I'm leaving link to want to check I don't know much about rom hacking
Notes on usage:
You need a ROM image (*.smc) of the European or USA version to use the editor. (The Japanese gives an error message)
The editor uses the graphics from the ROM.
Open: opens a level in a ROM image.
Save: saves the currently opened level into the same place (overwrite).
Export level: exports the currently opened level. (3490 bytes)
Import level: imports the currently opened level.
Room display area:
Click to select a tile. Ctrl-click to select multiple tiles.
Start here: sets start position to the selected tile.
Flip start: flip the start direction
Guard here: put guard into the selected tile. (max. 1 guard per room)
Flip guard: flip the guard in the current room.
Delete guard: remove the guard from the current room.
Guard type...: lets you select the type of the guard in the current room from a list.
Guard skill...: lets you modify the skill of the guard from the current room.
Room links...: lets you modify the room links.
Unlike the DOS version, rooms are numbered 0-23. 255 means no room, 254 means no room and don't show above.
How tiles work:
Each position has a foreground tile index, a background tile index and a door event index.
The background tile index is simply an index into a list of images.
The foreground tile index is a bit more complicated.
It is an index into a table with the following entries:
- Background layer index: an index into a list of images.
- Foreground layer index: an index into a list of images.
- Object: a number which identifies an object.
- Attributes: bits describing whether the tile is wall or floor.
For buttons, the door event index is an index into the door events, which are similar to the DOS version ones.
It can also mean:
For doors: 00=closed, FF=open
For teleports: if the index is the same for two teleports, they belong to each other.
What is missing:
Objects are shown as text.
The level type cannot be changed.
Checkpoints cannot be changed.
You can't tell if a wall is fake just by looking. (But if you select it, you'll see.)
Link Forum: http://forum.princed.org/viewtopic.php?f=121&t=1654