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Improve tetramesh docstring and add function to manual. * geometry.txi: Add tetramesh to manual. * delaunay.m, delaunay3.m, delaunayn.m: Update seealso cross-references. * tetramesh.m: Update docstring. Use Octave coding conventions.
author Rik <octave@nomad.inbox5.com>
date Mon, 09 Apr 2012 15:34:57 -0700
parents 34a9fdaa6ea3
children fd3acd55dd42
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14540:ac8520c03fc9 14541:759944521fd6
17 ## <http://www.gnu.org/licenses/>. 17 ## <http://www.gnu.org/licenses/>.
18 18
19 ## -*- texinfo -*- 19 ## -*- texinfo -*-
20 ## @deftypefn {Function File} tetramesh (@var{T}, @var{X}) 20 ## @deftypefn {Function File} tetramesh (@var{T}, @var{X})
21 ## @deftypefnx {Function File} tetramesh (@var{T}, @var{X}, @var{C}) 21 ## @deftypefnx {Function File} tetramesh (@var{T}, @var{X}, @var{C})
22 ## @deftypefnx {Function File} {[@var{h}] =} tetramesh (...) 22 ## @deftypefnx {Function File} tetramesh (@dots{}, @var{property}, @var{val}, @dots{})
23 ## @deftypefnx {Function File} {[@var{h}] =} tetramesh (..., @var{PROP}, @var{VAL}) 23 ## @deftypefnx {Function File} {@var{h} =} tetramesh (@dots{})
24 ## 24 ##
25 ## The function displays the tetrahedrons defined in the m by 4 matrix @var{T} 25 ## Display the tetrahedrons defined in the m-by-4 matrix @var{T}
26 ## as 3D patches. @var{T} is usually the output of a Delaunay triangulation of a 26 ## as 3-D patches. @var{T} is typically the output of a Delaunay triangulation
27 ## 3D set of points. 27 ## of a 3-D set of points. Every row of @var{T} contains four indices into
28 ## Every row of @var{T} contains four indices into the n by 3 matrix @var{X} 28 ## the n-by-3 matrix @var{X} of the vertices of a tetrahedron. Every row in
29 ## of the vertices of a tetrahedron. 29 ## @var{X} represents one point in 3-D space.
30 ## Every row in @var{X} represents one point in 3D space.
31 ## 30 ##
32 ## If the vector @var{C} is supplied it must contain indices into the current 31 ## The vector @var{C} specifies the color of each tetrahedron as an index
33 ## colormap. Called without @var{C} it is set to 1:m, where m is the number of 32 ## into the current colormap. The default value is 1:m where m is the number
34 ## tetrahedrons, the indices are scaled to map to the full range of the colormap. 33 ## of tetrahedrons; the indices are scaled to map to the full range of the
35 ## If more tetrahedrons than entries in the colormap are given the entries of 34 ## colormap. If there are more tetrahedrons than colors in the colormap then
36 ## @var{C} are cyclic repeated. 35 ## the values in @var{C} are cyclically repeated.
37 ## 36 ##
38 ## When called with one output argument @var{H} it returns a vector of patch 37 ## Calling @code{tetramesh (@dots{}, "property", "value", @dots{})} passes all
39 ## handles,each representing one tetrahedron in the order given by @var{T}. 38 ## property/value pairs directly to the patch function as additional arguments.
40 ## One use case for @var{H} is to turn the respective patch 'Visible' property
41 ## 'on' or 'off'.
42 ## 39 ##
43 ## Calling tetramesh(...,'param','value','param','value'...) passes all 40 ## The optional return value @var{h} is a vector of patch handles where each
44 ## option/value pairs directly as additional arguments to the patch function for 41 ## handle represents one tetrahedron in the order given by @var{T}.
45 ## every tetrahedron. 42 ## A typical use case for @var{h} is to turn the respective patch "visible"
43 ## property "on" or "off".
46 ## 44 ##
47 ## The command 45 ## Type @code{demo tetramesh} to see examples on using @code{tetramesh}.
48 ## 46 ## @seealso{delaunay3, delaunayn, trimesh, patch}
49 ##@example
50 ## @group
51 ## demo tetramesh
52 ## @end group
53 ## @end example
54 ##
55 ## @noindent
56 ## will show some examples how to use it.
57 #### @seealso{patch}
58 ## @end deftypefn 47 ## @end deftypefn
59 48
60 ## Author: Martin Helm <martin@mhelm.de> 49 ## Author: Martin Helm <martin@mhelm.de>
61 50
62 function [h] = tetramesh (varargin) 51 function h = tetramesh (varargin)
63 52
64 [reg, prop] = parseparams (varargin); 53 [reg, prop] = parseparams (varargin);
65 54
66 if (length (reg) < 2 || length (reg) > 3) 55 if (length (reg) < 2 || length (reg) > 3)
67 print_usage () 56 print_usage ();
68 endif 57 endif
69 58
70 T = reg{1}; 59 T = reg{1};
71 X = reg{2}; 60 X = reg{2};
72 61
73 if (! ismatrix (T) || size (T, 2) != 4) 62 if (! ismatrix (T) || columns (T) != 4)
74 error ("tetramesh: T must be a n by 4 matrix") 63 error ("tetramesh: T must be a n-by-4 matrix");
75 endif 64 endif
76 if (! ismatrix (X) || size (X, 2) != 3) 65 if (! ismatrix (X) || columns (X) != 3)
77 error ("tetramesh: X must be a n by 3 matrix") 66 error ("tetramesh: X must be a n-by-3 matrix");
78 endif 67 endif
79 68
80 size_T = size (T, 1); 69 size_T = rows (T);
81 colmap = colormap (); 70 colmap = colormap ();
82 71
83 # do we need to enable gnuplot workaround?
84 shrink = strcmp (graphics_toolkit (), "gnuplot");
85
86 if (length (reg) < 3) 72 if (length (reg) < 3)
87 size_colmap = size (colmap, 1); 73 size_colmap = size (colmap, 1);
88 C = mod ((1:size_T)' - 1, size_colmap) + 1; 74 C = mod ((1:size_T)' - 1, size_colmap) + 1;
89 if (size_T < size_colmap && size_T > 1) 75 if (size_T < size_colmap && size_T > 1)
90 # expand to the available range of colors 76 ## expand to the available range of colors
91 C = floor ((C - 1) * (size_colmap - 1) / (size_T - 1)) + 1; 77 C = floor ((C - 1) * (size_colmap - 1) / (size_T - 1)) + 1;
92 endif 78 endif
93 else 79 else
94 C = reg{3}; 80 C = reg{3};
95 if (! isvector (C) || size_T != length (C)) 81 if (! isvector (C) || size_T != length (C))
96 error ("tetramesh: C must be a vector of the same length as T") 82 error ("tetramesh: C must be a vector of the same length as T");
97 endif 83 endif
98 endif 84 endif
99 85
100 h = zeros (1, size_T); 86 h = zeros (1, size_T);
101 if (shrink) 87 if (strcmp (graphics_toolkit (), "gnuplot"))
102 # tiny reduction of the tetrahedron size to help gnuplot by 88 ## tiny reduction of the tetrahedron size to help gnuplot by
103 # avoiding identical faces with different colors 89 ## avoiding identical faces with different colors
104 for ii = 1:size_T 90 for i = 1:size_T
105 [th, p] = __shrink__ ([1 2 3 4], X(T(ii, :), :), 1 - 1e-7); 91 [th, p] = __shrink__ ([1 2 3 4], X(T(i, :), :), 1 - 1e-7);
106 h(ii) = patch ("Faces", th, "Vertices", p, "FaceColor", ... 92 hvec(i) = patch ("Faces", th, "Vertices", p,
107 colmap(C(ii), :), prop{:}); 93 "FaceColor", colmap(C(i), :), prop{:});
108 endfor 94 endfor
109 else 95 else
110 for ii = 1:size_T 96 for i = 1:size_T
111 th = [1 2 3; 2 3 4; 3 4 1; 4 1 2]; 97 th = [1 2 3; 2 3 4; 3 4 1; 4 1 2];
112 h(ii) = patch ("Faces", th, "Vertices", X(T(ii, :), :), "FaceColor", ... 98 hvec(i) = patch ("Faces", th, "Vertices", X(T(i, :), :),
113 colmap(C(ii), :), prop{:}); 99 "FaceColor", colmap(C(i), :), prop{:});
114 endfor 100 endfor
115 endif 101 endif
116 102
117 if (nargout == 0) #return nothing 103 if (nargout > 0)
118 clear h; 104 h = hvec;
119 endif 105 endif
106
120 endfunction 107 endfunction
121 108
122 ## shrink the tetrahedron relative to its center of gravity 109 ## shrink the tetrahedron relative to its center of gravity
123 function [tri, p] = __shrink__ (T, X, sf) 110 function [tri, p] = __shrink__ (T, X, sf)
124 midpoint = repmat (sum (X(T, :), 1) / 4, 12, 1); 111 midpoint = repmat (sum (X(T, :), 1) / 4, 12, 1);
125 p = [X([1 2 3], :); X([2 3 4], :); X([3 4 1], :); X([4 1 2], :)]; 112 p = [X([1 2 3], :); X([2 3 4], :); X([3 4 1], :); X([4 1 2], :)];
126 p = sf * (p - midpoint) + midpoint; 113 p = sf * (p - midpoint) + midpoint;
127 tri = reshape (1:12, 3, 4)'; 114 tri = reshape (1:12, 3, 4)';
128 endfunction 115 endfunction
129 116
117
130 %!demo 118 %!demo
119 %! clf;
131 %! d = [-1 1]; 120 %! d = [-1 1];
132 %! [x,y,z] = meshgrid (d, d, d); 121 %! [x,y,z] = meshgrid (d, d, d);
133 %! x = [x(:); 0]; 122 %! x = [x(:); 0];
134 %! y = [y(:); 0]; 123 %! y = [y(:); 0];
135 %! z = [z(:); 0]; 124 %! z = [z(:); 0];
136 %! tetra = delaunay3 (x, y, z); 125 %! tetra = delaunay3 (x, y, z);
137 %! X = [x(:) y(:) z(:)]; 126 %! X = [x(:) y(:) z(:)];
138 %! clf () 127 %! colormap (jet (64));
139 %! colormap (jet (64))
140 %! h = tetramesh (tetra, X); 128 %! h = tetramesh (tetra, X);
141 %! for ii=1:2:length(h); 129 %! set (h(1:2:end), "Visible", "off");
142 %! set(h(ii), "Visible", "off"); 130 %! axis equal;
143 %! endfor 131 %! view (30, 20);
144 %! axis equal 132 %! title ("Using jet (64), every other tetrahedron invisible");
145 %! view (30, 20)
146 %! title ("Using jet (64), every other tetrahedron invisible")
147 133
148 %!demo 134 %!demo
135 %! clf;
149 %! d = [-1 1]; 136 %! d = [-1 1];
150 %! [x,y,z] = meshgrid (d, d, d); 137 %! [x,y,z] = meshgrid (d, d, d);
151 %! x = [x(:); 0]; 138 %! x = [x(:); 0];
152 %! y = [y(:); 0]; 139 %! y = [y(:); 0];
153 %! z = [z(:); 0]; 140 %! z = [z(:); 0];
154 %! tetra = delaunay3 (x, y, z); 141 %! tetra = delaunay3 (x, y, z);
155 %! X = [x(:) y(:) z(:)]; 142 %! X = [x(:) y(:) z(:)];
156 %! clf ()
157 %! colormap (gray (256)); 143 %! colormap (gray (256));
158 %! tetramesh (tetra, X, 21:20:241, "EdgeColor", "w") 144 %! tetramesh (tetra, X, 21:20:241, "EdgeColor", "w");
159 %! axis equal 145 %! axis equal;
160 %! view (30, 20) 146 %! view (30, 20);
161 %! title ("Using gray (256) and white edges") 147 %! title ("Using gray (256) and white edges");
148