Loading textures from stream

[Manel Goucha]

Hi,

I'm trying to load a texture from a stream to apply on a plane face, but it only load if the texture is loaded from file, from the stream the glGenTexture doesn't seem to be generating a new texture

can anyone help me ont his?

thks

[Manel Goucha]

Using all delphi code:

delphi code:

procedure LoadTextures
var
  Stream: TFileStream;
  Texture: Integer;
begin
  Stream := TFileStream.Create('File.bmp', fmOpenRead);
  LoadTextureFromStream(Stream, Texture);
  Stream.Free;
end;

Code for loading textures from a Stream

procedure LoadTextureFromStream(Stream: TStream; var Texture: GLuint);
var
  FileHeader: BITMAPFILEHEADER;
  InfoHeader: BITMAPINFOHEADER;
  Palette: array of RGBQUAD;
  BitmapLength: LongWord;
  PaletteLength: LongWord;
  Width, Height : Integer;
  pData : Pointer;
  p,j,ExpandBMP,Rmask,Gmask,Bmask : Integer;
  Format : Word;
begin
  Stream.Position := 0;
   Stream.ReadBuffer(FileHeader, SizeOf(FileHeader));  // FileHeader
   Stream.ReadBuffer(InfoHeader, SizeOf(InfoHeader));  // InfoHeader
   PaletteLength := InfoHeader.biClrUsed;
   case InfoHeader.biBitCount of
   1,4:
   begin
    ExpandBMP := InfoHeader.biBitCount;
    InfoHeader.biBitCount := 8;
   end;
   else
    ExpandBMP := 0;
   end;
   case InfoHeader.biCompression of
   0: // BI_RGB
      begin
        case InfoHeader.biBitCount of
        15,16: begin Rmask := $7c00; GMask := $03e0; BMask := $001f; end;
        // assuming big endian
        24: begin Rmask := $ff; GMask := $ff00; Bmask := $ff0000; end;
        32: begin Rmask := $ff0000; Gmask := $ff00; Bmask := $ff; end;
        end;
      end;
   1, // BI_RLE8
   2: // BI_RLE4
      raise EInvalidGraphic.create('Compressed Bitmaps not handled');
   3: // BI_BitFields
      begin
        case InfoHeader.biBitCount of
        15,16,32: begin
                    Stream.ReadBuffer(Rmask,sizeof(Rmask));
                    Stream.ReadBuffer(Gmask,sizeof(Gmask));
                    Stream.ReadBuffer(Bmask,sizeof(Bmask));
                  end;
        end;
      end;
   end;
   if (InfoHeader.biBitCount=24) then
    Format := GL_RGB
   else
    Format := GL_RGBA;
 
   SetLength(Palette, PaletteLength);
   Stream.ReadBuffer(Palette, PaletteLength);          // Palette
   Width := InfoHeader.biWidth;
   Height := InfoHeader.biHeight;
 
   BitmapLength := InfoHeader.biSizeImage;
   if BitmapLength = 0 then
     BitmapLength := Width * Height * InfoHeader.biBitCount Div 8;
   GetMem(pData, BitmapLength);
   try
     Stream.ReadBuffer(pData^, BitmapLength);            // Bitmap Data
  // Bitmaps are stored BGR and not RGB, so swap the R and B bytes.
    if (Rmask<>$ff0000) then
        SwapRGB(pData, Width*Height);
    if (InfoHeader.biBitCount=32) then
    begin
      SwapRGBA(pData,Width*Height);
    end;
    Texture :=CreateTexture(Width, Height, format, pData);
  finally
    FreeMem(pData);
  end;
end;

OpenGL Code:

function CreateTexture(Width, Height, Format: Word; pData: Pointer): Integer;
var
  Texture: GLuint;
begin
  glGenTextures(1, @Texture);
  glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
  glBindTexture(GL_TEXTURE_2D, Texture);
  glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
 
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 
  if Format = GL_RGBA
  then gluBuild2DMipmaps(GL_TEXTURE_2D, GL_RGBA, Width, Height, GL_RGBA, GL_UNSIGNED_BYTE, pData)
  else gluBuild2DMipmaps(GL_TEXTURE_2D, 3, Width, Height, GL_RGB, GL_UNSIGNED_BYTE, pData);
 
  result := Texture;
end;

But it doesn't seem to work, the texture doesn't load.