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function [V,F,UV,TF,N,NF] = readOBJ(filename,varargin)  % READOBJ reads an OBJ file with vertex/face information  %  % [V,F,UV,TF,N,NF] = readOBJ(filename)  % [V,F,UV,TF,N,NF] = readOBJ(filename,'ParameterName',ParameterValue,...)  %  % Input:  %  filename  path to .obj file  %  Optional:  %    'Quads' whether to output face information in X by 4 matrices (faces  %      with degree larger than 4 are still triangulated). A trailing zero  %      will mean a triangle was read.  % Outputs:  %  V  #V by 3 list of vertices  %  F  #F by 3 list of triangle indices  %  UV  #V by 2 list of texture coordinates  %  TF  #F by 3 list of triangle texture coordinates  %  N  #V by 3 list of normals  %  NF  #F by 3 list of triangle corner normal indices into N  %  % Examples:  %   % read a quad/triangle mesh and display it  %   [V,F] = readOBJ('quads.obj','Quads',true);  %   % Turn triangles into degenerate quads   %   DF = (F==0).*F(:,[4 1 2 3])+(F~=0).*F;  %   trisurf(DF,V(:,1),V(:,2),V(:,3));  %  %  % See also: load_mesh, readOBJfast, readOFF  % default values  quads = false;  % Map of parameter names to variable names  params_to_variables = containers.Map( ...    {'Quads'}, ...    {'quads'});  v = 1;  while v <= numel(varargin)    param_name = varargin{v};    if isKey(params_to_variables,param_name)      assert(v+1<=numel(varargin));      v = v+1;      % Trick: use feval on anonymous function to use assignin to this workspace       feval(@()assignin('caller',params_to_variables(param_name),varargin{v}));    else      error('Unsupported parameter: %s',varargin{v});    end    v=v+1;  end  numv = 0;  numf = 0;  numuv = 0;  numtf = 0;  numn = 0;  numnf = 0;  % simplex size  if quads    ss = 4;  else    ss = 3;  end  % Amortized array allocation  V = zeros(10000,3);  F = zeros(10000,ss);  UV = zeros(10000,3);  TF = zeros(10000,ss);  N = zeros(10000,3);  NF = zeros(10000,ss);  triangulated = false;  all_ss = true;  fp = fopen( filename, 'r' );  type = fscanf( fp, '%s', 1 );  count = 0;  while strcmp( type, '' ) == 0      line = fgets(fp);      if strcmp( type, 'v' ) == 1          v = sscanf( line, '%lf %lf %lf' );          numv = numv+1;          if(numv>size(V,1))            V = cat(1,V,zeros(10000,3));          end          V(numv,:) = [v(1:3)'];      elseif strcmp( type, 'vt')          v = sscanf( line, '%f %f %f' );          numuv = numuv+1;          if size(UV,2)>2 && length(v) == 2              UV = UV(:,1:2);          end          if(numuv>size(UV,1))            UV = cat(1,UV,zeros(10000,length(v)));          end          UV(numuv,:) = [v'];      elseif strcmp( type, 'vn')          n = sscanf( line, '%f %f %f' );          numn = numn+1;          if(numn>size(N,1))            N = cat(1,N,zeros(10000,3));          end          N(numn,:) = [n'];      elseif strcmp( type, 'f' ) == 1          [t, count] = sscanf(line,'%d/%d/%d %d/%d/%d %d/%d/%d %d/%d/%d %d/%d/%d');          if (count>2)              tf = t(2:3:end);              nf = t(3:3:end);              t = t(1:3:end);          else              [t, count] = sscanf(line, '%d/%d %d/%d %d/%d %d/%d %d/%d');              if (count>2)                  tf = t(2:2:end);                  t = t(1:2:end);                  nf = -ones(numel(t),1);              else                [t, count] = sscanf(line, '%d//%d %d//%d %d//%d %d//%d %d//%d');                if (count>2)                    nf = t(2:2:end);                    t = t(1:2:end);                    tf = -ones(numel(t),1);                else                    [t, count] = sscanf( line, '%d %d %d %d %d %d %d %d %d %d %d\n' );                    if (count>2)                      tf = -ones(numel(t),1);                      nf = -ones(numel(t),1);                    else                      [t, count] = sscanf( line, '%d// %d// %d// %d// %d// %d// %d// %d// %d// %d// %d//\n' );                      tf = -ones(numel(t),1);                      nf = -ones(numel(t),1);                    end                end              end          end          t = t + (t<0).*   (numv+1);          tf = tf + (tf<0).*(numuv+1);          nf = nf + (nf<0).*(numn+1);          assert(numel(t) == numel(tf));          assert(numel(t) == numel(nf));          if numel(t) > ss            if ~triangulated              warning('Trivially triangulating high degree facets');            end            triangulated = true;          end          j = 2;          i = 1;          %Vt = V(t,:);          %[~,A] = affine_fit(Vt);          %VtA = Vt*A;          %VtA0 = Vt*A;          %[~,alpha] = curvature(VtA);          %flip = -sign(sum(alpha));          %E = [1:size(VtA,1);2:size(VtA,1) 1]';          %[dV,dF] = triangle(VtA,E,[]);          %if size(dF,1)>2          %  tsurf(dF,dV);          %  hold on;          %  plot(VtA0([1:end 1],1),VtA0([1:end 1],2),'LineWidth',3);          %  hold off          %  pause          %end          while true            if numel(t) > ss              corners = [1 2 3];              %plot(VtA0([1:end 1],1),VtA0([1:end 1],2));              %hold on;              %plot(VtA([1:3],1),VtA([1:3],2),'LineWidth',3);              %hold off;              %expand_axis(2);              %pause;              %[~,alpha] = curvature(VtA,[1 2;2 3]);              %alpha = flip * alpha(2);              %others = VtA(setdiff(1:end,corners),:);              %these = VtA(corners,:);              %w = inpolygon(others(:,1),others(:,2),these(:,1),these(:,2));              %alpha              %if alpha>=0 && ~any(w)              %  % lazy              %  t = t([2:end 1]);              %  VtA = VtA([2:end 1],:);              %  continue;              %end            else              if all_ss && numel(t)
   
    size(F,1))              F = cat(1,F,zeros(10000,ss));            end            F(numf,1:numel(corners)) = [t(corners)'];            numtf = numtf+1;            if(numtf>size(TF,1))              TF = cat(1,TF,zeros(10000,ss));            end            TF(numtf,1:numel(corners)) = [tf(corners)'];            numnf = numnf+1;            if(numnf>size(NF,1))              NF = cat(1,NF,zeros(10000,ss));            end            NF(numnf,1:numel(corners)) = [nf(corners)'];            if numel(t) <= ss              break;            end            t = t([1 3:end]);            %VtA = VtA([1 3:end],:);            if numel(t) < 3              break;            end          end      elseif strcmp( type, '#' ) == 1          %fscanf( fp, '%s\n', 1 );          % ignore line      end      type = fscanf( fp, '%s', 1 );  end  fclose( fp );  %try  %    F = cell2mat(F);  %end  V = V(1:numv,:);  F = F(1:numf,:);  UV = UV(1:numuv,:);  TF = TF(1:numtf,:);  N = N(1:numn,:);  NF = NF(1:numnf,:);  %% transform into array if all faces have the same number of vertices  if (size(UV,1)>0) UV = UV; endend
   

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