Three follow-up fixes to the per-screen music:
- Decode music in the H_TIMI VBlank interrupt (MusicVBlank) instead of
once per Halt() in the game loops. The heavy per-step VDP work in
ScrollDraw could overrun a VBlank, dropping the decode rate so the
music slowed only while moving; the ISR keeps tempo steady regardless.
The playing track is mapped into the unused bank-3 window (0xA000) and
left there for the screen, so the ISR reads it with no bank switching
and never races the main code's bank-2 tile/sprite swaps. PlayTrack()
switches tracks under DI/EI. The game loops revert to plain Halt()s.
- PlayTrack() mutes the OPLL (key-off all 9 channels) before starting the
next track, silencing the note that lingered across screen changes.
- TitleScreen()/ShowHints() zero the hardware scroll offset before drawing
their absolute-coord images. Gameplay rests at g_BaseX/g_BaseY in
{0,64,128,192}; without the reset the returning title/hints screen
appeared horizontally shifted (only after finishing on a non-zero base).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
jurjen.ladeniusandClaude Opus 4.8
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