1 ## Copyright (C) 2002 Etienne Grossmann <etienne@egdn.net>
3 ## This program is free software; you can redistribute it and/or modify it under
4 ## the terms of the GNU General Public License as published by the Free Software
5 ## Foundation; either version 3 of the License, or (at your option) any later
8 ## This program is distributed in the hope that it will be useful, but WITHOUT
9 ## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 ## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
13 ## You should have received a copy of the GNU General Public License along with
14 ## this program; if not, see <http://www.gnu.org/licenses/>.
16 ## s = vrml_thick_surf (x, y, z [, options] )
17 ## s = vrml_thick_surf (z [, options] )
19 ## Returns vrml97 code for a Shape -> IndexedFaceSet node representing a
20 ## surface passing through the given points.
22 ## The surface may look smoother than that returned by vrml_surf, but it
23 ## has twice as many facets.
25 ## x : RxC or C : X coordinates of the points on the surface
26 ## y : RxC or R : Y " "
29 ## s : string : The code
31 ## If x and y are omitted, they are assumed to be 1:C and 1:R, resp
32 ## Points presenting one or more 'inf' or 'nan' coordinates are ignored.
36 ## "col" , col : 3 : Color, default = [0.3,0.4,0.9]
37 ## or 3xP : color of vertices (vrml colorPerVertex is TRUE).
39 ## "tran", tran : 1x1 : Transparency, default = 0
42 ## : 1 : vrml creaseAngle value. The browser may smoothe the
43 ## crease between facets whose angle is less than a.
45 ## "smooth" : same as "creaseAngle",pi.
47 function s = vrml_thick_surf (x, y, z, varargin)
51 col = [0.3, 0.4, 0.9] ;
52 smooth = creaseAngle = nan ;
55 if (nargin <= 1) || ischar(y), # Cruft to allow not passing x and y
58 xx = ones(R,1)*[1:C] ;
59 yy = [1:R]'*ones(1,C) ;
62 s = vrml_surf ( xx, yy, zz, y, z, varargin{:} );
66 s = vrml_surf ( xx, yy, zz, y, varargin{:} );
69 x = xx ; y = yy ; z = zz ;
73 filename = "vrml_thick_surf" ;
78 opt1 = " tran col creaseAngle " ;
86 if ! isnan (smooth), creaseAngle = pi ; end
88 if any (size (x) == 1), x = ones(R,1)*x(:)' ; end
89 if any (size (y) == 1), y = y(:)*ones(1,C) ; end
91 pts = [x(:)';y(:)';z(:)'];
93 keepp = all (!isnan(pts) & finite(pts)) ;
95 trgs = zeros(3,4*(R-1)*(C-1)) ;
99 ## Points are numbered as
101 ## 1 R+1 .. (C-1)*R+1
107 ## Triangles are numbered as :
110 ## _______________________________
111 ## | /| /| /| /|-R+1/|
112 ## | 1 / |R+1/ | / | / |R*C/ |
113 ## | / | / | / | / | / |
114 ## | /X+1| /X+R| / | / | / |
116 ## -------------------------------
118 ## | 2 / |R+2/ | / | / | / |
119 ## | / | / | / | / | / |
120 ## | / | / | / | / | / |
122 ## -------------------------------
125 ## -------------------------------
127 ## | R / |2*R/ | / | / |C*R/ |
128 ## | / | / | / | / | / |
129 ## | /X+R| / | / | / | /C*R|
130 ## |/ |/ |/ |/ |/ X+ |
131 ## -------------------------------
133 ## (x,y), (x,y+1), (x+1,y) i.e. n, n+1, n+R
135 trgs(1,tmp) = ([1:R-1]'*ones(1,C-1) + R*ones(R-1,1)*[0:C-2])(:)';
136 trgs(2,tmp) = ([ 2:R ]'*ones(1,C-1) + R*ones(R-1,1)*[0:C-2])(:)';
137 trgs(3,tmp) = ([1:R-1]'*ones(1,C-1) + R*ones(R-1,1)*[1:C-1])(:)';
139 ## (x+1,y), (x,y+1), (x+1,y+1) i.e. n+R, n+1, n+R+1
142 trgs(1,tmp) = ([1:R-1]'*ones(1,C-1) + R*ones(R-1,1)*[1:C-1])(:)';
143 trgs(2,tmp) = ([ 2:R ]'*ones(1,C-1) + R*ones(R-1,1)*[0:C-2])(:)';
144 trgs(3,tmp) = ([ 2:R ]'*ones(1,C-1) + R*ones(R-1,1)*[1:C-1])(:)';
146 ## (x,y), (x+1,y+1), (x+1,y) i.e. n, n+1, n+R+1
149 trgs(1,tmp) = ([1:R-1]'*ones(1,C-1) + R*ones(R-1,1)*[0:C-2])(:)';
150 trgs(2,tmp) = ([2:R ]'*ones(1,C-1) + R*ones(R-1,1)*[1:C-1])(:)';
151 trgs(3,tmp) = ([1:R-1]'*ones(1,C-1) + R*ones(R-1,1)*[1:C-1])(:)';
153 ## (x,y), (x,y+1), (x+1,y+1) i.e. n, n+1, n+R+1
156 trgs(1,tmp) = ([1:R-1]'*ones(1,C-1) + R*ones(R-1,1)*[0:C-2])(:)';
157 trgs(2,tmp) = ([ 2:R ]'*ones(1,C-1) + R*ones(R-1,1)*[0:C-2])(:)';
158 trgs(3,tmp) = ([ 2:R ]'*ones(1,C-1) + R*ones(R-1,1)*[1:C-1])(:)';
163 keept = all (reshape(keepp(trgs),3,4*(R-1)*(C-1)));
164 ## keept = all (keepp(trgs)) ;
165 keepip = find (keepp);
166 keepit = find (keept);
167 renum = cumsum (keepp);
169 pts = pts (:,keepip) ;
170 trgs = reshape(renum (trgs (:,keepit)), 3, columns(keepit));
173 s = vrml_faces (pts, trgs, "col", col, "tran", tran, "creaseAngle", creaseAngle);
175 ## x=-1:0.1:1;y=(x=ones(columns(x),1)*x)';
176 ## r = sqrt (x.^2+y.^2); c = cos(2*pi*r.^2)./(2+r.^2);
178 ## holes = ind2sub (size (c), [7,7,9,10,15,16;8,9,10,11,14,14]')
180 ## vrml_browse ("tmp.wrl",vrml_thick_surf (x, y, c))
181 ## or save_vrml ("tmp.wrl", vrml_thick_surf (x, y, c))