Flags ponder

Just pondering...

NetLane

The 🍦 vanilla NetLane.m_flags member is a ushort containing 16 bits. Can we concatenate a 🚦 TM:PE custom ushort flags on to it, creating a 32-bit uint word?

In theory it should be as simple as (pseudo-code): lane_flags = lane.m_flags | tmpeLane.flags.

In the table below, I list the 32 bits (1-indexed) and their purpose. As you can see, this combines the following features:

Vanilla flags
Vehicle restrictions
Parking restrictions
Lane customisations (see #515)

More could be added if a 64-bit word was used, and I think that would be useful to consider; we could encode lots of useful info in the flags, for example:

Whether the lane exits by segment start/end node (two flags, so if direction is both, both flags would be set)
Lane speed limit as an index (or value if sufficient bits available)
Anything that can reduce calculations required for vehicle AIs and pathfinder

While moving to 64-bit might seem excessive, particularly for lanes, it could significantly reduce the number of data sources required and would make code much more legible. In addition, the save/load process could potentially be greatly simplified in to just 3 main collections (the flags for lanes, segments and nodes).

bit	from	name	meaning
	🍦	`None`
`1`	🍦	`Created`	Created; can use.
`2`	🍦	`Deleted`	Deleted; do not use.
`3`	🍦	`Inverted`	?
`4`	🍦	`JoinedJunction`	?
	🍦	`JoinedJunctionInverted`	`Inverted
`5`	🍦	`Forward`	Arrow forward
`6`	🍦	`Left`	Arrow left
`7`	🍦	`Right`	Arrow right
`8`	🍦	`Merge`	Arrow merge
	🍦	`LeftForward`	`Left
	🍦	`LeftRight`	`Left
	🍦	`ForwardRight`	`Forward
	🍦	`LeftForwardRight`	`Left
`9`	🍦	`Stop`	Bus stop
`10`	🍦	`Stop2`	Tram stop
	🍦	`Stops`	`Stop
`11`	🍦	`YieldStart`
`12`	🍦	`YieldEnd`
`13`	🍦	`StartOneWayLeft`
`14`	🍦	`StartOneWayRight`
`15`	🍦	`EndOneWayLeft`
`16`	🍦	`EndOneWayRight`
	🍦	`StartOneWayLeftInverted`	`Inverted
	🍦	`StartOneWayRightInverted`	`Inverted
	🍦	`EndOneWayLeftInverted`	`Inverted
	🍦	`EndOneWayRightInverted`	`Inverted
`17`	🚦	`AllowCars`	Allow passenger cars
`18`	🚦	`AllowTaxis`
`19`	🚦	`AllowCargo`	Allow cargo trucks/trains
`20`	🚦	`AllowPassenger`	Allow PT vehicles
`21`	🚦	`AllowServices`	Allow city service vehicles
`22`	🚦	`AllowEmergency`	Allow emergency services
`23`	🚦	`AllowLocal`	Allow local vehicles
`24`	🚦	`AllowCity`	Allow city vehicles
`25`	🚦	`AllowRegional`	Allow regional vehicles
`26`	🚦	`ParkingForward`	Allow parking forward lane
`27`	🚦	`ParkingBackward`	Allow parking backward lane
`28`	🚦	`BikeLane`
`29`	🚦	`BusLane`
`30`	🚦	`TaxiRank`
`31`	🚦	`LoadingBay`
`32`	🚦	`ParkingLane`