Fellow Monks, I recently tried to do some graphics with perl, and ended up in using SDL_perl, using frozen bubble(btw, great game) as a reference. However, my little game, a clone of that old side-scrolling shoot-em up's, is kinda slow, which I think mainly is reasoned in the way I did the whole thing. So all I ask is to give me some hints, how it could be improved and maybe if there is a major mistake I did.
The code:

#!/usr/bin/perl -w

use strict;
use SDL::App;
use SDL::Surface;
use SDL::Event;

$| = 1;
my (@update_rects, @fire_items, %images, $app, $event, $background);

sub init_sdl {
    my $sdlflags = SDL_ANYFORMAT | SDL_HWSURFACE | SDL_DOUBLEBUF | SDL
+_HWACCEL | SDL_ASYNCBLIT;
    $app = new SDL::App ( -flags => $sdlflags,-title => 'Space',-width
+ => '800',-height => '600');
    $event = new SDL::Event;
    $event->set(SDL_SYSWMEVENT,SDL_IGNORE);
    $background = new SDL::Surface(-width => $app->width, -height => $
+app->height, -depth => 32, -Amask => '0 but true');


    #load images
    foreach ('ship', 'beam1') {
    $images{$_} = new SDL::Surface(-name => "/home/mirage/perl/space/i
+mages/$_.png");
    $images{$_}->{-surface} or die "FATAL: Couldn't load image file $_
+.\n";
    }
    
}

sub put_image($$$) {
    my ($image, $x, $y) = @_;
    my $rect = new SDL::Rect(-width => $image->width, -height => $imag
+e->height);
    my $drect = new SDL::Rect(-width => $image->width, -height => $ima
+ge->height, -x => $x, -y => $y);
    $image->blit($rect, $app, $drect);
    push @update_rects, $drect;
}

#sub fillrect {
#    my ($width, $height, $x, $y) = @_;
#    my $rect = new SDL::Rect(-width => $width, -height => $height, -x
+ => $x, -y => $y);
#    $app->fill($rect,0x000000);
#}

sub erase_image_from($$$$$) {
    my ($width, $height, $x, $y, $img) = @_;
    my $drect = new SDL::Rect(-width => $width, -height => $height, -x
+ => $x, '-y' => $y);
    $img->blit($drect, $app, $drect);
    push @update_rects, $drect;
}

sub erase_image($$$$) {
    my ($width, $height, $x, $y) = @_;
    erase_image_from($width, $height, $x, $y, $background);
}

sub handle_fire {
    my ($new, $x, $y) = @_;
    my $skip = 0;
    if($new){ push(@fire_items, $x.' '.$y); }
    my $i = 0;
    while($i < @fire_items) {
        my ($xc, $yc) = split(' ',$fire_items[$i]);
        splice(@fire_items,$i,1) and $skip = 1 unless $xc < $app->widt
+h + $images{'beam1'}->width;
        if($skip){ $skip = 0; next; }
        &erase_image($images{'beam1'}->width, $images{'beam1'}->height
+,$xc-10,$yc);
        &put_image($images{'beam1'}, $xc, $yc);
        $fire_items[$i]=join(' ',$xc + 10, $yc);
        $i++;    
    }
}

&init_sdl;

my $x = 50;
my $y = ($app->height / 2) - $images{'ship'}->height;
my ($xplus, $yplus, $xminus, $yminus, $fire) = 0;

while(1) {
$event->pump();
if ($event->poll != 0) {
    if ($event->type == SDL_KEYDOWN) {
        my $key = $event->key_sym();
        
        $xplus = 1 if $key eq SDLK_RIGHT;
        $xminus = 1 if $key eq SDLK_LEFT;
        $yminus = 1 if $key eq SDLK_UP;
        $yplus = 1 if $key eq SDLK_DOWN;
        $fire = 1 if $key eq SDLK_SPACE;

        exit if $key eq SDLK_ESCAPE;
    }

    if ($event->type == SDL_KEYUP) {
        my $key = $event->key_sym();
        
        $xplus = 0 if $key eq SDLK_RIGHT;
        $xminus = 0 if $key eq SDLK_LEFT;
        $yminus = 0 if $key eq SDLK_UP;
        $yplus = 0 if $key eq SDLK_DOWN;
        $fire = 0 if $key eq SDLK_SPACE;
    }    
}


#delete if movement
if($xplus or $xminus or $yplus or $yminus) {
&erase_image($images{'ship'}->width, $images{'ship'}->height,$x,$y);
}

#change values if key is pressed
my $step = 10;
$x+=$step if $xplus and $x < ($app->width - $images{'ship'}->width);
$x-=$step if $xminus and $x >= $step;
$y+=$step if $yplus and $y < ($app->height - $images{'ship'}->height);
$y-=$step if $yminus and $y >= $step ;

#draw gunshots, possibly add new one
&handle_fire($fire, $x, $y);

#draw ship
&put_image($images{'ship'},$x,$y);
$app->update(@update_rects);
@update_rects=();
&SDL::DisplayFormat($images{'ship'}->{-surface});
&SDL::Delay(20);
}

__END__
[download]

Thanks!

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