Graphics¶
This chapter discusses the location and formats of the various forms of graphical data used in the game.
Field Sprites¶
Field sprites are those used on the field. In particular, they are generally used to display the player and the NPCs.
Player¶
The field sprites for party members are made up of several components. First, the actual graphical data is stored in $300 byte arrays at $1B:8000. Each sheet is composed of 32 8x8 tiles. The data is stored with 3 bits per pixel.
These sheets are composed into 16 different frames using the OAM flags stored at $15:C0C4. Each frame has eight bytes of data, where the even bytes are the tile numbers for the upper left, upper right, lower left and lower right component tiles, respectively, and the odd bytes are the tile flags for the same tiles. In the default data, the flags are used to set the horizontal flip bit if appropriate and to set the priority for each tile to 2.
The coordinates for the four tiles of the player sprite are determined by the data at $15:C0B4, which consists of four bytes per tile (corresponding to the full OAM entry). Only the X and Y coordinates are set, with both the flags and tile bytes being set to zero. Note that the base coordinates for the player sprite are 112, 109, which is neither centered nor exactly aligned with a tile boundary. In addition, on the second frame of horizontal movement, the Y coordinate is reduced further by one.
The palette for each class’s sprite is stored in the array at $15:B2FA. Each class receives one byte, which determines which of the four player sprite palettes to use.
The palettes themselves are stored at $0D:8000, which consists of four separate eight color palettes, with each palette potentially being shared by multiple characters (only the paladin Cecil palette is unique).
Title Screen¶
The title screen is a simple static image displayed at the start of the game. Do note that the title screen in the original Japanese release has some form of animation. That is not currently documented here.
Tiles¶
The title screen tile data is stored with 4 bits per pixel at $08:C000. There is room for 256 tiles, though not all 256 are used in this release.
Tilemap¶
A standard SNES tilemap is stored in the 2048 bytes starting at $08:E000. The data is sufficient to render a 256x256 image.
Palette¶
The eight 16-color palettes used by the screen are stored at $08:E800.
Outdoor Maps¶
Outdoor maps are composed from a set of 128 16x16 composed tiles, each created by drawing from a pool of 256 8x8 base tiles.
Base Tiles¶
The outdoor maps are implemented via mode 7, so each pixel is represented by a single byte, which directly indexes the palette data in CG-RAM.
Each 8x8 tile uses a single 16-color palette, with the upper four bits of each pixel in that tile determined by the data in the following table, where each 8x8 tile is one byte (even though only the upper four bits are used):
| Map | Address |
|---|---|
| Overworld | $14:8600 |
| Underworld | $14:8700 |
| Moon | $14:8800 |
The lower four bits of each pixel’s value are loaded from a separate table:
| Map | Address |
|---|---|
| Overworld | $1D:8000 |
| Underworld | $1D:A000 |
| Moon | $1D:C000 |
In this table, two pixels are defined per byte, with the first pixel of each pair using the lower four bits, and the second pixel using the upper four bits. These four bits are extracted, shifted to the correct location, and combined with the previously-specified bits for the tile to determine the final index into the palette.
The tables for the overworld and underworld are both 8192 bytes each, but the table for the moon is only 5056 bytes (158 tiles instead of 256).
The palette data itself is standard SNES palette data, loaded from the offset listed in the following table:
| Map | Address |
|---|---|
| Overworld | $14:8900 |
| Underworld | $14:8980 |
| Moon | $14:8A00 |
Each palette consists of 128 bytes, making up 64 colors.
Composed Tiles¶
The 16x16 composed tiles are composed from the 8x8 tiles via the data in the following tables:
| Map | Address |
|---|---|
| Overworld | $14:8000 |
| Underworld | $14:8200 |
| Moon | $14:8400 |
Each 512 byte block is actually composed of four separate 128-byte arrays. The four arrays, in order, specify the tiles to use in the upper left, upper right, lower left and lower right segments of the composed tile, in that order. In other words, the first 128 bytes determine the upper left tile for each of the 128 composed tiles, and so on.
Tilemaps¶
The tilemaps for the outdoor maps are stored in a slightly compressed form at the following addresses:
| Map | Row Offsets | Compressed Tilemap |
|---|---|---|
| Overworld | $16:8000 | $16:8480 |
| Underworld | $16:8200 | $16:C480 |
| Moon | $16:8400 | $16:E180 |
The row offset data is a series of 16-bit offsets for each row of tiles, allowing one to index directly to a particular row (which allows the game to avoid loading all rows into memory at once, as that would be extremely expensive in terms of memory usage.
The actual compressed tilemap data is a mostly basic run-length encoding scheme. If the high bit of the value is not set, the value is directly copied to the tilemap, except potentially for the values of $00, $10, $20 and $30. In those cases, if the map is the overworld, a four byte sequence will instead be written. The first byte in the sequence is the specified value. The following three bytes are equal to $70 plus the value divided by 16 and multiplied by 3 plus either 0, 1 or 2.
If the high bit of the value is set, the low seven bits determine the tile number, and the following byte is the number of tiles to write minus one. (This allows a value of $FF, for instance, to encode a full row of 256 tiles.)
All tile numbers refer to the 16x16 composed tiles.
Each row of data in the compressed tilemap is additionally terminated with a single $FF.
Animation¶
There are two classes of animated outdoor tiles: ocean tiles and waterfall tiles. Both of these are animated in similar fashions, with custom code directly manipulating the tiles as stored in RAM.
For the ocean tiles, every other frame, a row selected based on a frame counter and the data table at $00:8E8C is rotated to the right, with each pixel moving once to the right, except for the final pixel, which is rotated back to the far left. Within the tiles, the ocean tiles make up tiles $80 through $83.
For the waterfall tiles, once per frame, a column selected via the frame counter and the data table at $00:8E7C is rotated downward, though the process is repeated so each pixel moves two spots per frame. The waterfall tiles range from $7A to $7D.