Entry 342

The opening stream's flashes over the stream: the cancel's and the end's

2026-10-01uivideo

Filescrates/piney-demo/src/lib.rscrates/piney-game/src/session.rscrates/piney-game/src/stream.rsdocs/engine/title.md

The title's intro stream has two white flashes, and the port got both wrong. A cancel push's flash was not modelled. The end flash was entered only once the stream had finished, then advanced 20 frames at once. So the stream's last 20 frames never faded to white, and the menu came in partway through the fade-out.

The game

PlayOpeningStream (INF demo.prg:0x004066b0) starts ccThExecuteStream at priority 33 with the stream number in its param +0x14. The count is 410 for volume 1's plain stream and 450 with m_ParoFLG. INF's switch on m_NowVol gives volumes 2-4 450 and 490. It waits for ccGetStreamAdrs() and then the stream's +0x17e bit 3. Then, each frame (0x00406838), before the stream's own task (the same priority, started later):

pad push & saveData.assignPADcancel (+0x8410) and s1   EntryFlash(50, 0x80ffffff), s1 = 0
the stream task's +0x14 == -1                           return
ccGetStreamFrame() == count - 20 and s1                 EntryFlash3(20, 20, 5, 0x80ffffff), s1 = 0
ccBreathThread(1)

The flashes go to scFadeDef over (0, 0, 512, 384). A cancel does not end the stream; the stream's own skip rule does that. It only flashes, and it spends s1, so the end flash never follows it. MUT (demo.prg 0x00419720), OUT (0x004153e0) and QUA (0x00307d40) run the same loop. OUT and QUA keep the count and the flag in swapped registers and load the rectangle's 512.0 and 384.0 from constants (OUT 0x0041db58, 0x0041db50).

The port

Demo keeps the count from its Request::Stream as stream_flash, the port's s1. While PlayOpeningStream holds the title, the session calls Demo::stream_tick(pad, frame) before each of the stream's steps, from its first step on, with StreamPlayer::frame(), the frame the last step drew. After the step, Demo::stream_fade draws scFadeDef over the stream's picture. Phase::Stream now just goes on to the title. The demo's own frame keeps sending the fade, so the flash runs on over the menu. advance_one is gone.

the_opening_stream_flashes: played through, the flash starts on the step that draws the stream's frame 391 (the check saw 390). It lies over the stream's last 20 frames (391-410). The stream then shows frame 0 twice as it ends, and the menu comes out of the white, 47 frames lit in all. With cancel pushed on the 100th step, white starts on that step and lasts 50 frames, the stream ends two steps later, and no second flash comes.