lwtin_is_closed()

int lwtin_is_closed

(

const LWTIN *

tin

)

Definition at line 93 of file lwtin.c.

References struct_tin_arcs::ax, struct_tin_arcs::ay, struct_tin_arcs::az, struct_tin_arcs::bx, struct_tin_arcs::by, struct_tin_arcs::bz, struct_tin_arcs::cnt, struct_tin_arcs::face, LWTIN::flags, FLAGS_GET_Z, LWTIN::geoms, getPoint4d_p(), lwalloc(), lwfree(), LWTIN::ngeoms, LWTRIANGLE::points, POINT4D::x, POINT4D::y, and POINT4D::z.

Referenced by lwgeom_is_closed().

{
        int i, j, k;
        int narcs, carc;
        int found;
        tin_arcs arcs;
        POINT4D pa, pb;
        LWTRIANGLE *patch;

        /* If surface is not 3D, it's can't be closed */
        if (!FLAGS_GET_Z(tin->flags)) return 0;

        /* Max theorical arcs number if no one is shared ... */
        narcs = 3 * tin->ngeoms;

        arcs = lwalloc(sizeof(struct struct_tin_arcs) * narcs);
        for (i=0, carc=0; i < tin->ngeoms ; i++)
        {

                patch = (LWTRIANGLE *) tin->geoms[i];
                for (j=0; j < 3 ; j++)
                {

                        getPoint4d_p(patch->points, j,   &pa);
                        getPoint4d_p(patch->points, j+1, &pb);

                        /* Make sure to order the 'lower' point first */
                        if ( (pa.x > pb.x) ||
                                (pa.x == pb.x && pa.y > pb.y) ||
                                (pa.x == pb.x && pa.y == pb.y && pa.z > pb.z) )
                        {
                                pa = pb;
                                getPoint4d_p(patch->points, j, &pb);
                        }

                        for (found=0, k=0; k < carc ; k++)
                        {

                                if (  ( arcs[k].ax == pa.x && arcs[k].ay == pa.y &&
                                        arcs[k].az == pa.z && arcs[k].bx == pb.x &&
                                        arcs[k].by == pb.y && arcs[k].bz == pb.z &&
                                        arcs[k].face != i) )
                                {
                                        arcs[k].cnt++;
                                        found = 1;

                                        /* Look like an invalid TIN
                                              anyway not a closed one */
                                        if (arcs[k].cnt > 2)
                                        {
                                                lwfree(arcs);
                                                return 0;
                                        }
                                }
                        }

                        if (!found)
                        {
                                arcs[carc].cnt=1;
                                arcs[carc].face=i;
                                arcs[carc].ax = pa.x;
                                arcs[carc].ay = pa.y;
                                arcs[carc].az = pa.z;
                                arcs[carc].bx = pb.x;
                                arcs[carc].by = pb.y;
                                arcs[carc].bz = pb.z;
                                carc++;

                                /* Look like an invalid TIN
                                      anyway not a closed one */
                                if (carc > narcs)
                                {
                                        lwfree(arcs);
                                        return 0;
                                }
                        }
                }
        }

        /* A TIN is closed if each edge
               is shared by exactly 2 faces */
        for (k=0; k < carc ; k++)
        {
                if (arcs[k].cnt != 2)
                {
                        lwfree(arcs);
                        return 0;
                }
        }
        lwfree(arcs);

        /* Invalid TIN case */
        if (carc < tin->ngeoms) return 0;

        return 1;
}

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