Metasprites

Metroid 2's metasprite format is very simple.

In fact, it's so simple, that it's virtually the same as the hardware's sprite format.

A metasprite is sprite made out of sprites. The “sprites” you see onscreen are actually collections of 8×8 pixel hardware sprites. Thus, metasprites are just lists of hardware sprites.

Accordingly, each sprite in the list is four bytes:

• Y position
• X position
• Tile number
• Attributes. Note that each enemy entry in $c600 has fields for the attributes that are XORed with these.
  • Bit 7 - Sprite Priority (0 = Above, 1 = Behind)
  • Bit 6 - Y flip (0 = Normal, 1 = Flipped)
  • Bit 5 - X flip (same)
  • Bit 4 - Palette number

A Y position of $FF lets the game know that the metasprite is done.

And that's about it.

TODO: Put an example here.

For convenience, here's the pointer list for the metasprites in bank 1 (which starts at 0x4000 in the ROM).

TODO: This is probably better suited for a “Locations of Data” page.

$425F
$429C
$42FE
$4360
$4391
$43C6
$4476
$44AB
$44E8
$45AC
$4606
$4660
$46B2
$425F
$42CD
$432F
$43EB
$441C
$4451
$4511
$4546
$4583
$45D9
$4633
$4689
$46DB
$4197
$41B0
$41C9
$41E2
$410F
$4120
$4131
$4142
$41FB
$4214
$422D
$4246
$4153
$4164
$4175
$4186
$410A
$4704
$4735
$476E
$4793
$47C4
$47FD
$4859
$4848
$4827
$4822
$489A
$489F
$48A4
$48B5
$48C6
$48D7
$48E8
$48F9
$490A
$491B
$492C
$4935
$40E1
$40B8
$4093
$408A

Figuring out which sprite is used by which enemy (and if there's even an easy way to determine that) is an exercise left to the reader/author.