View source for Data Bindings

The game exposes values to the [[HUD]] using Bindings. The [[HUD]] elements can register to a binding and receive a callback when the value changes. Bindings are indexed using a name and a type. The type is currently one of: int, string, float or bool.

== Registering to a Bind ==
You can register a function to get called when a value gets changed. This is an example from the ammo hud panel:
<pre>
bind.register("player_ammo_total", "int", function(value) {
	ammoTotalLabel.text = value;
});
</pre>

== Existing Binds ==
This is an overview of the bindings available in Empires. You can get an up to date list by typing <code>emp_binding_list</code> in your console.

=== Int ===
*player_mines_deployed - The amount of mines currently placed by the player
*player_ammo_current - The amount of ammo in the clip of the current weapon
*player_ammo_total - The amount of ammo in total
*player_mines_max - The maximum amount of mines the player can place
*player_ammo_clipsize - The maximum amount of ammo in a clip
*player_stamina - The stamina of the player from 0 to 100
*player_health_max - The maximum health of the player, normally 100.
*player_ammo_type - The type of ammo currently held.
*player_health - The current health of the player
*team_tickets - The amount of tickets the team of the player has
*team_tanks - The amount of vehicles the current team has on the field.
*team_tanks_max - The amount of vehicles the current team can place on the field.
*game_seconds_left - The amount of seconds left in the game.
*tickets_total - The total amount of tickets in the game.
*game_play_time_left - The amount of seconds left in the game.
*game_preparation_time_left - The amount of seconds left to prepare before the game starts.
*game_suddendeath_countdown - The amount of seconds left until sudden death.
*game_commander_freeze_left - The amount of seconds until the commander vehicle.
*game_length - The amount of seconds elapsed since the start of the game.

=== String ===
*team_name - The name of the current team. One of: brenodi, northern, spectator, unassigned, unknown.

=== Float ===
*team_res_total - The amount of res the team has.
*team_res_income - The resource income per second for the team of the player.
*player_wages - The amount of wages the current player has.

== Adding a bind in C++ code ==
Binds usually live in either the C_EmpPlayer class, the C_EmpTeam class or the GameRules class. To create a new bind in the Player class, perform the following steps:

* Add a new bind member variable to the emp_player.h file:
<pre>
  std::shared_ptr< EmpDataBinding<int> > _healthBinding;
  std::shared_ptr< EmpDataBinding<int> > _staminaBinding;
+ std::shared_ptr< EmpDataBinding<int> > _yourNewBinding;
</pre>
* In the constructor implementation of the player class, create the actual binding:
<pre>
  _healthBinding = EmpDataBindingManager<int>::GetBinding("player_health");
  _staminaBinding = EmpDataBindingManager<int>::GetBinding("player_stamina");
+ _yourNewBinding = EmpDataBindingManager<int>::GetBinding("your_new_binding");
</pre>
* In the UpdateDataBindings function, set the actual value the bind is supposed to have:
<pre>
  _healthMaxBinding->Set(GetMaxHealth());
  _staminaBinding->Set(GetStamina());
+ _yourNewBinding->Set(42);
</pre>
* Your new binding should now show up in the <code>emp_bindings_list</code> [[Console_commands|command]] in the Empires console.

=== Choosing a Type ===
* For values that are strings or booleans the choice is simple, use the same type as the original value.
* If your original type is a number and it changes very frequently (multiple times per second), try to use an int if that doesn't cause big artifacts on the [[HUD]]. This makes the HUD update less often resulting in a smoother game.
* If the value changes less often or you actually need the extra precision, use a float.

[[Category:VGUI]]