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-- File: Poly_Connect.cdl
-- Created: Mon Mar 6 15:16:16 1995
-- Author: Laurent PAINNOT
-- <lpa@metrox>
---Copyright: Matra Datavision 1995
class Connect from Poly
---Purpose:
-- Provides an algorithm to explore, inside a triangulation, the
-- adjacency data for a node or a triangle.
-- Adjacency data for a node consists of triangles which
-- contain the node.
-- Adjacency data for a triangle consists of:
-- - the 3 adjacent triangles which share an edge of the triangle,
-- - and the 3 nodes which are the other nodes of these adjacent triangles.
-- Example
-- Inside a triangulation, a triangle T
-- has nodes n1, n2 and n3.
-- It has adjacent triangles AT1, AT2 and AT3 where:
-- - AT1 shares the nodes n2 and n3,
-- - AT2 shares the nodes n3 and n1,
-- - AT3 shares the nodes n1 and n2.
-- It has adjacent nodes an1, an2 and an3 where:
-- - an1 is the third node of AT1,
-- - an2 is the third node of AT2,
-- - an3 is the third node of AT3.
-- So triangle AT1 is composed of nodes n2, n3 and an1.
-- There are two ways of using this algorithm.
-- - From a given node you can look for one triangle that
-- passes through the node, then look for the triangles
-- adjacent to this triangle, then the adjacent nodes. You
-- can thus explore the triangulation step by step (functions
-- Triangle, Triangles and Nodes).
-- - From a given node you can look for all the triangles
-- that pass through the node (iteration method, using the
-- functions Initialize, More, Next and Value).
-- A Connect object can be seen as a tool which analyzes a
-- triangulation and translates it into a series of triangles. By
-- doing this, it provides an interface with other tools and
-- applications working on basic triangles, and which do not
-- work directly with a Poly_Triangulation.
uses
Array1OfInteger from TColStd,
Triangulation from Poly
is
Create (T : Triangulation from Poly) returns Connect from Poly;
---Purpose: Constructs an algorithm to explore the adjacency data of
-- nodes or triangles for the triangulation T.
Triangulation(me) returns Triangulation from Poly;
---Purpose: Returns the triangulation analyzed by this tool.
---C++: inline
Triangle(me; N : Integer) returns Integer;
---Purpose: Returns the index of a triangle containing the node at
-- index N in the nodes table specific to the triangulation analyzed by this tool
---C++: inline
Triangles(me; T: Integer; t1, t2, t3: out Integer);
---Purpose: Returns in t1, t2 and t3, the indices of the 3 triangles
-- adjacent to the triangle at index T in the triangles table
-- specific to the triangulation analyzed by this tool.
-- Warning
-- Null indices are returned when there are fewer than 3
-- adjacent triangles.
Nodes(me; T: Integer; n1, n2, n3: out Integer);
---Purpose: Returns, in n1, n2 and n3, the indices of the 3 nodes
-- adjacent to the triangle referenced at index T in the
-- triangles table specific to the triangulation analyzed by this tool.
-- Warning
-- Null indices are returned when there are fewer than 3 adjacent nodes.
Initialize(me: in out; N: Integer);
---Purpose: Initializes an iterator to search for all the triangles
-- containing the node referenced at index N in the nodes
-- table, for the triangulation analyzed by this tool.
-- The iterator is managed by the following functions:
-- - More, which checks if there are still elements in the iterator
-- - Next, which positions the iterator on the next element
-- - Value, which returns the current element.
-- The use of such an iterator provides direct access to the
-- triangles around a particular node, i.e. it avoids iterating on
-- all the component triangles of a triangulation.
-- Example
-- Poly_Connect C(Tr);
-- for
-- (C.Initialize(n1);C.More();C.Next())
-- {
-- t = C.Value();
-- }
More(me) returns Boolean;
---Purpose: Returns true if there is another element in the iterator
-- defined with the function Initialize (i.e. if there is another
-- triangle containing the given node).
---C++: inline
Next(me: in out)
---Purpose: Advances the iterator defined with the function Initialize to
-- access the next triangle.
-- Note: There is no action if the iterator is empty (i.e. if the
-- function More returns false).-
is static;
Value(me) returns Integer;
---Purpose: Returns the index of the current triangle to which the
-- iterator, defined with the function Initialize, points. This is
-- an index in the triangles table specific to the triangulation
-- analyzed by this tool
fields
myTriangulation : Triangulation from Poly;
myTriangles : Array1OfInteger from TColStd;
myAdjacents : Array1OfInteger from TColStd;
mytr : Integer from Standard;
myfirst : Integer from Standard;
mynode : Integer from Standard;
myothernode : Integer from Standard;
mysense : Boolean from Standard;
mymore : Boolean from Standard;
end Connect;
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