[sdlgit/SDL_perl.git] / lib / SDL / Tutorial / Images.pm

package SDL::Tutorial::Images;

use strict;
use warnings;

my %images;
BEGIN
{
	%images = (
	left => [qw(
		47 49 46 38 37 61 10 00 10 00 E7 00 00 00 00 00 01 01 01 02 02 02 03 03
		03 04 04 04 05 05 05 06 06 06 07 07 07 08 08 08 09 09 09 0A 0A 0A 0B 0B
		0B 0C 0C 0C 0D 0D 0D 0E 0E 0E 0F 0F 0F 10 10 10 11 11 11 12 12 12 13 13
		13 14 14 14 15 15 15 16 16 16 17 17 17 18 18 18 19 19 19 1A 1A 1A 1B 1B
		1B 1C 1C 1C 1D 1D 1D 1E 1E 1E 1F 1F 1F 20 20 20 21 21 21 22 22 22 23 23
		23 24 24 24 25 25 25 26 26 26 27 27 27 28 28 28 29 29 29 2A 2A 2A 2B 2B
		2B 2C 2C 2C 2D 2D 2D 2E 2E 2E 2F 2F 2F 30 30 30 31 31 31 32 32 32 33 33
		33 34 34 34 35 35 35 36 36 36 37 37 37 38 38 38 39 39 39 3A 3A 3A 3B 3B
		3B 3C 3C 3C 3D 3D 3D 3E 3E 3E 3F 3F 3F 40 40 40 41 41 41 42 42 42 43 43
		43 44 44 44 45 45 45 46 46 46 47 47 47 48 48 48 49 49 49 4A 4A 4A 4B 4B
		4B 4C 4C 4C 4D 4D 4D 4E 4E 4E 4F 4F 4F 50 50 50 51 51 51 52 52 52 53 53
		53 54 54 54 55 55 55 56 56 56 57 57 57 58 58 58 59 59 59 5A 5A 5A 5B 5B
		5B 5C 5C 5C 5D 5D 5D 5E 5E 5E 5F 5F 5F 60 60 60 61 61 61 62 62 62 63 63
		63 64 64 64 65 65 65 66 66 66 67 67 67 68 68 68 69 69 69 6A 6A 6A 6B 6B
		6B 6C 6C 6C 6D 6D 6D 6E 6E 6E 6F 6F 6F 70 70 70 71 71 71 72 72 72 73 73
		73 74 74 74 75 75 75 76 76 76 77 77 77 78 78 78 79 79 79 7A 7A 7A 7B 7B
		7B 7C 7C 7C 7D 7D 7D 7E 7E 7E 7F 7F 7F 80 80 80 81 81 81 82 82 82 83 83
		83 84 84 84 85 85 85 86 86 86 87 87 87 88 88 88 89 89 89 8A 8A 8A 8B 8B
		8B 8C 8C 8C 8D 8D 8D 8E 8E 8E 8F 8F 8F 90 90 90 91 91 91 92 92 92 93 93
		93 94 94 94 95 95 95 96 96 96 97 97 97 98 98 98 99 99 99 9A 9A 9A 9B 9B
		9B 9C 9C 9C 9D 9D 9D 9E 9E 9E 9F 9F 9F A0 A0 A0 A1 A1 A1 A2 A2 A2 A3 A3
		A3 A4 A4 A4 A5 A5 A5 A6 A6 A6 A7 A7 A7 A8 A8 A8 A9 A9 A9 AA AA AA AB AB
		AB AC AC AC AD AD AD AE AE AE AF AF AF B0 B0 B0 B1 B1 B1 B2 B2 B2 B3 B3
		B3 B4 B4 B4 B5 B5 B5 B6 B6 B6 B7 B7 B7 B8 B8 B8 B9 B9 B9 BA BA BA BB BB
		BB BC BC BC BD BD BD BE BE BE BF BF BF C0 C0 C0 C1 C1 C1 C2 C2 C2 C3 C3
		C3 C4 C4 C4 C5 C5 C5 C6 C6 C6 C7 C7 C7 C8 C8 C8 C9 C9 C9 CA CA CA CB CB
		CB CC CC CC CD CD CD CE CE CE CF CF CF D0 D0 D0 D1 D1 D1 D2 D2 D2 D3 D3
		D3 D4 D4 D4 D5 D5 D5 D6 D6 D6 D7 D7 D7 D8 D8 D8 D9 D9 D9 DA DA DA DB DB
		DB DC DC DC DD DD DD DE DE DE DF DF DF E0 E0 E0 E1 E1 E1 E2 E2 E2 E3 E3
		E3 E4 E4 E4 E5 E5 E5 E6 E6 E6 E7 E7 E7 E8 E8 E8 E9 E9 E9 EA EA EA EB EB
		EB EC EC EC ED ED ED EE EE EE EF EF EF F0 F0 F0 F1 F1 F1 F2 F2 F2 F3 F3
		F3 F4 F4 F4 F5 F5 F5 F6 F6 F6 F7 F7 F7 F8 F8 F8 F9 F9 F9 FA FA FA FB FB
		FB FC FC FC FD FD FD FE FE FE FF FF FF 2C 00 00 00 00 10 00 10 00 00 08
		36 00 FF 09 1C 48 B0 A0 C1 83 08 13 22 04 C0 10 80 C2 7F 0C 05 46 4C E8
		70 60 C5 85 15 27 52 6C A8 30 E3 45 8C 0D 39 76 FC 38 F2 A1 44 91 1B 4F
		82 24 88 D2 64 C1 80 00 3B
	)],
	center => [qw(
		47 49 46 38 37 61 10 00 10 00 E7 00 00 00 00 00 01 01 01 02 02 02 03 03
		03 04 04 04 05 05 05 06 06 06 07 07 07 08 08 08 09 09 09 0A 0A 0A 0B 0B
		0B 0C 0C 0C 0D 0D 0D 0E 0E 0E 0F 0F 0F 10 10 10 11 11 11 12 12 12 13 13
		13 14 14 14 15 15 15 16 16 16 17 17 17 18 18 18 19 19 19 1A 1A 1A 1B 1B
		1B 1C 1C 1C 1D 1D 1D 1E 1E 1E 1F 1F 1F 20 20 20 21 21 21 22 22 22 23 23
		23 24 24 24 25 25 25 26 26 26 27 27 27 28 28 28 29 29 29 2A 2A 2A 2B 2B
		2B 2C 2C 2C 2D 2D 2D 2E 2E 2E 2F 2F 2F 30 30 30 31 31 31 32 32 32 33 33
		33 34 34 34 35 35 35 36 36 36 37 37 37 38 38 38 39 39 39 3A 3A 3A 3B 3B
		3B 3C 3C 3C 3D 3D 3D 3E 3E 3E 3F 3F 3F 40 40 40 41 41 41 42 42 42 43 43
		43 44 44 44 45 45 45 46 46 46 47 47 47 48 48 48 49 49 49 4A 4A 4A 4B 4B
		4B 4C 4C 4C 4D 4D 4D 4E 4E 4E 4F 4F 4F 50 50 50 51 51 51 52 52 52 53 53
		53 54 54 54 55 55 55 56 56 56 57 57 57 58 58 58 59 59 59 5A 5A 5A 5B 5B
		5B 5C 5C 5C 5D 5D 5D 5E 5E 5E 5F 5F 5F 60 60 60 61 61 61 62 62 62 63 63
		63 64 64 64 65 65 65 66 66 66 67 67 67 68 68 68 69 69 69 6A 6A 6A 6B 6B
		6B 6C 6C 6C 6D 6D 6D 6E 6E 6E 6F 6F 6F 70 70 70 71 71 71 72 72 72 73 73
		73 74 74 74 75 75 75 76 76 76 77 77 77 78 78 78 79 79 79 7A 7A 7A 7B 7B
		7B 7C 7C 7C 7D 7D 7D 7E 7E 7E 7F 7F 7F 80 80 80 81 81 81 82 82 82 83 83
		83 84 84 84 85 85 85 86 86 86 87 87 87 88 88 88 89 89 89 8A 8A 8A 8B 8B
		8B 8C 8C 8C 8D 8D 8D 8E 8E 8E 8F 8F 8F 90 90 90 91 91 91 92 92 92 93 93
		93 94 94 94 95 95 95 96 96 96 97 97 97 98 98 98 99 99 99 9A 9A 9A 9B 9B
		9B 9C 9C 9C 9D 9D 9D 9E 9E 9E 9F 9F 9F A0 A0 A0 A1 A1 A1 A2 A2 A2 A3 A3
		A3 A4 A4 A4 A5 A5 A5 A6 A6 A6 A7 A7 A7 A8 A8 A8 A9 A9 A9 AA AA AA AB AB
		AB AC AC AC AD AD AD AE AE AE AF AF AF B0 B0 B0 B1 B1 B1 B2 B2 B2 B3 B3
		B3 B4 B4 B4 B5 B5 B5 B6 B6 B6 B7 B7 B7 B8 B8 B8 B9 B9 B9 BA BA BA BB BB
		BB BC BC BC BD BD BD BE BE BE BF BF BF C0 C0 C0 C1 C1 C1 C2 C2 C2 C3 C3
		C3 C4 C4 C4 C5 C5 C5 C6 C6 C6 C7 C7 C7 C8 C8 C8 C9 C9 C9 CA CA CA CB CB
		CB CC CC CC CD CD CD CE CE CE CF CF CF D0 D0 D0 D1 D1 D1 D2 D2 D2 D3 D3
		D3 D4 D4 D4 D5 D5 D5 D6 D6 D6 D7 D7 D7 D8 D8 D8 D9 D9 D9 DA DA DA DB DB
		DB DC DC DC DD DD DD DE DE DE DF DF DF E0 E0 E0 E1 E1 E1 E2 E2 E2 E3 E3
		E3 E4 E4 E4 E5 E5 E5 E6 E6 E6 E7 E7 E7 E8 E8 E8 E9 E9 E9 EA EA EA EB EB
		EB EC EC EC ED ED ED EE EE EE EF EF EF F0 F0 F0 F1 F1 F1 F2 F2 F2 F3 F3
		F3 F4 F4 F4 F5 F5 F5 F6 F6 F6 F7 F7 F7 F8 F8 F8 F9 F9 F9 FA FA FA FB FB
		FB FC FC FC FD FD FD FE FE FE FF FF FF 2C 00 00 00 00 10 00 10 00 00 08
		36 00 FF 09 1C 48 B0 A0 C1 83 08 13 26 04 C0 10 80 C2 7F 0C 05 46 5C 48
		D0 E1 42 8B 13 2F 66 54 B8 F1 60 C3 8F 16 2F 3E 1C D8 11 E1 C7 87 13 4B
		4A DC D8 70 E4 C1 80 00 3B
	)],
	right => [qw(
		47 49 46 38 37 61 10 00 10 00 E7 00 00 00 00 00 01 01 01 02 02 02 03 03
		03 04 04 04 05 05 05 06 06 06 07 07 07 08 08 08 09 09 09 0A 0A 0A 0B 0B
		0B 0C 0C 0C 0D 0D 0D 0E 0E 0E 0F 0F 0F 10 10 10 11 11 11 12 12 12 13 13
		13 14 14 14 15 15 15 16 16 16 17 17 17 18 18 18 19 19 19 1A 1A 1A 1B 1B
		1B 1C 1C 1C 1D 1D 1D 1E 1E 1E 1F 1F 1F 20 20 20 21 21 21 22 22 22 23 23
		23 24 24 24 25 25 25 26 26 26 27 27 27 28 28 28 29 29 29 2A 2A 2A 2B 2B
		2B 2C 2C 2C 2D 2D 2D 2E 2E 2E 2F 2F 2F 30 30 30 31 31 31 32 32 32 33 33
		33 34 34 34 35 35 35 36 36 36 37 37 37 38 38 38 39 39 39 3A 3A 3A 3B 3B
		3B 3C 3C 3C 3D 3D 3D 3E 3E 3E 3F 3F 3F 40 40 40 41 41 41 42 42 42 43 43
		43 44 44 44 45 45 45 46 46 46 47 47 47 48 48 48 49 49 49 4A 4A 4A 4B 4B
		4B 4C 4C 4C 4D 4D 4D 4E 4E 4E 4F 4F 4F 50 50 50 51 51 51 52 52 52 53 53
		53 54 54 54 55 55 55 56 56 56 57 57 57 58 58 58 59 59 59 5A 5A 5A 5B 5B
		5B 5C 5C 5C 5D 5D 5D 5E 5E 5E 5F 5F 5F 60 60 60 61 61 61 62 62 62 63 63
		63 64 64 64 65 65 65 66 66 66 67 67 67 68 68 68 69 69 69 6A 6A 6A 6B 6B
		6B 6C 6C 6C 6D 6D 6D 6E 6E 6E 6F 6F 6F 70 70 70 71 71 71 72 72 72 73 73
		73 74 74 74 75 75 75 76 76 76 77 77 77 78 78 78 79 79 79 7A 7A 7A 7B 7B
		7B 7C 7C 7C 7D 7D 7D 7E 7E 7E 7F 7F 7F 80 80 80 81 81 81 82 82 82 83 83
		83 84 84 84 85 85 85 86 86 86 87 87 87 88 88 88 89 89 89 8A 8A 8A 8B 8B
		8B 8C 8C 8C 8D 8D 8D 8E 8E 8E 8F 8F 8F 90 90 90 91 91 91 92 92 92 93 93
		93 94 94 94 95 95 95 96 96 96 97 97 97 98 98 98 99 99 99 9A 9A 9A 9B 9B
		9B 9C 9C 9C 9D 9D 9D 9E 9E 9E 9F 9F 9F A0 A0 A0 A1 A1 A1 A2 A2 A2 A3 A3
		A3 A4 A4 A4 A5 A5 A5 A6 A6 A6 A7 A7 A7 A8 A8 A8 A9 A9 A9 AA AA AA AB AB
		AB AC AC AC AD AD AD AE AE AE AF AF AF B0 B0 B0 B1 B1 B1 B2 B2 B2 B3 B3
		B3 B4 B4 B4 B5 B5 B5 B6 B6 B6 B7 B7 B7 B8 B8 B8 B9 B9 B9 BA BA BA BB BB
		BB BC BC BC BD BD BD BE BE BE BF BF BF C0 C0 C0 C1 C1 C1 C2 C2 C2 C3 C3
		C3 C4 C4 C4 C5 C5 C5 C6 C6 C6 C7 C7 C7 C8 C8 C8 C9 C9 C9 CA CA CA CB CB
		CB CC CC CC CD CD CD CE CE CE CF CF CF D0 D0 D0 D1 D1 D1 D2 D2 D2 D3 D3
		D3 D4 D4 D4 D5 D5 D5 D6 D6 D6 D7 D7 D7 D8 D8 D8 D9 D9 D9 DA DA DA DB DB
		DB DC DC DC DD DD DD DE DE DE DF DF DF E0 E0 E0 E1 E1 E1 E2 E2 E2 E3 E3
		E3 E4 E4 E4 E5 E5 E5 E6 E6 E6 E7 E7 E7 E8 E8 E8 E9 E9 E9 EA EA EA EB EB
		EB EC EC EC ED ED ED EE EE EE EF EF EF F0 F0 F0 F1 F1 F1 F2 F2 F2 F3 F3
		F3 F4 F4 F4 F5 F5 F5 F6 F6 F6 F7 F7 F7 F8 F8 F8 F9 F9 F9 FA FA FA FB FB
		FB FC FC FC FD FD FD FE FE FE FF FF FF 2C 00 00 00 00 10 00 10 00 00 08
		3A 00 FF 09 1C 48 B0 A0 C1 83 08 13 2A 04 C0 10 80 C2 7F 0C 05 46 4C E8
		70 60 45 84 13 27 52 6C F8 50 62 C5 8B 05 1B 8A 04 79 50 E3 43 93 1B 51
		1A CC 48 D2 A2 49 8E 1D 0B 06 04 00 3B
	)],
);
}

use Pod::ToDemo sub
{
	(undef, my $filename) = @_;
	(my $imagebase        = $filename) =~ s/\.\w+$//;
	my @img_files         = map { $imagebase . "_$_.gif" }
		qw( left center right );
	my $demo_source       = <<'END_HERE';
package Walker;

sub new
{
	my ($class, @images) = @_;
	my @frames           = map { SDL::Surface->new( -name => $_ ) } @images;
	my $frame_rect       = SDL::Rect->new(
		-height => $frames[0]->height(),
		-width  => $frames[0]->width(),
		-x      => 0,
		-y      => 0,
	);
	my $self             = 
	{
		frames      => \@frames,
		frame_rect  => $frame_rect,
	};
	bless $self, $class;
}

sub frames
{
	my $self        = shift;
	$self->{frames} = shift if @_;
	$self->{frames};
}

sub frame_rect
{
	my $self            = shift;
	$self->{frame_rect} = shift if @_;
	$self->{frame_rect};
}

sub next_frame
{
	my $self   = shift;
	my $frames = $self->frames();
	my $frame  = shift @$frames;

	push @$frames, $frame;
	$self->frames( $frames );

	return $frame;
}

package main;

use strict;

use SDL;
use SDL::App;
use SDL::Surface;
use SDL::Color;

# change these values as necessary
my $title                                = 'My SDL Animation';
my ($width,      $height,      $depth)   = (  640,  480,   16 );
my ($bg_r,       $bg_g,        $bg_b)    = ( 0xff, 0xff, 0xff );
my ($start_x,    $end_x)                 = (   20,  600       );
my $sleep_msec                           = 0.05;

my $app = SDL::App->new(
	-width  => $width,
	-height => $height,
	-depth  => $depth,
);

my $bg_color = SDL::Color->new(
	-r => $bg_r,
	-g => $bg_g,
	-b => $bg_b,
);

my $background = SDL::Rect->new(
	-width  => $width,
	-height => $height,
);

my $pos = SDL::Rect->new(
	-width  => 16,
	-height => 16,
	-x      => 0,
	-y      => 240,
);

my $walker = Walker->new(qw(
END_HERE

$demo_source .= join( ' ', @img_files ) . "));" . <<'END_HERE';

for my $x ( $start_x .. $end_x )
{
	draw_background( $app, $background, $bg_color );
	$pos->x( $x );
	draw_walker( $walker, $app, $pos );
	$app->update( $background );
	select( undef, undef, undef, $sleep_msec );
}

# you'll want to remove this
sleep 2;

sub draw_background
{
	my ($app, $background, $bg_color) = @_;
	$app->fill( $background, $bg_color );
}

sub draw_walker
{
	my ($walker, $app, $pos) = @_;
	my $frame                = $walker->next_frame();
	my $frame_rect           = $walker->frame_rect();
	$frame->blit( $frame_rect, $app, $pos );
}
END_HERE

	Pod::ToDemo::write_demo( $filename, "#$^X\n$demo_source" );
	write_files( $imagebase );
};
		
sub write_files
{
	my $imagebase = shift;

	for my $image (qw( left center right ))
	{
		my $file = join('', map { chr( hex( $_ ) ) } @{ $images{ $image } });
		write_file( $imagebase . "_$image" . '.gif', $file );
	}
}

sub write_file
{
    my ($file, $contents) = @_;

	die "Cowardly refusing to overwrite '$file'\n" if -e $file;
	open my $out, '>', $file or die "Cannot write '$file': $!\n";
	binmode $out;
	print $out $contents;
}

__END__

=head1 NAME

SDL::Tutorial::Images

=head1 SYNOPSIS

	# to read this tutorial
	$ perldoc SDL::Tutorial::Images

	# to create a demo animation program based on this tutorial
	$ perl -MSDL::Tutorial::Images=sdl_images.pl -e 1

=head1 ANIMATING IMAGES

Since you're already familiar with the concepts behind animation, it's time to
learn how to work with images.  As usual, the important point is that computer animation is just I<simulating> motion by painting several slightly different frames to the screen every second.

There are two ways to vary an image on screen.  One is to change its
coordinates so it's at a slightly different position.  This is very easy to do;
it's just like animating a rectangle.  The other way is to change the image
itself so it's slightly different.  This is a little more difficult, as you'll
need to draw the alternate image beforehand somehow.

=head2 Loading Images

As usual, start with an L<SDL::App> object representing the image window.  Then
preload the image file.  This is easy; just pass the C<name> parameter to the
L<SDL::Surface> constructor:

	use SDL::Surface;

	my $frame = SDL::Surface->new( -name => 'frame1.png' );

B<Note:> you'll need to have compiled SDL Perl (and probably SDL) to support
JPEG and PNG files for this to work.

That's it; now you have an SDL::Surface object containing the image.  You can
use the C<height()>, C<width()>, and C<bpp()> methods to retrieve its height,
width, and bits per pixel, if you need them.

=head2 Displaying Images

Drawing an image onto the screen requires blitting it from one surface to
another.  (Remember, "blitting" means copying bits in memory.)  The C<blit()>
method of SDL::Surface objects comes in handy.  Its arguments are a little odd,
though.  Assuming C<$app> is the SDL::App object, as usual:

	use SDL::Rect;

	my $frame_rect = SDL::Rect->new(
		-height => $frame->height(),
		-width  => $frame->width(),
		-x      => 0,
		-y      => 0,
	);

	my $dest_rect  = SDL::Rect->new(
		-height => $frame->height(),
		-width  => $frame->width(),
		-x      => 0,
		-y      => 0,
	);

	$frame->blit( $frame_rect, $app, $dest_rect );
	$app->update( $dest_rect );

Here we have two L<SDL::Rect> objects which represent rectangular regions of a
Surface.  C<$frame_rect> represents the entire area of C<$frame>, while
C<$dest_rect> represents the area of the main window in which to blit the
frame.  This may be clearer with more descriptive variable names:

	$source_surface->blit(
		$area_of_source_to_blit,
		$destination_surface,
		$destination_area
	);

As usual, call C<update()> on C<$app> to see the change.

Requiring the source and destination Rect objects may seem tedious in this
simple example, but it's highly useful for copying only part of surface to part
of another.  For example, animating this image is a matter of changing the C<x>
and C<y> coordinates of C<$dest_rect>:

	for my $x ( 1 .. 100 )
	{
		$dest_rect->x( $x );
		$frame->blit( $frame_rect, $app, $dest_rect );
		$app->update( $dest_rect );
	}

Of course, you'll have to redraw all or part of the screen to avoid artifacts,
as discussed in the previous tutorial.

=head2 Multi-Image Animation

That covers moving a single image around the screen.  What if you want
something more?  For example, what if you want to animate a stick figure
walking?

You'll need several frames, just as in a flip-book.  Each frame should be slightly different than the one before it.  It's probably handy to encapsulate all of this in a C<Walker> class:

	package Walker;

	use SDL::Surface;

	sub new
	{
		my ($class, @images) = @_;
		my $self = [ map { SDL::Surface->new( -name => $_ ) } @images ];

		bless $self, $class;
	}

	sub next_frame
	{
		my $self  = shift;
		my $frame = shift @$self;

		push @$self, $frame;
		return $frame;
	}

To use this class, instantiate an object:

	my $walker = Walker->new( 'frame1.png', 'frame2.png', 'frame3.png' );

Then call C<next_frame()> within the loop:

	for my $x ( 1 .. 100 )
	{
		my $frame = $walker->next_frame();

		$dest_rect->x( $x );
		$frame->blit( $frame_rect, $app, $dest_rect );
		$app->update( $dest_rect );
	}

Again, the rest of the frame drawing is missing from this example so as not to
distract from this technique.  You'll probably want to abstract the undrawing
and redrawing into a separate subroutine so you don't have to worry about it
every time.

It'd be easy to make C<next_frame()> much smarter, selecting an image
appropriate to the direction of travel, using a bored animation when the
character is no longer moving, or adding other characteristics to the
character.  As you can see, the hard part of this technique is generating the
images beforehand.  That can add up to a tremendous amount of art and that's
one reason for the popularity of 3D models... but that's another tutorial much
further down the road.

More importantly, it's time to discuss how to make these animations run more
smoothly.  More on that next time.

=head1 SEE ALSO

=over 4

=item L<SDL::Tutorial>

basic SDL tutorial

=item L<SDL::Tutorial::Animation>

non-image animation

=back

=head1 AUTHOR

chromatic, E<lt>chromatic@wgz.orgE<gt>

Written for and maintained by the Perl SDL project, L<http://sdl.perl.org/>.

=head1 BUGS

No known bugs.

=head1 COPYRIGHT

Copyright (c) 2004, chromatic.  All rights reserved.  This module is
distributed under the same terms as Perl itself, in the hope that it is useful
but certainly under no guarantee.
Commit	Line	Data
8fde61e3	1	package SDL::Tutorial::Images;
	2
	3	use strict;
	4	use warnings;
	5
	6	my %images;
	7	BEGIN
	8	{
	9	%images = (
	10	left => [qw(
	11	47 49 46 38 37 61 10 00 10 00 E7 00 00 00 00 00 01 01 01 02 02 02 03 03
	12	03 04 04 04 05 05 05 06 06 06 07 07 07 08 08 08 09 09 09 0A 0A 0A 0B 0B
	13	0B 0C 0C 0C 0D 0D 0D 0E 0E 0E 0F 0F 0F 10 10 10 11 11 11 12 12 12 13 13
	14	13 14 14 14 15 15 15 16 16 16 17 17 17 18 18 18 19 19 19 1A 1A 1A 1B 1B
	15	1B 1C 1C 1C 1D 1D 1D 1E 1E 1E 1F 1F 1F 20 20 20 21 21 21 22 22 22 23 23
	16	23 24 24 24 25 25 25 26 26 26 27 27 27 28 28 28 29 29 29 2A 2A 2A 2B 2B
	17	2B 2C 2C 2C 2D 2D 2D 2E 2E 2E 2F 2F 2F 30 30 30 31 31 31 32 32 32 33 33
	18	33 34 34 34 35 35 35 36 36 36 37 37 37 38 38 38 39 39 39 3A 3A 3A 3B 3B
	19	3B 3C 3C 3C 3D 3D 3D 3E 3E 3E 3F 3F 3F 40 40 40 41 41 41 42 42 42 43 43
	20	43 44 44 44 45 45 45 46 46 46 47 47 47 48 48 48 49 49 49 4A 4A 4A 4B 4B
	21	4B 4C 4C 4C 4D 4D 4D 4E 4E 4E 4F 4F 4F 50 50 50 51 51 51 52 52 52 53 53
	22	53 54 54 54 55 55 55 56 56 56 57 57 57 58 58 58 59 59 59 5A 5A 5A 5B 5B
	23	5B 5C 5C 5C 5D 5D 5D 5E 5E 5E 5F 5F 5F 60 60 60 61 61 61 62 62 62 63 63
	24	63 64 64 64 65 65 65 66 66 66 67 67 67 68 68 68 69 69 69 6A 6A 6A 6B 6B
	25	6B 6C 6C 6C 6D 6D 6D 6E 6E 6E 6F 6F 6F 70 70 70 71 71 71 72 72 72 73 73
	26	73 74 74 74 75 75 75 76 76 76 77 77 77 78 78 78 79 79 79 7A 7A 7A 7B 7B
	27	7B 7C 7C 7C 7D 7D 7D 7E 7E 7E 7F 7F 7F 80 80 80 81 81 81 82 82 82 83 83
	28	83 84 84 84 85 85 85 86 86 86 87 87 87 88 88 88 89 89 89 8A 8A 8A 8B 8B
	29	8B 8C 8C 8C 8D 8D 8D 8E 8E 8E 8F 8F 8F 90 90 90 91 91 91 92 92 92 93 93
	30	93 94 94 94 95 95 95 96 96 96 97 97 97 98 98 98 99 99 99 9A 9A 9A 9B 9B
	31	9B 9C 9C 9C 9D 9D 9D 9E 9E 9E 9F 9F 9F A0 A0 A0 A1 A1 A1 A2 A2 A2 A3 A3
	32	A3 A4 A4 A4 A5 A5 A5 A6 A6 A6 A7 A7 A7 A8 A8 A8 A9 A9 A9 AA AA AA AB AB
	33	AB AC AC AC AD AD AD AE AE AE AF AF AF B0 B0 B0 B1 B1 B1 B2 B2 B2 B3 B3
	34	B3 B4 B4 B4 B5 B5 B5 B6 B6 B6 B7 B7 B7 B8 B8 B8 B9 B9 B9 BA BA BA BB BB
	35	BB BC BC BC BD BD BD BE BE BE BF BF BF C0 C0 C0 C1 C1 C1 C2 C2 C2 C3 C3
	36	C3 C4 C4 C4 C5 C5 C5 C6 C6 C6 C7 C7 C7 C8 C8 C8 C9 C9 C9 CA CA CA CB CB
	37	CB CC CC CC CD CD CD CE CE CE CF CF CF D0 D0 D0 D1 D1 D1 D2 D2 D2 D3 D3
	38	D3 D4 D4 D4 D5 D5 D5 D6 D6 D6 D7 D7 D7 D8 D8 D8 D9 D9 D9 DA DA DA DB DB
	39	DB DC DC DC DD DD DD DE DE DE DF DF DF E0 E0 E0 E1 E1 E1 E2 E2 E2 E3 E3
	40	E3 E4 E4 E4 E5 E5 E5 E6 E6 E6 E7 E7 E7 E8 E8 E8 E9 E9 E9 EA EA EA EB EB
	41	EB EC EC EC ED ED ED EE EE EE EF EF EF F0 F0 F0 F1 F1 F1 F2 F2 F2 F3 F3
	42	F3 F4 F4 F4 F5 F5 F5 F6 F6 F6 F7 F7 F7 F8 F8 F8 F9 F9 F9 FA FA FA FB FB
	43	FB FC FC FC FD FD FD FE FE FE FF FF FF 2C 00 00 00 00 10 00 10 00 00 08
	44	36 00 FF 09 1C 48 B0 A0 C1 83 08 13 22 04 C0 10 80 C2 7F 0C 05 46 4C E8
	45	70 60 C5 85 15 27 52 6C A8 30 E3 45 8C 0D 39 76 FC 38 F2 A1 44 91 1B 4F
	46	82 24 88 D2 64 C1 80 00 3B
	47	)],
	48	center => [qw(
	49	47 49 46 38 37 61 10 00 10 00 E7 00 00 00 00 00 01 01 01 02 02 02 03 03
	50	03 04 04 04 05 05 05 06 06 06 07 07 07 08 08 08 09 09 09 0A 0A 0A 0B 0B
	51	0B 0C 0C 0C 0D 0D 0D 0E 0E 0E 0F 0F 0F 10 10 10 11 11 11 12 12 12 13 13
	52	13 14 14 14 15 15 15 16 16 16 17 17 17 18 18 18 19 19 19 1A 1A 1A 1B 1B
	53	1B 1C 1C 1C 1D 1D 1D 1E 1E 1E 1F 1F 1F 20 20 20 21 21 21 22 22 22 23 23
	54	23 24 24 24 25 25 25 26 26 26 27 27 27 28 28 28 29 29 29 2A 2A 2A 2B 2B
	55	2B 2C 2C 2C 2D 2D 2D 2E 2E 2E 2F 2F 2F 30 30 30 31 31 31 32 32 32 33 33
	56	33 34 34 34 35 35 35 36 36 36 37 37 37 38 38 38 39 39 39 3A 3A 3A 3B 3B
	57	3B 3C 3C 3C 3D 3D 3D 3E 3E 3E 3F 3F 3F 40 40 40 41 41 41 42 42 42 43 43
	58	43 44 44 44 45 45 45 46 46 46 47 47 47 48 48 48 49 49 49 4A 4A 4A 4B 4B
	59	4B 4C 4C 4C 4D 4D 4D 4E 4E 4E 4F 4F 4F 50 50 50 51 51 51 52 52 52 53 53
	60	53 54 54 54 55 55 55 56 56 56 57 57 57 58 58 58 59 59 59 5A 5A 5A 5B 5B
	61	5B 5C 5C 5C 5D 5D 5D 5E 5E 5E 5F 5F 5F 60 60 60 61 61 61 62 62 62 63 63
	62	63 64 64 64 65 65 65 66 66 66 67 67 67 68 68 68 69 69 69 6A 6A 6A 6B 6B
	63	6B 6C 6C 6C 6D 6D 6D 6E 6E 6E 6F 6F 6F 70 70 70 71 71 71 72 72 72 73 73
	64	73 74 74 74 75 75 75 76 76 76 77 77 77 78 78 78 79 79 79 7A 7A 7A 7B 7B
65	7B 7C 7C 7C 7D 7D 7D 7E 7E 7E 7F 7F 7F 80 80 80 81 81 81 82 82 82 83 83
66	83 84 84 84 85 85 85 86 86 86 87 87 87 88 88 88 89 89 89 8A 8A 8A 8B 8B
67	8B 8C 8C 8C 8D 8D 8D 8E 8E 8E 8F 8F 8F 90 90 90 91 91 91 92 92 92 93 93
68	93 94 94 94 95 95 95 96 96 96 97 97 97 98 98 98 99 99 99 9A 9A 9A 9B 9B
69	9B 9C 9C 9C 9D 9D 9D 9E 9E 9E 9F 9F 9F A0 A0 A0 A1 A1 A1 A2 A2 A2 A3 A3
70	A3 A4 A4 A4 A5 A5 A5 A6 A6 A6 A7 A7 A7 A8 A8 A8 A9 A9 A9 AA AA AA AB AB
71	AB AC AC AC AD AD AD AE AE AE AF AF AF B0 B0 B0 B1 B1 B1 B2 B2 B2 B3 B3
72	B3 B4 B4 B4 B5 B5 B5 B6 B6 B6 B7 B7 B7 B8 B8 B8 B9 B9 B9 BA BA BA BB BB
73	BB BC BC BC BD BD BD BE BE BE BF BF BF C0 C0 C0 C1 C1 C1 C2 C2 C2 C3 C3
74	C3 C4 C4 C4 C5 C5 C5 C6 C6 C6 C7 C7 C7 C8 C8 C8 C9 C9 C9 CA CA CA CB CB
75	CB CC CC CC CD CD CD CE CE CE CF CF CF D0 D0 D0 D1 D1 D1 D2 D2 D2 D3 D3
76	D3 D4 D4 D4 D5 D5 D5 D6 D6 D6 D7 D7 D7 D8 D8 D8 D9 D9 D9 DA DA DA DB DB
77	DB DC DC DC DD DD DD DE DE DE DF DF DF E0 E0 E0 E1 E1 E1 E2 E2 E2 E3 E3
78	E3 E4 E4 E4 E5 E5 E5 E6 E6 E6 E7 E7 E7 E8 E8 E8 E9 E9 E9 EA EA EA EB EB
79	EB EC EC EC ED ED ED EE EE EE EF EF EF F0 F0 F0 F1 F1 F1 F2 F2 F2 F3 F3
80	F3 F4 F4 F4 F5 F5 F5 F6 F6 F6 F7 F7 F7 F8 F8 F8 F9 F9 F9 FA FA FA FB FB
81	FB FC FC FC FD FD FD FE FE FE FF FF FF 2C 00 00 00 00 10 00 10 00 00 08
82	36 00 FF 09 1C 48 B0 A0 C1 83 08 13 26 04 C0 10 80 C2 7F 0C 05 46 5C 48
83	D0 E1 42 8B 13 2F 66 54 B8 F1 60 C3 8F 16 2F 3E 1C D8 11 E1 C7 87 13 4B
84	4A DC D8 70 E4 C1 80 00 3B
85	)],
86	right => [qw(
87	47 49 46 38 37 61 10 00 10 00 E7 00 00 00 00 00 01 01 01 02 02 02 03 03
88	03 04 04 04 05 05 05 06 06 06 07 07 07 08 08 08 09 09 09 0A 0A 0A 0B 0B
89	0B 0C 0C 0C 0D 0D 0D 0E 0E 0E 0F 0F 0F 10 10 10 11 11 11 12 12 12 13 13
90	13 14 14 14 15 15 15 16 16 16 17 17 17 18 18 18 19 19 19 1A 1A 1A 1B 1B
91	1B 1C 1C 1C 1D 1D 1D 1E 1E 1E 1F 1F 1F 20 20 20 21 21 21 22 22 22 23 23
92	23 24 24 24 25 25 25 26 26 26 27 27 27 28 28 28 29 29 29 2A 2A 2A 2B 2B
93	2B 2C 2C 2C 2D 2D 2D 2E 2E 2E 2F 2F 2F 30 30 30 31 31 31 32 32 32 33 33
94	33 34 34 34 35 35 35 36 36 36 37 37 37 38 38 38 39 39 39 3A 3A 3A 3B 3B
95	3B 3C 3C 3C 3D 3D 3D 3E 3E 3E 3F 3F 3F 40 40 40 41 41 41 42 42 42 43 43
96	43 44 44 44 45 45 45 46 46 46 47 47 47 48 48 48 49 49 49 4A 4A 4A 4B 4B
97	4B 4C 4C 4C 4D 4D 4D 4E 4E 4E 4F 4F 4F 50 50 50 51 51 51 52 52 52 53 53
98	53 54 54 54 55 55 55 56 56 56 57 57 57 58 58 58 59 59 59 5A 5A 5A 5B 5B
99	5B 5C 5C 5C 5D 5D 5D 5E 5E 5E 5F 5F 5F 60 60 60 61 61 61 62 62 62 63 63
100	63 64 64 64 65 65 65 66 66 66 67 67 67 68 68 68 69 69 69 6A 6A 6A 6B 6B
101	6B 6C 6C 6C 6D 6D 6D 6E 6E 6E 6F 6F 6F 70 70 70 71 71 71 72 72 72 73 73
102	73 74 74 74 75 75 75 76 76 76 77 77 77 78 78 78 79 79 79 7A 7A 7A 7B 7B
103	7B 7C 7C 7C 7D 7D 7D 7E 7E 7E 7F 7F 7F 80 80 80 81 81 81 82 82 82 83 83
104	83 84 84 84 85 85 85 86 86 86 87 87 87 88 88 88 89 89 89 8A 8A 8A 8B 8B
105	8B 8C 8C 8C 8D 8D 8D 8E 8E 8E 8F 8F 8F 90 90 90 91 91 91 92 92 92 93 93
106	93 94 94 94 95 95 95 96 96 96 97 97 97 98 98 98 99 99 99 9A 9A 9A 9B 9B
107	9B 9C 9C 9C 9D 9D 9D 9E 9E 9E 9F 9F 9F A0 A0 A0 A1 A1 A1 A2 A2 A2 A3 A3
108	A3 A4 A4 A4 A5 A5 A5 A6 A6 A6 A7 A7 A7 A8 A8 A8 A9 A9 A9 AA AA AA AB AB
109	AB AC AC AC AD AD AD AE AE AE AF AF AF B0 B0 B0 B1 B1 B1 B2 B2 B2 B3 B3
110	B3 B4 B4 B4 B5 B5 B5 B6 B6 B6 B7 B7 B7 B8 B8 B8 B9 B9 B9 BA BA BA BB BB
111	BB BC BC BC BD BD BD BE BE BE BF BF BF C0 C0 C0 C1 C1 C1 C2 C2 C2 C3 C3
112	C3 C4 C4 C4 C5 C5 C5 C6 C6 C6 C7 C7 C7 C8 C8 C8 C9 C9 C9 CA CA CA CB CB
113	CB CC CC CC CD CD CD CE CE CE CF CF CF D0 D0 D0 D1 D1 D1 D2 D2 D2 D3 D3
114	D3 D4 D4 D4 D5 D5 D5 D6 D6 D6 D7 D7 D7 D8 D8 D8 D9 D9 D9 DA DA DA DB DB
115	DB DC DC DC DD DD DD DE DE DE DF DF DF E0 E0 E0 E1 E1 E1 E2 E2 E2 E3 E3
116	E3 E4 E4 E4 E5 E5 E5 E6 E6 E6 E7 E7 E7 E8 E8 E8 E9 E9 E9 EA EA EA EB EB
117	EB EC EC EC ED ED ED EE EE EE EF EF EF F0 F0 F0 F1 F1 F1 F2 F2 F2 F3 F3
118	F3 F4 F4 F4 F5 F5 F5 F6 F6 F6 F7 F7 F7 F8 F8 F8 F9 F9 F9 FA FA FA FB FB
119	FB FC FC FC FD FD FD FE FE FE FF FF FF 2C 00 00 00 00 10 00 10 00 00 08
120	3A 00 FF 09 1C 48 B0 A0 C1 83 08 13 2A 04 C0 10 80 C2 7F 0C 05 46 4C E8
121	70 60 45 84 13 27 52 6C F8 50 62 C5 8B 05 1B 8A 04 79 50 E3 43 93 1B 51
122	1A CC 48 D2 A2 49 8E 1D 0B 06 04 00 3B
123	)],
124	);
125	}
126
127	use Pod::ToDemo sub
128	{
129	(undef, my $filename) = @_;
130	(my $imagebase = $filename) =~ s/\.\w+$//;
131	my @img_files = map { $imagebase . "_$_.gif" }
132	qw( left center right );
133	my $demo_source = <<'END_HERE';
134	package Walker;
135
136	sub new
137	{
138	my ($class, @images) = @_;
139	my @frames = map { SDL::Surface->new( -name => $_ ) } @images;
140	my $frame_rect = SDL::Rect->new(
141	-height => $frames[0]->height(),
142	-width => $frames[0]->width(),
143	-x => 0,
144	-y => 0,
145	);
146	my $self =
147	{
148	frames => \@frames,
149	frame_rect => $frame_rect,
150	};
151	bless $self, $class;
152	}
153
154	sub frames
155	{
156	my $self = shift;
157	$self->{frames} = shift if @_;
158	$self->{frames};
159	}
160
161	sub frame_rect
162	{
163	my $self = shift;
164	$self->{frame_rect} = shift if @_;
165	$self->{frame_rect};
166	}
167
168	sub next_frame
169	{
170	my $self = shift;
171	my $frames = $self->frames();
172	my $frame = shift @$frames;
173
174	push @$frames, $frame;
175	$self->frames( $frames );
176
177	return $frame;
178	}
179
180	package main;
181
182	use strict;
183
184	use SDL;
185	use SDL::App;
186	use SDL::Surface;
187	use SDL::Color;
188
189	# change these values as necessary
190	my $title = 'My SDL Animation';
191	my ($width, $height, $depth) = ( 640, 480, 16 );
192	my ($bg_r, $bg_g, $bg_b) = ( 0xff, 0xff, 0xff );
193	my ($start_x, $end_x) = ( 20, 600 );
194	my $sleep_msec = 0.05;
195
196	my $app = SDL::App->new(
197	-width => $width,
198	-height => $height,
199	-depth => $depth,
200	);
201
202	my $bg_color = SDL::Color->new(
203	-r => $bg_r,
204	-g => $bg_g,
205	-b => $bg_b,
206	);
207
208	my $background = SDL::Rect->new(
209	-width => $width,
210	-height => $height,
211	);
212
213	my $pos = SDL::Rect->new(
214	-width => 16,
215	-height => 16,
216	-x => 0,
217	-y => 240,
218	);
219
220	my $walker = Walker->new(qw(
221	END_HERE
222
223	$demo_source .= join( ' ', @img_files ) . "));" . <<'END_HERE';
224
225	for my $x ( $start_x .. $end_x )
226	{
227	draw_background( $app, $background, $bg_color );
228	$pos->x( $x );
229	draw_walker( $walker, $app, $pos );
230	$app->update( $background );
231	select( undef, undef, undef, $sleep_msec );
232	}
233
234	# you'll want to remove this
235	sleep 2;
236
237	sub draw_background
238	{
239	my ($app, $background, $bg_color) = @_;
240	$app->fill( $background, $bg_color );
241	}
242
243	sub draw_walker
244	{
245	my ($walker, $app, $pos) = @_;
246	my $frame = $walker->next_frame();
247	my $frame_rect = $walker->frame_rect();
248	$frame->blit( $frame_rect, $app, $pos );
249	}
250	END_HERE
251
252	Pod::ToDemo::write_demo( $filename, "#$^X\n$demo_source" );
253	write_files( $imagebase );
254	};
255
256	sub write_files
257	{
258	my $imagebase = shift;
259
260	for my $image (qw( left center right ))
261	{
262	my $file = join('', map { chr( hex( $_ ) ) } @{ $images{ $image } });
263	write_file( $imagebase . "_$image" . '.gif', $file );
264	}
265	}
266
267	sub write_file
268	{
269	my ($file, $contents) = @_;
270
271	die "Cowardly refusing to overwrite '$file'\n" if -e $file;
272	open my $out, '>', $file or die "Cannot write '$file': $!\n";
273	binmode $out;
274	print $out $contents;
275	}
276
277	__END__
278
279	=head1 NAME
280
281	SDL::Tutorial::Images
282
283	=head1 SYNOPSIS
284
285	# to read this tutorial
286	$ perldoc SDL::Tutorial::Images
287
288	# to create a demo animation program based on this tutorial
289	$ perl -MSDL::Tutorial::Images=sdl_images.pl -e 1
290
291	=head1 ANIMATING IMAGES
292
293	Since you're already familiar with the concepts behind animation, it's time to
294	learn how to work with images. As usual, the important point is that computer animation is just I<simulating> motion by painting several slightly different frames to the screen every second.
295
296	There are two ways to vary an image on screen. One is to change its
297	coordinates so it's at a slightly different position. This is very easy to do;
298	it's just like animating a rectangle. The other way is to change the image
299	itself so it's slightly different. This is a little more difficult, as you'll
300	need to draw the alternate image beforehand somehow.
301
302	=head2 Loading Images
303
304	As usual, start with an L<SDL::App> object representing the image window. Then
305	preload the image file. This is easy; just pass the C<name> parameter to the
306	L<SDL::Surface> constructor:
307
308	use SDL::Surface;
309
310	my $frame = SDL::Surface->new( -name => 'frame1.png' );
311
312	B<Note:> you'll need to have compiled SDL Perl (and probably SDL) to support
313	JPEG and PNG files for this to work.
314
315	That's it; now you have an SDL::Surface object containing the image. You can
316	use the C<height()>, C<width()>, and C<bpp()> methods to retrieve its height,
317	width, and bits per pixel, if you need them.
318
319	=head2 Displaying Images
320
321	Drawing an image onto the screen requires blitting it from one surface to
322	another. (Remember, "blitting" means copying bits in memory.) The C<blit()>
323	method of SDL::Surface objects comes in handy. Its arguments are a little odd,
324	though. Assuming C<$app> is the SDL::App object, as usual:
325
326	use SDL::Rect;
327
328	my $frame_rect = SDL::Rect->new(
329	-height => $frame->height(),
330	-width => $frame->width(),
331	-x => 0,
332	-y => 0,
333	);
334
335	my $dest_rect = SDL::Rect->new(
336	-height => $frame->height(),
337	-width => $frame->width(),
338	-x => 0,
339	-y => 0,
340	);
341
342	$frame->blit( $frame_rect, $app, $dest_rect );
343	$app->update( $dest_rect );
344
345	Here we have two L<SDL::Rect> objects which represent rectangular regions of a
346	Surface. C<$frame_rect> represents the entire area of C<$frame>, while
347	C<$dest_rect> represents the area of the main window in which to blit the
348	frame. This may be clearer with more descriptive variable names:
349
350	$source_surface->blit(
351	$area_of_source_to_blit,
352	$destination_surface,
353	$destination_area
354	);
355
356	As usual, call C<update()> on C<$app> to see the change.
357
358	Requiring the source and destination Rect objects may seem tedious in this
359	simple example, but it's highly useful for copying only part of surface to part
360	of another. For example, animating this image is a matter of changing the C<x>
361	and C<y> coordinates of C<$dest_rect>:
362
363	for my $x ( 1 .. 100 )
364	{
365	$dest_rect->x( $x );
366	$frame->blit( $frame_rect, $app, $dest_rect );
367	$app->update( $dest_rect );
368	}
369
370	Of course, you'll have to redraw all or part of the screen to avoid artifacts,
371	as discussed in the previous tutorial.
372
373	=head2 Multi-Image Animation
374
375	That covers moving a single image around the screen. What if you want
376	something more? For example, what if you want to animate a stick figure
377	walking?
378
379	You'll need several frames, just as in a flip-book. Each frame should be slightly different than the one before it. It's probably handy to encapsulate all of this in a C<Walker> class:
380
381	package Walker;
382
383	use SDL::Surface;
384
385	sub new
386	{
387	my ($class, @images) = @_;
388	my $self = [ map { SDL::Surface->new( -name => $_ ) } @images ];
389
390	bless $self, $class;
391	}
392
393	sub next_frame
394	{
395	my $self = shift;
396	my $frame = shift @$self;
397
398	push @$self, $frame;
399	return $frame;
400	}
401
402	To use this class, instantiate an object:
403
404	my $walker = Walker->new( 'frame1.png', 'frame2.png', 'frame3.png' );
405
406	Then call C<next_frame()> within the loop:
407
408	for my $x ( 1 .. 100 )
409	{
410	my $frame = $walker->next_frame();
411
412	$dest_rect->x( $x );
413	$frame->blit( $frame_rect, $app, $dest_rect );
414	$app->update( $dest_rect );
415	}
416
417	Again, the rest of the frame drawing is missing from this example so as not to
418	distract from this technique. You'll probably want to abstract the undrawing
419	and redrawing into a separate subroutine so you don't have to worry about it
420	every time.
421
422	It'd be easy to make C<next_frame()> much smarter, selecting an image
423	appropriate to the direction of travel, using a bored animation when the
424	character is no longer moving, or adding other characteristics to the
425	character. As you can see, the hard part of this technique is generating the
426	images beforehand. That can add up to a tremendous amount of art and that's
427	one reason for the popularity of 3D models... but that's another tutorial much
428	further down the road.
429
430	More importantly, it's time to discuss how to make these animations run more
431	smoothly. More on that next time.
432
433	=head1 SEE ALSO
434
435	=over 4
436
437	=item L<SDL::Tutorial>
438
439	basic SDL tutorial
440
441	=item L<SDL::Tutorial::Animation>
442
443	non-image animation
444
445	=back
446
447	=head1 AUTHOR
448
449	chromatic, E<lt>chromatic@wgz.orgE<gt>
450
451	Written for and maintained by the Perl SDL project, L<http://sdl.perl.org/>.
452
453	=head1 BUGS
454
455	No known bugs.
456
457	=head1 COPYRIGHT
458
459	Copyright (c) 2004, chromatic. All rights reserved. This module is
460	distributed under the same terms as Perl itself, in the hope that it is useful
461	but certainly under no guarantee.