vb_read_vrml_image

 Read 2D Image from vrml-file

   img1(Nx, Ny) : R color image 
   img2(Nx, Ny) : G color image 
   img3(Nx, Ny) : B color image 

         Texture2 {
                    image 400 400 3
  0x000603 0x010603 0x030703 0x060704 0x060503 0x080703 0x070502 0x070502
  0x090504 0x090404 0x090305 0x090307 0x080307 0x070206 0x090307 0x0b0408
         }
 
 imageデータの並び :[ Nx  Ny ]
 jx ; X-index  左から右 (from Left to Right)
 jy : Y-index　下から上 (from Down to Up)
 
 for jy=1:Ny
     for jx=1:Nx
         image(jx,jy)
     end
 end
 
 1つのデータ '0x0b0307' が、1ピクセルのRGB(3つの16進数)を表す
 RGB = [0b　03　07]

 Copyright (C) 2011, ATR All Rights Reserved.
 License : New BSD License(see VBMEG_LICENSE.txt)

0001 function    [img1,img2,img3] = vb_read_vrml_image(fname)
0002 % Read 2D Image from vrml-file
0003 %
0004 %   img1(Nx, Ny) : R color image
0005 %   img2(Nx, Ny) : G color image
0006 %   img3(Nx, Ny) : B color image
0007 %
0008 %         Texture2 {
0009 %                    image 400 400 3
0010 %  0x000603 0x010603 0x030703 0x060704 0x060503 0x080703 0x070502 0x070502
0011 %  0x090504 0x090404 0x090305 0x090307 0x080307 0x070206 0x090307 0x0b0408
0012 %         }
0013 %
0014 % imageデータの並び :[ Nx  Ny ]
0015 % jx ; X-index  左から右 (from Left to Right)
0016 % jy : Y-index　下から上 (from Down to Up)
0017 %
0018 % for jy=1:Ny
0019 %     for jx=1:Nx
0020 %         image(jx,jy)
0021 %     end
0022 % end
0023 %
0024 % 1つのデータ '0x0b0307' が、1ピクセルのRGB(3つの16進数)を表す
0025 % RGB = [0b　03　07]
0026 %
0027 % Copyright (C) 2011, ATR All Rights Reserved.
0028 % License : New BSD License(see VBMEG_LICENSE.txt)
0029 
0030 key.start  = 'Texture2';
0031 key.start2 = 'image';
0032 key.end    = '}';
0033 key.braket = '{';
0034 
0035 [Nskip, Nline, Mmax] = vb_read_vrml_line(fname,key);
0036 
0037 fid=fopen(fname);
0038 
0039 % Skip lines until data
0040 for n=1:Nskip
0041     next_line = fgetl(fid);
0042 end
0043 
0044 ix   = strfind(next_line,'image'); 
0045 
0046 if isempty(ix),
0047 % No image data
0048     img1=[];img2=[];img3=[];
0049     return;
0050 end;
0051 
0052 dim  = next_line( (ix+5):end );
0053 Ndim = sscanf(dim,'%d %d %d');
0054 
0055 Nx    = Ndim(1);
0056 Ny    = Ndim(2);
0057 Nbyte = Ndim(3);
0058 
0059 fprintf('NX = %d , NY = %d\n', Nx,Ny);
0060 
0061 % Start read data
0062 img = zeros(Nx*Ny,Nbyte);
0063 n2   = 0;
0064 
0065 % Read data
0066 for n=1:Nline
0067     next_line = fgetl(fid);
0068     
0069     % one line consists of 8 strings
0070     % each string '0x0b0307' represents three 2-char Hex integer
0071     % '0x0b0307' -> '0b' ,　'03' ,　'07'
0072 
0073     str = strrep(next_line,'0x','');    % eliminate '0x'
0074     x   = sscanf( str,'%2x');            % read 2-char Hex integer
0075     M   = length(x)/Nbyte;
0076 
0077     n1  = n2 + 1;
0078     n2  = n2 + M;
0079     img(n1:n2,:) = reshape(x,[Nbyte M])';
0080 
0081 end
0082 
0083 fclose(fid);
0084 
0085 if n2 ~= (Nx*Ny),
0086     error('Read format error');
0087 end
0088 
0089 % Reshape 2D-matrix and Scale value
0090 img1  = reshape(img(:,1), [Nx Ny])/256;
0091 img2  = reshape(img(:,2), [Nx Ny])/256;
0092 img3  = reshape(img(:,3), [Nx Ny])/256;
0093