Ubuntu Manpage: DANDR - Draws an isosurface when used in conjunction with entry INIT3D.

NAME

       DANDR - Draws an isosurface when used in conjunction with entry INIT3D.

SYNOPSIS

       CALL DANDR (NV,NW,ST1,LX,NX,NY,IS2,IU,S,IOBJS,MV)

STATUS

       This routine is part of the obsolete Isosrfhr utility.  Isosrfhr has been replaced by the
       Isosurface utility.  To see the Isosurface utility overview man page, type "man
       isosurface".

DESCRIPTION

NV (an input expression of type INTEGER) defines the range to be used for the V
dimension of the 3-D UVW grid.

NW (an input expression of type INTEGER) defines the range to be used for the W
dimension of the 3-D UVW grid.

ST1 (an input array of type REAL) used as scratch work space. It must be
dimensioned at least of size NV*NW*2 words.

LX (an input array of type INTEGER) which is the first dimension of array IS2.
It must be of a length to hold NX bits. On a 64 bit machine it would be
LX=(NX-1)/64+1.

NX (an input expression of type INTEGER) defines the range of cells in the X-
direction of the XY pixel model of the image plane. A silhouette of the parts
of the picture processed so far is stored in this model. Lines to be drawn
are tested for visibility by examining the silhouette. Lines in the
silhouette are hidden. Lines out of the silhouette are visible. The solution
is approximate because the silhouette is not formed exactly. See IS2.

NY (an input expression of type INTEGER) defines the range of cells in the Y-
direction of the XY pixel model of the image plane. NY is also the second
dimension of array IS2.

IS2 (an input array of type INTEGER) which holds the XY pixel model of the image
plane. It is dimensioned LX by NY. The pixel model contains NX by NY
elements. The sizes of NX and NY vary with the choice of options. For
example, if hidden lines are drawn, NX and NY (and LX) can be smaller than
when hidden lines are not drawn. If some visible lines are not drawn, NX and
NY (and LX) must be made larger. As a guide, some examples which have been
adequate are:
GIVEN USE

NU NV NW NX NY
--------------------------------
100 100 60 200 200
60 60 60 110 110
40 40 40 75 75

IU (an input expression of type INTEGER) defines the unit number of a scratch
file for the package. ST1 will be written NU times on this file.

S (an input array of type REAL, dimensioned 4) contains the world coordinates of
the area where the picture is to be drawn. That is, all plotting coordinates
generated will be bounded as follows: X coordinates will be between S(1) and
S(2), Y coordinates will be between S(3) and S(4). To prevent distortion,
have S(2)-S(1) = S(4)-S(3).

All coordinates should be in a range between 10. and 1010.

IOBJS (an input array of type INTEGER) which describes the objects to be drawn in VW
space. It is of size NV by NW. The actual first dimension of IOBJS in the
calling program is MV.

Entry DANDR is called NU times to process any object contours in the VW cross
sections defined by IOBJS. Slabs are processed from back to front such that
on the I-th call to DANDR, the slab at U = NU+1-I is processed. IOBJS(J,K) =
1 if any object contains the point (NU+1-I,J,K) and IOBJS(J,K) = 0 otherwise.

MV (an input expression of type INTEGER) defines the actual first dimension of
the array IOBJS in the calling program. When plotting all of IOBJS, NV = MV.

USAGE

       Entries DANDR and DANDR must be used in tandem to create a plot.  First call entry DANDR
       to create a set of 2-D perspective planes which are output to a scratch file.  Then, in
       the calling program you must loop over the U dimension of UVW space starting at the last
       slab, NU, and moving forward to slab 1.  Initially set all elements of IOBJS to zeros.
       Then, at all locations (J,K) where the surface of an object would appear, set IOBJS(J,K) =
       1.  When IOBJS(J,K) has been defined for that VW slab (U = NU - I + 1), call the entry
       DANDR, which draws any object contours based on the 2-D perspective defined for that slab.

       An Isosrfhr example of the logical structure of a program follows:

        C  Entry DANDR writes NU 2-D perspective planes, ST1(NV,NW,2),
        C   of the UVW grid, viewed from the position EYE, to a scratch file.
        C
             CALL DANDR(EYE,NU,NV,NW,ST1,LX,NY,IS2,IU,S)
        C
        C NU is the extent of the U dimension.
        C
             DO 1 IBKWDS = 1,NU
             I = NU+1-IBKWDS
        C
        C You must define the presence of the objects at each VW grid point for
        C all slabs in the U direction. Ones are used to indicate the presence
        C of an object.  Zeros indicate no object.
        C
        C      IF (OBJ.EQ.YES) IOBJS(J,K) = 1
        C      IF (OBJ.EQ.NO)  IOBJS(J,K) = 0
        C
        C  DANDR reads ST1(NV,NW,2) for slab I.
        C
           1 CALL DANDR(NV,NW,ST1,LX,NX,NY,IS2,IU,S,IOBJS,MV)

EXAMPLES

       Use the ncargex command to see the following relevant examples:  tisohr

ACCESS

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

COPYRIGHT

       Copyright (C) 1987-2009
       University Corporation for Atmospheric Research
       The use of this Software is governed by a License Agreement.