[Disclaimer: I am not a user of SDL and I do not have it installed. The following is untested guesswork (actually, perl -c says "syntax OK", but untested beyond that).]

After looking at your posted code, I had a similar thought to what ++bliako wrote.

I can see that you've copied the code from "[PDF] SDL::Manual": a visual inspection shows no problems there.

Try replacing this entire call: 

$app->add_event_handler(sub {
    ...
});

[download]

with

{
    my %paddle_move;
    my $key_joiner;

    BEGIN {
        $key_joiner = '~';
        %paddle_move = (
            SDL_KEYDOWN . $key_joiner . SDLK_UP, -2,
            SDL_KEYDOWN . $key_joiner . SDLK_DOWN, 2,
            SDL_KEYUP . $key_joiner . SDLK_UP, 0,
            SDL_KEYUP . $key_joiner . SDLK_DOWN, 0,
        );
    }

    $app->add_event_handler(sub {
        my $event = shift;
        my $paddle_key = $event->type . $key_joiner . $event->key_sym;

        if (exists $paddle_move{$paddle_key}) {
            $player1->{v_y} = $paddle_move{$paddle_key};
        }
    });
}

[download]

That will set up all of the possible values for $player1->{v_y} once, at compile time. Assigning those values now only requires a single if condition, instead of the multiple if and elsif conditions you currently have.

— Ken

In reply to Re: pong paddles are not going equally fast by kcott
in thread pong paddles are not going equally fast by Anonymous Monk

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.