feat(packages): ludic.npc - the other people in a place: kinds, spots, acts, names and lines as open registries (a kind's routine is steps by the hour - a spot, an act, how long - with its own start and plan as function values, readable from .lres), a census on the half hour by weight (after dark only who stays out) with an extra the place asks for, walking round what is in the way and never into the water or up a scramble, no act where the place says nobody stops, facing a player within notice and back to the errand, leaving only out of every player's sight, unique names, posts that never walk (a vendor), lines by prio and chance with the story's words through a port and choices, a guest's copy of a host's people; greeted, talked and arrived as facts

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/ludic.npc/walk.ludic

@@ -0,0 +1,90 @@
+# walk.ludic - walking to the target: turn toward it, step, never into the water and never up a
+# scramble - step round it instead - and give up on a target that gets no closer for twenty seconds
+export function npc_walk(p: NpcPerson, dt: float) -> void {
+  var gx = p.tx
+  var gz = p.tz
+  if p.via_on {
+    gx = p.vx
+    gz = p.vz
+  }
+  let dx = gx - p.x
+  let dz = gz - p.z
+  if Math.sqrt(dx * dx + dz * dz) < 1.2 {
+    np_arrive(p)
+    return
+  }
+  let dg = npc_d(p.x, p.z, p.tx, p.tz)
+  if dg < p.best - 1.0 {
+    p.best = dg
+    p.prog_t = 0.0
+  } else { p.prog_t = p.prog_t + dt }
+  if p.prog_t > 20.0 {
+    np_stuck(p)
+    return
+  }
+  var sp = p.speed
+  if sp < 0.1 { sp = 1.2 }
+  if p.stalk { sp = Math.min(sp, 0.7) }
+  let want = Math.atan2(-dx, -dz)
+  let r = 3.0 * dt
+  p.yaw = p.yaw + Math.clamp(npc_wrap(want - p.yaw), -r, r)
+  let step = sp * dt
+  let nx = p.x - Math.sin(p.yaw) * step
+  let nz = p.z - Math.cos(p.yaw) * step
+  let nh = NpcWorld.ground(nx, nz)
+  if nh < NpcWorld.water(nx, nz) + 0.4 or nh - p.y > step * 1.4 {
+    p.stall = p.stall + dt
+    if p.stall > p.stall_max { p.stall_max = p.stall }
+    if p.detours < 10 and np_detour(p, want) {
+      p.detours += 1
+      return
+    }
+    np_stuck(p)
+    return
+  }
+  p.x = nx
+  p.z = nz
+  p.y = nh
+  p.stall = 0.0
+  p.phase = p.phase + step * 2.6
+}
+
+# there: a step round something ends, or the errand begins, facing what it came for
+function np_arrive(p: NpcPerson) -> void {
+  if p.via_on {
+    p.via_on = false
+    return
+  }
+  let fx = p.fx
+  let fz = p.fz
+  npc_do(p, p.next_act, p.next_t)
+  p.fx = fx
+  p.fz = fz
+  p.stall = 0.0
+  if p.act != NPCA_WALK { np_fact(NPC_F_ARRIVED, p, -1) }
+}
+
+function np_detour(p: NpcPerson, want: float) -> bool {
+  for k in 0 .. 8 {
+    let ang = want + float((k / 2 + 1) * (1 - 2 * (k % 2))) * 0.6
+    let x = p.x - Math.sin(ang) * 6.0
+    let z = p.z - Math.cos(ang) * 6.0
+    if npc_line_ok(p.x, p.z, x, z) {
+      p.via_on = true
+      p.vx = x
+      p.vz = z
+      p.yaw = ang
+      return true
+    }
+  }
+  return false
+}
+
+function np_stuck(p: NpcPerson) -> void {
+  p.fails += 1
+  p.via_on = false
+  if p.fails >= 3 {
+    p.fails = 0
+    npc_wander(p)
+  } else { npc_plan(p) }
+}