NAME

       TDDTRI - Draw the triangles defined by a triangle list.

SYNOPSIS

       CALL TDDTRI (RTRI, MTRI, NTRI, ITWK)

C-BINDING SYNOPSIS

       #include <ncarg/ncargC.h>

       void c_tddtri(float *rtri, int mtri, int *ntri, int *itwk)

DESCRIPTION

       This routine draws the triangles defined by a triangle list.  The triangles are drawn in the order
       specified by the contents of the permutation array ITWK.

       The exact manner in which each triangle is drawn depends on the rendering style selected for it.
       Generally, it is first filled with a user-selected color; if a wire-frame image is desired and no lines
       are to be considered hidden, this step may be skipped.  The fill color can be a specific one chosen by
       the user (sometimes, it is useful to pick the background color) or one selected from a range of user-
       specified colors according to the angle between a line from the light source to the center of the
       triangle and the normal to the plane of the triangle (which results in a shading of the surface).  After
       the triangle is filled, line segments representing its boundary and/or its intersection with planes of
       constant U, V, and/or W may be drawn in a user-specified contrasting color.

       The arguments of TDDTRI are as follows:

       RTRI    (an  input array, of type REAL, dimensioned 10 x MTRI) - a list of triangles, probably created by
               means of calls to TDSTRI, TDITRI, and/or TDMTRI, and sorted, probably  by  means  of  a  call  to
               TDOTRI.

               If you put triangles in the triangle list directly, keep in mind the following: For each value of
               i  from  1  to  NTRI,  RTRI(1,i), RTRI(2,i), and RTRI(3,i) are the U, V, and W coordinates of the
               first vertex of the triangle, RTRI(4,i), RTRI(5,i), and RTRI(6,i) are the U, V, and W coordinates
               of the second vertex of the triangle, RTRI(7,i), RTRI(8,i), and RTRI(9,i) are the  U,  V,  and  W
               coordinates  of  the  third  vertex of the triangle, and RTRI(10,i)=REAL(irst), where irst is the
               index of the desired rendering style array for  the  triangle.  The  order  of  the  vertices  is
               meaningful:  they must be given in counter-clockwise order as viewed from the "top". It is better
               if all of the triangles in a triangle list are about the same size.

       MTRI    (an input expression of type INTEGER) - the second dimension of RTRI and thus the maximum  number
               of triangles the triangle list will hold.

       NTRI    (an input expression of type INTEGER) - specifies the number of triangles currently in the list.

       ITWK    (an  input  array,  of  type  INTEGER, dimensioned at least NTRI) - contains a permutation of the
               integers from 1 to NTRI (probably generated by calling the routine TDOTRI).

C-BINDING DESCRIPTION

       The C-binding argument descriptions are the same as the FORTRAN argument descriptions.

ACCESS

       To use TDDTRI or c_tddtri, load the NCAR Graphics libraries ncarg, ncarg_gks, and ncarg_c, preferably  in
       that order.

SEE ALSO

       Online:  tdclrs,  tdctri, tdgeti, tdgetr, tdgrds, tdgrid, tdgtrs, tdinit, tditri, tdlbla, tdlbls, tdline,
       tdlnpa, tdmtri, tdotri, tdpack, tdpack_params, tdpara, tdplch, tdprpa, tdprpi,  tdprpt,  tdseti,  tdsetr,
       tdsort, tdstri, tdstrs

COPYRIGHT

       Copyright (C) 1987-2009
       University Corporation for Atmospheric Research

       The use of this Software is governed by a License Agreement.

UNIX                                                July 1997                                     TDDTRI(3NCARG)