Zone 66 Tileset Format

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Zone 66 Tileset Format
Zone 66 Tileset Format.png
Format typeTileset
HardwareVGA
Max tile count232-1
PaletteShared VGA
Tile names?No
Minimum tile size (pixels)0×0
Maximum tile size (pixels)65535×65535
Plane count1
Plane arrangementLinear VGA
Transparent pixels?No
Hitmap pixels?No
Metadata?None
Supports sub-tilesets?No
Compressed tiles?No
Hidden data?No
Games

This file format is used by Zone 66 to store tiles used for drawing maps, among other things.

File format

Signature

There is no signature, however careful processing of the header can be used to check whether the file is valid (e.g. no tiles are stored past the end of the file, the first tile's offset is always zero, etc.)

Header

Each tileset begins with the following header.

Data type Name Description
UINT32LE count Number of images in the file
UINT32LE[count] offsets Array of file offsets
BYTE[] data Start of first tile's image data

Each offset is relative to the start of the first tile's data, so the first tile will always have an offset of zero even though it starts some distance into the file.

Image data

Each tile begins with its dimensions, followed by the pixel data.

Data type Name Description
UINT16LE width Width of tile, in pixels
UINT16LE height Height of tile, in pixels

The image data is encoded in a type of RLE. Each byte read should perform one of the following actions:

Byte value Action
0xFF End of image data
0xFE Go to the start of the next row
0xFD Read next byte, then move right that many pixels
0x00 Invalid

Any pixels skipped over by one of the above jumps should be left black (value 0x00). Each line is always terminated by 0xFE (even if the exact number of pixels to fill the whole line has been read), except the last line which is terminated by 0xFF.

If the byte read isn't in the table above, it is a length of data to read. That many bytes should be read in from the file and each byte treated as the value of the next pixel.

Note: Some files (e.g. maingrfx.z66) write pixels beyond the width of the image, and consequently may overrun a buffer if this situation is not catered for.

Credits

This file format was reverse engineered by john_doe. If you find this information helpful in a project you're working on, please give credit where credit is due. (A link back to this wiki would be nice too!)