vehicle chooses between brake speed and block brake speed

src/openrct2/GameStateSnapshots.cpp

@@ -455,6 +455,7 @@ struct GameStateSnapshots final : public IGameStateSnapshots
         COMPARE_FIELD(Vehicle, target_seat_rotation);
         COMPARE_FIELD(Vehicle, BoatLocation.x);
         COMPARE_FIELD(Vehicle, BoatLocation.y);
+        COMPARE_FIELD(Vehicle, BlockBrakeSpeed);
     }
 
     void CompareSpriteDataLitter(const Litter& spriteBase, const Litter& spriteCmp, GameStateSpriteChange& changeData) const

src/openrct2/ride/Vehicle.cpp

@@ -7381,6 +7381,60 @@ void Vehicle::Sub6DBF3E()
     }
 }
 
+/**
+ * Determine whether to use block brake speed or brake speed. If block brake is closed or no block brake present, use the
+ * brake's speed; if block brake is open, use maximum of brake speed or block brake speed.
+ */
+uint8_t Vehicle::ChooseBrakeSpeed() const
+{
+    if (GetTrackType() != TrackElemType::Brakes)
+        return brake_speed;
+    auto trackElement = MapGetTrackElementAtOfTypeSeq(TrackLocation, GetTrackType(), 0);
+    if (trackElement != nullptr)
+    {
+        if (trackElement->AsTrack()->IsBrakeClosed())
+            return brake_speed;
+        else
+            return std::max<uint8_t>(brake_speed, BlockBrakeSpeed);
+    }
+    return brake_speed;
+}
+
+/**
+ * Populate the vehicle's brake_speed and BlockBrakeSpeed values.
+ */
+void Vehicle::PopulateBrakeSpeed(const CoordsXYZ& vehicleTrackLocation, TrackElement& brake)
+{
+    auto trackSpeed = brake.GetBrakeBoosterSpeed();
+    brake_speed = trackSpeed;
+    if (brake.GetTrackType() != TrackElemType::Brakes)
+    {
+        BlockBrakeSpeed = trackSpeed;
+        return;
+    }
+    // As soon as feasible, encode block brake speed into track element so the lookforward can be skipped here.
+
+    CoordsXYE output = CoordsXYE(vehicleTrackLocation.x, vehicleTrackLocation.y, reinterpret_cast<TileElement*>(&brake));
+    int32_t outputZ = vehicleTrackLocation.z;
+    uint16_t timeoutCount = 256;
+    do
+    {
+        if (output.element->AsTrack()->GetTrackType() == TrackElemType::BlockBrakes)
+        {
+            BlockBrakeSpeed = output.element->AsTrack()->GetBrakeBoosterSpeed();
+            return;
+        }
+        if (output.element->AsTrack()->GetTrackType() != TrackElemType::Brakes)
+        {
+            break;
+        }
+        timeoutCount--;
+    } while (TrackBlockGetNext(&output, &output, &outputZ, nullptr) && timeoutCount);
+
+    // If block brake is not found, use the track's speed
+    BlockBrakeSpeed = trackSpeed;
+}
+
 /**
  *
  *  rct2: 0x006DB08C
@@ -7550,7 +7604,7 @@ bool Vehicle::UpdateTrackMotionForwardsGetNewTrack(uint16_t trackType, const Rid
     }
     SetTrackDirection(location.direction);
     SetTrackType(trackType);
-    brake_speed = tileElement->AsTrack()->GetBrakeBoosterSpeed();
+    PopulateBrakeSpeed(TrackLocation, *tileElement->AsTrack());
     if (trackType == TrackElemType::OnRidePhoto)
     {
         trigger_on_ride_photo(TrackLocation, tileElement);
@@ -7597,8 +7651,9 @@ Loc6DAEB9:
             && curRide.breakdown_reason_pending == BREAKDOWN_BRAKES_FAILURE;
         if (!hasBrakesFailure || curRide.mechanic_status == RIDE_MECHANIC_STATUS_HAS_FIXED_STATION_BRAKES)
         {
-            auto brakeSpeed = brake_speed << 16;
-            if (brakeSpeed < _vehicleVelocityF64E08)
+            auto brakeSpeed = ChooseBrakeSpeed();
+
+            if ((brakeSpeed << 16) < _vehicleVelocityF64E08)
             {
                 acceleration = -_vehicleVelocityF64E08 * 16;
             }
@@ -7955,7 +8010,7 @@ bool Vehicle::UpdateTrackMotionBackwardsGetNewTrack(uint16_t trackType, const Ri
     direction &= 3;
     SetTrackType(trackType);
     SetTrackDirection(direction);
-    brake_speed = tileElement->AsTrack()->GetBrakeBoosterSpeed();
+    PopulateBrakeSpeed(TrackLocation, *tileElement->AsTrack());
 
     // There are two bytes before the move info list
     uint16_t trackTotalProgress = GetTrackProgress();
@@ -7986,7 +8041,9 @@ bool Vehicle::UpdateTrackMotionBackwards(const CarEntry* carEntry, const Ride& c
 
         if (trackType == TrackElemType::Brakes)
         {
-            if (-(brake_speed << 16) > _vehicleVelocityF64E08)
+            auto brakeSpeed = ChooseBrakeSpeed();
+
+            if (-(brakeSpeed << 16) > _vehicleVelocityF64E08)
             {
                 acceleration = _vehicleVelocityF64E08 * -16;
             }
@@ -9408,4 +9465,5 @@ void Vehicle::Serialise(DataSerialiser& stream)
     stream << seat_rotation;
     stream << target_seat_rotation;
     stream << BoatLocation;
+    stream << BlockBrakeSpeed;
 }

src/openrct2/ride/Vehicle.h

@@ -210,6 +210,7 @@ struct Vehicle : EntityBase
     uint8_t seat_rotation;
     uint8_t target_seat_rotation;
     CoordsXY BoatLocation;
+    uint8_t BlockBrakeSpeed;
 
     constexpr bool IsHead() const
     {
@@ -377,6 +378,8 @@ private:
     void UpdateLandscapeDoor() const;
     void UpdateLandscapeDoorBackwards() const;
     int32_t CalculateRiderBraking() const;
+    uint8_t ChooseBrakeSpeed() const;
+    void PopulateBrakeSpeed(const CoordsXYZ& vehicleTrackLocation, TrackElement& brake);
 
     void Loc6DCE02(const Ride& curRide);
 };