SDLx_C_Interface.pl

use strict;
use warnings;
use Time::HiRes qw( time sleep );
use SDL;
use SDLx::App;
use SDL::Event;
use SDL::Events;

use SDLx::Controller::Interface;
my$app = SDLx::App->new( w=> 200, h=> 200, title=>"timestep", delay=> 10 );

#The initial x and y for this object.
my$spring = SDLx::Controller::Interface->new( x=> 100, y=> 100 );

#we have a constant x velocity of 20
my$constant = SDLx::Controller::Interface->new( x=> 0, y=> 20, v_x=> 20 );

#NO need to send an acceleration for x,y or rotation
$constant->set_acceleration( sub { return ( 0, 0, 0 ) } );

#a hooke's law acceleration for the spring
my$accel = sub {
my ( $t, $state ) = @_;
my$k = 10;
my$b = 1;
my$ax = ( ( -1 * $k ) * ( $state->x ) - $b * $state->v_x );
return ( $ax, 0, 0 );
};
$spring->set_acceleration($accel);

#This is how we will render the spring. Notice the x, and y are not tied to how they will show on the screen
my$render = sub {
my$state = shift;
$app->draw_rect( [ 100 - $state->x, $state->y, 2, 2 ], 0xFF0FFF );
};

#an event handler to exit
my$event = sub {
$_[1]->stop if$_[0]->type == SDL_QUIT;
};


$app->add_event_handler($event);

#clear the screen
$app->add_show_handler( sub { $app->draw_rect( [ 0, 0, $app->w, $app->h ], 0x000000 ) } );

#add the spring
$spring->attach($app, $render );

#add the constant_velocity
$constant->attach( $app,
sub {
my$state = shift;
$app->draw_rect( [ $state->x, $state->y, 4, 4 ], 0xFFFFFF );
 }
);

#add the final update
$app->add_show_handler( sub { $app->update() } );

$app->run();