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Ultima > I Mondain > Development > Local Map Tile Type

EGA Local Tiles Data Type

   The castle and towne maps use tiles from the local tile file (EGATOWN.BIN). It has a fixed length of 1,632 bytes long. Tiles are 8x8 pixels. EGA formatting of each tile makes a tile size 32 bytes. This figures out to 51 tiles in the file. 

   EGA formatting assigns four bits to each pixel (16 colors in EGA, this link shows them) but the bits are not contiguous. Formatting is similar to the global map tiles except that in the local map bits are grouped in 8 bit words. I'll just refer to them as bytes. One byte describes one line of 8 pixels in a line of the tile. The first byte is the least significant bits (LSBs) of the EGA color table index. The next byte's bits are the second order followed by a byte containing the third order bits. The final byte contains the most significant bits (MSBs) of the index. In this manner, each group of four bites forms one scan-line of pixels in each tile.

The list of original tiles from the game are displayed here.