Flintlock
Emperor
- Joined
- Sep 25, 2004
- Messages
- 1,220
For a taste of what replacing the unit AI would involve, here's the replacement leader unit AI:
It's 170 lines and took me a few days of free time to write including EXE analysis and debugging. Replacing all the unit AI would be a big job but still just small enough to be tempting. I estimate it would take maybe 2 months if mod development continues apace. Then again, in the software industry, a good rule of thumb to estimate time requirements is to take your best guess and multiply it by 5, and a 10 month job is not tempting.
As for what the replacement AI does, it's nothing exotic. It's similar to the base AI without the bugs and with some better heuristics. For example, it will always form an army if the AI player doesn't already have one and it knows rushing infrastructure is not worth much in highly corrupt cities (wonders excepted). It will always start a science age if it can, that's maybe not optimal but I couldn't think of a practical way to compute the value of a science age in shields so that it could be compared with rushing production. One "cute" feature is that it knows about the science age bug and the mod settings so it won't start one if the patch is not applied.
Code:
void __fastcall
patch_Unit_ai_move_leader (Unit * this)
{
Tile * tile = tile_at (this->Body.X, this->Body.Y);
int continent_id = tile->vtable->m46_Get_ContinentID (tile);
// Duplicate some logic from the base function. I'm pretty sure this disbands the unit if it's on a continent with no cities of the same civ.
if (leaders[this->Body.CivID].ContinentStat1[continent_id] == 0) {
Unit_disband (this);
return;
}
// Flee if the unit is near an enemy without adequate escort
int has_adequate_escort; {
int escorter_count = 0;
int any_healthy_escorters = 0;
int index;
for (int escorter_id = Unit_next_escorter_id (this, __, &index, 1); escorter_id >= 0; escorter_id = Unit_next_escorter_id (this, __, &index, 0)) {
Unit * escorter = get_unit_ptr (escorter_id);
if ((escorter != NULL) && (escorter->Body.X == this->Body.X) && (escorter->Body.Y == this->Body.Y)) {
escorter_count++;
int remaining_health = Unit_get_max_hp (escorter) - escorter->Body.Damage;
any_healthy_escorters |= remaining_health >= 3;
}
}
has_adequate_escort = (escorter_count > 0) && any_healthy_escorters;
}
if ((! has_adequate_escort) && any_enemies_near_unit (this, 49)) {
Unit_set_state (this, __, UnitState_Fleeing);
byte done = this->vtable->work (this);
if (done || (this->Body.UnitState != 0))
return;
}
// Move along path if the unit already has one set
byte next_move = Unit_pop_next_move_from_path (this);
if (next_move > 0) {
this->vtable->Move (this, __, next_move, 0);
return;
}
// Start a science age if we can
// It would be nice to compute a value for this and compare it to the option of rushing production but it's hard to come up with a valuation
if (is->current_config.patch_science_age_bug && Unit_ai_can_start_science_age (this)) {
Unit_start_science_age (this);
return;
}
// Estimate the value of creating an army. First test if that's even a possiblity and if not leave the value at -1 so rushing production is
// always preferable (note we can't use Unit_ai_can_form_army for this b/c it returns false for units not in a city). The value of forming
// an army is "infinite" if we don't already have one and otherwise it depends on the army unit's shield cost +/- 25% for each point of
// aggression divided by the number of armies already in the field.
int num_armies = leaders[this->Body.CivID].Armies_Count;
int form_army_value = -1;
if ((this->Body.leader_kind & LK_Military) &&
((num_armies + 1) * p_bic_data->General.ArmySupportCities <= leaders[this->Body.CivID].Cities_Count) &&
(p_bic_data->General.BuildArmyUnitID >= 0) &&
(p_bic_data->General.BuildArmyUnitID < p_bic_data->UnitTypeCount)) {
if (num_armies < 1)
form_army_value = INT_MAX;
else {
form_army_value = p_bic_data->UnitTypes[p_bic_data->General.BuildArmyUnitID].Cost;
int aggression_level = p_bic_data->Races[leaders[this->Body.CivID].RaceID].AggressionLevel; // aggression level varies between -2 and +2
form_army_value = (form_army_value * (4 + aggression_level)) / 4;
if (num_armies > 1)
form_army_value /= num_armies;
}
}
// Estimate the value of rushing production in every city on this continent and remember the highest one
City * best_rush_loc = NULL;
int best_rush_value = -1;
if (p_cities->Cities != NULL)
for (int n = 0; n <= p_cities->LastIndex; n++) {
City * city = get_city_ptr (n);
if ((city != NULL) && (city->Body.CivID == this->Body.CivID)) {
Tile * city_tile = tile_at (city->Body.X, city->Body.Y);
if ((continent_id == city_tile->vtable->m46_Get_ContinentID (city_tile)) &&
Unit_can_hurry_production (this, __, city, 0)) {
// Base value is equal to the number of shields rushing would save
int value = City_get_order_cost (city) - City_get_order_progress (city) - city->Body.ProductionIncome;
if (value <= 0)
continue;
// Consider distance: Reduce the value by the number of shields produced while the leader is en route to rush.
// This isn't an exact measure b/c the unit can spend more than its max MP per turn but it should be a close
// estimate.
int dist_in_turns; {
int dist_in_mp;
Trade_Net_set_unit_path (p_trade_net, __, this->Body.X, this->Body.Y, city->Body.X, city->Body.Y, this, this->Body.CivID, 1, &dist_in_mp);
dist_in_mp += this->Body.Moves; // Add MP already spent this turn to the distance
int max_mp = Unit_get_max_move_points (this);
if ((dist_in_mp >= 0) && (max_mp > 0))
dist_in_turns = dist_in_mp / max_mp;
else
continue; // No path or unit cannot move
}
value -= dist_in_turns * city->Body.ProductionIncome;
if (value <= 0)
continue;
// Consider corruption: Scale down the value of rushing an improvement by the corruption rate of the city.
// This is to reflect the fact that infrastructure is more valuable in less corrupt cities. But do not apply
// this to wonders since their benefit is in most cases not lessened by local corruption.
Improvement * improv = (city->Body.Order_Type == COT_Improvement) ? &p_bic_data->Improvements[city->Body.Order_ID] : NULL;
int is_wonder = (improv != NULL) && (0 != (improv->Characteristics & (ITC_Small_Wonder | ITC_Wonder)));
if ((improv != NULL) && (! is_wonder)) {
int good_shields = city->Body.ProductionIncome;
int corrupt_shields = city->Body.ProductionLoss;
if (good_shields + corrupt_shields > 0)
value = (value * good_shields) / (good_shields + corrupt_shields);
else
continue;
}
if ((value > 0) && (value > best_rush_value)) {
best_rush_loc = city;
best_rush_value = value;
}
}
}
}
// Hurry production or form an army depending on the estimated values of doing so. We might have to move to a (different) city if that's where
// we want to rush production or if we want to form an army but aren't already in a city.
City * in_city = get_city_ptr (tile->vtable->m45_Get_City_ID (tile));
City * moving_to_city = NULL;
if ((best_rush_loc != NULL) && (best_rush_value > form_army_value)) {
if (best_rush_loc == in_city) {
Unit_hurry_production (this);
return;
} else
moving_to_city = best_rush_loc;
} else if ((form_army_value > -1) && (Unit_ai_can_form_army (this))) {
Unit_form_army (this);
return;
} else if (in_city == NULL) {
// Nothing to do. Try to find a close, established city to move to & wait in.
int lowest_unattractiveness = INT_MAX;
if ((in_city == NULL) && (p_cities->Cities != NULL))
for (int n = 0; n <= p_cities->LastIndex; n++) {
City * city = get_city_ptr (n);
if ((city != NULL) && (city->Body.CivID == this->Body.CivID)) {
Tile * city_tile = tile_at (city->Body.X, city->Body.Y);
if (continent_id == city_tile->vtable->m46_Get_ContinentID (city_tile)) {
// TODO: Technically this distance calculation should account for edge wrapping
int unattractiveness = 10 * (int_abs (this->Body.X - city->Body.X) + int_abs (this->Body.Y - city->Body.Y));
unattractiveness = (10 + unattractiveness) / (10 + city->Body.Population.Size);
if (city->Body.CultureIncome > 0)
unattractiveness /= 5;
if (unattractiveness < lowest_unattractiveness) {
lowest_unattractiveness = unattractiveness;
moving_to_city = city;
}
}
}
}
}
if (moving_to_city) {
int first_move = Trade_Net_set_unit_path (p_trade_net, __, this->Body.X, this->Body.Y, moving_to_city->Body.X, moving_to_city->Body.Y, this, this->Body.CivID, 0x101, NULL);
if (first_move > 0) {
Unit_set_escortee (this, __, -1);
this->vtable->Move (this, __, first_move, 0);
return;
}
}
// Nothing to do, nowhere to go, just fortify in place.
Unit_set_escortee (this, __, -1);
Unit_set_state (this, __, UnitState_Fortifying);
}As for what the replacement AI does, it's nothing exotic. It's similar to the base AI without the bugs and with some better heuristics. For example, it will always form an army if the AI player doesn't already have one and it knows rushing infrastructure is not worth much in highly corrupt cities (wonders excepted). It will always start a science age if it can, that's maybe not optimal but I couldn't think of a practical way to compute the value of a science age in shields so that it could be compared with rushing production. One "cute" feature is that it knows about the science age bug and the mod settings so it won't start one if the patch is not applied.
That's too bad. It's looking like the GOG version of Complete is unique since so far no one has reported that they have a different version that matches it.
