mainextracttest.html

Delaunay三角形的网格剖分程序

<TITLE>COG 2.1: Extracting geometries</TITLE>

<H1>Extracting Geometries from a Cogenerator</H1>

 <P>Usually we create the geometry description and the grid generator
input together.  This is usually convenient because, if we know the
geometry, we can use appropriate grid generation parameters. 

 <P>But the grid generation algorithm and the geometry description are
completely separated from modular point of view.  We can extract the
geometry description from one cogenerator and use it in another one.
Of course, often the grids will be worse.  But this possibility is
especially interesting for the user of the public domain version: in
this version the grid generation with curved cooridinates and unions
is forbidden, but the use of the related geometries is allowed.

 <P>For example, the following code creates geometry and grid
generator <A HREF="mainwzcomplextest.html#wing">for the wing</A>:

<PRE>
#include &lt;math.h&gt;
#include "coglib.hxx"

int main()
{
  cogenOctree ortho = new CogenOctree();
  wz2dmap c2,ce;
  wzFloat h=0.3,b=0.2;
  wzFloat h0 = h/(1+b),hr=sqrt(h*h+(1+b)*(1+b)),phi=atan2(h,1+b);
  wzFloat delta=0.02;
  ce = new wz2Dexp();
  ce-&gt;stretch(hr);
  ce-&gt;rotate(-phi);
  ce-&gt;shift(-b,h);
  wz2Dshukovski* cs = new  wz2Dshukovski(ce);
  cs-&gt;setYofCircleCenter(h0);
  c2 = cs;
  ortho-&gt;addBox(wzRegion(1),0,10.0);
  ortho-&gt;addBox(wzRegion(2),-10,0.02);
  cogenChart chart = new CogenChart(ortho-&gt;generator(),c2);
</PRE>

 <P>Now, in the public domain version the grid generator cannot be
used. So, we use a standard grid generator which is available:

<PRE>
  cogenOctree other = new CogenOctree();
  other-&gt;setBorder(-2.0,2.0,-1,1);
  cogenRefine gen   = new CogenRefine(other-&gt;generator());
  other-&gt;refinementGlobal(0.05,0.05,0.1);
  gen-&gt;refinementNearPoint(0.02,0.02,0, 0.2,0.2,0, 1.0,0.0,0);
  gen-&gt;refinementNearPoint(0.05,0.05,0, 0.5,0.5,0, -1.0,0.0,0);
/*
*/
</PRE>

<PRE>
//  wzgrid grid = (*other)();
  wzgrid grid = (*other)(chart-&gt;geometry());
//  wzgrid grid = (*gen)();
//  wzgrid grid = (*gen)(chart-&gt;geometry());
  grid->write("test.sg");
}
</PRE>