SDLx::Controller::Interface

Section: User Contributed Perl Documentation (3)
Updated: 2021-01-27
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NAME

SDLx::Controller::Interface - Interface Physics and Rendering with the Controller with callbacks

SYNOPSIS

 use SDL;
 use SDLx::App;
 use SDLx::Controller::Interface;

 #SDLx::App is a controller
 my $app = SDLx::App->new(width => 200, height => 200 ); 

 my $ball = SDLx::Controller::Interface->new( x=> 10, y => 50, v_x => 10, v_y=> 20 );
 #Set the initial state of the ball's physics, this is optional

 $ball->set_acceleration( 
    sub { 
              my ($time, $current_state) = @_;
              return( 0, -10, 0 ); # Return accelerations (x,y,rotation)
        }
 );

 my $ball_render = sub {
       my $state = shift;
 
       $app->draw_rect( undef, 0 );
       $app->draw_rect( [$state->x, $state->y, 10,10], [255,0,0,255] );
       $app->update();
 };


 $ball->attach( $app, $ball_render, @params ); 

 $app->run();

 $ball->detach(); #can be called at anytime (for example when ball 'dies')

DESCRIPTION

METHODS

set_acceleration

Allows you to set the acceleration callback for defining the interface's behaviour in terms of x,y and rotation.

  $interface->set_acceleration ( 
      sub {
         my ($time, $current_state) = @_; 
       
         return ( $accel_x, $accel_y, $torque );
      }
  );

These accelerations are arbitrary and can be set to any frame of reference. Your render callback will handle how to interpret it.

The callback will receive the time and the current state as a "SDLx::Controller::State" element.

attach

Attaches the interface to a controller with a render callback

  $interface->attach( $controller, $render, @params );

Where $render is a callback that receives the interpolated "SDLx::Controller::State".

  my $render = sub {
        my ($state, @params) = @_; 
        # draw the current $state.
  };

The @params are any extra parameters you would like to pass to the $render callback.

current

  my $current_state = $interface->current();

Returns the current state of the interface as a "SDLx::Controller::State".

  my $previous_state = $interface->previous();

Returns the previous state of the interface as a "SDLx::Controller::State".

detach

  $interface->detach();

If $interface has been "attach()"'ed to any controller it will be detached now.

OTHER METHODS

Don't use these unless you really really want to.

acceleration

Call the acceleration callback once.

interpolate

Interpolate the current state

evaluate

Evaluate the new current and previous state.

update

Update the states by integrating with time.

AUTHORS

See ``AUTHORS'' in SDL.