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.