ETS updates

Two updates to the energy transfer system.
1. Previously, for fighters missing a system (e.g. shields), the energy would be treated as if all energy from that system was routed to the other systems.  So, for example, a fighter's typical speed would be faster without shields than with shields.  A new AI profile flag now treats the other systems as if the energy had not been transferred.
2. At some point in development, Volition intended the `$Power Output` ships.tbl field to affect ETS.  A new AI profile flag now treats the power output as a factor of energy applied to energy systems.

Author: Goober5000

code/ai/ai_flags.h

@@ -174,6 +174,8 @@ namespace AI {
 		Unify_usage_ai_shield_manage_delay,
 		Disable_ai_transferring_energy,
 		Freespace_1_missile_behavior,
+		ETS_uses_power_output,
+		ETS_energy_same_regardless_of_system_presence,
 
 		NUM_VALUES
 	};

code/ai/ai_profiles.cpp

@@ -703,6 +703,11 @@ void parse_ai_profiles_tbl(const char *filename)
 
 				set_flag(profile, "$enable freespace 1 style missile behavior:", AI::Profile_Flags::Freespace_1_missile_behavior);
 
+				set_flag(profile, "$ETS uses ship class power output:", AI::Profile_Flags::ETS_uses_power_output);
+
+				set_flag(profile, "$ETS energy same regardless of system presence:", AI::Profile_Flags::ETS_energy_same_regardless_of_system_presence);
+
+
 				// end of options ----------------------------------------
 
 				// if we've been through once already and are at the same place, force a move

code/ai/aicode.cpp

@@ -2097,7 +2097,7 @@ float get_wing_lowest_av_ab_speed(object *objp)
 	}
 	else
 	{
-		recharge_scale = Energy_levels[shipp->engine_recharge_index] * 2.0f * The_mission.ai_profile->afterburner_recharge_scale[Game_skill_level];
+		recharge_scale = ets_power_factor(objp) * Energy_levels[shipp->engine_recharge_index] * 2.0f * The_mission.ai_profile->afterburner_recharge_scale[Game_skill_level];
 		recharge_scale = sip->afterburner_recover_rate * recharge_scale / (sip->afterburner_burn_rate + sip->afterburner_recover_rate * recharge_scale);
 		lowest_max_av_ab_speed = recharge_scale * (objp->phys_info.afterburner_max_vel.xyz.z - objp->phys_info.max_vel.xyz.z) + objp->phys_info.max_vel.xyz.z;
 	}
@@ -2125,7 +2125,7 @@ float get_wing_lowest_av_ab_speed(object *objp)
 			}
 			else
 			{
-				recharge_scale = Energy_levels[shipp->engine_recharge_index] * 2.0f * The_mission.ai_profile->afterburner_recharge_scale[Game_skill_level];
+				recharge_scale = ets_power_factor(o) * Energy_levels[oshipp->engine_recharge_index] * 2.0f * The_mission.ai_profile->afterburner_recharge_scale[Game_skill_level];
 				recharge_scale = osip->afterburner_recover_rate * recharge_scale / (osip->afterburner_burn_rate + osip->afterburner_recover_rate * recharge_scale);
 				cur_max = recharge_scale * (o->phys_info.afterburner_max_vel.xyz.z - o->phys_info.max_vel.xyz.z) + o->phys_info.max_vel.xyz.z;
 			}
@@ -4796,7 +4796,7 @@ void ai_fly_to_target_position(const vec3d* target_pos, bool* pl_done_p=NULL, bo
 		max_allowed_speed = 0.9f * get_wing_lowest_max_speed(Pl_objp);
 		max_allowed_ab_speed = 0.95f * get_wing_lowest_av_ab_speed(Pl_objp);
 		if (ab_allowed) {
-			float self_ab_scale = Energy_levels[shipp->engine_recharge_index] * 2.0f * The_mission.ai_profile->afterburner_recharge_scale[Game_skill_level];
+			float self_ab_scale = ets_power_factor(Pl_objp) * Energy_levels[shipp->engine_recharge_index] * 2.0f * The_mission.ai_profile->afterburner_recharge_scale[Game_skill_level];
 			self_ab_scale = sip->afterburner_recover_rate * self_ab_scale / (sip->afterburner_burn_rate + sip->afterburner_recover_rate * self_ab_scale);
 			self_ab_speed = 0.95f * (self_ab_scale * (Pl_objp->phys_info.afterburner_max_vel.xyz.z - Pl_objp->phys_info.max_vel.xyz.z) + Pl_objp->phys_info.max_vel.xyz.z);
 		}

code/hud/hudets.cpp

@@ -25,7 +25,7 @@
 #include "weapon/weapon.h"
 #include "globalincs/alphacolors.h"
 
-float Energy_levels[NUM_ENERGY_LEVELS] = {0.0f,  0.0833f, 0.167f, 0.25f, 0.333f, 0.417f, 0.5f, 0.583f, 0.667f, 0.75f, 0.833f, 0.9167f, 1.0f};
+float Energy_levels[NUM_ENERGY_LEVELS] = {0.0f,  1.0f/12, 2.0f/12, 3.0f/12, 4.0f/12, 5.0f/12, 6.0f/12, 7.0f/12, 8.0f/12, 9.0f/12, 10.0f/12, 11.0f/12, 1.0f};
 bool Weapon_energy_cheat = false;
 
 // -------------------------------------------------------------------------------------------------
@@ -54,6 +54,53 @@ void ets_init_ship(object* obj)
 	set_default_recharge_rates(obj);
 }
 
+int ets_properties(object* objp)
+{
+	int properties = 0;
+	ship* ship_p = &Ships[objp->instance];
+	ship_info* ship_info_p = &Ship_info[ship_p->ship_info_index];
+
+	if (ship_has_energy_weapons(ship_p))
+		properties |= HAS_WEAPONS;
+
+	if (!(objp->flags[Object::Object_Flags::No_shields]) && !ship_info_p->flags[Ship::Info_Flags::Intrinsic_no_shields])
+		properties |= HAS_SHIELDS;
+
+	if (ship_has_engine_power(ship_p))
+		properties |= HAS_ENGINES;
+
+	return properties;
+}
+
+// returns the energy that should be dedicated towards a single ETS system
+// in retail, this is always 1.0
+float ets_power_factor(object *objp, bool include_power_output)
+{
+	auto shipp = &Ships[objp->instance];
+	int properties = ets_properties(objp);
+
+	if (The_mission.ai_profile->flags[AI::Profile_Flags::ETS_energy_same_regardless_of_system_presence] && (properties != (HAS_WEAPONS | HAS_SHIELDS | HAS_ENGINES)))
+	{
+		// in retail, the effect of having a missing system (e.g. an unshielded ship) is as if all that energy were redirected to other systems, so take the inverse of that
+		constexpr float missing_single_factor = 2.0f/3;
+		constexpr float missing_double_factor = 1.0f/3;
+
+		float missing_factor = (properties == HAS_WEAPONS || properties == HAS_SHIELDS || properties == HAS_ENGINES) ? missing_double_factor : missing_single_factor;
+
+		if (The_mission.ai_profile->flags[AI::Profile_Flags::ETS_uses_power_output] && include_power_output)
+			return Ship_info[shipp->ship_info_index].power_output * missing_factor;
+		else
+			return missing_factor;
+	}
+	else
+	{
+		if (The_mission.ai_profile->flags[AI::Profile_Flags::ETS_uses_power_output] && include_power_output)
+			return Ship_info[shipp->ship_info_index].power_output;
+		else
+			return 1.0f;
+	}
+}
+
 // -------------------------------------------------------------------------------------------------
 // update_ets() is called once per frame for every OBJ_SHIP in the game.  
 // The amount of energy to send to the weapons and shields is calculated.
@@ -83,14 +130,15 @@ void update_ets(object* objp, float fl_frametime)
 		return;
 	}
 
+	// See?  Volition did, at one point, intend for power output to affect ETS!
 	//	new_energy = fl_frametime * sinfo_p->power_output;
 
 	// update weapon energy
 	max_new_weapon_energy = fl_frametime * ship_p->max_weapon_regen_per_second * max_g;
 	if ( objp->flags[Object::Object_Flags::Player_ship] ) {
-		ship_p->weapon_energy += Energy_levels[ship_p->weapon_recharge_index] * max_new_weapon_energy * The_mission.ai_profile->weapon_energy_scale[Game_skill_level];
+		ship_p->weapon_energy += ets_power_factor(objp) * Energy_levels[ship_p->weapon_recharge_index] * max_new_weapon_energy * The_mission.ai_profile->weapon_energy_scale[Game_skill_level];
 	} else {
-		ship_p->weapon_energy += Energy_levels[ship_p->weapon_recharge_index] * max_new_weapon_energy;
+		ship_p->weapon_energy += ets_power_factor(objp) * Energy_levels[ship_p->weapon_recharge_index] * max_new_weapon_energy;
 	}
 
 	if ( ship_p->weapon_energy > sinfo_p->max_weapon_reserve ){
@@ -100,9 +148,9 @@ void update_ets(object* objp, float fl_frametime)
 	float shield_delta;
 	max_new_shield_energy = fl_frametime * ship_p->max_shield_regen_per_second * shield_get_max_strength(ship_p, true); // recharge rate is unaffected by $Max Shield Recharge
 	if ( objp->flags[Object::Object_Flags::Player_ship] ) {
-		shield_delta = Energy_levels[ship_p->shield_recharge_index] * max_new_shield_energy * The_mission.ai_profile->shield_energy_scale[Game_skill_level];
+		shield_delta = ets_power_factor(objp) * Energy_levels[ship_p->shield_recharge_index] * max_new_shield_energy * The_mission.ai_profile->shield_energy_scale[Game_skill_level];
 	} else {
-		shield_delta = Energy_levels[ship_p->shield_recharge_index] * max_new_shield_energy;
+		shield_delta = ets_power_factor(objp) * Energy_levels[ship_p->shield_recharge_index] * max_new_shield_energy;
 	}
 
 	if (Missiontime - Ai_info[ship_p->ai_index].last_hit_time < fl2f(sinfo_p->shield_regen_hit_delay))
@@ -170,16 +218,32 @@ void update_ets(object* objp, float fl_frametime)
 
 float ets_get_max_speed(object* objp, float engine_energy)
 {
+	// NOTE: ets_power_factor() doesn't need to be called in this function, because all the factors cancel out.  But
+	// the system presence does need to be checked since it affects the recharge indexes.
+
 	Assertion(objp != NULL, "Invalid object pointer passed!");
 	Assertion(objp->type == OBJ_SHIP, "Object needs to be a ship object!");
 	Assertion(engine_energy >= 0.0f && engine_energy <= 1.0f, "Invalid float passed, needs to be in [0, 1], was %f!", engine_energy);
 
 	ship* shipp = &Ships[objp->instance];
-
 	ship_info* sip = &Ship_info[shipp->ship_info_index];
 
+	float initial_engine_recharge_energy_level;
+	if (The_mission.ai_profile->flags[AI::Profile_Flags::ETS_energy_same_regardless_of_system_presence])
+	{
+		int properties = ets_properties(objp);
+		if (properties == (HAS_WEAPONS | HAS_SHIELDS | HAS_ENGINES))
+			initial_engine_recharge_energy_level = Energy_levels[INTIAL_ENGINE_RECHARGE_INDEX];
+		else if (properties == HAS_WEAPONS || properties == HAS_SHIELDS || properties == HAS_ENGINES)
+			initial_engine_recharge_energy_level = Energy_levels[ALL_INDEX];
+		else
+			initial_engine_recharge_energy_level = Energy_levels[ONE_HALF_INDEX];
+	}
+	else
+		initial_engine_recharge_energy_level = Energy_levels[INTIAL_ENGINE_RECHARGE_INDEX];
+
 	// check for a shortcuts first before doing linear interpolation
-	if ( engine_energy == Energy_levels[INTIAL_ENGINE_RECHARGE_INDEX] ){
+	if ( engine_energy == initial_engine_recharge_energy_level ){
 		return sip->max_speed;
 	} else if ( engine_energy == 0.0f ){
 		return 0.5f * sip->max_speed;
@@ -188,11 +252,11 @@ float ets_get_max_speed(object* objp, float engine_energy)
 	} else {
 		// do a linear interpolation to find the current max speed, using points (0,1/2 default_max_speed) (.333,default_max_speed)
 		// x = x1 + (y-y1) * (x2-x1) / (y2-y1);
-		if ( engine_energy < Energy_levels[INTIAL_ENGINE_RECHARGE_INDEX] ){
-			return 0.5f*sip->max_speed + (engine_energy  * (0.5f*sip->max_speed) ) / Energy_levels[INTIAL_ENGINE_RECHARGE_INDEX];
+		if ( engine_energy < initial_engine_recharge_energy_level ){
+			return 0.5f*sip->max_speed + (engine_energy  * (0.5f*sip->max_speed) ) / initial_engine_recharge_energy_level;
 		} else {
 			// do a linear interpolation to find the current max speed, using points (.333,default_max_speed) (1,max_overclock_speed)
-			return sip->max_speed + (engine_energy - Energy_levels[INTIAL_ENGINE_RECHARGE_INDEX]) * (sip->max_overclocked_speed - sip->max_speed) / (1.0f - Energy_levels[INTIAL_ENGINE_RECHARGE_INDEX]);
+			return sip->max_speed + (engine_energy - initial_engine_recharge_energy_level) * (sip->max_overclocked_speed - sip->max_speed) / (1.0f - initial_engine_recharge_energy_level);
 		}
 	}
 }
@@ -203,6 +267,7 @@ void ets_update_max_speed(object* ship_objp)
 	Assertion(ship_objp->type == OBJ_SHIP, "Object needs to be a ship object!");
 
 	// calculate the top speed of the ship based on the energy flow to engines
+	// (note: this doesn't need the power factor; see comments in ets_get_max_speed())
 	float x = Energy_levels[Ships[ship_objp->instance].engine_recharge_index];
 	ship_objp->phys_info.max_vel.xyz.z = ets_get_max_speed(ship_objp, x);
 }
@@ -335,23 +400,13 @@ void set_recharge_rates(object* obj, int shields, int weapons, int engines) {
 // engines to their default levels
 void set_default_recharge_rates(object* obj)
 {
-	int ship_properties;
-
 	ship* ship_p = &Ships[obj->instance];
 	ship_info* ship_info_p = &Ship_info[ship_p->ship_info_index];
 
 	if ( ship_info_p->power_output == 0 )
 		return;
 
-	ship_properties = 0;	
-	if (ship_has_energy_weapons(ship_p))
-		ship_properties |= HAS_WEAPONS;
-	
-	if (!(obj->flags[Object::Object_Flags::No_shields]) && !ship_info_p->flags[Ship::Info_Flags::Intrinsic_no_shields])
-		ship_properties |= HAS_SHIELDS;
-
-	if (ship_has_engine_power(ship_p))
-		ship_properties |= HAS_ENGINES;
+	int ship_properties = ets_properties(obj);
 
 	// the default charge rate depends on what systems are on each ship
 	switch ( ship_properties ) {

code/hud/hudets.h

@@ -42,6 +42,8 @@ enum SYSTEM_TYPE {WEAPONS, SHIELDS, ENGINES};
 
 void update_ets(object* obj, float fl_frametime);
 void ets_init_ship(object* obj);
+int ets_properties(object* objp);
+float ets_power_factor(object* objp, bool include_power_output = true);
 void ai_manage_ets(object* obj);
 
 void increase_recharge_rate(object* obj, SYSTEM_TYPE enum_value);

code/model/animation/modelanimation_driver.cpp

@@ -111,7 +111,7 @@ namespace animation {
 		int objnum = get_pmi_objnum(pmi);
 		Assertion(objnum >= 0, "Invalid object used in animation property driver!");
 		Assertion(Objects[objnum].type == OBJ_SHIP, "Non-ship object used in ship animation property driver!");
-		return Energy_levels[Ships[Objects[objnum].instance].*ets_property];
+		return ets_power_factor(&Objects[objnum], false) * Energy_levels[Ships[Objects[objnum].instance].*ets_property];
 	}
 
 	std::function<float(polymodel_instance*)> parse_ship_property_driver_source() {

code/parse/sexp.cpp

@@ -20516,7 +20516,7 @@ int sexp_gse_recharge_pct(int node, int op_num)
 		return SEXP_NAN_FOREVER;
 
 	// recharge pct
-	return (int)(100.0f * Energy_levels[index]);
+	return (int)(100.0f * ets_power_factor(ship_entry->objp(), false) * Energy_levels[index]);
 }
 
 /*

code/ship/afterburner.cpp

@@ -235,7 +235,7 @@ void afterburners_update(object *objp, float fl_frametime)
 
 			if ( shipp->afterburner_fuel < sip->afterburner_fuel_capacity ) {
 				float recharge_scale;
-				recharge_scale = Energy_levels[shipp->engine_recharge_index] * 2.0f * The_mission.ai_profile->afterburner_recharge_scale[Game_skill_level];
+				recharge_scale = ets_power_factor(objp) * Energy_levels[shipp->engine_recharge_index] * 2.0f * The_mission.ai_profile->afterburner_recharge_scale[Game_skill_level];
 				shipp->afterburner_fuel += (sip->afterburner_recover_rate * fl_frametime * recharge_scale);
 
 				if ( shipp->afterburner_fuel >  sip->afterburner_fuel_capacity){