Flappy/Notes

Flappy uses an unusual binary format for its title screen (and afterward).

The table that generates the title screen is at $38D1 in the ROM. Each hexadecimal value is a binary interpretation of eight horizontal tiles, with each character representing four.

$7B=01111011 $0E=00001110 and so on.

The result at top is a 32x14 pixel grid. 38DA seems to set vertical position onscreen, and binary follows until 3910.

Similarly, at 3914 there is binary for a 32x7 pixel grid.

At 27BA and 27CB there are two numbers 96 and 95, which set what tiles are used for the entire title screen, apart from blank tile 40, and the pointered-in text.

Oddly the game only uses two brick background tiles (95/96), filling the other space with three extended fonts. The topmost font is the one commonly used. Text strings are stored together and grabbed via pointers.

Title text is prepared at 35ce / 360c and stored at 37cc / 362a.