Entry 201

"The later volumes' title: five items, the previous volume's save, every branch of the opening checked on the four volumes"

2026-09-26volumes

Filescrates/piney-demo/src/opening.rscrates/piney-demo/src/names.rscrates/piney-demo/src/lib.rscrates/piney-demo/src/dataload.rscrates/piney-demo/examples/demo_probe.rstools/test_demo_rs.pydocs/engine/title.md

After 0200 Mutation reached its title, but only the memory-card question drew. The logo and menu did not. The port's ccOpening_Control said it held volume 1 only.

Where the volumes differ

Fifteen of the control's functions branch on m_NowVol (+0x8). A scan of the overlay found them:

• the eight Set*;
• ChangeMainAct, SwitchCur;
• AllAnimate, AllTransparency, AllDraw;
• PlayOpeningStream, SetVolCcs, Init.

Infection's own DEMO.PRG holds all four volumes' branches and animation names. Its DATA.BIN holds title2-title4 too. voldiff.py ported says:

• Mutation's copies of these functions are byte for byte Infection's;
• Outbreak's and Quarantine's are recompiled copies.

So Infection's code for m_NowVol 2-4 is the later titles. Running each Set* in eemu for volumes 1-4 and dumping the control's name arrays gave the names at once (title.md, "Volumes 2-4"):

• five items, the fourth the previous volume's save ("CONVERT");
• the backdrop ne{n}1/ne{n}0;
• a fifth dummy in each panel;
• items 3 and 4 swapping volume 1's 30 and 40 dummy objects.

The behaviour then came from the branches themselves:

• SwitchCur's neighbour rule over five items;
• SetNeutral's jump to the cursor's own item;
• ChangeMainAct's second table (3 to SetNextData);
• SetParodyGame on item 4;
• the per-frame loops over items 3 and 4;
• AllTransparency leaving item 3 alone while its panel is open;
• SetNextData (SetDataLoad with a mode argument, clearing m_OptSW);
• PlayNextData, whose flash ends with m_NextSW 0, so the window closes before it leaves with m_StartMode 4;
• PlayOpeningStream's streams 21/22, 50/51 and 75/76.

One piece is Mutation's alone. Infection's ccThDemo never raises m_Max_CurNO from Init's 3. Mutation's calls a new function after Init (MUT 0x00419630) that sets 4 on volumes 2-4. Opening::set_max_cur is that call, made where the title starts. Nothing sets m_ParoFLG on any disc, so the fifth item stays hidden.

NextDataLoad_Control is Data_Control with m_PrevFlg 1, set after its own Init. The port keeps it as a second DataLoad (new_next, init_next). What that flag changes inside Data_Control is the next step.

Checked

test_demo_rs.py now runs these checks once per volume through a volumes decorator:

• set (with setnext), switch, cursor, count, transparency, animation, draw;
• Main (actions 10 and 11 allowed from volume 2);
• Play* (with a playnext sweep like playload's);
• the boot.

The eemu machine takes the volume in m_NowVol. The probe takes a vol N line and loads title<N>. All 18 tests pass on the four volumes, and Infection's results are unchanged. Mutation now shows its own logo and backdrop, and a four-item menu with the cursor on CONVERT.