(svn r22639) -Feature: [NewGRF] Support for ship props 14/15 (ocean/canal speed fraction).

3 files changed, 17 insertions, 4 deletions

diff --git a/src/engine_type.h b/src/engine_type.h
index 4de250e42..6f93bfbb6 100644
--- a/src/engine_type.h
+++ b/src/engine_type.h
@@ -72,6 +72,8 @@ struct ShipVehicleInfo {
 	SoundID sfx;
 	bool old_refittable;   ///< Is ship refittable; only used during initialisation. Later use EngineInfo::refit_mask.
 	byte visual_effect;    ///< Bitstuffed NewGRF visual effect data
+	byte ocean_speed_frac; ///< Fraction of maximum speed for ocean tiles.
+	byte canal_speed_frac; ///< Fraction of maximum speed for canal/river tiles.
 };
 
 /**
diff --git a/src/newgrf.cpp b/src/newgrf.cpp
index ffd8e37fd..ba9aab9f0 100644
--- a/src/newgrf.cpp
+++ b/src/newgrf.cpp
@@ -1194,10 +1194,11 @@ static ChangeInfoResult ShipVehicleChangeInfo(uint engine, int numinfo, int prop
 				break;
 
 			case 0x14: // Ocean speed fraction
+				svi->ocean_speed_frac = buf->ReadByte();
+				break;
+
 			case 0x15: // Canal speed fraction
-				/** @todo Speed fractions for ships on oceans and canals */
-				buf->ReadByte();
-				ret = CIR_UNHANDLED;
+				svi->canal_speed_frac = buf->ReadByte();
 				break;
 
 			case 0x16: // Retire vehicle early
diff --git a/src/ship_cmd.cpp b/src/ship_cmd.cpp
index 142dec0c6..76b8d786f 100644
--- a/src/ship_cmd.cpp
+++ b/src/ship_cmd.cpp
@@ -155,7 +155,12 @@ static void CheckIfShipNeedsService(Vehicle *v)
  */
 void Ship::UpdateCache()
 {
-	this->vcache.cached_max_speed = GetVehicleProperty(this, PROP_SHIP_SPEED, ShipVehInfo(this->engine_type)->max_speed);
+	const ShipVehicleInfo *svi = ShipVehInfo(this->engine_type);
+
+	/* Get speed fraction for the current water type. Aqueducts are always canals. */
+	byte speed_frac = (!IsTileType(this->tile, MP_TUNNELBRIDGE) && GetWaterClass(this->tile) == WATER_CLASS_SEA) ? svi->ocean_speed_frac : svi->canal_speed_frac;
+	/* speed_frac == 0 means no reduction while 0xFF means reduction to 1/256. */
+	this->vcache.cached_max_speed = GetVehicleProperty(this, PROP_SHIP_SPEED, svi->max_speed) * (256 - speed_frac) / 256;
 
 	this->UpdateVisualEffect();
 }
@@ -545,6 +550,11 @@ static void ShipController(Ship *v)
 			if (!HasBit(r, VETS_ENTERED_WORMHOLE)) {
 				v->tile = gp.new_tile;
 				v->state = TrackToTrackBits(track);
+
+				/* Update ship cache when the water class changes. Aqueducts are always canals. */
+				WaterClass old_wc = IsTileType(gp.old_tile, MP_TUNNELBRIDGE) ? WATER_CLASS_CANAL : GetWaterClass(gp.old_tile);
+				WaterClass new_wc = IsTileType(gp.new_tile, MP_TUNNELBRIDGE) ? WATER_CLASS_CANAL : GetWaterClass(gp.new_tile);
+				if (old_wc != new_wc) v->UpdateCache();
 			}
 
 			v->direction = (Direction)b[2];