function bundle = wf_loadr14(filename)
% WF_LOAD Loads a wavefront object from a file.
% OBJ = WF_LOAD(FILENAME) Loads a 3D model contained in the file with
% the given FILENAME. The file must be in the format specified by the
% Wavefront specification. The full specification can be found in the
% following URL:
%
% http://netghost.narod.ru/gff/vendspec/waveobj/obj_spec.txt
%
% Generally speaking, a wavefront object is a structure which contains
% the XYZ coordinates of points in a 3D space. These points are used as
% reference points to define polygons, lines, curves and surfaces which
% define the object. The structure contains the required information to
% construct the 3D object. This information may specify a set of
% vertices and the way in which such a set should be connected to form a
% polygon.
%
% Example 1
% ---------
% This is an example of how a simple cube would be represented in a .obj
% file:
%
% # Vertices
% v -0.5 -0.5 -0.5
% v -0.5 -0.5 0.5
% v -0.5 0.5 -0.5
% v -0.5 0.5 0.5
% v 0.5 -0.5 -0.5
% v 0.5 -0.5 0.5
% v 0.5 0.5 -0.5
% v 0.5 0.5 0.5
%
% # Triangle facets
% f 1 7 5
% f 1 3 7
% f 2 6 8
% f 2 8 4
% f 1 4 3
% f 1 2 4
% f 3 8 7
% f 3 4 8
% f 5 7 8
% f 5 8 6
% f 1 5 6
% f 1 6 2
%
% In the example above the vertices of the cube are defined first,
% and then the vertices are joined to form triangular facets, which form
% the cube. In this case, the 1st ( -0.5 -0.5 -0.5 ), 7th ( 0.5 0.5
% -0.5 ) and 5th ( 0.5 -0.5 -0.5 ) vertices form the first face, and
% so on.
%
% NOTES:
% - Parser is very lazy and will not generate errors on for badly
% formated OBJ files.
% - Parser does not implement some statements (free-form geometry
% statements), however a warning is displayed when a non-implemented
% method is encountered.
%
% See also ISWF
file = fopen(filename,'r');
if file < 0
error([ 'Could not open file: ' filename ]);
else
disp(['Reading file: ' filename]);
end
% Initialize object fields
bundle.vertex = [];
bundle.vtex = [];
bundle.vnorm = [];
bundle.vparam = [];
bundle.points = {};
bundle.lines = {};
bundle.faces = {};
bundle.curvs = [];
bundle.curvs2 = [];
bundle.surfs = [];
bundle.conn = [];
curv_surf = [];
while ~feof(file)
elems = getline(file);
if ~isempty(elems)
command = lower(elems{1});
if command(1)=='#' % It is a comment, do nothing
elseif strcmp(command,'v') % GEOMETRIC VERTICES
x = str2double(elems{2});
y = str2double(elems{3});
z = str2double(elems{4});
if length(elems)>=5
w = str2double(elems{5});
else
w = 1;
end
bundle.vertex = [ bundle.vertex; x y z w ];
elseif strcmp(command,'vt') % TEXTURE VERTICES
u = str2double(elems{2});
v = str2double(elems{3});
if length(elems)>=4
w = str2double(elems{4});
else
w = 0;
end
bundle.vtex = [ bundle.vtex; u v w ];
elseif strcmp(command,'vn') % VERTEX NORMALS
i = str2double(elems{2});
j = str2double(elems{3});
k = str2double(elems{4});
bundle.vnorm = [ bundle.vnorm; i j k ];
elseif strcmp(command,'vp') % PARAMETER SPACE VERTICES
u = str2double(elems{2});
v = str2double(elems{3});
if length(elems)>=4
w = str2double(elems{4});
else
w = 1;
end
bundle.vparam = [ bundle.vparam; u v w ];
elseif strcmp(command,'cstype') % CURVE/SURFACE TYPE
if length(elems)==2
rat = false;
type = lower(elems{2});
elseif length(elems)==3
if strcmpi(elems{2},'rat')
rat = true;
end
type = lower(elems{3});
end
if sum(strcmp(type, {'bmatrix','bezier','bspline',...
'cardinal','taylor'}))
curv_surf = getFFCurvSurf(file,rat,type);
end
elseif strcmp(command,'curv') % CURVE
if isempty(curv_surf)
error(' ERROR: CSTYPE not defined while defining CURV');
else
curv = curv_surf; % Makes a copy with the same values
end
curv.u0 = str2double(elems{2});
curv.u1 = str2double(elems{3});
curv.v = zeros(length(elems)-3,1);
curv.v(1) = getTriplet(elems{4}, bundle);
curv.v(2) = getTriplet(elems{5}, bundle);
for i=3:size(curv.v,1)
curv.v(i) = getTriplet(elems{i+3}, bundle);
end
curv = getCSBodyStatements(file,curv);
bundle.curvs = [ bundle.curvs ; curv ];
elseif strcmp(command,'curv2') % CURVE 2
if isempty(curv_surf)
error(' ERROR: CSTYPE not defined while defining CURV2');
else
curv2 = curv_surf; % Makes a copy with the same values
end
curv2.vp = zeros(length(elems)-1,1);
curv2.vp(1) = handleNegVert(str2double(elems{2}), ...
size(bundle.vparam,1));
curv2.vp(2) = handleNegVert(str2double(elems{3}), ...
size(bundle.vparam,1));
for i=3:size(curv2.vp,1)
curv2.vp(i) = handleNegVert(str2double(elems{i+1}), ...
size(bundle.vparam,1));
end
curv2 = getCSBodyStatements(file,curv2);
bundle.curvs2 = [ bundle.curvs2 ; curv2 ];
elseif strcmp(command,'surf') % SURFACE
if isempty(curv_surf)
error(' ERROR: CSTYPE not defined while defining SURF');
else
surf = curv_surf; % Makes a copy with the same values
end
surf.s0 = str2double(elems{2});
surf.s1 = str2double(elems{3});
surf.t0 = str2double(elems{4});
surf.t1 = str2double(elems{5});
surf.v = zeros(length(elems)-5,3);
for i=1:size(surf.v,1)
[ surf.v(i,1) surf.v(i,2) surf.v(i,3) ] = ...
getTriplet(elems{i+5}, bundle);
end
surf = getCSBodyStatements(file,surf);
bundle.surfs = [ bundle.surfs ; surf ];
elseif strcmp(command,'p') % POINT
p = zeros(length(elems)-1,1);
for i=1:size(p,1)
p(i) = getTriplet(elems{i+1}, bundle);
end
bundle.points = [ bundle.points ; p ];
elseif strcmp(command,'l') % LINE
l = zeros(length(elems)-1,2);
for i=1:size(l,1)
[ l(i,1) l(i,2) ] = getTriplet(elems{i+1}, bundle);
end
bundle.lines = [ bundle.lines ; l ];
elseif strcmp(command,'f') % FACE
f = zeros(length(elems)-1,3);
for i=1:size(f,1)
[ f(i,1) f(i,2) f(i,3) ] = getTriplet(elems{i+1}, bundle);
end
bundle.faces{end+1,1} = f;
elseif strcmp(command,'con') % CONNECTIVITY
conn.surf_1 = str2double(elems{2});
conn.q0_1 = str2double(elems{3});
conn.q1_1 = str2double(elems{4});
conn.curv2d_1=str2double(elems{5});
conn.surf_2 = str2double(elems{6});
conn.q0_2 = str2double(elems{7});
conn.q1_2 = str2double(elems{8});
conn.curv2d_2=str2double(elems{9});
bundle.conn = [ bundle.conn ; conn ];
elseif strcmp(command,'g') % GROUP NAME
unimplemented(command,filename);
elseif strcmp(command,'s') % SMOOTHING GROUP
unimplemented(command,filename);
elseif strcmp(command,'mg') % MERGING GROUP
unimplemented(command,filename);
elseif strcmp(command,'o') % OBJECT NAME
unimplemented(command,filename);
elseif strcmp(command,'bevel') % BEVEL INTERPOLATION
unimplemented(command,filename);
elseif strcmp(command,'c_interp')% COLOUR INTERPOLATION
unimplemented(command,filename);
elseif strcmp(command,'d_interp')% DISSOLVE INTERPOLATION
unimplemented(command,filename);
elseif strcmp(command,'lod') % LEVEL OF DETAIL
unimplemented(command,filename);
elseif strcmp(command,'maplib') % LIBRARY MAP
unimplemented(command,filename);
elseif strcmp(command,'usemap') % TEXTURE MAP
unimplemented(command,filename);
elseif strcmp(command,'usemtl') % MATERIAL
unimplemented(command,filename);
elseif strcmp(command,'mtllib') % MATERIAL LIBRARY
unimplemented(command,filename);
elseif strcmp(command,'shadow_obj')% SHADOW
unimplemented(command,filename);
elseif strcmp(command,'trace_obj')% RAY TRACING
unimplemented(command,filename);
else
disp(['Unknown element: ' command ]);
end
end
end
fclose(file);
function curv_surf = getFFCurvSurf(fid,rat,type)
% Create Curvature/Surface object
curv_surf.type = type;
curv_surf.israt = rat;
doit = 1;
while doit && ~feof(fid)
pos = ftell(fid);
elems = getline(fid);
if ~isempty(elems)
command = lower(elems{1});
if strcmp(command,'deg') % DEGREE
if strcmp(curv_surf.type,'cardinal')
curv_surf.degu = 3;
else
curv_surf.degu = str2double(elems{2});
end
if length(elems)>=3
if strcmp(curv_surf.type,'cardinal')
curv_surf.degv = 3;
else
curv_surf.degv = str2double(elems{3});
end
end
elseif strcmp(command,'bmat') % BASIS MATRIX
if strcmpi(elems{2},'u')
deg = curv_surf.degu;
elseif strcmpi(elems{2},'v')
deg = curv_surf.degv;
end
mat = zeros(deg+1);
idx = 3;
for i=1:deg+1;
for j=1:deg+1;
mat(i,j) = str2double(elems{idx});
idx = idx + 1;
end
end
if strcmpi(elems{2},'u')
curv_surf.matu = mat;
elseif strcmpi(elems{2},'v')
curv_surf.matv = mat;
end
elseif strcmp(command,'step') % STEP
curv_surf.stepu = str2double(elems{2});
if length(elems)>=3
curv_surf.stepv = str2double(elems{3});
end
elseif strcmp(command,'ctech') % CURVE APPROX TECHNIQUE
unimplemented(command,' ');
elseif strcmp(command,'stech') % SURFACE APPROX TECHNIQUE
unimplemented(command,' ');
else % NON CURV/SURF ELEMENT - UNREAD
doit = 0;
fseek(fid,pos,'bof');
end
end
end
function strs = getline(fid)
% Lines can be logically joined with the line continuation character ( \ )
% at the end of a line.
doit = 1;
strs = {};
while doit && ~feof(fid)
line = fgetl(fid);
line = strtrim(line);
if ~isempty(line)
elems = my_explode(line);
if strcmp('\', elems{length(elems)})
elems(length(elems)) = [];
else
doit = 0;
end
strs = vertcat(strs,elems);
end
end
function elems = my_explode(line)
elems = {};
i = 1;
while ~isempty(line)
[ elem line ] = strtok(line);
elems{i} = elem;
i = i + 1;
end
function [ v vt vn ] = getTriplet(str, bundle)
str = strrep(str,'/',',');
str = strrep(str,',,',',0,');
x = str2num(str);
v = handleNegVert(x(1), size(bundle.vertex,1));
if isempty(x(2))
vt = NaN;
else
vt = handleNegVert(x(2), size(bundle.vtex,1));
end
if isempty(x(3))
vn = NaN;
else
vn = handleNegVert(x(3), size(bundle.vnorm,1));
end
function cs = getCSBodyStatements(fid,cs)
% Body statements are valid only when they appear between the free-form
% element statement (curv, curv2, surf) and the end statement. If they
% are anywhere else in the .obj file, they do not have any effect.
%
% You can use body statements to specify the following values:
% parameter
% knot vector
% trimming loop
% hole
% special curve
% special point
cs.body = {};
doit = true;
while doit && ~feof(fid)
pos = ftell(fid);
elems = getline(fid);
if ~isempty(elems)
command = lower(elems{1});
if strcmp(command,'parm') % PARAMETER
x = struct;
x.type = command;
x.p = zeros(length(elems)-2,1);
x.p(1) = str2double(elems{3});
x.p(2) = str2double(elems{4});
for i=3:size(x.p,1)
x.p(i) = str2double(elems{i+2});
end
if strcmpi(elems{2},'u')
x.dir = 'u';
elseif strcmpi(elems{2},'v')
x.dir = 'v';
end
cs.body = [ cs.body ; x ];
elseif strcmp(command,'trim') || ... % TRIM or
strcmp(command,'hole') || ... % HOLE or
strcmp(command,'scrv') % SPECIAL CURVE
x = struct;
x.type = command;
x.curv = zeros((length(elems)-1)/3,1);
x.u = zeros((length(elems)-1)/3,2);
for i=1:size(x.curv,1)
x.u(i,1) = str2double(elems{i*3-1});
x.u(i,2) = str2double(elems{i*3});
x.curv(i)= str2double(elems{i*3+1});
end
cs.body = [ cs.body ; x ];
elseif strcmp(command,'sp') % SPECIAL POINT
x = struct;
x.type = command;
x.vp = zeros(length(elems)-1,1);
for i=1:size(x.vp,1)
x.vp(i)= str2double(elems{i+1});
end
cs.body = [ cs.body ; x ];
elseif strcmp(command,'end') % END
doit = false;
else % NON CURV/SURF ELEMENT - UNREAD
doit = false;
fseek(fid,pos,'bof');
end
end
end
function unimplemented(command, file)
disp(['WARNING: ' command ' was found if file ' file ...
' but it was omitted by the parser! ']);
function v = handleNegVert(v1, v2)
if v1<0
v = 1 + v2 + v1;
else
v = v1;
end
