Entry 356

"Each arrival in a town draws its own walking PCs: the session counts frames from power-on"

2026-10-02worldengine

Filescrates/piney-game/src/session.rscrates/piney-game/src/world.rsdocs/engine/field-game.md

Issue #32: the PCs walking a Root Town were the same on every visit. In the game they change each time the party comes back.

A town's set-up runs ccInitRand (INF SLUS_202.67:0x001d9900). It seeds the game's MT19937 with 4352 and draws it ccSys+0x358 times. ccRegisterRandomNpc then picks the walking PCs' npcTbl rows from that generator (65, docs/engine/field-game.md). The port had the count as an input, World::set_rand_count, but nothing ever set it. So every town drew from a generator drawn 0 times, and picked the same rows.

The count is a frame counter. In ccSystem::Ctrl (0x0010a6bc), after the wait on sceGsSyncV for the frame rate, the game adds one to ccSys+0x358 once per game frame. ccSystem's set-up (0x0010a944) zeroes it at power-on. Session now keeps the same count (sys_frames, one a step from power-on). It hands the count to every town it sets up: on Log in, and on each enter_world into a town. The port's frames cannot equal the game's (its load times differ), but two arrivals now differ as they do in the game.

each_arrival_in_town_has_its_own_pcs goes from event 3's field to Mac Anu, then Dun Loireag, then Mac Anu again, by the console's town. It compares the rows of the walking PCs on the two arrivals. With the count left at 0 the rows are the same and the test fails.