A framework to compute the shape as seen in
a projection plane. This is done by calculating
the visible and the hidden parts of the shape.
HLRBRep_PolyAlgo works with three types of entity:
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#include <HLRBRep_PolyAlgo.hxx>
Public Member Functions |
| HLRBRep_PolyAlgo () |
| Constructs an empty framework for the
calculation of the visible and hidden lines of a shape in a projection.
Use the functions:
|
| HLRBRep_PolyAlgo (const Handle< HLRBRep_PolyAlgo > &A) |
| HLRBRep_PolyAlgo (const TopoDS_Shape &S) |
Standard_Integer | NbShapes () const |
TopoDS_Shape & | Shape (const Standard_Integer I) |
void | Remove (const Standard_Integer I) |
| remove the Shape of Index .
|
Standard_Integer | Index (const TopoDS_Shape &S) const |
| return the index of the Shape <S> and return 0 if
the Shape <S> is not found.
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void | Load (const TopoDS_Shape &S) |
| Loads the shape S into this framework.
Warning S must have already been triangulated.
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Handle_HLRAlgo_PolyAlgo | Algo () const |
const HLRAlgo_Projector & | Projector () const |
| Sets the parameters of the view for this framework.
These parameters are defined by an HLRAlgo_Projector object,
which is returned by the Projector function on a Prs3d_Projector object.
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void | Projector (const HLRAlgo_Projector &P) |
Standard_Real | Angle () const |
void | Angle (const Standard_Real Ang) |
Standard_Real | TolAngular () const |
void | TolAngular (const Standard_Real Tol) |
Standard_Real | TolCoef () const |
void | TolCoef (const Standard_Real Tol) |
void | Update () |
| Launches calculation of outlines of the shape
visualized by this framework. Used after setting the point of view and
defining the shape or shapes to be visualized.
|
void | InitHide () |
Standard_Boolean | MoreHide () const |
void | NextHide () |
void | Hide (Standard_Address &Coordinates, HLRAlgo_EdgeStatus &status, TopoDS_Shape &S, Standard_Boolean ®1, Standard_Boolean ®n, Standard_Boolean &outl, Standard_Boolean &intl) |
void | InitShow () |
Standard_Boolean | MoreShow () const |
void | NextShow () |
void | Show (Standard_Address &Coordinates, TopoDS_Shape &S, Standard_Boolean ®1, Standard_Boolean ®n, Standard_Boolean &outl, Standard_Boolean &intl) |
TopoDS_Shape | OutLinedShape (const TopoDS_Shape &S) const |
| Make a shape with the internal outlines in each
face.
|
Standard_Boolean | Debug () const |
void | Debug (const Standard_Boolean B) |
Detailed Description
- shapes to be visualized (these shapes must
have already been triangulated.)
- edges in these shapes (these edges are
defined as polygonal lines on the
triangulation of the shape, and are the basic
entities which will be visualized or hidden), and
- triangles in these shapes which hide the edges.
HLRBRep_PolyAlgo is based on the principle
of comparing each edge of the shape to be
visualized with each of the triangles produced
by the triangulation of the shape, and
calculating the visible and the hidden parts of each edge.
For a given projection, HLRBRep_PolyAlgo
calculates a set of lines characteristic of the
object being represented. It is also used in
conjunction with the HLRBRep_PolyHLRToShape extraction
utilities, which reconstruct a new, simplified
shape from a selection of calculation results.
This new shape is made up of edges, which
represent the shape visualized in the projection.
HLRBRep_PolyAlgo works with a polyhedral
simplification of the shape whereas
HLRBRep_Algo takes the shape itself into
account. When you use HLRBRep_Algo, you
obtain an exact result, whereas, when you use
HLRBRep_PolyAlgo, you reduce computation
time but obtain polygonal segments.
An HLRBRep_PolyAlgo object provides a framework for:
- defining the point of view
- identifying the shape or shapes to be visualized
- calculating the outlines
- calculating the visible and hidden lines of the shape.
Warning
- Superimposed lines are not eliminated by this algorithm.
- There must be no unfinished objects inside the shape you wish to visualize.
- Points are not treated.
- Note that this is not the sort of algorithm
used in generating shading, which calculates
the visible and hidden parts of each face in a
shape to be visualized by comparing each
face in the shape with every other face in the same shape.
Constructor & Destructor Documentation
- Projector to define the point of view
- Load to select the shape or shapes to be visualized
- Update to compute the visible and hidden lines of the shape.
Warning
The shape or shapes to be visualized must have already been triangulated.
Member Function Documentation
The documentation for this class was generated from the following file: