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R8218/importStl.m
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importStl.m
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function varargout=importStl(filename,mode)
% STL_Import is a tool designed to import into MATLAB both binary and ASCII STL files.
%
% This scprit is mainly a collage betwwen file axchange fileid 22409 and 3642, plus
% some other features that can be considered new on FEX.
%
% SYNOPSIS:
%
%
% %mode 1 (default)
% [p,t,tnorm]=STL_Import(filename,mode)
%
% %mode 2
% [v,tnorm])=STL_Import(filename,mode)
%
%
% INPUT:
%
% filename: string representing the name fo the file
%
% mode:
%
%
% mode=1 (if omitted is automatically set to one)
%
% set the the output to:
%
% output=[p,t,tnorm]
%
% where
%
% p=points (unique) of the model nx3 array
%
% t=triangles indexes of the model
%
% tnorm= normals of triangles
%
%
% mode=2
%
% set the the output to:
%
% output=[v,tnorm]
%
% where
%
% v= vertex of the model(not unique points) of the model nx3 array. Each
% three points we have a triangle in consecutive order.
%
% tnorm= normals of triangles
%
% EXAMPLES:
%
% [p,t,tnorm]=STL_Import('link1.stl',1);
% [pv,tnorm]=STL_Import('link1.stl',2);
%
%
% Visit:
%
% http://giaccariluigi.altervista.org/blog/
%
% Author: Giaccari Luigi (giaccariluigi@msn.com)
if nargin<2
mode=1;%default value
end
if ~(mode==1 || mode==2)
error('invalid mode')
end
if nargout<3 && mode==1
error('invalid input number /mode setting')
end
if nargout>2 && mode==2
error('invalid input number /mode setting')
end
%open file
fid=fopen(filename, 'r'); %Open the file, assumes STL ASCII format.
if fid == -1
error('File could not be opened, check name or path.')
end
M = fread(fid,inf,'uint8=>uint8');
fclose(fid);
if( isbinary(M) )
[v,tnorm]=ImportSTL_binary(M);
else
clear M;
[v,tnorm]=ImportSTL_ASCII(filename);
end
clear M
varargout = cell(1,nargout);
switch mode
case 1
[p,t]=fv2pt(v,length(v)/3);%gets points and triangles
varargout{1} = p;
varargout{2} = t;
varargout{3} = tnorm;
case 2
varargout{1} = v;
varargout{2} = tnorm;
end
end
function [v,tnorm]=ImportSTL_ASCII(filename)
%counting the number of vertex
vnum=0;
fid=fopen(filename, 'r'); %Open the file, assumes STL ASCII format.
while feof(fid) == 0 % test for end of file, if not then do stuff
tline = fgetl(fid); % reads a line of data from file.
fword = sscanf(tline, '%s '); % make the line a character string
if strncmpi(fword, 'v',1) ; % Checking if a "V"ertex line, as "V" is 1st char.
vnum = vnum + 1; % If a V we count the # of V's
end
end
fclose(fid);
numt=ceil(vnum/3);%triangles number equals vertex number/3
tnorm=zeros(numt,3);%preallocate for normals
v=zeros(vnum,3);%not unique vertex
c=0;%vertex counter
fnum=0;
fid=fopen(filename, 'r'); %REOpen the file
while feof(fid) == 0 % test for end of file, if not then do stuff
tline = fgetl(fid); % reads a line of data from file.
fword = sscanf(tline, '%s '); % make the line a character string
%% Check vertex
if strncmpi(fword, 'v',1) ; % Checking if a "V"ertex line, as "V" is 1st char.
c = c + 1; % If a V we count the # of V's
v(c,:) = sscanf(tline, '%*s %f %f %f'); % & if a V, get the XYZ data of it.
%% Check facet normal
elseif strncmpi(fword, 'f',1) ; % Checking if a "V"ertex line, as "V" is 1st char.
fnum =fnum + 1; % If a V we count the # of V's
tnorm(fnum,:) = sscanf(tline, '%*s %*s %f %f %f'); % & if a V, get the XYZ data of it.
% %% Check for color
% elseif strncmpi(fword, 'c',1) ; % Checking if a "C"olor line, as "C" is 1st char.
% VColor = sscanf(tline, '%*s %f %f %f'); % & if a C, get the RGB color data of the face.
% % Keep this color, until the next color is used.
end
end
fclose(fid);
end
function [p,t]=fv2pt(v,fnum)
%gets points and triangle indexes given vertex and facet number
c=size(v,1);
%triangles with vertex id data
t=zeros(3,fnum);
t(:)=1:c;
%now we have to keep unique points fro vertex
[p,i,j]=unique(v,'rows'); %now v=p(j) p(i)=v;
t(:)=j(t(:));
t=t';
end
%
function tf = isbinary(A)
% ISBINARY determines if an STL file is binary or ASCII.
% Look for the string 'endsolid' near the end of the file
if isempty(A) || length(A) < 16
error('MATLAB:stlread:incorrectFormat', ...
'File does not appear to be an ASCII or binary STL file.');
end
% Read final 16 characters of M
i2 = length(A);
i1 = i2 - 100;%100 empirical value
str = char( A(i1:i2)' );
k = strfind(lower(str), 'endsolid');
if ~isempty(k)
tf = false; % ASCII
else
tf = true; % Binary
end
end
function [V,N]=ImportSTL_binary(M)
if length(M) < 84
error('MATLAB:stlread:incorrectFormat', ...
'Incomplete header information in binary STL file.');
end
% Bytes 81-84 are an unsigned 32-bit integer specifying the number of faces
% that follow.
numFaces = typecast(M(81:84),'uint32');
%numFaces = double(numFaces);
if numFaces == 0
warning('MATLAB:stlread:nodata','No data in STL file.');
return
end
T = M(85:end);
V = NaN(3*numFaces,3);
N = NaN(numFaces,3);
numRead = 0;
while numRead < numFaces
% Each facet is 50 bytes
% - Three single precision values specifying the face normal vector
% - Three single precision values specifying the first vertex (XYZ)
% - Three single precision values specifying the second vertex (XYZ)
% - Three single precision values specifying the third vertex (XYZ)
% - Two unused bytes
i1 = 50 * numRead + 1;
i2 = i1 + 50 - 1;
facet = T(i1:i2)';
n = typecast(facet(1:12),'single');
v1 = typecast(facet(13:24),'single');
v2 = typecast(facet(25:36),'single');
v3 = typecast(facet(37:48),'single');
n = double(n);
v = double([v1; v2; v3]);
% Figure out where to fit these new vertices, and the face, in the
% larger F and V collections.
fInd = numRead + 1;
vInd1 = 3 * (fInd - 1) + 1;
vInd2 = vInd1 + 3 - 1;
V(vInd1:vInd2,:) = v;
N(fInd,:) = n;
numRead = numRead + 1;
end
end
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