Function getTrackAtCursor

src/OpenLoco/src/Ui/Windows/Vehicle.cpp:4609–4634

0x004A40C5

        // 0x004A40C5
        static std::optional<GameCommands::VehiclePlacementArgs> getTrackAtCursor(const int16_t x, const int16_t y)
        {
            auto [interaction, viewport] = ViewportInteraction::getMapCoordinatesFromPos(x, y, ~ViewportInteraction::InteractionItemFlags::track);
            if (interaction.type != ViewportInteraction::InteractionItem::track)
            {
                return {};
            }

            // Get the best progress along the track relative to the cursor
            auto* trackElement = static_cast<World::TrackElement*>(interaction.object);
            World::Pos3 loc(interaction.pos.x, interaction.pos.y, trackElement->baseHeight());
            auto progress = getTrackProgressAtCursor({ x, y }, *viewport, *trackElement, loc);

            // Get the coordinates of the first tile of the possibly multi-tile road
            const auto& trackDataArr = World::TrackData::getTrackPiece(trackElement->trackId());
            const auto& trackData = trackDataArr[trackElement->sequenceIndex()];
            auto trackOffset2 = Math::Vector::rotate(World::Pos2(trackData.x, trackData.y), trackElement->rotation());
            auto trackOffset = World::Pos3(trackOffset2.x, trackOffset2.y, trackData.z);
            auto trackFirstTile = loc - trackOffset;

            GameCommands::VehiclePlacementArgs placementArgs;
            placementArgs.pos = trackFirstTile;
            placementArgs.trackProgress = progress;
            placementArgs.trackAndDirection = trackElement->rotation() | (trackElement->trackId() << 3);
            return { placementArgs };
        }

        // 0x004B6444
        static std::optional<GameCommands::VehiclePlacementArgs> getVehicleRailPlacementArgsFromCursor(const Vehicles::VehicleHead& head, const int16_t x, const int16_t y)