vlookup.h

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#ifndef VLOOKUP_H
 
#define VLOOKUP_H
 
// CodeSnippet provided by John W. Ratcliff
// on March 23, 2006.
//
// mailto: jratcliff@infiniplex.net
//
// Personal website: http://jratcliffscarab.blogspot.com
// Coding Website:   http://codesuppository.blogspot.com
// FundRaising Blog: http://amillionpixels.blogspot.com
// Fundraising site: http://www.amillionpixels.us
// New Temple Site:  http://newtemple.blogspot.com
//
// This snippet shows how to 'hide' the complexity of
// the STL by wrapping some useful piece of functionality
// around a handful of discrete API calls.
//
// This API allows you to create an indexed triangle list
// from a collection of raw input triangles.  Internally
// it uses an STL set to build the lookup table very rapidly.
//
// Here is how you would use it to build an indexed triangle
// list from a raw list of triangles.
//
// (1) create a 'VertexLookup' interface by calling
//
//     VertexLook vl = Vl_createVertexLookup();
//
// (2) For each vertice in each triangle call:
//
//     unsigned int i1 = Vl_getIndex(vl,p1);
//     unsigned int i2 = Vl_getIndex(vl,p2);
//     unsigned int i3 = Vl_getIndex(vl,p3);
//
//     save the 3 indices into your triangle list array.
//
// (3) Get the vertex array by calling:
//
//     const double *vertices = Vl_getVertices(vl);
//
// (4) Get the number of vertices so you can copy them into
//     your own buffer.
//     unsigned int vcount = Vl_getVcount(vl);
//
// (5) Release the VertexLookup interface when you are done with it.
//     Vl_releaseVertexLookup(vl);
//
// Teaches the following lessons:
//
//    How to wrap the complexity of STL and C++ classes around a
//    simple API interface.
//
//    How to use an STL set and custom comparator operator for
//    a complex data type.
//
//    How to create a template class.
//
//    How to achieve significant performance improvements by
//    taking advantage of built in STL containers in just
//    a few lines of code.
//
//    You could easily modify this code to support other vertex
//    formats with any number of interpolants.
//
//    Hide C++ classes from the rest of your application by
//    keeping them in the CPP and wrapping them in a namespace
// Uses an STL set to create an index table for a bunch of vertex positions
// used typically to re-index a collection of raw triangle data.
 
namespace ConvexDecomposition
{
 
typedef void * VertexLookup;
 
VertexLookup  Vl_createVertexLookup(void);
void          Vl_releaseVertexLookup(VertexLookup vlook);
 
unsigned int  Vl_getIndex(VertexLookup vlook,const double *pos);  // get index.
const double * Vl_getVertices(VertexLookup vlook);
 
unsigned int  Vl_getVcount(VertexLookup vlook);
 
};
 
 
#endif