PRO triangulate_full, nc, tr, ntr

; Description: This module generates the list of all possible triangles that can be formed from
;              a set of "nc" points in two dimensions. The indices of each of the three vertices
;              for each triangle are returned via the array "tr", and the number of triangles
;              that have been formed are returned via the parameter "ntr".
;
; Input Parameters:
;
;   nc - INTEGER/LONG - The number of points for which triangles are to be formed. If this number
;                       is less than three, then the module returns with non-sensical values for
;                       the output parameters.
;
; Output Parameters:
;
;   tr - LONG ARRAY - A 3 by "ntr" array of LONGS where each triplet of numbers represents the
;                     indices of the points corresponding to the three vertices of each triangle.
;   ntr - LONG - The number of triangles that have been formed. This number is easily calculated
;                from the analytical formula:
;
;                ntr = nc * (nc - 1) * (nc - 2) / 6
;
; Author: Dan Bramich (dan.bramich@hotmail.co.uk)
;
; History:
;
;   31/07/2008 - Module created (dmb)

;Check that "nc" is a number of the correct type and with a value that is greater than or equal
;to three

;Calculate the number of triangles that will be formed

;Generate an array containing the triangles formed by the set of points