1 /*=========================================================================
2
3 Program: Visualization Toolkit
4 Module: vtkMarchingContourFilter.h
5
6 Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
7 All rights reserved.
8 See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
9
10 This software is distributed WITHOUT ANY WARRANTY; without even
11 the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
12 PURPOSE. See the above copyright notice for more information.
13
14 =========================================================================*/
15 /**
16 * @class vtkMarchingContourFilter
17 * @brief generate isosurfaces/isolines from scalar values
18 *
19 * vtkMarchingContourFilter is a filter that takes as input any dataset and
20 * generates on output isosurfaces and/or isolines. The exact form
21 * of the output depends upon the dimensionality of the input data.
22 * Data consisting of 3D cells will generate isosurfaces, data
23 * consisting of 2D cells will generate isolines, and data with 1D
24 * or 0D cells will generate isopoints. Combinations of output type
25 * are possible if the input dimension is mixed.
26 *
27 * This filter will identify special dataset types (e.g., structured
28 * points) and use the appropriate specialized filter to process the
29 * data. For examples, if the input dataset type is a volume, this
30 * filter will create an internal vtkMarchingCubes instance and use
31 * it. This gives much better performance.
32 *
33 * To use this filter you must specify one or more contour values.
34 * You can either use the method SetValue() to specify each contour
35 * value, or use GenerateValues() to generate a series of evenly
36 * spaced contours. It is also possible to accelerate the operation of
37 * this filter (at the cost of extra memory) by using a
38 * vtkScalarTree. A scalar tree is used to quickly locate cells that
39 * contain a contour surface. This is especially effective if multiple
40 * contours are being extracted. If you want to use a scalar tree,
41 * invoke the method UseScalarTreeOn().
42 *
43 * @warning
44 * For unstructured data or structured grids, normals and gradients
45 * are not computed. This calculation will be implemented in the
46 * future. In the mean time, use vtkPolyDataNormals to compute the surface
47 * normals.
48 *
49 * @sa
50 * vtkMarchingCubes vtkSliceCubes vtkDividingCubes vtkMarchingSquares
51 * vtkImageMarchingCubes
52 */
53
54 #ifndef vtkMarchingContourFilter_h
55 #define vtkMarchingContourFilter_h
56
57 #include "vtkFiltersGeneralModule.h" // For export macro
58 #include "vtkPolyDataAlgorithm.h"
59
60 #include "vtkContourValues.h" // Needed for direct access to ContourValues
61
62 class vtkIncrementalPointLocator;
63 class vtkScalarTree;
64
65 class VTKFILTERSGENERAL_EXPORT vtkMarchingContourFilter : public vtkPolyDataAlgorithm
66 {
67 public:
68 vtkTypeMacro(vtkMarchingContourFilter,vtkPolyDataAlgorithm);
69 void PrintSelf(ostream& os, vtkIndent indent) override;
70
71 /**
72 * Construct object with initial range (0,1) and single contour value
73 * of 0.0.
74 */
75 static vtkMarchingContourFilter *New();
76
77 //@{
78 /**
79 * Methods to set / get contour values.
80 */
81 void SetValue(int i, double value);
82 double GetValue(int i);
83 double *GetValues();
84 void GetValues(double *contourValues);
85 void SetNumberOfContours(int number);
86 int GetNumberOfContours();
87 void GenerateValues(int numContours, double range[2]);
88 void GenerateValues(int numContours, double rangeStart, double rangeEnd);
89 //@}
90
91 /**
92 * Modified GetMTime Because we delegate to vtkContourValues
93 */
94 vtkMTimeType GetMTime() override;
95
96 //@{
97 /**
98 * Set/Get the computation of normals. Normal computation is fairly
99 * expensive in both time and storage. If the output data will be
100 * processed by filters that modify topology or geometry, it may be
101 * wise to turn Normals and Gradients off.
102 */
103 vtkSetMacro(ComputeNormals,vtkTypeBool);
104 vtkGetMacro(ComputeNormals,vtkTypeBool);
105 vtkBooleanMacro(ComputeNormals,vtkTypeBool);
106 //@}
107
108 //@{
109 /**
110 * Set/Get the computation of gradients. Gradient computation is
111 * fairly expensive in both time and storage. Note that if
112 * ComputeNormals is on, gradients will have to be calculated, but
113 * will not be stored in the output dataset. If the output data
114 * will be processed by filters that modify topology or geometry, it
115 * may be wise to turn Normals and Gradients off.
116 */
117 vtkSetMacro(ComputeGradients,vtkTypeBool);
118 vtkGetMacro(ComputeGradients,vtkTypeBool);
119 vtkBooleanMacro(ComputeGradients,vtkTypeBool);
120 //@}
121
122 //@{
123 /**
124 * Set/Get the computation of scalars.
125 */
126 vtkSetMacro(ComputeScalars,vtkTypeBool);
127 vtkGetMacro(ComputeScalars,vtkTypeBool);
128 vtkBooleanMacro(ComputeScalars,vtkTypeBool);
129 //@}
130
131 //@{
132 /**
133 * Enable the use of a scalar tree to accelerate contour extraction.
134 */
135 vtkSetMacro(UseScalarTree,vtkTypeBool);
136 vtkGetMacro(UseScalarTree,vtkTypeBool);
137 vtkBooleanMacro(UseScalarTree,vtkTypeBool);
138 //@}
139
140 //@{
141 /**
142 * Set / get a spatial locator for merging points. By default,
143 * an instance of vtkMergePoints is used.
144 */
145 void SetLocator(vtkIncrementalPointLocator *locator);
146 vtkGetObjectMacro(Locator,vtkIncrementalPointLocator);
147 //@}
148
149 /**
150 * Create default locator. Used to create one when none is
151 * specified. The locator is used to merge coincident points.
152 */
153 void CreateDefaultLocator();
154
155 protected:
156 vtkMarchingContourFilter();
157 ~vtkMarchingContourFilter() override;
158
159 int RequestData(vtkInformation *, vtkInformationVector **, vtkInformationVector *) override;
160 int FillInputPortInformation(int port, vtkInformation *info) override;
161
162 vtkContourValues *ContourValues;
163 vtkTypeBool ComputeNormals;
164 vtkTypeBool ComputeGradients;
165 vtkTypeBool ComputeScalars;
166 vtkIncrementalPointLocator *Locator;
167 vtkTypeBool UseScalarTree;
168 vtkScalarTree *ScalarTree;
169
170 //special contouring for structured points
171 void StructuredPointsContour(int dim, vtkDataSet *input, vtkPolyData *output);
172 //special contouring for image data
173 void ImageContour(int dim, vtkDataSet *input, vtkPolyData *output);
174 //default if not structured data
175 void DataSetContour(vtkDataSet *input, vtkPolyData *output);
176 private:
177 vtkMarchingContourFilter(const vtkMarchingContourFilter&) = delete;
178 void operator=(const vtkMarchingContourFilter&) = delete;
179 };
180
181 /**
182 * Set a particular contour value at contour number i. The index i ranges
183 * between 0<=i<NumberOfContours.
184 */
SetValue(int i,double value)185 inline void vtkMarchingContourFilter::SetValue(int i, double value)
186 {
187 this->ContourValues->SetValue(i,value);
188 }
189
190 /**
191 * Get the ith contour value.
192 */
GetValue(int i)193 inline double vtkMarchingContourFilter::GetValue(int i)
194 {
195 return this->ContourValues->GetValue(i);
196 }
197
198 /**
199 * Get a pointer to an array of contour values. There will be
200 * GetNumberOfContours() values in the list.
201 */
GetValues()202 inline double *vtkMarchingContourFilter::GetValues()
203 {
204 return this->ContourValues->GetValues();
205 }
206
207 /**
208 * Fill a supplied list with contour values. There will be
209 * GetNumberOfContours() values in the list. Make sure you allocate
210 * enough memory to hold the list.
211 */
GetValues(double * contourValues)212 inline void vtkMarchingContourFilter::GetValues(double *contourValues)
213 {
214 this->ContourValues->GetValues(contourValues);
215 }
216
217 /**
218 * Set the number of contours to place into the list. You only really
219 * need to use this method to reduce list size. The method SetValue()
220 * will automatically increase list size as needed.
221 */
SetNumberOfContours(int number)222 inline void vtkMarchingContourFilter::SetNumberOfContours(int number)
223 {
224 this->ContourValues->SetNumberOfContours(number);
225 }
226
227 /**
228 * Get the number of contours in the list of contour values.
229 */
GetNumberOfContours()230 inline int vtkMarchingContourFilter::GetNumberOfContours()
231 {
232 return this->ContourValues->GetNumberOfContours();
233 }
234
235 /**
236 * Generate numContours equally spaced contour values between specified
237 * range. Contour values will include min/max range values.
238 */
GenerateValues(int numContours,double range[2])239 inline void vtkMarchingContourFilter::GenerateValues(int numContours,
240 double range[2])
241 {
242 this->ContourValues->GenerateValues(numContours, range);
243 }
244
245 /**
246 * Generate numContours equally spaced contour values between specified
247 * range. Contour values will include min/max range values.
248 */
GenerateValues(int numContours,double rangeStart,double rangeEnd)249 inline void vtkMarchingContourFilter::GenerateValues(int numContours,
250 double rangeStart,
251 double rangeEnd)
252 {
253 this->ContourValues->GenerateValues(numContours, rangeStart, rangeEnd);
254 }
255
256 #endif
257