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lib/Algorithm/Easing/Bounce.pm  view on Meta::CPAN

package Algorithm::Easing::Bounce;

use Moose;

use Math::Trig qw(:pi);

use constant EPSILON => 0.000001;

extends 'Algorithm::Easing::Ease';

use namespace::clean;

sub ease_in  {
    my $self = shift;
    my ($t,$b,$c,$d) = (shift,shift,shift,shift);

    return $b if ($t < EPSILON);
    return $c if ($d < EPSILON);

    return $c - $self->ease_out($d - $t, 0, $c, $d) + $b;
}

sub ease_out {
    my $self = shift;
    my ($t,$b,$c,$d) = (shift,shift,shift,shift);

    return $b if ($t < EPSILON);
    return $c if ($d < EPSILON);

    if (($t /= $d) < (1 / 2.75)) {
        return $c * (7.5625 * $t * $t) + $b;
    } elsif ($t < (2 / 2.75)) {
        my $post_fix = $t-=(1.5 / 2.75);
        return $c * (7.5625 * ($post_fix) * $t + 0.75) + $b;
    } elsif ($t < (2.5/2.75)) {
        my $post_fix = $t -= (2.25 / 2.75);
        return $c * (7.5625 * ($post_fix) * $t + 0.9375) + $b;
    } else {
        my $post_fix = $t -= (2.625 / 2.75);
        return $c * (7.5625 * ($post_fix) * $t + 0.984375) + $b;
    }
}

sub ease_both {
    my $self = shift;
    my ($t,$b,$c,$d) = (shift,shift,shift,shift);

    return $b if ($t < EPSILON);
    return $c if ($d < EPSILON);

    if ($t < $d / 2) {
        return $self->ease_in($t * 2, 0, $c, $d) * 0.5 + $b;
    }
    else {
        return $self->ease_out($t * 2 - $d, 0, $c, $d) * 0.5 + $c * 0.5 + $b;
    }
}

1;

__END__

# MAN3 POD

=head1 NAME

Algorithm::Easing::Bounce - Calculate eased translations between two positive whole integer values over time

=cut

=head1 SYNOPSIS
        use Algorithm::Easing;
        use Algorithm::Easing::Bounce;

        # this example produces traditional 'bounce' output;

        my $translation = Algorithm::Easing::Bounce->new;

        # total time for eased translation as a real positive integer value
        my $d = 2.5;

        # begin
        my $b = 0;

        # change
        my $c = 240;

        # time passed in seconds as a real positive integer between each frame
        my $frame_time = 0.0625;

        my @p = [319,0];

        for(my $t = 0; $t < 2.5; $t += 0.0625) {
            $p[1] = $translation->ease_out($t,$b,$c,$d)

            # plot
            ...;
        }

=cut