Method updateRoad

src/OpenLoco/src/Vehicles/Vehicle1.cpp:54–133

0x004A9969

    // 0x004A9969
    bool Vehicle1::updateRoad()
    {
        uint16_t curveSpeedFraction = std::numeric_limits<uint16_t>::max();
        Speed16 newTargetSpeed = kSpeed16Max;
        RoutingManager::RingView ring(routingHandle);
        bool isOnRackRail = false;
        for (auto iter = ring.rbegin(); iter != ring.rend(); ++iter)
        {
            auto res = RoutingManager::getRouting(*iter);
            isOnRackRail |= (res & (1 << 13)) != 0; // rackrail
            uint8_t roadId = (res >> 3) & 0xF;
            curveSpeedFraction = std::min(curveSpeedFraction, World::TrackData::getRoadMiscData(roadId).curveSpeedFraction);
            if (res & (1 << 12))
            {
                const auto* bridgeObj = ObjectManager::get<BridgeObject>((res & 0xE00) >> 9);
                if (bridgeObj->maxSpeed != kSpeed16Null)
                {
                    newTargetSpeed = std::min(bridgeObj->maxSpeed, newTargetSpeed);
                }
            }
        }

        Vehicle train(head);
        if (train.veh2->var_4F != -1)
        {
            const auto* roadObj = ObjectManager::get<RoadObject>(train.veh2->var_4F);
            const Speed32 fractionalSpeed = Speed32(static_cast<uint32_t>(curveSpeedFraction) * roadObj->maxSpeed.getRaw());
            newTargetSpeed = std::min(toSpeed16(fractionalSpeed + 1.0_mph), newTargetSpeed);
            newTargetSpeed = std::max(newTargetSpeed, 12_mph);

            if (train.head->has38Flags(Flags38::fasterAroundCurves))
            {
                newTargetSpeed += newTargetSpeed / 4;
                newTargetSpeed = std::min(roadObj->maxSpeed, newTargetSpeed);
            }
        }
        else
        {
            const Speed32 fractionalSpeed = Speed32(static_cast<uint32_t>(curveSpeedFraction) * (60_mph).getRaw());
            newTargetSpeed = toSpeed16(fractionalSpeed);
        }

        newTargetSpeed = std::min(newTargetSpeed, train.veh2->maxSpeed);
        if (isOnRackRail)
        {
            newTargetSpeed = std::min(newTargetSpeed, train.veh2->rackRailMaxSpeed);
        }

        // TODO: Original CS Bug. Fix when we diverge on replays
        // newTargetSpeed = std::min(newTargetSpeed, toSpeed16(speedFromDistanceInATick(var_3C)) + 5_mph);
        newTargetSpeed = std::min(newTargetSpeed, Speed16(static_cast<uint32_t>(var_3C) >> 15) + 5_mph);

        if ((train.head->hasVehicleFlags(VehicleFlags::manualControl) && train.head->manualPower <= -20)
            || train.head->hasVehicleFlags(VehicleFlags::commandStop))
        {
            if (train.veh2->currentSpeed == 0.0_mph)
            {
                newTargetSpeed = 0_mph;