69 lines
2.8 KiB
Text
69 lines
2.8 KiB
Text
# ride.ludic - the rider's stick steers what they are on: a horse walks, canters on stamina and
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# stops at water, a slope or a trunk; a boat is rowed - a stroke and a turn handed to its hull,
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# which the water floats, the wind drifts and the lake bed stops
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const VE_ROW: float = 630.0 # N: a full stroke forward, about 3 m/s on Maroon Lake's hull
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const VE_ROW_TURN: float = 270.0 # N.m: the oars pulled against each other, about 1.1 rad/s
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const VE_WIND: float = 70.0 # N on a boat in a full wind
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export function vehicle_update(vehicles_st: mut VehiclesState, ix: float, iz: float, run: bool, dt: float) -> void {
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let v = vehicles_st.ve_cur
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if v == null { return }
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if v.kind == VEHICLE_BOAT { ve_row(vehicles_st, v, ix, iz, dt) } else { ve_ride_horse(vehicles_st, v, ix, iz, run, dt) }
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VehicleWorld.placed(v)
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VehicleRider.ride_at(v.x, v.y + v.seat_h, v.z, v.yaw, Math.abs(v.speed))
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}
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# the stick is the oars: forward and back a stroke, left and right the two pulled against each
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# other; the swell at the edge takes the outward share of a stroke
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function ve_row(vehicles_st: mut VehiclesState, v: Vehicle, ix: float, iz: float, dt: float) -> void {
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ve_hull_read(v)
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let take = ve_swell(vehicles_st, v, iz, dt)
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VehicleHull.row(v.nid, iz * VE_ROW * (1.0 - take), -ix * VE_ROW_TURN)
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let d = Math.abs(v.speed) * dt
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if d > 0.0 { ve_say(vehicles_st, VEHICLE_MOVED, v, d) }
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}
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# where the hull is now, and how fast it goes along its bow
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function ve_hull_read(v: Vehicle) -> void {
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if not VehicleHull.read(v.nid) { return }
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v.x = VehicleHull.x()
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v.y = VehicleHull.y()
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v.z = VehicleHull.z()
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v.yaw = VehicleHull.yaw()
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v.speed = VehicleHull.speed()
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}
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# a boat gets a longer leash than a swimmer and the same current at the end of it: the outward
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# part of the stroke only, so a boat at the limit can always be put about. The share it takes.
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function ve_swell(vehicles_st: mut VehiclesState, v: Vehicle, iz: float, dt: float) -> float {
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var fx = -Math.sin(v.yaw)
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var fz = -Math.cos(v.yaw)
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if iz < 0.0 {
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fx = -fx
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fz = -fz
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}
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let take = Math.clamp(VehicleWorld.swell(v.x, v.z, fx, fz), 0.0, 1.0)
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if take > 0.55 and vehicles_st.ve_swell_said < 0.0 {
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vehicles_st.ve_swell_said = 14.0
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ve_say(vehicles_st, VEHICLE_SWELL, v, take)
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}
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vehicles_st.ve_swell_said = vehicles_st.ve_swell_said - dt
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return take
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}
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# every boat: its hull read back, and the wind pushing it across the lake, ridden or not
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export function vehicles_tick(vehicles_st: VehiclesState, dt: float) -> void {
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let l = ve_all(vehicles_st)
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let w = VehicleWorld.wind() * VE_WIND
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let wy = VehicleWorld.wind_yaw()
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for i in 0 .. len(l) {
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let v = l[i]
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if v.kind == VEHICLE_BOAT {
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if w > 0.0 { VehicleHull.drift(v.nid, -Math.sin(wy) * w, -Math.cos(wy) * w) }
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if v.rider < 0 {
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ve_hull_read(v)
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VehicleWorld.placed(v)
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}
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}
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}
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}
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