Resource provider regeneration

Implemented resource regeneration computation in the
verse.compute_provider_regeneration() function.

Created the PLANET_RES_REGEN update type, and added the corresponding
implementation.

Added resource regeneration constants registration.

legacyworlds-server-data/db-structure/parts/functions/145-resource-providers-functions.sql

@@ -0,0 +1,61 @@
+-- LegacyWorlds Beta 6
+-- PostgreSQL database scripts
+--
+-- Resource providers functions
+--
+-- Copyright(C) 2004-2012, DeepClone Development
+-- --------------------------------------------------------
+
+
+/*
+ * Compute resource provider regeneration
+ * 
+ * This function computes the quantity in a resource provider after it has
+ * been regenerated.
+ * 
+ * Parameters:
+ *		_quantity		The current quantity of resources in the provider
+ *		_max			The maximal amount of resources supported by the
+ *							provider
+ *		_recovery_rate	The provider's recovery rate
+ *
+ * Returns:
+ *		?				The new quantity of resources.
+ */
+CREATE OR REPLACE FUNCTION verse.compute_provider_regeneration(
+				_quantity		DOUBLE PRECISION ,
+				_max			DOUBLE PRECISION ,
+				_recovery_rate	DOUBLE PRECISION )
+		RETURNS DOUBLE PRECISION
+		STRICT IMMUTABLE
+		SECURITY INVOKER
+	AS $compute_provider_regeneration$
+
+DECLARE
+	_uc_recovery	DOUBLE PRECISION;
+	_uc_dampening	DOUBLE PRECISION;
+	_uc_ticks		DOUBLE PRECISION;
+	_result			DOUBLE PRECISION;
+
+BEGIN
+	_uc_recovery := sys.get_constant( 'game.resources.recovery' );
+	_uc_dampening := sys.get_constant( 'game.resources.recoveryDampening' );
+	_uc_ticks := 1440; -- FIXME: this should be a constant
+	
+	_result := ( 1 - _quantity / _max ) ^ _uc_dampening;
+	_result := _quantity + _result * _recovery_rate * _uc_recovery / _uc_ticks;
+
+	IF _result > _max THEN
+		_result := _max;
+	END IF;
+
+	RETURN _result;
+END;
+$compute_provider_regeneration$ LANGUAGE PLPGSQL;
+
+
+REVOKE EXECUTE
+	ON FUNCTION verse.compute_provider_regeneration(
+		DOUBLE PRECISION , DOUBLE PRECISION ,
+		DOUBLE PRECISION )
+	FROM PUBLIC;