ludic/packages/ludic.vehicles/README.md

ludic.vehicles

Each player's boat and horse: called to one of four berths off a pier head or four bays at a trough, made there the first time and fetched there after, owned by one player and ridden by one at a time, ridden over water or land, and got off onto a spot the rider's own safe-spot rule found. Uses ludic.base and nothing else.

import "ludic.vehicles"

The package never draws, prices or words anything. A game draws a vehicle when VehicleWorld.made says one exists and moves its model on placed; it charges for a hire and says the words; and it binds the rider to its walking body (in Maroon Lake, ludic.character through the game).

The rules it keeps

• Nothing is parked for anyone. A vehicle has an owner and a rider; vehicle_find(kind) is this player's own and nothing else may pick "the" boat. A place is taken while a boat lies in it or a horse is tied at it (home_x, home_z), within half a place's spacing.
• Where a body is put down is one question with one answer. Getting off asks the rider's safe_spot - a wade of up to 1.25 m within its search from a boat, beside the right flank from a horse - and a boat too far out refuses and says so (VEHICLE_NO_LANDING) rather than dropping the rider in the lake.
• Steering follows signed speed: backing up with the stick left swings the nose right.
• A stale rider locks a vehicle for ever, so getting off is vehicle_dismount or vehicle_drop.

The ports

export port VehicleWorld {
  ground: fn(float, float) -> float                       # required
  water: fn(float, float) -> float                        # the surface (unbound: never wet)
  blocked: fn(float, float, float) -> bool                # (x, z, r): a collider in a horse's way
  swell: fn(float, float, float, float) -> float          # (x, z, fx, fz): a stroke's share lost
  wind: fn() -> float                                     # 0..1
  wind_yaw: fn() -> float                                 # the yaw the wind pushes toward
  next_id: fn() -> int                                    # an id across machines
  made: fn(Vehicle) -> void                               # draw it
  placed: fn(Vehicle) -> void                             # move its model
  gone: fn(Vehicle) -> void                               # its owner left
}
export port VehicleRider {
  board(x, z, yaw), ride_at(x, y, z, yaw, speed), step_off(x, z),
  safe_spot(x, z, from_y, max_depth) -> bool, safe_x(), safe_z()
}

API

VEHICLE_HORSE, VEHICLE_BOAT, VEHICLE_PLACES, VEHICLE_HAY_MIN	the kinds, four places each, and the hay a horse needs to go
Vehicle { kind, nid, x, y, z, yaw, speed, fuel, food, seat_h, bob, owned, owner, rider, home_x, home_z }	a vehicle (change one through the verbs)
vehicles_dock_at(x, z, yaw), vehicles_rail_at(x, z, yaw), vehicles_dock_yaw()	where the places are measured from
vehicle_berth_x/z(k), vehicle_post_x/z(k), vehicle_bay_x/z(k), vehicle_place_x/z(kind, k)	the places
vehicle_call_for(pid, kind, k) -> bool, vehicle_in_place(kind, k), vehicle_free_place(kind), vehicle_mine_in_place(kind)	calling one to a place
vehicle_of(pid, kind), vehicle_find(kind), vehicle_nearest(x, z, reach), vehicles_all(), vehicle_current(), vehicle_ride_kind()	questions
vehicle_mount(v) -> bool, vehicle_dismount() -> bool, vehicle_drop()	on and off
vehicle_update(ix, iz, run, dt)	a frame of riding from the rider's stick (bind it where the body hands its stick over)
vehicle_own(v), vehicle_feed(v, hay), vehicle_follow(v, x, y, z, yaw), vehicles_release(pid), vehicle_restore(kind, owned, food)	hiring, hay, a tied horse's wandering, a player leaving, a saved word
vehicles_tick(dt)	the idle boats' bob (the game calls it where the world is run)
vehicle_facts() -> Queue<VehicleFact>	{ what, nid, kind, owner, x, z, v }: VEHICLE_MOUNTED, _DISMOUNTED, _NO_LANDING, _MOVED (v: metres), _SWELL (every 14 s), _HUNGRY, _FED
vehicles_reset(), vehicles_system() -> System	"vehicles": this player's own saved by kind (hired, hay) - where they lie is not saved

Tests

ludic test packages/ludic.vehicles

A fake shore with a pier head and a trough: berths and bays, calling and fetching, a taken place, a player leaving, a hungry horse, riding a horse into a trunk and to the water's edge, rowing to the shore, the swell and the wind, getting off near a shore and far from one, and the save.