Added more comments to the example and another particle

examples/SDLx/SDLx_C_Object.pl

@@ -7,40 +7,61 @@
 use SDL::Events;
 
 use SDLx::Controller::Object;
-my $app          = SDLx::App->new( w => 200, h => 200, title => "timestep" );
+my $app = SDLx::App->new( w => 200, h => 200, title => "timestep" );
 
+#The initial x and y for this object. 
+my $spring = SDLx::Controller::Object->new( x => 100, y => 100 );
 
+#we have a constant x velocity of 20
+my $constant = SDLx::Controller::Object->new( x => 0, y => 20, v_x => 20 );
 
-my $spring  = SDLx::Controller::Object->new(x=> 100, y => 100);
+#NO need to send an acceleration for x,y or rotation
+$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);
-
-
-my $event = sub
-{	
-     return 0 if $_[0]->type == SDL_QUIT;
-     return 1;
+	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);
 
-my $render = sub 
-{ 
-    my $state = shift;
-    $app->draw_rect( [ 0, 0, $app->w, $app->h ], 0x0 );
-    $app->draw_rect(  [ 100 - $state->x , $state->y, 2, 2 ], 0xFF0FFF );
-    $app->update();
+#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 {
+	return 0 if $_[0]->type == SDL_QUIT;
+	return 1;
+};
+
+
 $app->add_event_handler($event);
+
+#clear the screen
+$app->add_show_handler( sub{ $app->draw_rect([0,0,$app->w, $app->h], 0x000000)} );
+
+#add the spring
 $app->add_object( $spring, $render );
 
+#add the constant_velocity
+$app->add_object(
+	$constant,
+	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_test();