feat(npc, nav): 17.5 - a person walks by the world's way where it has one (NpcWorld.way: the next corner toward the target, asked every half second, on reaching it or for a new target; the errand begins only at the target itself; the step round and the give-up stay the fallback), way_test round a wall; and ludic.nav reads a mesh file into the shim's own memory and frees it once parsed, so loading a map leaves nothing in Ludic's never-freed heap

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

packages/ludic.nav/build.ludic

@@ -47,8 +47,8 @@ export function nav_polygons(nav_st: NavState, kind: int) -> int {
   return nvc_polys(h)
 }
 
-# a kind's mesh written to a file, and read back. Reading holds the file's bytes for good (a slice
-# is never given back), so a mesh is loaded once per map, never per frame
+# a kind's mesh written to a file, and read back - through the asset pack when it is in one - into the
+# shim's own memory, which it frees once the tiles are made, so a map swap leaves nothing behind
 export function nav_save_file(nav_st: NavState, kind: int, path: string) -> bool {
   let h = nv_mesh(nav_st, kind)
   if h == null { return false }
@@ -59,8 +59,14 @@ export function nav_save_file(nav_st: NavState, kind: int, path: string) -> bool
   return Fs.write_bytes(path, buf, n)
 }
 export function nav_load_file(nav_st: mut NavState, kind: int, path: string) -> bool {
-  if not Fs.exists(path) { return false }
-  let buf = Fs.read_bytes(path)
-  if buf == null or len(buf) == 0 { return false }
-  return nv_set(nav_st, kind, nvc_load(buf, len(buf)))
+  let f = file_open(path, "rb")
+  if f == null { return false }
+  file_seek(f, 0, 2)
+  let n = file_tell(f)
+  file_seek(f, 0, 0)
+  let buf = nvc_stage(n)
+  var got = 0
+  if buf != null { got = file_read(f, buf, n) }
+  file_close(f)
+  return nv_set(nav_st, kind, nvc_load_staged(buf, got))
 }

packages/ludic.nav/native.ludic

@@ -13,3 +13,5 @@ extern function nvc_path(h: pointer, f: int, sx: float, sy: float, sz: float, ex
 extern function nvc_partial(h: pointer) -> int = "nav_partial"
 extern function nvc_raycast(h: pointer, f: int, sx: float, sy: float, sz: float, ex: float, ez: float) -> int = "nav_raycast"
 extern function nvc_random_near(h: pointer, f: int, x: float, y: float, z: float, r: float, seed: int, out: pointer) -> int = "nav_random_near"
+extern function nvc_stage(size: int) -> pointer = "nav_stage"
+extern function nvc_load_staged(buf: pointer, size: int) -> pointer = "nav_load_staged"

packages/ludic.nav/native/shim/nav_shim.cpp

@@ -7,6 +7,7 @@
 #include <DetourNavMeshQuery.h>
 #include <DetourCommon.h>
 #include <cstring>
+#include <cstdlib>
 #include <cmath>
 #include <vector>
 

packages/ludic.nav/native/shim/nav_tiles.inl

@@ -100,3 +100,12 @@ NAV_SHIM void *nav_load(const unsigned char *buf, int size) {
   }
   return nav_open(mesh);
 }
+
+// a file read straight into the shim's own memory rather than a Ludic slice (which is never given
+// back): nav_stage hands out the room, nav_load_staged parses it and frees it, whatever the outcome
+NAV_SHIM unsigned char *nav_stage(int size) { return size > 0 ? static_cast<unsigned char *>(malloc(size)) : nullptr; }
+NAV_SHIM void *nav_load_staged(unsigned char *buf, int size) {
+  void *h = buf ? nav_load(buf, size) : nullptr;
+  free(buf);
+  return h;
+}