//
// This unit is part of the GLScene Engine https://github.com/glscene
//
{
   Simple X format support for Delphi (Microsoft's favorite format)
}
unit FileX;

interface

{$I GLScene.inc}

uses
  // VCL
  Classes, SysUtils,


  GLVectorTypes, GLVectorGeometry, GLVectorLists, GLPersistentClasses, GLUtils;

type
  TDXNode = class;

  TDXFileHeader = record
    Magic : array[0..3] of AnsiChar;
    Major : array[0..1] of AnsiChar;
    Minor : array[0..1] of AnsiChar;
    FileType : array[0..3] of AnsiChar;
    FloatType : array[0..3] of AnsiChar;
  end;

  TDXNode = class (TList)
    private
      FName,
      FTypeName : String;
      FOwner : TDXNode;
      function GetItem(index : Integer) : TDXNode;

    public
      constructor CreateOwned(AOwner : TDXNode);
      constructor Create; virtual;
      procedure Clear; override;
      property Name : String read FName write FName;
      property TypeName : String read FTypeName write FTypeName;
      property Owner : TDXNode read FOwner;
      property Items[index : Integer] : TDXNode read GetItem;

  end;

  TDXMaterialList = class;
  TDXMaterial = class (TPersistentObject)
    private
      FDiffuse : TVector4f;
      FSpecPower : Single;
      FSpecular,
      FEmissive : TVector3f;
      FTexture : String;

    public
      constructor CreateOwned(AOwner : TDXMaterialList);

      property Diffuse : TVector4f read FDiffuse write FDiffuse;
      property SpecPower : Single read FSpecPower write FSpecPower;
      property Specular : TVector3f read FSpecular write FSpecular;
      property Emissive : TVector3f read FEmissive write FEmissive;
      property Texture : String read FTexture write FTexture;

  end;

  TDXMaterialList = class (TDXNode)
    private
      function GetMaterial(index : Integer) : TDXMaterial;

    public
      property Items[index : Integer] : TDXMaterial read GetMaterial;

  end;

  TDXFrame = class (TDXNode)
    private
      FMatrix : TMatrix;

    public
      constructor Create; override;

      function GlobalMatrix : TMatrix;
      property Matrix : TMatrix read FMatrix write FMatrix;

  end;

  TDXMesh = class (TDXNode)
    private
      FVertices,
      FNormals,
      FTexCoords  : TAffineVectorList;
      FVertexIndices,
      FNormalIndices,
      FMaterialIndices,
      FVertCountIndices : TIntegerList;
      FMaterialList : TDXMaterialList;

    public
      constructor Create; override;
      destructor Destroy; override;

      property Vertices : TAffineVectorList read FVertices;
      property Normals : TAffineVectorList read FNormals;
      property TexCoords : TAffineVectorList read FTexCoords;
      property VertexIndices : TIntegerList read FVertexIndices;
      property NormalIndices : TIntegerList read FNormalIndices;
      property MaterialIndices : TIntegerList read FMaterialIndices;
      property VertCountIndices : TIntegerList read FVertCountIndices;
      property MaterialList : TDXMaterialList read FMaterialList;
  end;

  TDXFile = class
    private
      FRootNode : TDXNode;
      FHeader : TDXFileHeader;

    protected
      procedure ParseText(Stream : TStream);
      procedure ParseBinary(Stream : TStream);

    public
      constructor Create;
      destructor Destroy; override;
      procedure LoadFromStream(Stream : TStream);
      //procedure SaveToStream(Stream : TStream);

      property Header : TDXFileHeader read FHeader;
      property RootNode : TDXNode read FRootNode;

  end;

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

// ----------------------------------------------------------------------
// Text parsing functions
// ----------------------------------------------------------------------

// RemoveComments
//
procedure RemoveComments(Text : TStringList);
var
  i, comment : Integer;
begin
  for i:=0 to Text.Count-1 do begin
    comment:=Pos('//',Text[i]);
    if comment>0 then
      Text[i]:=Copy(Text[i], 0, comment-1);
    comment:=Pos('#',Text[i]);
    if comment>0 then
      Text[i]:=Copy(Text[i], 0, comment-1);
  end;
end;


// ----------------------------------------------------------------------
// TDXFile
// ----------------------------------------------------------------------

// Create
//
constructor TDXFile.Create;
begin
  FRootNode:=TDXNode.Create;
end;

// Destroy
//
destructor TDXFile.Destroy;
begin
  FRootNode.Free;

  inherited;
end;

// LoadFromStream
//
procedure TDXFile.LoadFromStream(Stream : TStream);
begin
  Stream.Read(FHeader, SizeOf(TDXFileHeader));
  Assert(Header.Magic = 'xof ', 'Invalid DirectX file');

  if Header.FileType = 'txt ' then
    ParseText(Stream)
  else
  if Header.FileType = 'bin ' then
    raise Exception.Create('FileX error, "bin" filetype not supported')
  else
  if Header.FileType = 'tzip' then
    raise Exception.Create('FileX error, "tzip" filetype not supported')
  else
  if Header.FileType = 'bzip' then
    raise Exception.Create('FileX error, "bzip" filetype not supported');

end;

procedure TDXFile.ParseBinary(Stream: TStream);
begin
  // To-do
end;

procedure TDXFile.ParseText(Stream: TStream);
var
  XText,
  TempBuffer : TStringList;
  Cursor : Integer;
  Buffer : String;

  function ContainsColon(Buffer : String) : Boolean;
  begin
    Result:=Pos(';', Buffer)>0;
  end;

  function ContainsBegin(Buffer : String) : Boolean;
  begin
    Result:=Pos('{', Buffer)>0;
  end;

  function ContainsEnd(Buffer : String) : Boolean;
  begin
    Result:=Pos('}', Buffer)>0;
  end;

  function ReadString : String;
  begin
    if Cursor<XText.Count then
      Result:=XText[Cursor]
    else
      Result:='';
    Inc(Cursor);
  end;

  function GetNodeData(var NodeType, NodeName : String) : Boolean;
  begin
    NodeType:='';
    NodeName:='';
    Result:=False;
    if Cursor<3 then exit;

    NodeType:=XText[Cursor-3];
    NodeName:=XText[Cursor-2];

    if ContainsBegin(NodeType)
    or ContainsEnd(NodeType)
    or ContainsColon(NodeType) then begin
      NodeType:=NodeName;
      NodeName:='';
    end;

    NodeType:=LowerCase(NodeType);
  end;

  function ReadInteger : Integer;
  var
    str : String;
  begin
    str:=ReadString;

    if ContainsColon(str) then str:=StringReplace(str, ';', '', [rfReplaceAll]);
    if ContainsBegin(str) then str:=StringReplace(str, '{', '', [rfReplaceAll]);
    if ContainsEnd(str) then str:=StringReplace(str, '}', '', [rfReplaceAll]);

    Result:=StrToInt(str);
  end;

  function ReadSingle : Single;
  var
    str : String;
  begin
    str:=ReadString;

    if ContainsColon(str) then str:=StringReplace(str, ';', '', [rfReplaceAll]);
    if ContainsBegin(str) then str:=StringReplace(str, '{', '', [rfReplaceAll]);
    if ContainsEnd(str) then str:=StringReplace(str, '}', '', [rfReplaceAll]);

    Result:=StrToFloatDef(str);
  end;

  function ReadMatrix : TMatrix;
  var
    i, j : Integer;
  begin
    try
      for j:=0 to 3 do
        for i:=0 to 3 do
          Result.V[i].V[j]:=ReadSingle;
    except
      on E:Exception do begin
        Result:=IdentityHMGMatrix;
      end;
    end;
  end;

  function ReadVector3f : TAffineVector;
  var
    str : String;
  begin
    str:=ReadString;
    str:=StringReplace(str, ';', ' ', [rfReplaceAll]);
    TempBuffer.CommaText:=str;
    if TempBuffer.Count > 1 then begin
      Result.V[0]:=StrToFloatDef(TempBuffer[0]);
      Result.V[1]:=StrToFloatDef(TempBuffer[1]);
      Result.V[2]:=StrToFloatDef(TempBuffer[2]);
    end else begin
      Result.V[0]:=StrToFloatDef(TempBuffer[0]);
      Result.V[1]:=ReadSingle;
      Result.V[2]:=ReadSingle;
    end;
  end;

  function ReadVector4f : TVector;
  var
    str : String;
  begin
    str:=ReadString;
    str:=StringReplace(str, ';', ' ', [rfReplaceAll]);
    TempBuffer.CommaText:=str;
    if TempBuffer.Count > 1 then begin
      Result.V[0]:=StrToFloatDef(TempBuffer[0]);
      Result.V[1]:=StrToFloatDef(TempBuffer[1]);
      Result.V[2]:=StrToFloatDef(TempBuffer[2]);
      Result.V[3]:=StrToFloatDef(TempBuffer[3]);
    end else begin
      Result.V[0]:=StrToFloatDef(TempBuffer[0]);
      Result.V[1]:=ReadSingle;
      Result.V[2]:=ReadSingle;
      Result.V[3]:=ReadSingle;
    end;
  end;

  function ReadTexCoord : TAffineVector;
  var
    str : String;
  begin
    str:=ReadString;
    str:=StringReplace(str, ';', ' ', [rfReplaceAll]);
    TempBuffer.CommaText:=str;
    if TempBuffer.Count > 1 then begin
      Result.V[0]:=StrToFloatDef(TempBuffer[0]);
      Result.V[1]:=StrToFloatDef(TempBuffer[1]);
    end else begin
      Result.V[0]:=StrToFloatDef(TempBuffer[0]);
      Result.V[1]:=ReadSingle;
    end;
    Result.V[2]:=0;
  end;

  procedure ReadMeshVectors(VectorList : TAffineVectorList);
  var
    i, NumVectors : Integer;
  begin
    NumVectors:=ReadInteger;
    for i:=0 to NumVectors-1 do
      VectorList.Add(ReadVector3f);
  end;

  procedure ReadMeshIndices(IndexList : TIntegerList; VertCountIndices : TIntegerList = nil);
  var
    str : String;
    i, j, NumFaces, NumIndices, jStart : Integer;
    Indices : array of Integer;
  begin
    NumFaces:=ReadInteger;
    for i:=0 to NumFaces-1 do begin
      str:=ReadString;
      str:=StringReplace(str, ';', ' ', [rfReplaceAll]);
      TempBuffer.CommaText:=str;
      NumIndices:=StrToInt(TempBuffer[0]);
      SetLength(Indices, NumIndices);
      jStart:=0;
      if TempBuffer.Count>1 then begin
        Indices[0]:=StrToInt(TempBuffer[1]);
        jStart:=1;
      end;
      for j:=jStart to NumIndices-1 do
        Indices[j]:=ReadInteger;
      case NumIndices of
        3 : begin
          IndexList.Add(Indices[0], Indices[1], Indices[2]);
          if Assigned(VertCountIndices) then VertCountIndices.Add(3);
        end;
        4 : begin
          IndexList.Add(Indices[0], Indices[1], Indices[2]);
          IndexList.Add(Indices[0], Indices[2], Indices[3]);
          if Assigned(VertCountIndices) then VertCountIndices.Add(6);
        end;
      end;
      SetLength(Indices, 0);
    end;
  end;

  procedure ReadTexCoords(VectorList : TAffineVectorList);
  var
    i, NumVectors : Integer;
  begin
    NumVectors:=ReadInteger;
    for i:=0 to NumVectors-1 do
      VectorList.Add(ReadTexCoord);
  end;

  procedure ReadMeshVertices(Mesh : TDXMesh);
  begin
    ReadMeshVectors(Mesh.Vertices);
    ReadMeshIndices(Mesh.VertexIndices, Mesh.VertCountIndices);
  end;

  procedure ReadMeshNormals(Mesh : TDXMesh);
  begin
    ReadMeshVectors(Mesh.Normals);
    ReadMeshIndices(Mesh.NormalIndices);
  end;

  procedure ReadMeshTexCoords(Mesh : TDXMesh);
  begin
    ReadTexCoords(Mesh.TexCoords);
  end;

  procedure ReadMeshMaterialList(Mesh : TDXMesh);
  var
    i, {NumMaterials,} NumIndices : Integer;
  begin
    {NumMaterials:=}ReadInteger;
    NumIndices:=ReadInteger;
    for i:=0 to NumIndices-1 do
      Mesh.MaterialIndices.Add(ReadInteger);
  end;

  procedure ReadMeshMaterial(Mesh : TDXMesh);
  begin
    with TDXMaterial.CreateOwned(Mesh.MaterialList) do begin
      Diffuse:=ReadVector4f;
      SpecPower:=ReadSingle;
      Specular:=ReadVector3f;
      Emissive:=ReadVector3f;
    end;
  end;

  procedure ReadTextureFilename(Mesh : TDXMesh);
  var
    Str : String;
  begin
    if Mesh.MaterialList.Count>0 then begin
      Str:=ReadString;
      Str:=StringReplace(Str, '"', '', [rfReplaceAll]);
      Str:=StringReplace(Str, ';', '', [rfReplaceAll]);
      Str:=Trim(Str);
      Mesh.MaterialList.Items[Mesh.MaterialList.Count-1].Texture:=Str;
    end;
  end;

  procedure ReadStruct(ParentNode : TDXNode);
  var
    Buffer,
    NodeType,
    NodeName : String;
    Loop : Boolean;
    NewNode : TDXNode;
  begin
    Loop:=True;
    while Loop do begin
      Buffer:=ReadString;
      if Cursor>XText.Count-1 then break;
      if ContainsEnd(Buffer) then
        Loop:=False
      else if ContainsBegin(Buffer) then begin
        GetNodeData(NodeType, NodeName);
        NewNode:=nil;

        // Frame
        if NodeType = 'frame' then begin
          NewNode:=TDXFrame.CreateOwned(ParentNode);
          ReadStruct(NewNode);

        // Frame transform matrix
        end else if NodeType = 'frametransformmatrix' then begin
          if ParentNode is TDXFrame then
            TDXFrame(ParentNode).Matrix:=ReadMatrix;
          ReadStruct(ParentNode);

        // Mesh
        end else if NodeType = 'mesh' then begin
          NewNode:=TDXMesh.CreateOwned(ParentNode);
          ReadMeshVertices(TDXMesh(NewNode));
          ReadStruct(NewNode);

        // Mesh normals
        end else if NodeType = 'meshnormals' then begin
          if ParentNode is TDXMesh then
            ReadMeshNormals(TDXMesh(ParentNode));
          ReadStruct(ParentNode);

        // Mesh texture coords
        end else if NodeType = 'meshtexturecoords' then begin
          if ParentNode is TDXMesh then
            ReadMeshTexCoords(TDXMesh(ParentNode));
          ReadStruct(ParentNode);

        // Mesh material list
        end else if NodeType = 'meshmateriallist' then begin
          if ParentNode is TDXMesh then
            ReadMeshMaterialList(TDXMesh(ParentNode));
          ReadStruct(ParentNode);

        // Mesh material
        end else if NodeType = 'material' then begin
          if ParentNode is TDXMesh then
            ReadMeshMaterial(TDXMesh(ParentNode));
          ReadStruct(ParentNode);

        // Material texture filename
        end else if NodeType = 'texturefilename' then begin
          if ParentNode is TDXMesh then
            ReadTextureFilename(TDXMesh(ParentNode));
          ReadStruct(ParentNode);

        // Unknown type
        end else begin
          //NewNode:=TDXNode.CreateOwned(ParentNode);
          //NodeType:='*'+NodeType;
          //ReadStruct(NewNode);
          ReadStruct(ParentNode);
        end;

        if Assigned(NewNode) then begin
          NewNode.TypeName:=NodeType;
          NewNode.Name:=NodeName;
        end;
      end;
    end;
  end;

begin
  XText:=TStringList.Create;
  TempBuffer:=TStringList.Create;
  XText.LoadFromStream(Stream);

  // Remove comments and white spaces
  RemoveComments(XText);
  XText.CommaText:=XText.Text;

  // Fix embedded open braces
  Cursor:=0;
  while Cursor<XText.Count-1 do begin
    Buffer:=ReadString;
    if Pos('{',Buffer)>1 then begin
      XText[Cursor-1]:=Copy(Buffer,0,Pos('{',Buffer)-1);
      XText.Insert(Cursor,'{');
    end;
  end;

  XText.SaveToFile('XText_dump.txt');

  // Start parsing
  Cursor:=0;
  while Cursor<XText.Count-1 do
    ReadStruct(RootNode);

  TempBuffer.Free;
  XText.Free;
end;


// ----------------------------------------------------------------------
// TDXMaterialList
// ----------------------------------------------------------------------

// GetMaterial
//
function TDXMaterialList.GetMaterial(index: Integer): TDXMaterial;
begin
  Result:=TDXMaterial(Get(index));
end;


// ----------------------------------------------------------------------
// TDXMesh
// ----------------------------------------------------------------------

// Create
//
constructor TDXMesh.Create;
begin
  inherited;

  FVertices:=TAffineVectorList.Create;
  FNormals:=TAffineVectorList.Create;
  FTexCoords:=TAffineVectorList.Create;
  FVertexIndices:=TIntegerList.Create;
  FNormalIndices:=TIntegerList.Create;
  FMaterialIndices:=TIntegerList.Create;
  FVertCountIndices:=TIntegerList.Create;
  FMaterialList:=TDXMaterialList.Create;
end;

// Destroy
//
destructor TDXMesh.Destroy;
begin
  FVertices.Free;
  FNormals.Free;
  FTexCoords.Free;
  FVertexIndices.Free;
  FNormalIndices.Free;
  FMaterialIndices.Free;
  FVertCountIndices.Free;
  FMaterialList.Free;

  inherited;
end;


// ----------------------------------------------------------------------
// TDXNode
// ----------------------------------------------------------------------

// Create
//
constructor TDXNode.Create;
begin
  // Virtual
end;

// CreateOwned
//
constructor TDXNode.CreateOwned(AOwner: TDXNode);
begin
  FOwner:=AOwner;
  Create;
  if Assigned(FOwner) then
    FOwner.Add(Self);
end;

// GetItem
//
function TDXNode.GetItem(index: Integer): TDXNode;
begin
  Result:=TDXNode(Get(index));
end;

// Clear
//
procedure TDXNode.Clear;
var
  i : integer;
begin
  for i:=0 to Count-1 do
    Items[i].Free;

  inherited;
end;


// ----------------------------------------------------------------------
// TDXFrame
// ----------------------------------------------------------------------

// Create
//
constructor TDXFrame.Create;
begin
  inherited;
  FMatrix:=IdentityHMGMatrix;
end;

// GlobalMatrix
//
function TDXFrame.GlobalMatrix: TMatrix;
begin
  if Owner is TDXFrame then
    Result:=MatrixMultiply(TDXFrame(Owner).GlobalMatrix, FMatrix)
  else
    Result:=FMatrix;
end;


// ----------------------------------------------------------------------
// TDXMaterial
// ----------------------------------------------------------------------

// CreateOwned
constructor TDXMaterial.CreateOwned(AOwner: TDXMaterialList);
begin
  Create;
  if Assigned(AOwner) then
    AOwner.Add(Self);
end;

end.
