriteHeader(ChunkType: Word; ChunkSize: Cardinal);

begin
  WriteWord(ChunkType);
  WriteCardinal(ChunkSize);
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.ReadHeader(var ChunkType: Word; var ChunkSize: Cardinal);

begin
  ChunkType := ReadWord;
  ChunkSize := ReadCardinal;
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.FinishHeader(StartPos, EndPos: Cardinal);

begin
  FStream.Position := StartPos + 2;
  WriteCardinal(EndPos - StartPos);
  FStream.Position := EndPos;
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.WritePoint(const P: TPoint3DS);

begin
  WriteSingle(P.X);
  WriteSingle(P.Y);
  WriteSingle(P.Z);
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.ReadPoint: TPoint3DS;

begin
  Result := DefPoint3DS;
  FStream.ReadBuffer(Result, SizeOf(Result));
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.WriteTexVertex(const T: TTexVert3DS);

begin
  WriteSingle(T.U);
  WriteSingle(T.V);
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.ReadTexVert: TTexVert3DS;

begin
  Result := DefTextVert3DS;
  Result.U := ReadSingle;
  Result.V := ReadSingle;
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.WriteFace(const F: TFace3DS);

begin
  WriteWord(F.v1);
  WriteWord(F.v2);
  WriteWord(F.v3);
  WriteWord(F.flag);
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.ReadFace: TFace3DS;

begin
  Result := DefFace3DS;
  Result.v1 := ReadWord;
  Result.v2 := ReadWord;
  Result.v3 := ReadWord;
  Result.flag := ReadWord;
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.WriteTrackHeader(const T: TTrackHeader3DS);

begin
  WriteWord(T.Flags);
  WriteCardinal(T.nu1);
  WriteCardinal(T.nu2);
  WriteCardinal(T.KeyCount);
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.ReadTrackHeader: TTrackHeader3DS;

begin
  Result := DefTrackHeader3DS;
  Result.Flags := ReadWord;
  Result.nu1 := ReadCardinal;
  Result.nu2 := ReadCardinal;
  Result.KeyCount := ReadCardinal;
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.WriteKeyHeader(const K: TKeyHeader3DS);

begin
  WriteCardinal(K.time);
  WriteWord(K.rflags);
  if (K.rflags and KeyUsesTension3DS) > 0 then
    WriteSingle(K.tension);
  if (K.rflags and KeyUsesCont3DS) > 0 then
    WriteSingle(K.continuity);
  if (K.rflags and KeyUsesBias3DS) > 0 then
    WriteSingle(K.bias);
  if (K.rflags and KeyUsesEaseTo3DS) > 0 then
    WriteSingle(K.easeto);
  if (K.rflags and KeyUsesEaseFrom3DS) > 0 then
    WriteSingle(K.easefrom);
end;

// ---------------------------------------------------------------------------------------------------------------------

function TFile3DS.ReadKeyHeader: TKeyHeader3DS;

begin
  Result := DefKeyHeader3DS;
  Result.time := ReadCardinal;
  Result.rflags := ReadWord;
  if (Result.rflags and KeyUsesTension3DS) > 0 then
    Result.tension := ReadSingle;
  if (Result.rflags and KeyUsesCont3DS) > 0 then
    Result.continuity := ReadSingle;
  if (Result.rflags and KeyUsesBias3DS) > 0 then
    Result.bias := ReadSingle;
  if (Result.rflags and KeyUsesEaseTo3DS) > 0 then
    Result.easeto := ReadSingle;
  if (Result.rflags and KeyUsesEaseFrom3DS) > 0 then
    Result.easefrom := ReadSingle;
end;

// ---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.ReadChunkData(Chunk: PChunk3DS);

// Reads the data out of the chunk detailed in Chunk and places a pointer to
// the data into the PChunk3DS structure, it will also return that pointer.

var
  I: Integer;

begin
  if Chunk.Data.Dummy = nil then // don't try to read the data if its already been read
  begin
    // seek to the beginning of the Chunk's data (harmless if the Chunk has no data)
    FStream.Position := Chunk.Position + 6;
    case Chunk.Tag of
      COLOR_F:
        begin
          Chunk.Data.ColorF := AllocMem(SizeOf(TColorF));  // allocate the memory to hold the data
          with Chunk.Data.ColorF^ do
          begin
            Red := ReadSingle; // Read the data out of the file
            Green := ReadSingle;
            Blue := ReadSingle;
          end;
        end;
      LIN_COLOR_F:
        begin
          Chunk.Data.LinColorF := AllocMem(SizeOf(TLinColorF));
          with Chunk.Data.LinColorF^ do
          begin
            Red := ReadSingle;
            Green := ReadSingle;
            Blue := ReadSingle;
          end;
        end;
      COLOR_24:
        begin
          Chunk.Data.Color24 := AllocMem(SizeOf(TColor24));
          with Chunk.Data.Color24^ do
          begin
            Red := ReadByte;
            Green := ReadByte;
            Blue := ReadByte;
          end;
        end;
      LIN_COLOR_24:
        begin
          Chunk.Data.LinColor24 := AllocMem(SizeOf(TLinColor24));
          with Chunk.Data.LinColor24^ do
          begin
            Red := ReadByte;
            Green := ReadByte;
            Blue := ReadByte;
          end;
        end;
      INT_PERCENTAGE:
        begin
          Chunk.Data.IntPercentage := AllocMem(SizeOf(TIntPercentage));
          Chunk.Data.IntPercentage^ := ReadShort;
        end;
      FLOAT_PERCENTAGE:
        begin
          Chunk.Data.FloatPercentage := AllocMem(SizeOf(TFloatPercentage));
          Chunk.Data.FloatPercentage^ := ReadSingle;
        end;
      MAT_MAPNAME:
        begin
          // Chunk.Data.MatMapname := AllocMem(SizeOf(TMatMapname));
          Chunk.Data.MatMapname := ReadString;
        end;
      M3D_VERSION:
        begin
          Chunk.Data.M3dVersion := AllocMem(SizeOf(TM3dVersion));
          Chunk.Data.M3dVersion^ := ReadInteger;
        end;
      MESH_VERSION:
        begin
          Chunk.Data.MeshVersion := AllocMem(SizeOf(TMeshVersion));
          Chunk.Data.MeshVersion^ := ReadInteger;
        end;
      MASTER_SCALE:
        begin
          Chunk.Data.MasterScale := AllocMem(SizeOf(TMasterScale));
          Chunk.Data.MasterScale^ := ReadSingle;
        end;
      LO_SHADOW_BIAS:
        begin
          Chunk.Data.LoShadowBias := AllocMem(SizeOf(TLoShadowBias));
          Chunk.Data.LoShadowBias^ := ReadSingle;
        end;
      SHADOW_FILTER:
        begin
          Chunk.Data.ShadowFilter := AllocMem(SizeOf(TShadowFilter));
          Chunk.Data.ShadowFilter^ := ReadSingle;
        end;
      SHADOW_RANGE:
        begin
          Chunk.Data.ShadowRange := AllocMem(SizeOf(TShadowRange));
          Chunk.Data.ShadowRange^ := ReadInteger;
        end;
      HI_SHADOW_BIAS:
        begin
          Chunk.Data.HiShadowBias := AllocMem(SizeOf(THiShadowBias));
          Chunk.Data.HiShadowBias^ := ReadSingle;
        end;
      RAY_BIAS:
        begin
          Chunk.Data.RayBias := AllocMem(SizeOf(TRayBias));
          Chunk.Data.RayBias^ := ReadSingle;
        end;
      SHADOW_MAP_SIZE:
        begin
          Chunk.Data.ShadowMapSize := AllocMem(SizeOf(TShadowMapSize));
          Chunk.Data.ShadowMapSize^ := ReadShort;
        end;
      SHADOW_SAMPLES:
        begin
          Chunk.Data.ShadowSamples := AllocMem(SizeOf(TShadowSamples));
          Chunk.Data.ShadowSamples^ := ReadShort;
        end;
      O_CONSTS:
        begin
          Chunk.Data.OConsts := AllocMem(SizeOf(TOConsts));
          Chunk.Data.OConsts^ := ReadPoint;
        end;
      BIT_MAP:
        begin
          // Chunk.Data.BitMapName := AllocMem(SizeOf(TBitMapName));
          Chunk.Data.BitMapName := ReadString;
        end;
      V_GRADIENT:
        begin
          Chunk.Data.VGradient := AllocMem(SizeOf(TVGradient));
          Chunk.Data.VGradient^ := ReadSingle;
        end;
      FOG:
        begin
          Chunk.Data.FOG := AllocMem(SizeOf(TFog));
          with Chunk.Data.FOG^ do
          begin
            NearPlaneDist := ReadSingle;
            NearPlaneDensity := ReadSingle;
            FarPlaneDist := ReadSingle;
            FarPlaneDensity := ReadSingle;
          end;
        end;
      LAYER_FOG:
        begin
          Chunk.Data.LayerFog := AllocMem(SizeOf(TLayerFog));
          with Chunk.Data.LayerFog^ do
          begin
            ZMin := ReadSingle;
            ZMax := ReadSingle;
            Density := ReadSingle;
            AType := ReadCardinal;
          end;
        end;
      DISTANCE_CUE:
        begin
          Chunk.Data.DistanceCue := AllocMem(SizeOf(TDistanceCue));
          with Chunk.Data.DistanceCue^ do
          begin
            NearPlaneDist := ReadSingle;
            NearPlaneDimming := ReadSingle;
            FarPlaneDist := ReadSingle;
            FarPlaneDimming := ReadSingle;
          end;
        end;
      VIEW_TOP, 
	  VIEW_BOTTOM, 
	  VIEW_LEFT, 
	  VIEW_RIGHT, 
	  VIEW_FRONT, 
	  VIEW_BACK:
        begin
          Chunk.Data.ViewStandard := AllocMem(SizeOf(TViewStandard));
          with Chunk.Data.ViewStandard^ do
          begin
            ViewWidth := ReadSingle;
            ViewTargetCoord := ReadPoint;
          end;
        end;
      VIEW_USER:
        begin
          Chunk.Data.ViewUser := AllocMem(SizeOf(TViewUser));
          with Chunk.Data.ViewUser^ do
          begin
            ViewWidth := ReadSingle;
            XYViewAngle := ReadSingle;
            YZViewAngle := ReadSingle;
            BankAngle := ReadSingle;
            ViewTargetCoord := ReadPoint;
          end;
        end;
      VIEW_CAMERA:
        begin
          // Chunk.Data.ViewCamera := AllocMem(SizeOf(TViewCamera));
          Chunk.Data.ViewCamera := ReadString;
        end;
      MAT_NAME:
        begin
          // Chunk.Data.MatName := AllocMem(SizeOf(TMatName));
          Chunk.Data.MatName := ReadString;
        end;
      MAT_SHADING:
        begin
          Chunk.Data.MatShading := AllocMem(SizeOf(TMatShading));
          FStream.Position := Chunk.Position + 6;
          Chunk.Data.MatShading^ := ReadShort;
        end;
      MAT_ACUBIC:
        begin
          Chunk.Data.MatAcubic := AllocMem(SizeOf(TMatAcubic));
          with Chunk.Data.MatAcubic^ do
          begin
            ShadeLevel := ReadByte;
            AntiAlias := ReadByte;
            Flags := ReadShort;
            MapSize := ReadCardinal;
            FrameInterval := ReadCardinal;
          end;
        end;
      MAT_SXP_TEXT_DATA, 
	  MAT_SXP_TEXT2_DATA, 
	  MAT_SXP_OPAC_DATA,
      MAT_SXP_BUMP_DATA, 
	  MAT_SXP_SPEC_DATA, 
	  MAT_SXP_SHIN_DATA,
      MAT_SXP_SELFI_DATA, 
	  MAT_SXP_TEXT_MASKDATA, 
	  MAT_SXP_TEXT2_MASKDATA,
      MAT_SXP_OPAC_MASKDATA, 
	  MAT_SXP_BUMP_MASKDATA, 
	  MAT_SXP_SPEC_MASKDATA,
      MAT_SXP_SHIN_MASKDATA, 
	  MAT_SXP_SELFI_MASKDATA, 
	  MAT_SXP_REFL_MASKDATA,
        PROC_DATA:
        begin
          Chunk.Data.IpasData := AllocMem(SizeOf(TIpasData));
          with Chunk.Data.IpasData^ do
          begin
            Size := Chunk.Size - 6;
            Data := AllocMem(Size);
            ReadData(Size, Data);
          end;
        end;
      MAT_WIRESIZE:
        begin
          Chunk.Data.MatWireSize := AllocMem(SizeOf(TMatWireSize));
          Chunk.Data.MatWireSize^ := ReadSingle;
        end;
      MAT_MAP_TILING:
        begin
          Chunk.Data.MatMapTiling := AllocMem(SizeOf(TMatMapTiling));
          Chunk.Data.MatMapTiling^ := ReadWord;
        end;
      MAT_MAP_TEXBLUR:
        begin
          Chunk.Data.MatMapTexblur := AllocMem(SizeOf(TMatMapTexblur));
          Chunk.Data.MatMapTexblur^ := ReadSingle;
        end;
      MAT_MAP_USCALE:
        begin
          Chunk.Data.MatMapUScale := AllocMem(SizeOf(TMatMapUScale));
          Chunk.Data.MatMapUScale^ := ReadSingle;
        end;
      MAT_MAP_VSCALE:
        begin
          Chunk.Data.MatMapVScale := AllocMem(SizeOf(TMatMapVScale));
          Chunk.Data.MatMapVScale^ := ReadSingle;
        end;
      MAT_MAP_UOFFSET:
        begin
          Chunk.Data.MatMapUOffset := AllocMem(SizeOf(TMatMapUOffset));
          Chunk.Data.MatMapUOffset^ := ReadSingle;
        end;
      MAT_MAP_VOFFSET:
        begin
          Chunk.Data.MatMapVOffset := AllocMem(SizeOf(TMatMapVOffset));
          Chunk.Data.MatMapVOffset^ := ReadSingle;
        end;
      MAT_MAP_ANG:
        begin
          Chunk.Data.MatMapAng := AllocMem(SizeOf(TMatMapAng));
          Chunk.Data.MatMapAng^ := ReadSingle;
        end;
      MAT_MAP_COL1:
        begin
          Chunk.Data.MatMapCol1 := AllocMem(SizeOf(TMatMapCol1));
          with Chunk.Data.MatMapCol1^ do
          begin
            Red := ReadByte;
            Green := ReadByte;
            Blue := ReadByte;
          end;
        end;
      MAT_MAP_COL2:
        begin
          Chunk.Data.MatMapCol2 := AllocMem(SizeOf(TMatMapCol2));
          with Chunk.Data.MatMapCol2^ do
          begin
            Red := ReadByte;
            Green := ReadByte;
            Blue := ReadByte;
          end;
        end;
      MAT_MAP_RCOL:
        begin
          Chunk.Data.MatMapRCol := AllocMem(SizeOf(TMatMapRCol));
          with Chunk.Data.MatMapRCol^ do
          begin
            Red := ReadByte;
            Green := ReadByte;
            Blue := ReadByte;
          end;
        end;
      MAT_MAP_GCOL:
        begin
          Chunk.Data.MatMapGCol := AllocMem(SizeOf(TMatMapGCol));
          with Chunk.Data.MatMapGCol^ do
          begin
            Red := ReadByte;
            Green := ReadByte;
            Blue := ReadByte;
          end;
        end;
      MAT_MAP_BCOL:
        begin
          Chunk.Data.MatMapBCol := AllocMem(SizeOf(TMatMapBCol));
          with Chunk.Data.MatMapBCol^ do
          begin
            Red := ReadByte;
            Green := ReadByte;
            Blue := ReadByte;
          end;
        end;
      MAT_BUMP_PERCENT:
        begin
          Chunk.Data.MatBumpPercent := AllocMem(SizeOf(TMatBumpPercent));
          Chunk.Data.MatBumpPercent^ := ReadShort;
        end;
      NAMED_OBJECT:
        begin
          // Chunk.Data.NamedObject := AllocMem(SizeOf(TNamedObject));
          Chunk.Data.NamedObject := ReadString;
        end;
      POINT_ARRAY:
        begin
          Chunk.Data.PointArray := AllocMem(SizeOf(TPointArray));
          with Chunk.Data.PointArray^ do
          begin
            Vertices := ReadWord;
            PointList := AllocMem(Vertices * SizeOf(TPoint3DS));
            // for I := 0 to Vertices - 1 do PointList[I] := ReadPoint;
            ReadData(Vertices * SizeOf(TPoint3DS), PointList);
          end;
        end;
      POINT_FLAG_ARRAY:
        begin
          Chunk.Data.PointFlagArray := AllocMem(SizeOf(TPointFlagArray));
          with Chunk.Data.PointFlagArray^ do
          begin
            Flags := ReadWord;
            FlagList := AllocMem(Flags * SizeOf(SmallInt));
            // for I := 0 to Flags - 1 do FlagList[I] := ReadShort;
            ReadData(Flags * SizeOf(SmallInt), FlagList);
          end;
        end;
      FACE_ARRAY:
        begin
          Chunk.Data.FaceArray := AllocMem(SizeOf(TFaceArray));
          with Chunk.Data.FaceArray^ do
          begin
            Faces := ReadWord;
            FaceList := AllocMem(Faces * SizeOf(TFace3DS));
            // for I := 0 to Faces - 1 do FaceList[I] := ReadFace;
            ReadData(Faces * SizeOf(TFace3DS), FaceList);
          end;
        end;
      MSH_MAT_GROUP:
        begin
          Chunk.Data.MshMatGroup := AllocMem(SizeOf(TMshMatGroup));
          with Chunk.Data.MshMatGroup^ do
          begin
            MatNameStr := AnsiString(StrPasFree(ReadString));
            Faces := ReadWord;
            if Faces > 0 then
            begin
              FaceList := AllocMem(Faces * SizeOf(Word));
              // for I := 0 to Faces - 1 do FaceList[I] := ReadWord;
              ReadData(Faces * SizeOf(Word), FaceList);
            end
            else
              FaceList := nil;
          end;
        end;
      MSH_BOXMAP:
        begin
          Chunk.Data.MshBoxmap := AllocMem(SizeOf(TMshBoxmap));
          for I := 0 to 5 do
            Chunk.Data.MshBoxmap[I] := ReadString;
        end;
      SMOOTH_GROUP:
        begin
          Chunk.Data.SmoothGroup := AllocMem(SizeOf(TSmoothGroup));
          with Chunk.Data.SmoothGroup^ do
          begin
            Groups := (Chunk.Size - 6) div 4;
            GroupList := AllocMem(Groups * SizeOf(Cardinal));
            // for I := 0 to Groups - 1 do GroupList[I] := ReadCardinal;
            ReadData(Groups * SizeOf(Cardinal), GroupList);
          end;
        end;
      TEX_VERTS:
        begin
          Chunk.Data.TexVerts := AllocMem(SizeOf(TTexVerts));
          with Chunk.Data.TexVerts^ do
          begin
            NumCoords := ReadWord;
            TextVertList := AllocMem(NumCoords * SizeOf(TTexVert3DS));
            // for I := 0 to NumCoords - 1 do TextVertList[I] := ReadTexVert;
            ReadData(NumCoords * SizeOf(TTexVert3DS), TextVertList);
          end;
        end;
      MESH_MATRIX:
        begin
          Chunk.Data.MeshMatrix := AllocMem(SizeOf(TMeshMatrix));
          for I := 0 to 11 do
            Chunk.Data.MeshMatrix[I] := ReadSingle;
        end;
      MESH_COLOR:
        begin
          Chunk.Data.MeshColor := AllocMem(SizeOf(TMeshColor));
          Chunk.Data.MeshColor^ := ReadByte;
        end;
      MESH_TEXTURE_INFO:
        begin
          Chunk.Data.MeshTextureInfo := AllocMem(SizeOf(TMeshTextureInfo));
          with Chunk.Data.MeshTextureInfo^ do
          begin
            MapType := ReadWord;
            XTiling := ReadSingle;
            YTiling := ReadSingle;
            IconPos := ReadPoint();
            IconScaling := ReadSingle;
            for I := 0 to 11 do
              XMatrix[I] := ReadSingle;
            IconWidth := ReadSingle;
            IconHeight := ReadSingle;
            CylIconHeight := ReadSingle;
          end;
        end;
      PROC_NAME:
        begin
          // Chunk.Data.ProcName := AllocMem(SizeOf(TProcName));
          Chunk.Data.ProcName := ReadString;
        end;
      N_DIRECT_LIGHT:
        begin
          Chunk.Data.NDirectLight := AllocMem(SizeOf(TNDirectLight));
          Chunk.Data.NDirectLight^ := ReadPoint;
        end;
      DL_EXCLUDE:
        begin
          // Chunk.Data.DlExclude := AllocMem(SizeOf(TDlExclude));
          Chunk.Data.DlExclude := ReadString;
        end;
      DL_INNER_RANGE:
        begin
          Chunk.Data.DlInnerRange := AllocMem(SizeOf(TDlInnerRange));
          Chunk.Data.DlInnerRange^ := ReadSingle;
        end;
      DL_OUTER_RANGE:
        begin
          Chunk.Data.DlOuterRange := AllocMem(SizeOf(TDlOuterRange));
          Chunk.Data.DlOuterRange^ := ReadSingle;
        end;
      DL_MULTIPLIER:
        begin
          Chunk.Data.DlMultiplier := AllocMem(SizeOf(TDlMultiplier));
          Chunk.Data.DlMultiplier^ := ReadSingle;
        end;
      DL_SPOTLIGHT:
        begin
          Chunk.Data.DlSpotlight := AllocMem(SizeOf(TDlSpotlight));
          with Chunk.Data.DlSpotlight^ do
          begin
            SpotlightTarg := ReadPoint;
            HotspotAngle := ReadSingle;
            FalloffAngle := ReadSingle;
          end;
        end;
      DL_LOCAL_SHADOW2:
        begin
          Chunk.Data.DlLocalShadow2 := AllocMem(SizeOf(TDlLocalShadow2));
          with Chunk.Data.DlLocalShadow2^ do
          begin
            LocalShadowBias := ReadSingle;
            LocalShadowFilter := ReadSingle;
            LocalShadowMapSize := ReadShort;
          end;
        end;
      DL_SPOT_ROLL:
        begin
          Chunk.Data.DlSpotRoll := AllocMem(SizeOf(TDlSpotRoll));
          Chunk.Data.DlSpotRoll^ := ReadSingle;
        end;
      DL_SPOT_ASPECT:
        begin
          Chunk.Data.DlSpotAspect := AllocMem(SizeOf(TDlSpotAspect));
          Chunk.Data.DlSpotAspect^ := ReadSingle;
        end;
      DL_SPOT_PROJECTOR:
        begin
          // Chunk.Data.DlSpotProjector := AllocMem(SizeOf(TDlSpotProjector));
          Chunk.Data.DlSpotProjector := ReadString;
        end;
      DL_RAY_BIAS:
        begin
          Chunk.Data.DlRayBias := AllocMem(SizeOf(TDlRayBias));
          Chunk.Data.DlRayBias^ := ReadSingle;
        end;
      N_CAMERA:
        begin
          Chunk.Data.NCamera := AllocMem(SizeOf(TNCamera));
          with Chunk.Data.NCamera^ do
          begin
            CameraPos := ReadPoint;
            TargetPos := ReadPoint;
            CameraBank := ReadSingle;
            CameraFocalLength := ReadSingle;
          end;
        end;
      CAM_RANGES:
        begin
          Chunk.Data.CamRanges := AllocMem(SizeOf(TCamRanges));
          with Chunk.Data.CamRanges^ do
          begin
            NearPlane := ReadSingle;
            FarPlane := ReadSingle;
          end;
        end;
      VIEWPORT_LAYOUT:
        begin
          Chunk.Data.ViewportLayout := AllocMem(SizeOf(TViewportLayout));
          with Chunk.Data.ViewportLayout^ do
          begin
            Form := ReadShort;
            Top := ReadShort;
            Ready := ReadShort;
            WState := ReadShort;
            SwapWS := ReadShort;
            SwapPort := ReadShort;
            SwapCur := ReadShort;
          end;
        end;
      VIEWPORT_SIZE:
        begin
          Chunk.Data.ViewportSize := AllocMem(SizeOf(TViewportSize));
          with Chunk.Data.ViewportSize^ do
          begin
            XPos := ReadWord;
            YPos := ReadWord;
            Width := ReadWord;
            Height := ReadWord;
          end;
        end;
      VIEWPORT_DATA_3, 
	  VIEWPORT_DATA:
        begin
          Chunk.Data.ViewportData := AllocMem(SizeOf(TViewportData));
          with Chunk.Data.ViewportData^ do
          begin
            Flags := ReadShort;
            AxisLockout := ReadShort;
            WinXPos := ReadShort;
            WinYPos := ReadShort;
            WinWidth := ReadShort;
            WinHeight := ReadShort;
            View := ReadShort;
            ZoomFactor := ReadSingle;
            Center := ReadPoint;
            HorizAng := ReadSingle;
            VertAng := ReadSingle;
            CamNameStr := AnsiString(StrPasFree(ReadString));
          end;
        end;
      XDATA_ENTRY:
        begin
          InitChunkData(Chunk);
          with Chunk.Data.XDataEntry^ do
          begin
            Size := (Chunk.Size) - 6;
            Data := AllocMem(Size);
            ReadData(Size, Data);
          end;
        end;
      XDATA_APPNAME:
        begin
          Chunk.Data.XDataAppName := ReadString;
        end;
      XDATA_STRING:
        begin
          Chunk.Data.XDataString := ReadString;
        end;
      KFHDR:
        begin
          Chunk.Data.KFHDR := AllocMem(SizeOf(TKFHdr));
          with Chunk.Data.KFHDR^ do
          begin
            Revision := ReadShort;
            FileName := StrPasFree(ReadString);
            AnimLength := ReadInteger;
          end;
        end;
      KFSEG:
        begin
          Chunk.Data.KFSEG := AllocMem(SizeOf(TKFSeg));
          with Chunk.Data.KFSEG^ do
          begin
            First := ReadInteger;
            Last := ReadInteger;
          end;
        end;
      KFCURTIME:
        begin
          Chunk.Data.KFCURTIME := AllocMem(SizeOf(TKFCurtime));
          Chunk.Data.KFCURTIME^ := ReadInteger;
        end;
      NODE_ID:
        begin
          Chunk.Data.KFID := AllocMem(SizeOf(TKFId));
          Chunk.Data.KFID^ := ReadShort;
        end;
      NODE_HDR:
        begin
          Chunk.Data.NodeHdr := AllocMem(SizeOf(TNodeHdr));
          with Chunk.Data.NodeHdr^ do
          begin
            ObjNameStr := StrPasFree(ReadString);
            Flags1 := ReadWord;
            Flags2 := ReadWord;
            ParentIndex := ReadShort;
          end;
        end;
      PIVOT:
        begin
          Chunk.Data.PIVOT := AllocMem(SizeOf(TPivot));
          Chunk.Data.PIVOT^ := ReadPoint;
        end;
      INSTANCE_NAME:
        begin
          Chunk.Data.InstanceName := ReadString;
        end;
      PARENT_NAME:
        ; // do nothing
      MORPH_SMOOTH:
        begin
          Chunk.Data.MorphSmooth := AllocMem(SizeOf(TMorphSmooth));
          Chunk.Data.MorphSmooth^ := ReadSingle;
        end;
      BOUNDBOX:
        begin
          Chunk.Data.BOUNDBOX := AllocMem(SizeOf(TBoundBox));
          with Chunk.Data.BOUNDBOX^ do
          begin
            Min := ReadPoint;
            Max := ReadPoint;
          end;
        end;
      POS_TRACK_TAG:
        begin
          Chunk.Data.PosTrackTag := AllocMem(SizeOf(TPosTrackTag));
          with Chunk.Data.PosTrackTag^ do
          begin
            TrackHdr := ReadTrackHeader;
            KeyHdrList := AllocMem(TrackHdr.KeyCount * SizeOf(TKeyHeader3DS));
            PositionList := AllocMem(TrackHdr.KeyCount * SizeOf(TPoint3DS));
            for I := 0 to TrackHdr.KeyCount - 1 do
            begin
              KeyHdrList[I] := ReadKeyHeader;
              PositionList[I] := ReadPoint;
            end;
          end;
        end;
      COL_TRACK_TAG:
        begin
          Chunk.Data.ColTrackTag := AllocMem(SizeOf(TColTrackTag));
          with Chunk.Data.ColTrackTag^ do
          begin
            TrackHdr := ReadTrackHeader;
            ColorList := AllocMem(TrackHdr.KeyCount * SizeOf(TFColor3DS));
            KeyHdrList := AllocMem(TrackHdr.KeyCount * SizeOf(TKeyHeader3DS));
            for I := 0 to TrackHdr.KeyCount - 1 do
            begin
              KeyHdrList[I] := ReadKeyHeader;
              ColorList[I].R := ReadSingle;
              ColorList[I].G := ReadSingle;
              ColorList[I].B := ReadSingle;
            end;
          end;
        end;
      ROT_TRACK_TAG:
        begin
          Chunk.Data.RotTrackTag := AllocMem(SizeOf(TRotTrackTag));
          with Chunk.Data.RotTrackTag^ do
          begin
            TrackHdr := ReadTrackHeader;
            KeyHdrList := AllocMem(TrackHdr.KeyCount * SizeOf(TKeyHeader3DS));
            RotationList := AllocMem(TrackHdr.KeyCount * SizeOf(TKFrotkey3DS));
            for I := 0 to TrackHdr.KeyCount - 1 do
            begin
              KeyHdrList[I] := ReadKeyHeader;
              RotationList[I].Angle := ReadSingle;
              RotationList[I].X := ReadSingle;
              RotationList[I].Y := ReadSingle;
              RotationList[I].Z := ReadSingle;
            end;
          end;
        end;
      SCL_TRACK_TAG:
        begin
          Chunk.Data.ScaleTrackTag := AllocMem(SizeOf(TScaleTrackTag));
          with Chunk.Data.ScaleTrackTag^ do
          begin
            TrackHdr := ReadTrackHeader;
            KeyHdrList := AllocMem(TrackHdr.KeyCount * SizeOf(TKeyHeader3DS));
            ScaleList := AllocMem(TrackHdr.KeyCount * SizeOf(TPoint3DS));
            for I := 0 to TrackHdr.KeyCount - 1 do
            begin
              KeyHdrList[I] := ReadKeyHeader;
              ScaleList[I].X := ReadSingle;
              ScaleList[I].Y := ReadSingle;
              ScaleList[I].Z := ReadSingle;
            end;
          end;
        end;
      MORPH_TRACK_TAG:
        begin
          Chunk.Data.MorphTrackTag := AllocMem(SizeOf(TMorphTrackTag));
          with Chunk.Data.MorphTrackTag^ do
          begin
            TrackHdr := ReadTrackHeader;
            KeyHdrList := AllocMem(TrackHdr.KeyCount * SizeOf(TKeyHeader3DS));
            MorphList := AllocMem(TrackHdr.KeyCount * SizeOf(TKFmorphKey3DS));
            for I := 0 to TrackHdr.KeyCount - 1 do
            begin
              KeyHdrList[I] := ReadKeyHeader;
              MorphList[I] := StrPasFree(ReadString);
            end;
          end;
        end;
      FOV_TRACK_TAG:
        begin
          Chunk.Data.FovTrackTag := AllocMem(SizeOf(TFovTrackTag));
          with Chunk.Data.FovTrackTag^ do
          begin
            TrackHdr := ReadTrackHeader;
            KeyHdrList := AllocMem(TrackHdr.KeyCount * SizeOf(TKeyHeader3DS));
            FOVAngleList := AllocMem(TrackHdr.KeyCount * SizeOf(Single));
            for I := 0 to TrackHdr.KeyCount - 1 do
            begin
              KeyHdrList[I] := ReadKeyHeader;
              FOVAngleList[I] := ReadSingle;
            end;
          end;
        end;
      ROLL_TRACK_TAG:
        begin
          Chunk.Data.RollTrackTag := AllocMem(SizeOf(TRollTrackTag));
          with Chunk.Data.RollTrackTag^ do
          begin
            TrackHdr := ReadTrackHeader;
            KeyHdrList := AllocMem(TrackHdr.KeyCount * SizeOf(TKeyHeader3DS));
            RollAngleList := AllocMem(TrackHdr.KeyCount * SizeOf(Single));
            for I := 0 to TrackHdr.KeyCount - 1 do
            begin
              KeyHdrList[I] := ReadKeyHeader;
              RollAngleList[I] := ReadSingle;
            end;
          end;
        end;
      HOT_TRACK_TAG:
        begin
          Chunk.Data.HotTrackTag := AllocMem(SizeOf(THotTrackTag));
          with Chunk.Data.HotTrackTag^ do
          begin
            TrackHdr := ReadTrackHeader;
            KeyHdrList := AllocMem(TrackHdr.KeyCount * SizeOf(TKeyHeader3DS));
            HotspotAngleList := AllocMem(TrackHdr.KeyCount * SizeOf(Single));
            for I := 0 to TrackHdr.KeyCount - 1 do
            begin
              KeyHdrList[I] := ReadKeyHeader;
              HotspotAngleList[I] := ReadSingle;
            end;
          end;
        end;
      FALL_TRACK_TAG:
        begin
          Chunk.Data.FallTrackTag := AllocMem(SizeOf(TFallTrackTag));
          with Chunk.Data.FallTrackTag^ do
          begin
            TrackHdr := ReadTrackHeader;
            KeyHdrList := AllocMem(TrackHdr.KeyCount * SizeOf(TKeyHeader3DS));
            FalloffAngleList := AllocMem(TrackHdr.KeyCount * SizeOf(Single));
            for I := 0 to TrackHdr.KeyCount - 1 do
            begin
              KeyHdrList[I] := ReadKeyHeader;
              FalloffAngleList[I] := ReadSingle;
            end;
          end;
        end;
      HIDE_TRACK_TAG:
        begin
          Chunk.Data.HideTrackTag := AllocMem(SizeOf(THideTrackTag));
          with Chunk.Data.HideTrackTag^ do
          begin
            TrackHdr := ReadTrackHeader;
            KeyHdrList := AllocMem(TrackHdr.KeyCount * SizeOf(TKeyHeader3DS));
            for I := 0 to TrackHdr.KeyCount - 1 do
              KeyHdrList[I] := ReadKeyHeader;
          end;
        end;
      M3DMAGIC, // Chunks that do not contain data, or only contain children
      MLIBMAGIC, 
	  MDATA, 
	  AMBIENT_LIGHT, 
	  SOLID_BGND, 
	  DEFAULT_VIEW, 
	  MAT_ENTRY,
      MAT_AMBIENT, 
	  MAT_DIFFUSE, 
	  MAT_SPECULAR, 
	  MAT_SHININESS, 
	  MAT_SHIN2PCT,
      MAT_SHIN3PCT, 
	  MAT_TRANSPARENCY, 
	  MAT_XPFALL, 
	  MAT_REFBLUR, 
	  MAT_SELF_ILPCT,
      MAT_TEXMAP, 
	  MAT_TEXMASK, 
	  MAT_TEX2MAP, 
	  MAT_TEX2MASK, 
	  MAT_OPACMAP,
      MAT_OPACMASK, 
	  MAT_REFLMAP, 
	  MAT_REFLMASK, 
	  MAT_BUMPMAP, 
	  MAT_BUMPMASK,
      MAT_SPECMAP, 
	  MAT_SPECMASK, 
	  MAT_SHINMAP, 
	  MAT_SHINMASK, 
	  MAT_SELFIMAP,
      MAT_SELFIMASK, 
	  N_TRI_OBJECT, 
	  KFDATA, 
	  AMBIENT_NODE_TAG, 
	  OBJECT_NODE_TAG,
      CAMERA_NODE_TAG, 
	  TARGET_NODE_TAG, 
	  LIGHT_NODE_TAG, 
	  SPOTLIGHT_NODE_TAG,
      L_TARGET_NODE_TAG, 
	  CMAGIC, 
	  XDATA_SECTION, 
	  XDATA_GROUP:
        ; // do nothing
    else // a truely hideous thing to do, but it helps with unknown chunks
      if Chunk.Size > 6 then // don't mess with dataless chunks
      begin
        Chunk.Data.Dummy := AllocMem(Chunk.Size - 6);
        ReadData(Chunk.Size - 6, Chunk.Data.Dummy);
      end;
    end; // end of case
  end;
end;

//---------------------------------------------------------------------------------------------------------------------

procedure TFile3DS.SeekChild(Chunk: PChunk3DS);

// Function skips to next Chunk on disk by seeking the next file position

var
  Offset: Integer;
begin
  Offset := 0;
  case Chunk.Tag of
    M3DMAGIC, 
    SMAGIC, 
    LMAGIC, 
    MATMAGIC, 
    MLIBMAGIC, 
    MDATA, 
    AMBIENT_LIGHT, 
    SOLID_BGND, 
    DEFAULT_VIEW, 
    MAT_ENTRY, 
    MAT_AMBIENT, 
    MAT_DIFFUSE, 
    MAT_SPECULAR, 
    MAT_SHININESS, 
    MAT_SHIN2PCT, 
    MAT_SHIN3PCT, 
    MAT_TRANSPARENCY, 
    MAT_XPFALL, 
    MAT_REFBLUR, 
    MAT_SELF_ILPCT, 
    MAT_TEXMAP, 
    MAT_TEXMASK, 
    MAT_TEX2MAP, 
    MAT_TEX2MASK, 
    MAT_OPACMAP, 
    MAT_OPACMASK, 
    MAT_REFLMAP, 
    MAT_REFLMASK, 
    MAT_BUMPMAP, 
    MAT_BUMPMASK, 
    MAT_SPECMAP, 
    MAT_SPECMASK, 
    MAT_SHINMAP, 
    MAT_SHINMASK, 
    MAT_SELFIMAP, 
    MAT_SELFIMASK, 
    N_TRI_OBJECT, 
    XDATA_SECTION, 
    XDATA_ENTRY, 
    KFDATA, 
    OBJECT_NODE_TAG, 
    CAMERA_NODE_TAG, 
    TARGET_NODE_TAG, 
    LIGHT_NODE_TAG, 
    SPOTLIGHT_NODE_TAG, 
    L_TARGET_NODE_TAG, 
    AMBIENT_NODE_TAG, 
    CMAGIC :
      ; // do nothing
    M3D_VERSION:
      Offset := SizeOf(Integer);
    COLOR_F:
      Offset := 3 * SizeOf(Single);
    COLOR_24:
      Offset := 3 * SizeOf(Byte);
    INT_PERCENTAGE:
      Offset := SizeOf(SmallInt);
    FLOAT_PERCENTAGE:
      Offset := SizeOf(Single);
    MAT_MAPNAME:
      FreeMem(ReadString);
    MESH_VERSION:
      Offset := SizeOf(Integer);
    MASTER_SCALE:
      Offset := SizeOf(Single);
    LO_SHADOW_BIAS:
      Offset := SizeOf(Single);
    HI_SHADOW_BIAS:
      Offset := SizeOf(Single);
    SHADOW_MAP_SIZE:
      Offset := SizeOf(SmallInt);
    SHADOW_SAMPLES:
      Offset := SizeOf(SmallInt);
    O_CONSTS:
      Offset := 12;
    V_GRADIENT:
      Offset := SizeOf(Single);
    NAMED_OBJECT:
      FreeMem(ReadString);
    BIT_MAP:
      FreeMem(ReadString);
    FOG:
      Offset := 4 * SizeOf(Single);
    LAYER_FOG:
      Offset := 3 * SizeOf(Single) + SizeOf(Integer);
    DISTANCE_CUE:
      Offset := 4 * SizeOf(Single);
    N_DIRECT_LIGHT:
      Offset := 12;
    DL_SPOTLIGHT:
      Offset := 12 + 2 * SizeOf(Single);
    N_CAMERA:
      Offset := 24 + 2 * SizeOf(Single);
    VIEWPORT_LAYOUT:
      Offset := 7 * SizeOf(SmallInt);
    VIEW_TOP,
    VIEW_BOTTOM,
    VIEW_LEFT,
    VIEW_RIGHT,
    VIEW_FRONT,
    VIEW_BACK:
      Offset := 12 + SizeOf(Single);
    VIEW_USER:
      Offset := 12 + 4 * SizeOf(Single);
    VIEW_CAMERA:
      FreeMem(ReadString);
    MAT_NAME:
      FreeMem(ReadString);
    MAT_ACUBIC:
      Offset := 2 * SizeOf(Byte) + 2 * SizeOf(Integer) + SizeOf(SmallInt);
    POINT_ARRAY,
    POINT_FLAG_ARRAY:
      Offset := Chunk.Size - 6;
    FACE_ARRAY:
      Offset := ReadWord * SizeOf(SmallInt) * 4;
    MSH_MAT_GROUP:
      Offset := Chunk.Size - 6;
    SMOOTH_GROUP:
      Offset := Chunk.Size - 6;
    TEX_VERTS:
      Offset := Chunk.Size - 6;
    MESH_MATRIX:
      Offset := 12 * SizeOf(Single);
    MESH_TEXTURE_INFO:
      Offset := Chunk.Size - 6;
    PROC_NAME:
      FreeMem(ReadString);
    DL_LOCAL_SHADOW2:
      Offset := 2 * SizeOf(Single) + SizeOf(SmallInt);
    KFHDR:
      begin
        ReadShort;
        FreeMem(ReadString);
        ReadInteger;
      end;
    KFSEG:
      Offset := 2 * SizeOf(Integer);
    KFCURTIME:
      Offset := SizeOf(Integer);
    NODE_HDR:
      begin
        FreeMem(ReadString);
        Offset := 2 * SizeOf(SmallInt) + SizeOf(SmallInt);
      end;
    NODE_ID:
      Offset := SizeOf(SmallInt);
    PIVOT:
      Offset := 12;
    INSTANCE_NAME:
      FreeMem(ReadString);
    MORPH_SMOOTH:
      Offset := SizeOf(Single);
    BOUNDBOX:
      Offset := 24;
    VPDATA:
      Offset := SizeOf(Integer);
  else
    Offset := Chunk.Size - 6;
  end;
  FStream.Seek(Offset, soFromCurrent);
end;

//---------------------------------------------------------------------------------------------------------------------

function TFile3DS.GetDatabaseRelease: TReleaseLevel;

begin
  Result := File3DSUtils.GetDatabaseRelease(Self, FDatabase);
end;

//---------------------------------------------------------------------------------------------------------------------

function TFile3DS.GetMeshRelease: TReleaseLevel;

begin
  Result := File3DSUtils.GetMeshRelease(Self, FDatabase);
end;

//---------------------------------------------------------------------------------------------------------------------

end.