#!/usr/bin/perl

# Sept 6, 2004 - program to OR all the yellow bear bits to the white bear image, so that it doesn't flicker as much

# one array for each bear image
my @yellow;
my @white;
my @bearbits = ( \@yellow, \@white );

$section = 0;

$offset = 0; # the scanline the data represent

$scanline = $offset;

open(BEAR, 'bear.txt');
while (<BEAR>)
	{
	if ( ( $left, $data, $comment ) = ( /^([A-Za-z]*|)\s*\.byte\s*\%([01]{8})\s*(?:;\s*(.*))?$/ ) )
		{
		if ( $left eq 'BearWhiteA' )
			{
			$section = 0;
			$scanline = $offset;
			}
		elsif ( $left eq 'BearYellowA' )
			{
			$section = 1;
			$scanline = $offset;
			}

		$data = uc( $data );

		if ( $section == 0 ) # yellow copy
			{
			push( @{$bearbits[ $section ]}, $data );
			}
		elsif ( $section == 1 ) # white copy - merge yellow's 1s into our 0s
			{
			push( @{$bearbits[ $section ]}, "$left\t.byte\t\%" . merge($bearbits[ 0 ][$scanline], $data) . ( $comment ? '; ' : '' ) . "$comment\r\n" );
			}
			
			
		$scanline++;
		}
	elsif ( $section == 1 )
		{
		push( @{$bearbits[ 1 ]}, $_ );
		}
	}

print $_ foreach ( @white );

#print "\nmerge('11110000','00000111') = ", merge('11110000','00000111'), "\n";
#print "\nmerge('10000000','00000001') = ", merge('10000000','00000001'), "\n";
#print "\nmerge('00000000','00000000') = ", merge('00000000','00000000'), "\n";
#print "\nmerge('11111111','00000111') = ", merge('11111111','00000111'), "\n";
#print "\nmerge('00000111','11111111') = ", merge('00000111','11111111'), "\n";
#print "\nmerge('00000001','00000000') = ", merge('00000001','00000000'), "\n";

sub merge()
	{
	my $source=shift;
	my $target=shift;

	$source = pack( "b8", $source );
	print "[source: $source]";
	$target = pack( "b8", $target );
	print "[target: $target]";
	return( unpack( "b8", $source | $target ) );
	}