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vtkPolygon Class Reference

a cell that represents an n-sided polygon. More...

#include <vtkPolygon.h>

Inheritance diagram for vtkPolygon:

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List of all members.

Public Methods

virtual const char * GetClassName ()
virtual int IsA (const char *type)
vtkCellMakeObject ()
int GetCellType ()
int GetCellDimension ()
int GetNumberOfEdges ()
int GetNumberOfFaces ()
vtkCellGetEdge (int edgeId)
vtkCellGetFace (int)
int CellBoundary (int subId, float pcoords[3], vtkIdList *pts)
void Contour (float value, vtkScalars *cellScalars, vtkPointLocator *locator, vtkCellArray *verts, vtkCellArray *lines, vtkCellArray *polys, vtkPointData *inPd, vtkPointData *outPd, vtkCellData *inCd, int cellId, vtkCellData *outCd)
void Clip (float value, vtkScalars *cellScalars, vtkPointLocator *locator, vtkCellArray *tris, vtkPointData *inPd, vtkPointData *outPd, vtkCellData *inCd, int cellId, vtkCellData *outCd, int insideOut)
int EvaluatePosition (float x[3], float *closestPoint, int &subId, float pcoords[3], float &dist2, float *weights)
void EvaluateLocation (int &subId, float pcoords[3], float x[3], float *weights)
int IntersectWithLine (float p1[3], float p2[3], float tol, float &t, float x[3], float pcoords[3], int &subId)
int Triangulate (int index, vtkIdList *ptIds, vtkPoints *pts)
void Derivatives (int subId, float pcoords[3], float *values, int dim, float *derivs)
void ComputeWeights (float x[3], float *weights)
int ParameterizePolygon (float p0[3], float p10[3], float &l10, float p20[3], float &l20, float n[3])
int Triangulate (vtkIdList *outTris)
int CellBoundary (int subId, float pcoords[3], vtkIdList &pts)
int Triangulate (int index, vtkIdList &ptIds, vtkPoints &pts)
int Triangulate (vtkIdList &outTris)

Static Public Methods

vtkPolygon * New ()
int IsTypeOf (const char *type)
vtkPolygon * SafeDownCast (vtkObject *o)
void ComputeNormal (vtkPoints *p, int numPts, int *pts, float n[3])
void ComputeNormal (vtkPoints *p, float n[3])
void ComputeNormal (int numPts, float *pts, float n[3])
int PointInPolygon (float x[3], int numPts, float *pts, float bounds[6], float n[3])
int IntersectPolygonWithPolygon (int npts, float *pts, float bounds[6], int npts2, float *pts2, float bounds2[3], float tol, float x[3])

Protected Methods

 vtkPolygon ()
 ~vtkPolygon ()
 vtkPolygon (const vtkPolygon &)
void operator= (const vtkPolygon &)
int EarCutTriangulation ()

Protected Attributes

float Tolerance
int SuccessfulTriangulation
float Normal [3]
vtkIdListTris
vtkTriangleTriangle
vtkQuadQuad
vtkScalarsTriScalars
vtkLineLine

Detailed Description

a cell that represents an n-sided polygon.

Date:
2000/12/10 20:08:16
Revision:
1.58

vtkPolygon is a concrete implementation of vtkCell to represent a 2D n-sided polygon. The polygons cannot have any internal holes, and cannot self-intersect.

Examples:
vtkPolygon (examples)

Definition at line 63 of file vtkPolygon.h.


Constructor & Destructor Documentation

vtkPolygon::vtkPolygon   [protected]
 

vtkPolygon::~vtkPolygon   [protected]
 

vtkPolygon::vtkPolygon const vtkPolygon &    [inline, protected]
 

Definition at line 156 of file vtkPolygon.h.


Member Function Documentation

vtkPolygon* vtkPolygon::New   [static]
 

Create an object with Debug turned off, modified time initialized to zero, and reference counting on.

Reimplemented from vtkObject.

virtual const char* vtkPolygon::GetClassName   [virtual]
 

Return the class name as a string. This method is defined in all subclasses of vtkObject with the vtkTypeMacro found in vtkSetGet.h.

Reimplemented from vtkCell.

int vtkPolygon::IsTypeOf const char *    type [static]
 

Return 1 if this class type is the same type of (or a subclass of) the named class. Returns 0 otherwise. This method works in combination with vtkTypeMacro found in vtkSetGet.h.

Reimplemented from vtkCell.

virtual int vtkPolygon::IsA const char *    type [virtual]
 

Return 1 if this class is the same type of (or a subclass of) the named class. Returns 0 otherwise. This method works in combination with vtkTypeMacro found in vtkSetGet.h.

Reimplemented from vtkCell.

vtkPolygon* vtkPolygon::SafeDownCast vtkObject   o [static]
 

Will cast the supplied object to vtkObject* is this is a safe operation (i.e., a safe downcast); otherwise NULL is returned. This method is defined in all subclasses of vtkObject with the vtkTypeMacro found in vtkSetGet.h.

Reimplemented from vtkCell.

vtkCell* vtkPolygon::MakeObject   [virtual]
 

See the vtkCell API for descriptions of these methods.

Reimplemented from vtkCell.

int vtkPolygon::GetCellType   [inline, virtual]
 

Return the type of cell.

Reimplemented from vtkCell.

Definition at line 71 of file vtkPolygon.h.

int vtkPolygon::GetCellDimension   [inline, virtual]
 

Return the topological dimensional of the cell (0,1,2, or 3).

Reimplemented from vtkCell.

Definition at line 72 of file vtkPolygon.h.

int vtkPolygon::GetNumberOfEdges   [inline, virtual]
 

Return the number of edges in the cell.

Reimplemented from vtkCell.

Definition at line 73 of file vtkPolygon.h.

int vtkPolygon::GetNumberOfFaces   [inline, virtual]
 

Return the number of faces in the cell.

Reimplemented from vtkCell.

Definition at line 74 of file vtkPolygon.h.

vtkCell* vtkPolygon::GetEdge int    edgeId [virtual]
 

Return the edge cell from the edgeId of the cell.

Reimplemented from vtkCell.

vtkCell* vtkPolygon::GetFace int    faceId [inline, virtual]
 

Return the face cell from the faceId of the cell.

Reimplemented from vtkCell.

Definition at line 76 of file vtkPolygon.h.

int vtkPolygon::CellBoundary int    subId,
float    pcoords[3],
vtkIdList   pts
[virtual]
 

Given parametric coordinates of a point, return the closest cell boundary, and whether the point is inside or outside of the cell. The cell boundary is defined by a list of points (pts) that specify a face (3D cell), edge (2D cell), or vertex (1D cell). If the return value of the method is != 0, then the point is inside the cell.

Reimplemented from vtkCell.

void vtkPolygon::Contour float    value,
vtkScalars   cellScalars,
vtkPointLocator   locator,
vtkCellArray   verts,
vtkCellArray   lines,
vtkCellArray   polys,
vtkPointData   inPd,
vtkPointData   outPd,
vtkCellData   inCd,
int    cellId,
vtkCellData   outCd
[virtual]
 

Generate contouring primitives. The scalar list cellScalars are scalar values at each cell point. The point locator is essentially a points list that merges points as they are inserted (i.e., prevents duplicates). Contouring primitives can be vertices, lines, or polygons. It is possible to interpolate point data along the edge by providing input and output point data - if outPd is NULL, then no interpolation is performed. Also, if the output cell data is non-NULL, the cell data from the contoured cell is passed to the generated contouring primitives. (Note: the CopyAllocate() method must be invoked on both the output cell and point data. The cellId refers to the cell from which the cell data is copied.)

Reimplemented from vtkCell.

void vtkPolygon::Clip float    value,
vtkScalars   cellScalars,
vtkPointLocator   locator,
vtkCellArray   tris,
vtkPointData   inPd,
vtkPointData   outPd,
vtkCellData   inCd,
int    cellId,
vtkCellData   outCd,
int    insideOut
[virtual]
 

Cut (or clip) the cell based on the input cellScalars and the specified value. The output of the clip operation will be one or more cells of the same topological dimension as the original cell. The flag insideOut controls what part of the cell is considered inside - normally cell points whose scalar value is greater than "value" are considered inside. If insideOut is on, this is reversed. Also, if the output cell data is non-NULL, the cell data from the clipped cell is passed to the generated contouring primitives. (Note: the CopyAllocate() method must be invoked on both the output cell and point data. The cellId refers to the cell from which the cell data is copied.)

Reimplemented from vtkCell.

int vtkPolygon::EvaluatePosition float    x[3],
float *    closestPoint,
int &    subId,
float    pcoords[3],
float &    dist2,
float *    weights
[virtual]
 

Given a point x[3] return inside(=1) or outside(=0) cell; evaluate parametric coordinates, sub-cell id (!=0 only if cell is composite), distance squared of point x[3] to cell (in particular, the sub-cell indicated), closest point on cell to x[3] (unless closestPoint is null, in which case, the closest point and dist2 are not found), and interpolation weights in cell. (The number of weights is equal to the number of points defining the cell). Note: on rare occasions a -1 is returned from the method. This means that numerical error has occurred and all data returned from this method should be ignored. Also, inside/outside is determine parametrically. That is, a point is inside if it satisfies parametric limits. This can cause problems for cells of topological dimension 2 or less, since a point in 3D can project onto the cell within parametric limits but be "far" from the cell. Thus the value dist2 may be checked to determine true in/out.

Reimplemented from vtkCell.

void vtkPolygon::EvaluateLocation int &    subId,
float    pcoords[3],
float    x[3],
float *    weights
[virtual]
 

Determine global coordinate (x[3]) from subId and parametric coordinates. Also returns interpolation weights. (The number of weights is equal to the number of points in the cell.)

Reimplemented from vtkCell.

int vtkPolygon::IntersectWithLine float    p1[3],
float    p2[3],
float    tol,
float &    t,
float    x[3],
float    pcoords[3],
int &    subId
[virtual]
 

Intersect with a ray. Return parametric coordinates (both line and cell) and global intersection coordinates, given ray definition and tolerance. The method returns non-zero value if intersection occurs.

Reimplemented from vtkCell.

int vtkPolygon::Triangulate int    index,
vtkIdList   ptIds,
vtkPoints   pts
[virtual]
 

Generate simplices of proper dimension. If cell is 3D, tetrahedron are generated; if 2D triangles; if 1D lines; if 0D points. The form of the output is a sequence of points, each n+1 points (where n is topological cell dimension) defining a simplex. The index is a parameter that controls which triangulation to use (if more than one is possible). If numerical degeneracy encountered, 0 is returned, otherwise 1 is returned.

Reimplemented from vtkCell.

void vtkPolygon::Derivatives int    subId,
float    pcoords[3],
float *    values,
int    dim,
float *    derivs
[virtual]
 

Compute derivatives given cell subId and parametric coordinates. The values array is a series of data value(s) at the cell points. There is a one-to-one correspondence between cell point and data value(s). Dim is the number of data values per cell point. Derivs are derivatives in the x-y-z coordinate directions for each data value. Thus, if computing derivatives for a scalar function in a hexahedron, dim=1, 8 values are supplied, and 3 deriv values are returned (i.e., derivatives in x-y-z directions). On the other hand, if computing derivatives of velocity (vx,vy,vz) dim=3, 24 values are supplied ((vx,vy,vz)1, (vx,vy,vz)2, ....()8), and 9 deriv values are returned ((d(vx)/dx),(d(vx)/dy),(d(vx)/dz), (d(vy)/dx),(d(vy)/dy), (d(vy)/dz), (d(vz)/dx),(d(vz)/dy),(d(vz)/dz)).

Reimplemented from vtkCell.

void vtkPolygon::ComputeNormal vtkPoints   p,
int    numPts,
int *    pts,
float    n[3]
[static]
 

Polygon specific

void vtkPolygon::ComputeNormal vtkPoints   p,
float    n[3]
[static]
 

void vtkPolygon::ComputeNormal int    numPts,
float *    pts,
float    n[3]
[static]
 

Compute the polygon normal from an array of points. This version assumes that the polygon is convex, and looks for the first valid normal.

void vtkPolygon::ComputeWeights float    x[3],
float *    weights
 

Compute interpolation weights using 1/r**2 normalized sum.

int vtkPolygon::ParameterizePolygon float    p0[3],
float    p10[3],
float &    l10,
float    p20[3],
float &    l20,
float    n[3]
 

Create a local s-t coordinate system for a polygon. The point p0 is the origin of the local system, p10 is s-axis vector, and p20 is the t-axis vector. (These are expressed in the modeling coordinate system and are vectors of dimension [3].) The values l20 and l20 are the lengths of the vectors p10 and p20, and n is the polygon normal.

int vtkPolygon::PointInPolygon float    x[3],
int    numPts,
float *    pts,
float    bounds[6],
float    n[3]
[static]
 

Determine whether point is inside polygon. Function uses ray-casting to determine if point is inside polygon. Works for arbitrary polygon shape (e.g., non-convex). Returns 0 if point is not in polygon; 1 if it is. Can also return -1 to indicate degenerate polygon.

int vtkPolygon::Triangulate vtkIdList   outTris
 

Triangulate this polygon. The user must provide the vtkIdList outTris. On output, the outTris list contains the ids of the points defining the triangulation. The ids are ordered into groups of three: each three-group defines one triangle.

int vtkPolygon::IntersectPolygonWithPolygon int    npts,
float *    pts,
float    bounds[6],
int    npts2,
float *    pts2,
float    bounds2[3],
float    tol,
float    x[3]
[static]
 

Method intersects two polygons. You must supply the number of points and point coordinates (npts, *pts) and the bounding box (bounds) of the two polygons. Also supply a tolerance squared for controlling error. The method returns 1 if there is an intersection, and 0 if not. A single point of intersection x[3] is also returned if there is an intersection.

int vtkPolygon::CellBoundary int    subId,
float    pcoords[3],
vtkIdList   pts
[inline]
 

For legacy compatibility. Do not use.

Definition at line 145 of file vtkPolygon.h.

int vtkPolygon::Triangulate int    index,
vtkIdList   ptIds,
vtkPoints   pts
[inline]
 

Definition at line 147 of file vtkPolygon.h.

int vtkPolygon::Triangulate vtkIdList   outTris [inline]
 

Definition at line 149 of file vtkPolygon.h.

void vtkPolygon::operator= const vtkPolygon &    [inline, protected]
 

Definition at line 157 of file vtkPolygon.h.

int vtkPolygon::EarCutTriangulation   [protected]
 

A fast triangulation method. Uses recursive divide and conquer based on plane splitting to reduce loop into triangles. The cell (e.g., triangle) is presumed properly initialized (i.e., Points and PointIds).


Member Data Documentation

float vtkPolygon::Tolerance [protected]
 

Definition at line 160 of file vtkPolygon.h.

int vtkPolygon::SuccessfulTriangulation [protected]
 

Definition at line 161 of file vtkPolygon.h.

float vtkPolygon::Normal[3] [protected]
 

Definition at line 162 of file vtkPolygon.h.

vtkIdList* vtkPolygon::Tris [protected]
 

Definition at line 163 of file vtkPolygon.h.

vtkTriangle* vtkPolygon::Triangle [protected]
 

Definition at line 164 of file vtkPolygon.h.

vtkQuad* vtkPolygon::Quad [protected]
 

Definition at line 165 of file vtkPolygon.h.

vtkScalars* vtkPolygon::TriScalars [protected]
 

Definition at line 166 of file vtkPolygon.h.

vtkLine* vtkPolygon::Line [protected]
 

Definition at line 167 of file vtkPolygon.h.


The documentation for this class was generated from the following file:
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