Level Data Format

Pointer Tables

Address	Description	Format
$05E000	Layer 1 data	0x200 levels, 3 bytes each (1,536 bytes)
$05E600	Layer 2 data	0x200 levels, 3* bytes each (1,536 bytes)
$05EC00	Sprite data	0x200 levels, 2** bytes each (1,024 bytes)

* If the long byte of the Layer 2 data is #$FF, it will get replaced by #$0C and the data will be interpreted as a BG tilemap rather than object data.
** All sprite data is located in bank 07.

Primary Level Header

The first five bytes of object data for Layer 1 is the primary level header, which dictates various information about the level. Layer 2 object data also contains this header, but it is skipped over and ignored.

Format
BBBLLLLL	CCCOOOOO	3MMMSSSS	TTPPPFFF	IIVVZZZZ

BBB	BG palette
LLLLL	Length of level (number of screens, -1)
CCC	Back area color
OOOOO	Level mode
3	Layer 3 priority
MMM	Music
SSSS	Sprite GFX setting
TT	Timer setting
PPP	Sprite palette
FFF	FG palette
II	Item memory setting
VV	Vertical scroll setting
ZZZZ	FG/BG GFX setting

Secondary Level Header

The secondary level header consists of four bytes, spread across four seperate tables with one byte per level.

Format
$05F000	$05F200	$05F400	$05F600
SSSSYYYY	33AAAXXX	MMMMFFBB	IUVEEEEE

SSSS	Layer 2 scroll setting
YYYY	Level entrance Y position
33	Layer 3 setting
AAA	Level entrance Mario action
XXX	Level entrance X position
MMMM	Midway entrance screen number
FF	FG initial position
BB	BG initial position
I	Disable No-Yoshi Intro flag
U	Unknown/unused vertical position flag
V	Vertical positioning flag
EEEEE	Level entrance screen number

Sprite Header

The first byte of sprite data is the sprite header, which handles some miscellaneous sprite-related information.

Format
SBMMMMMM

S	Sprite buoyancy
B	Sprite buoyancy (disable sprite-Layer 2 interaction)
MMMMMM	Sprite memory*

* Although values up to #$3F are possible, only up to #$12 are actually intended for use.

Object Data

Object data is used to define Layer 1 and Layer 2 foreground data. The Z order of the objects is determined by the order they're written; an object earlier in the data, for instance, will appear below an object written later.

The data consists of a five byte header, followed by a list of all the objects. If the first byte of an object is #$FF, it indicates the end of the data has been reached.

Standard Objects

Standard objects are 3 bytes long. The 'settings byte' usage varies depending on the object, but generally specifies the height and width of the object.

Format
NBBYYYYY	bbbbXXXX	SSSSSSSS

N	New Screen flag
BBbbbb	Object number
YYYYY	Y position
XXXX	X position
SSSSSSSS	Settings

The "new screen" flag increases the object high X position by one. In order to increase it by a larger amount, a screen jump must be used.
In vertical levels, the X and Y position values are swapped.

Extended Objects

Extended objects function as standard object 00, and are also 3 bytes long.

Format
N00YYYYY	0000XXXX	BBBBBBBB

N	New Screen flag
YYYYY	Y position
XXXX	X position
BBBBBBBB	Extended object number

The "new screen" flag increases the object high X position by one. In order to increase it by a larger amount, a screen jump must be used.
In vertical levels, the X and Y position values are swapped.

Screen Exits

Screen exits function as extended object 00. Unlike the rest of object data, they're 4 bytes long rather than 3.

Format
000PPPPP	0000WUSH	00000000	DDDDDDDD

PPPPP	Screen number
W	Water flag* (secondary exit)
U	LM-modified flag**
S	Secondary exit flag
H	High bit of destination level*
DDDDDDDD	Lower 8 bits of destination level

* Added by Lunar Magic; not used in the original game.
** Indicates the screen exit uses the secondary exit flag added by LM rather than SMW's default functionality.

In vanilla SMW, if the last screen exit in the data has the secondary exit flag set, all screen exits in the level will be interpreted as secondary exits.

Screen Jump

Screen jumps function as extended object 01, and change the high X position of proceding objects to a specified screen. They can be used to skip over screens if no objects exit on them, or to move back a screen to change the Z ordering of an object crossing over a screen boundary. Like standard and extended objects, they consist of three bytes.

Format
000PPPPP	0000----	00000001

PPPPP	Screen number
----	Currently unused

Background Data

When Layer 2 is stored as a background tilemap (see the note on the pointer table), it's written as a raw tilemap with no header, compressed in the LC_RLE1 format.

Format
RLLLLLLL	...

R	RLE flag
LLLLLLL	Length
...	If the RLE flag is clear, the following (length + 1) bytes are intepreted as direct tile data. If the RLE flag is set, the following byte is repeated (length + 1) times.

The entire left half of the BG is stored first, then the right half. A command of FF FF indicates the end of the data.

Sprite Data

Sprite data consists of a single-byte header, followed by a list of all the sprites. If the first byte of a sprite is #$FF, it indicates the end of the data has been reached.

Format
yyyyEESY	XXXXssss	NNNNNNNN

Yyyyy	Y position
EE	Extra bits
XXXX	X position
Sssss	Screen number
NNNNNNNN	Sprite ID

In vertical levels, the X and Y position values are swapped.

Secondary Entrances

Secondary entrance data consists of four bytes, spread across four seperate tables with one byte per secondary exit ID.

Format
$05F800	$05FA00	$05FC00	$05FE00
DDDDDDDD	BBFFYYYY	XXXSSSSS	L---HAAA

DDDDDDDD	Low byte of destination level
BB	BG initial position
FF	FG initial position
YYYY	Entrance Y position
XXX	Entrance X position
SSSSS	Entrance screen number
L	Slippery level flag*
---	Currently unused
H	High bit of destination level*
AAA	Entrance Mario action

* Added by Lunar Magic; not used in the original game.