Sticky bit
The "sticky bit" (or "chain bit") is one of the per-sprite attributes stored in the Sprite Control Bank 3 (bit 6).
Bit | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Def | Y position | Sticky bit | Sprite size |
Setting it to 1 makes the corresponding sprite "stick" to the right of the precedent one.
The GPU will automatically place it to the right of the precedent sprite, use the same Y position, the same size in tiles and the same vertical shrinking coefficient. Only the horizontal shrinking coefficient is left independant.
Chained sprites can also be called "driven sprites".
Changing the driving sprite's attributes will change all those of the consecutively chained sprites.
Changing driven sprites attributes won't affect it until it is unchained (saved in VRAM but ignored by GPU).