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:

bind.register("player_ammo_total", "int", function(value) {
	ammoTotalLabel.text = value;
});

Existing Binds

This is an overview of the bindings available in Empires. You can get an up to date list by typing emp_binding_list 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
• player_wages - The amount of wages the current player has.
• team_tickets - The amount of tickets the team of the player has
• team_res_total - The amount of resources the team of the player has
• team_res_income - The resource income per second for the team of the player
• 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.
• enemy_tickets - The amount of tickets of the enemy team (if applicable)

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:

  std::shared_ptr< EmpDataBinding<int> > _healthBinding;
  std::shared_ptr< EmpDataBinding<int> > _staminaBinding;
+ std::shared_ptr< EmpDataBinding<int> > _yourNewBinding;

• In the constructor implementation of the player class, create the actual binding:

  _healthBinding = EmpDataBindingManager<int>::GetBinding("player_health");
  _staminaBinding = EmpDataBindingManager<int>::GetBinding("player_stamina");
+ _yourNewBinding = EmpDataBindingManager<int>::GetBinding("your_new_binding");

• In the UpdateDataBindings function, set the actual value the bind is supposed to have:

  _healthMaxBinding->Set(GetMaxHealth());
  _staminaBinding->Set(GetStamina());
+ _yourNewBinding->Set(42);

• Your new binding should now show up in the emp_bindings_list command in the Empires console.