route and frontier ask for the grid once per plan and fall back to the window
when there is none. With it: one plan crosses a whole map, GO WARP / GO OUT /
GO ROUTE route to their warp or connection tile rather than to the nearest tile
of an edge that reads Unknown, a tile-pair wall is planned around instead of
being learned by walking into it, and the frontier is the nearest unstood
walkable tile anywhere on the map instead of the nearest one on screen.
The walkable predicate answered for the ten-by-nine screen window and Unknown
everywhere else. MapGrid is the same rule over every tile of the loaded map:
block ids out of wOverworldMap, a blocks-to-tiles read of the tileset header s
blockset through the new bank-aware ROM read, the tileset s collision list as
before, and the TilePairCollisionsLand values as directed walls both ways.
The reader checks itself before it answers: the decode is compared against the
window predicate over the player s own neighbourhood, and a frame where the
window can answer for none of it -- a battle, a text box, a frame mid-warp -- is
refused, because wOverworldMap shares its bytes with the picture buffer. Every
refusal is named (GridRefusal) and leaves the window predicate in charge.
Cached per map id and size, so a map is decoded once on arrival rather than once
per question, and owned beside the session ledgers: never checkpointed.
MemoryReader::read8 reads the CPU bus, where banks 1 and up are whichever bank
the cartridge last switched to, so a table in another bank could only be read by
writing the mapper register -- and the joypad is the only write this workspace
makes into a running game. read_rom takes a bank and a CPU address and reads the
cartridge image the process already holds instead. Defaulted to None, so every
reader without a cartridge behind it narrows rather than guesses.
resolve_wram.py is a second reading of the disassembly beside gen_symbols.py:
it walks ram/wram.asm with a cursor that is only ever live while anchored on an
address symbols.rs already pins, re-derives 40 of the 63 it carries with no
disagreement, and emits an address only when a pinned one after it agrees too.
wOverworldMap, wCurMapTileset, wTilesetBank and wTilesetBlocksPtr come out of
that pass; no address is hand-written and nothing else in the table moves.
