coordinates.html

Delaunay三角形的网格剖分程序

<TITLE>COG 2.1: Coordinates</TITLE>

<H1>Coordinates</H1>

 <P>The basic definitions for coordinates are defined in 
 <A HREF="wzmap.hxx">wzmap.hxx</A>, available coordinates are defined
in
 <A HREF="wzmaps.hxx">wzmaps.hxx</A>.

 <P>The basic design ideas have been:

 <UL>
 <LI> Compositions should be possible;
 <LI> All this should be fast enough for typical 3D applications;
 <LI> Nice to use for a typical user;
 </UL>

 <P>Now, the point is that in a typical 3D application we will have:

 <UL>
 <LI> a clear distinction between local coordinates and the global,
Euclidean coordinates - and the possibility to mingle them should be
minimized;
 <LI> it is typically combined with some affine transformation of the
global coordinates, but typically not for the local coordinates.  This
typical transformation is often only a shift, so, if there is some
econonmy possible for shifts, it should be used.
 </UL>

 <P>Therefore, instead of implementing affine transformations as
separate coordinate transformations (which would be the more
"beautiful" way) we have implemented affine transformations on one
side (the "global" x side) as part of all coordinates and maps.