Unit: no battle pad holds both NEXT and BACK, over every sub-state with and
without a potion and a ball, and NEXT is on none with a cursor accepting input
(the assertion the top-level menu failed before this branch). A battle frame
with a cursor accepting input is the fly's turn, against real WRAM, for all
four menus plus the two frames that correctly are not one. The bag deals
ITEM / THROW BALL / BACK, and BACK alone when the bag is empty.
ROM-gated, from the live rung-9 forest checkpoint: no pad with both buttons, no
NEXT while a menu accepts input, the longest NEXT/BACK alternation under four,
and every battle entered also left, each on a bounded number of macros. The
battle rules ask the scene the pad was dealt for rather than wIsInBattle, so
the $ff frame a lost battle passes through -- which reads Unknown, whose pad is
NEXT and BACK by contract -- is not accused of a battle rule.
The test fails on v0.4.2 from the same checkpoint with "NEXT was on the pad
while a battle menu was accepting input", NEXT dealt on battle/main, and a run
that never leaves map 51.
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.
