Here are a few more palette tricks used by the game, in addition to those posted in the FF4kster thread a while back. (
http://slickproductions.org/forum/index.php?topic=1713.msg22009#msg22009)
15:C4D3 - Lava pulsating glow.When in the underground, palette 1 (0-based) is overwritten every frame, pulled from one of 4 consecutive palettes stored at 14:FA16 (ROM A7C16). The pulse pattern which says which of the 4 to use at any moment is defined by an 8-byte entry at 15:C503 (ROM AC703).
15:C3C3 - Big Whale running lights in flight.When flying in the whale, just one color of the palette used by the whale is overwritten, pulled in sequence from an 8-color table at 15:C3E0 (ROM AC5E0).
15:C3F0 - Psychedelic trippy Tower of Babil colors.When event flag 66 is set (after Kain steals the crystal), and when in either the Overworld or Underground, the frame counter byte itself is used to make a funky color entry and written to the palette used by the Tower tiles. Oddly the tower tiles use a different palette index for the two different worlds, but the effect is the same. Black is used instead when the flag isn't set.
I can't imagine these would be very useful to anyone. But if anybody wanted to say, turn the Underground into something that wasn't so yellow and lava-ish, there ya go! Of course, these kinds of routines could certainly be modified or mimicked to add pulsing or other effects to different maps entirely.
We have EVEN MORE themes now, but some old ones are gone...