ch21.htm

《Perl 5 Unreleased》

&nbsp;75 Transform {<BR>
&nbsp;76 translation .45 .25 0<BR>
&nbsp;77 } # End Transform<BR>
&nbsp;78 Cylinder {<BR>
&nbsp;79 parts ALL<BR>
&nbsp;80 radius .05<BR>
&nbsp;81 height .5<BR>
&nbsp;82 }<BR>
&nbsp;83<BR>
&nbsp;84 } # End Separator<BR>
&nbsp;85<BR>
&nbsp;86 Separator {<BR>
&nbsp;87 Material {<BR>
&nbsp;88 ambientColor .5 .5 .5<BR>
&nbsp;89 } # End Material<BR>
&nbsp;90 Transform {<BR>
&nbsp;91 translation .55 .3 0<BR>
&nbsp;92 } # End Transform<BR>
&nbsp;93 Cylinder {<BR>
&nbsp;94 parts ALL<BR>
&nbsp;95 radius .05<BR>
&nbsp;96 height .6<BR>
&nbsp;97 }<BR>
&nbsp;98<BR>
&nbsp;99 } # End Separator<BR>
100<BR>
101&nbsp;&nbsp;Separator {<BR>
102&nbsp;&nbsp;Material {<BR>
103&nbsp;&nbsp;ambientColor .6 .6 .6<BR>
104&nbsp;&nbsp;} # End Material<BR>
105&nbsp;&nbsp;Transform {<BR>
106&nbsp;&nbsp;translation .65 .35 0<BR>
107&nbsp;&nbsp;} # End Transform<BR>
108&nbsp;&nbsp;Cylinder {<BR>
109&nbsp;&nbsp;parts ALL<BR>
110&nbsp;&nbsp;radius .05<BR>
111&nbsp;&nbsp;height .7<BR>
112&nbsp;&nbsp;}<BR>
113<BR>
114&nbsp;&nbsp;} # End Separator<BR>
115<BR>
116&nbsp;&nbsp;Separator {<BR>
117&nbsp;&nbsp;Material {<BR>
118&nbsp;&nbsp;ambientColor .7 .7 .7<BR>
119&nbsp;&nbsp;} # End Material<BR>
120&nbsp;&nbsp;Transform {<BR>
121&nbsp;&nbsp;translation .75 .4 0<BR>
122&nbsp;&nbsp;} # End Transform<BR>
123&nbsp;&nbsp;Cylinder {<BR>
124&nbsp;&nbsp;parts ALL<BR>
125&nbsp;&nbsp;radius .05<BR>
126&nbsp;&nbsp;height .8<BR>
127&nbsp;&nbsp;}<BR>
128<BR>
129&nbsp;&nbsp;} # End Separator<BR>
130<BR>
131&nbsp;&nbsp;Separator {<BR>
132&nbsp;&nbsp;Material {<BR>
133&nbsp;&nbsp;ambientColor .8 .8 .8<BR>
134&nbsp;&nbsp;} # End Material<BR>
135&nbsp;&nbsp;Transform {<BR>
136&nbsp;&nbsp;translation .85 .45 0<BR>
137&nbsp;&nbsp;} # End Transform<BR>
138&nbsp;&nbsp;Cylinder {<BR>
139&nbsp;&nbsp;parts ALL<BR>
140&nbsp;&nbsp;radius .05<BR>
141&nbsp;&nbsp;height .9<BR>
142&nbsp;&nbsp;}<BR>
143<BR>
144&nbsp;&nbsp;} # End Separator<BR>
145<BR>
146&nbsp;&nbsp;} # End Separator</FONT></TT>
</BLOCKQUOTE>
<HR>
<P>
The <TT><FONT FACE="Courier">for</FONT></TT> loop in Listing 21.5
is a pretty canned approach to generating the test data for this
chapter. In most cases, you'll want to generate your data in a
function of some sort and then display it. A sample usage of such
a function is shown in Listing 21.7.
<HR>
<BLOCKQUOTE>
<B>Listing 21.7. Using a function to get data for display.<BR>
</B>
</BLOCKQUOTE>
<BLOCKQUOTE>
<TT><FONT FACE="Courier">&nbsp;1 #!/usr/bin/perl<BR>
&nbsp;2<BR>
&nbsp;3 use VRML;<BR>
&nbsp;4 use VRML::Cylinder;<BR>
&nbsp;5<BR>
&nbsp;6 sub getResults {<BR>
&nbsp;7&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;my
@answers;<BR>
&nbsp;8&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;my
$i;<BR>
&nbsp;9&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;for
($i = 0; $i &lt; 9; $i++) {<BR>
10&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;$answers[$i]
= $i;<BR>
11&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}
<BR>
12&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return
(@answers);<BR>
13 }<BR>
14<BR>
15 my $header = VRML::new();<BR>
16 $header-&gt;VRML::startHeader;<BR>
17<BR>
18 $header-&gt;VRML::startSeparator;<BR>
19<BR>
20 $header-&gt;VRML::setPointLight('location' =&gt; [1,1,1], 'color'
=&gt;<BR>
&nbsp;&nbsp;&nbsp;&Acirc;[0.2, 0.2, 0.5]);<BR>
21 $width = 0.1;<BR>
22 my @cubeb;<BR>
23<BR>
24 @results = &amp;getResults();<BR>
25<BR>
26 foreach $i (@results) {<BR>
27&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;$j
= $width / 2 + $i * $width;<BR>
28&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;$ht
= $i * 0.1 + 0.1;<BR>
29&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;$cubeb[$i]
= $header-&gt;VRML::putCylinder(<BR>
30&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'radius'
=&gt; $width/2, 'height' =&gt; $ht , 'parts' =&gt;<BR>
&nbsp;&nbsp; &Acirc;'ALL',<BR>
31&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'translation'
=&gt; [$j,$ht/2,0],<BR>
32&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'ambientColor'
=&gt; [$i/10, $i/10,$i/10]<BR>
33&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;);
<BR>
34&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}
<BR>
35<BR>
36 $header-&gt;VRML::stopSeparator;</FONT></TT>
</BLOCKQUOTE>
<HR>
<P>
In Listing 21.7, the subroutine <TT><FONT FACE="Courier">getResults</FONT></TT>
is used to generate the data required for display. The <TT><FONT FACE="Courier">getResults</FONT></TT>
subroutine in this example is only doing what the <TT><FONT FACE="Courier">for</FONT></TT>
loop did. However, there is nothing preventing you from replacing
the <TT><FONT FACE="Courier">getResults</FONT></TT> code to access
data, for example.
<P>
More than one column of data is also possible. Look at Listing
21.8. The output from this run is not listed here but is shown
in Figure 21.3.
<P>
<A HREF="f21-3.gif" tppabs="http://www.mcp.com/815097600/0-672/0-672-30891-6/f21-3.gif" ><B>Figure 21.3 : </B><I>Using boxes and cylinders to represent data.</I></A>
<HR>
<BLOCKQUOTE>
<B>Listing 21.8. Using multiple columns.<BR>
</B>
</BLOCKQUOTE>
<BLOCKQUOTE>
<TT><FONT FACE="Courier">&nbsp;1&nbsp;#!/usr/bin/perl<BR>
&nbsp;2<BR>
&nbsp;3 use VRML;<BR>
&nbsp;4 use VRML::Cube;<BR>
&nbsp;5 use VRML::Cylinder;<BR>
&nbsp;6<BR>
&nbsp;7 sub getResults {<BR>
&nbsp;8&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;my
@answers;<BR>
&nbsp;9&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;my
$i;<BR>
10&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;for
($i = 0; $i &lt; 9; $i++) {<BR>
11&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;$answers[$i]
= $i;<BR>
12&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}
<BR>
13&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return
(@answers);<BR>
14 }<BR>
15<BR>
16 my $header = VRML::new();<BR>
17 $header-&gt;VRML::startHeader;<BR>
18<BR>
19 $header-&gt;VRML::startSeparator;<BR>
20 $width = 0.1;<BR>
21 my @cyl;<BR>
22<BR>
23 @results = &amp;getResults();<BR>
24<BR>
25 foreach $i (@results) {<BR>
26&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;$j
= $width / 2 + $i * $width;<BR>
27&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;$ht
= $i * 0.1 + 0.1;<BR>
28&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;$cyl[$i]
= $header-&gt;VRML::putCylinder(<BR>
29&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'radius'
=&gt; $width/2, 'height' =&gt; $ht , 'parts' =&gt;<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&Acirc;'ALL',
<BR>
30&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'translation'
=&gt; [$j,$ht/2,0],<BR>
31&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'ambientColor'
=&gt; [$i/10, $i/10,$i/10]<BR>
32&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;);
<BR>
33&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}
<BR>
34<BR>
35 #<BR>
36 # Start second column.<BR>
37 #<BR>
38 $width = 0.1;<BR>
39 my @cub;<BR>
40<BR>
41 @results = &amp;getResults();<BR>
42<BR>
43 foreach $i (@results) {<BR>
44&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;$j
= $width / 2 + $i * $width;<BR>
45&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;$ht
= $i * 0.1 + 0.1;<BR>
46&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;$cub[$i]
= $header-&gt;VRML::putCube(<BR>
47&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'width'
=&gt; $width/2, 'height' =&gt; $ht , 'depth' =&gt;<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&Acirc;$width,
<BR>
48&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'translation'
=&gt; [$j,$ht/2,$width],<BR>
49&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'ambientColor'
=&gt; [$i/10, $i/10,$i/10]<BR>
50&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;);
<BR>
51&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
}<BR>
52 $header-&gt;VRML::stopSeparator;</FONT></TT>
</BLOCKQUOTE>
<HR>
<P>
In the code shown in Listing 21.8, two columns of data are created.
Note the use of the Z offset in doing the translation of <TT><FONT FACE="Courier">Cylinder</FONT></TT>s.
Also note that only one separator node is used for the entire
image and one for each node.
<H2><A NAME="HowtoViewYourWorld"><B><FONT SIZE=5 COLOR=#FF0000>How
to View Your World</FONT></B></A></H2>
<P>
There are several VRML viewers available on the market today.
Some are totally free of charge, some free of charge up to 30
days, and the rest require a fee of anywhere from $50 to thousands
of dollars. The following is a list of some of the vendors, their
viewers, and what they have to offer. Most of the browsers are
for Windows NT or Windows 95, but there are quite a few for UNIX
workstations. A few of these are listed here. However, I would
advise you to do a search on the Internet for a more comprehensive
list. Here's the list:
<UL>
<LI>WorldView-A Windows 95, NT, and 3.1 product by InterVista,
Inc.
<LI>NavFlyer-Made by Micro Green, Inc. Requires Win32 if you are
running under Windows NT. Also requires the WinG graphics library.
<LI>WbFX-Runs with Mosaic and the 16-bit version of Netscape only.
Made only for Windows 3.1 by Paper Software, Inc.
</UL>
<P>