#!/bin/perl

# sirts.pl (c) 1996-1997 Jason D. Hartline and Prescient Code Solutions.
#
# This is the engine behind The SIRTS Generator at http://www.coder.com/
# creations/stereo/.  This code is released as is.  Use it at your own risk.
# This code may be distributed or modified in accordance with the GNU Public 
# Licence avilable with this source file at http://www.coder.com/creations/
# stereo/GPL.gz.  This source file can be obtained from http://www.coder.com/
# creations/stereo/sirts.perl.  Questions and comments may be sent to 
# jason@coder.com.    
#
 
$opts{'level'}=0;
$opts{'color'}=0;
$opts{'depth'}=15;
$opts{'cool'}=.05;
$opts{'width'}=70;
$opts{'symbol'}=.4;
$opts{'space'}=.02;
$opts{'bg'}='';
$opts{'fg'}='';
$opts{'bright'}='';
$opts{'colors'}='';



@cool=('Prescient Code!','CAN+YOU_SEE~SIRTS?','CROSS_YOUR*EYES!','CooL',
	'Code','IDEA','WORLD WIDE+WEB','code IN perl','STEREO','SIRTS',
	'POP OUT','three dimensional','3d fun','alt.3d');

$badchars='<>&"';

foreach (33..37,39..47,58,59,61,63,64,91..96,123..126)
{
    push @symbol,chr;
}

@digits = ('0'..'9');
@loweralpha=('a'..'z');
@alpha=('a'..'z','A'..'Z');
@upperalpha=('A'..'Z');
@alphanum=('0'..'9','a'..'z','A'..'Z');

@color=('#ffffff','#000000','#ff0000','#00ff00','#0000ff','#ff00ff','#00ffff',
	'#ffff00');







srand;
$last=0;
$next=0;

@text = <>;

# Remove comments and options from input file.
# This uses postscript style comments where lines beginning with %
# are ignored and lines beginning with %% are options.
foreach (@text)
{
    chomp;
    if (!m/^%/)
    {
	push @input, $_;	
    }
    elsif (m/^%%/)
    {
	push @opt,$_;
    }
}

#extract optinos
foreach (@opt)
{
    s/%%(.*)/$1/s;
    ($cmd,$opt)=split '=';
    $opts{lc $cmd}=$opt;
}


sub random
{
    @_[rand($#_+1)];
}

if ($opts{'colors'})
{
    @color=split(',',$opts{'colors'});
}

if ($opts{'bright'})
{
    push @color,$opts{'bright'};
}

if ($opts{'fg'})
{
    $text .= '<font color="'.$opts{'fg'}.'">';
}

foreach $in (@input)
{
    @s=();
    if ($opts{'cool'}&& rand() < $opts{'cool'})
    {
	@s = reverse(split("",random(@cool)));
    }
    while ($#s < $opts{'depth'})
    {
	$rand=rand();
	if ($rand < $opts{'symbol'})
	{
	    push @s,(&random(@symbol));
	}
	elsif ($rand > (1.0-$opts{'space'}))
	{
	    push @s,' ';
	}
	else
	{
	    push @s,&random(@alphanum);	
	}	    
    }

    if ($opts{'color'})
    {
	foreach (@s) 
	{
	    if (rand()<$opts{'color'})
	    {
		$color=random(@color);
		$_="<font color=\"$color\">".$_."</font>";
	    }
	}
    }
    while ($#s > $opts{'depth'})
    {
	push @ns,pop @s;
    }


    
    @in=split '','               '.$in;
    for (;$#in < $opts{'width'};push (@in,' ')) {}
    @in=@in[1..$opts{'width'}];
    $last=0;
    

    foreach (@in)
    {
	$next = (!m/\d/s)?$opts{'level'}:ord($_)-ord("0");
	$diff=$next-$last;
        for(;$diff>0;$diff--)
	   { push @ns,pop @s;}
	for(;$diff<0;$diff++)
	   { push @s,pop @ns;}
	unshift @s, pop @s;
        
	$text .= $s[0];
	$last=$next;
    }
    $text .= "\n";
}

if ($opts{'fg'})
{
    $text .= '</font>';
}

print $text;


exit;