Feature: Industries with neutral stations (e.g. Oil Rig) only supply/accept cargo to/from their neutral station. (#7234)

This change is a controlled by a game setting, located under Environment ->
Industries which allows toggling the behaviour. It defaults to enabled.

"Company stations can serve industries with attached neutral stations"

When enabled, industries with attached neutral station (such as Oil Rigs) may
also be served by company-owned stations built nearby. This is the traditional
behaviour.

When disabled, these industries may only be served by their neutral station.
Any nearby company-owned stations won't be able to serve them, nor will the
neutral station serve anything else other than the industry.

1 files changed, 23 insertions, 2 deletions

diff --git a/src/station_cmd.cpp b/src/station_cmd.cpp
index e6864d70d..a9460e562 100644
--- a/src/station_cmd.cpp
+++ b/src/station_cmd.cpp
@@ -506,6 +506,8 @@ CargoArray GetProductionAroundTiles(TileIndex tile, int w, int h, int rad)
 	const Industry *i;
 	FOR_ALL_INDUSTRIES(i) {
 		if (!ta.Intersects(i->location)) continue;
+		/* Skip industry with neutral station */
+		if (i->neutral_station != NULL && !_settings_game.station.serve_neutral_industries) continue;
 
 		for (uint j = 0; j < lengthof(i->produced_cargo); j++) {
 			CargoID cargo = i->produced_cargo[j];
@@ -523,8 +525,9 @@ CargoArray GetProductionAroundTiles(TileIndex tile, int w, int h, int rad)
  * @param h Y extent of area
  * @param rad Search radius in addition to given area
  * @param always_accepted bitmask of cargo accepted by houses and headquarters; can be NULL
+ * @param ind Industry associated with neutral station (e.g. oil rig) or NULL
  */
-CargoArray GetAcceptanceAroundTiles(TileIndex tile, int w, int h, int rad, CargoTypes *always_accepted)
+CargoArray GetAcceptanceAroundTiles(TileIndex tile, int w, int h, int rad, CargoTypes *always_accepted, const Industry *ind)
 {
 	CargoArray acceptance;
 	if (always_accepted != NULL) *always_accepted = 0;
@@ -547,6 +550,15 @@ CargoArray GetAcceptanceAroundTiles(TileIndex tile, int w, int h, int rad, Cargo
 	for (int yc = y1; yc != y2; yc++) {
 		for (int xc = x1; xc != x2; xc++) {
 			TileIndex tile = TileXY(xc, yc);
+
+			if (!_settings_game.station.serve_neutral_industries) {
+				if (ind != NULL) {
+					if (!IsTileType(tile, MP_INDUSTRY)) continue;
+					if (Industry::GetByTile(tile) != ind) continue;
+				} else {
+					if (IsTileType(tile, MP_INDUSTRY) && Industry::GetByTile(tile)->neutral_station != NULL) continue;
+				}
+			}
 			AddAcceptedCargo(tile, acceptance, always_accepted);
 		}
 	}
@@ -572,7 +584,8 @@ void UpdateStationAcceptance(Station *st, bool show_msg)
 			st->rect.right  - st->rect.left + 1,
 			st->rect.bottom - st->rect.top  + 1,
 			st->GetCatchmentRadius(),
-			&st->always_accepted
+			&st->always_accepted,
+			_settings_game.station.serve_neutral_industries ? NULL : st->industry
 		);
 	}
 
@@ -3795,6 +3808,8 @@ void FindStationsAroundTiles(const TileArea &location, StationList *stations)
 	uint min_y = (y > max_rad) ? y - max_rad : 0;
 	uint max_y = y + location.h + max_rad;
 
+	IndustryID ind = IsTileType(location.tile, MP_INDUSTRY) ? GetIndustryIndex(location.tile) : INVALID_INDUSTRY;
+
 	if (min_x == 0 && _settings_game.construction.freeform_edges) min_x = 1;
 	if (min_y == 0 && _settings_game.construction.freeform_edges) min_y = 1;
 	if (max_x >= MapSizeX()) max_x = MapSizeX() - 1;
@@ -3809,6 +3824,9 @@ void FindStationsAroundTiles(const TileArea &location, StationList *stations)
 			/* st can be NULL in case of waypoints */
 			if (st == NULL) continue;
 
+			/* Check if neutral station is attached to us */
+			if (!_settings_game.station.serve_neutral_industries && st->industry != NULL && st->industry->index != ind) continue;
+
 			if (_settings_game.station.modified_catchment) {
 				int rad = st->GetCatchmentRadius();
 				int rad_x = cx - x;
@@ -3918,6 +3936,9 @@ void BuildOilRig(TileIndex tile)
 	st->string_id = GenerateStationName(st, tile, STATIONNAMING_OILRIG);
 
 	assert(IsTileType(tile, MP_INDUSTRY));
+	/* Mark industry as associated both ways */
+	st->industry = Industry::GetByTile(tile);
+	st->industry->neutral_station = st;
 	DeleteAnimatedTile(tile);
 	MakeOilrig(tile, st->index, GetWaterClass(tile));