CERN Program Library Long Writeup W5013 - CERNLIB ...

Geant 3.15 GEANT User’s Guide DRAW115
Origin : P.Zanarini Submitted: 01.01.86
Revision : Revised: 11.12.92
Documentation : P.Zanarini, F.Carminati
Drawing a Volume Projection view – Case 2
CALL GDRVOL
(NNAMS,CHNAMS,LNUMBS,NRS,THETA,PHI,PSI,U0,V0,SU,SV)
Draws an orthographic parallel projection or a perspective projection (depending on the option chosen via
GDOPT) of the volume CHNAMS(N),LNUMBS(N) with all its descendants, at the position U0,V0 (user coordinates),
with the scale factors SU and SV. The object is seen from THETA and PHI angles, and the resulting 2D
projection is also rotated by an angle PSI on the screen plane. These parameters, as well as zoom parameters
set by GDZOOM,define the current view parameters, and they are copied in /GCDRAW/. Attributes like colour,
fill area, line width, line style, visibility, etc. can be set by the GSATT routine for CHNAMS(N) and or its
descendants [GEOM 500]. This routine differs from GDRAW in the following aspects:
• The object to be drawn is identified by a full path. This gives the possibility of drawing a particular
copy or division of a volume, or even a volume that has more than one mother in the geometry
tree. CHNAMS(1),...,CHNAMS(N) contain the volume names and LNUMBS(1),...,LNUMBS(N), the
volume numbers defining the path to go from the top volume to the one to be drawn.
• The object can be drawn either with respect to the MAster Reference System (NRS=0) or with respect
to its Daugther Reference System (i.e. the Local R.S.); in the first case it is drawn in its position in the
real world, while in the second one it is drawn like GDRAW would do.
• In this latter case, track and hit points will be drawn with respect to the DRS of the volume last drawn
by this routine, and not with respect to the MARS as is done normally (to reset to the normal case a call
with NRS=0 or NNAMS=0 is required).
NNAMS
CHNAMS
LNUMBS
NRS
THETA
PHI
PSI
U0
V0
SU
SV
(INTEGER) number of elements levels in the arrays CHNAMS, LNUMBS. The bottom volume of
this path is also the one that is actually drawn;
(CHARACTER*4) array of volume name (dimensioned at least to NNAMS);
array of volume numbers (dimensioned at least to NNAMS);
reference system used:
NRS=0 to have the volume(s) drawn with respect to the MARS
NRS≠0 to have the volume(s) drawn with respect to the DRS
θ angle between the line of sight and the Z axis of MARS;
φ angle between the projection of the line of sight on plane X Yand the X axis of MARS
ψ angle by which the projected image will be rotated on the screen plane
u coordinate on the screen of the volume origin
v coordinate on the screen of the volume origin
scale factor for u coordinates
scale factor for v coordinates
Two examples of use of GDRVOL are shown in fig 9 and 10.
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