TGeoPgon

 dummy ctor

 Default constructor

 Default constructor

 Default constructor in GEANT3 style
 param[0] = phi1
 param[1] = dphi
 param[2] = nedges
 param[3] = nz

 param[4] = z1
 param[5] = Rmin1
 param[6] = Rmax1
 ...

 destructor

 Computes capacity of the shape in [length^3]

 compute bounding box for a polygone

 Compute normal to closest surface from POINT.

 test if point is inside this shape
 check total z range

 compute distance from inside point to surface of the polygone
 first find out in which Z section the point is in

 Locates index IPSEC of the phi sector containing POINT.

 Returns lists of PGON phi crossings for a ray starting from POINT.

 Performs ray propagation between Z segments.

 Performs ray propagation between Z segments.

 Check boundary crossing inside phi slices. Return distance snext to first crossing
 if smaller than stepmax.
 Protection in case point is in phi gap or close to phi boundaries and exiting

 Check boundary crossing inside phi slices. Return distance snext to first crossing
 if smaller than stepmax.

 Check crossing of a given pgon slice, from a starting point inside the slice

 Compute distance from outside point to surface of the polygone

 compute closest distance from point px,py to each corner

--- Divide this polygone shape belonging to volume "voldiv" into ndiv volumes
 called divname, from start position with the given step. Returns pointer
 to created division cell volume in case of Z divisions. Phi divisions are
 allowed only if nedges%ndiv=0 and create polygone "segments" with nedges/ndiv edges.
 Z divisions can be performed if the divided range is in between two consecutive Z planes.
 In case a wrong division axis is supplied, returns pointer to volume that was divided.

--- Fill vector param[4] with the bounding cylinder parameters. The order
 is the following : Rmin, Rmax, Phi1, Phi2

 Inspect the PGON parameters.

 Creates a TBuffer3D describing *this* shape.
 Coordinates are in local reference frame.

 Fill TBuffer3D structure for segments and polygons.

 Computes projected pgon radius (inner or outer) corresponding to a given Z
 value. Fills corresponding coefficients of:
   Rpg(z) = a + b*z
 Note: ipl must be in range [0,fNz-2]

 Computes projected distance at a given Z for a given ray inside a given sector
 and fills coefficients:
   Rproj = a + b*z

 Compute safety from POINT to segment between planes ipl, ipl+1 within safmin.

 computes the closest distance from given point to this shape, according
 to option. The matching point on the shape is stored in spoint.

 Save a primitive as a C++ statement(s) on output stream "out".

 Set PGON dimensions starting from an array.

 create polygone mesh points

 create polygone mesh points

 Return number of vertices of the mesh representation

/// fill size of this 3-D object
/    TVirtualGeoPainter *painter = gGeoManager->GetGeomPainter();
/    if (!painter) return;
/    Int_t n;

/    n = fNedges+1;

/    Int_t numPoints = fNz*2*n;
/    Int_t numSegs   = 4*(fNz*n-1+(fDphi == 360));
/    Int_t numPolys  = 2*(fNz*n-1+(fDphi == 360));
/    painter->AddSize3D(numPoints, numSegs, numPolys);

 Fills a static 3D buffer and returns a reference.

 constructors