There are several categories of shapes files in Ultima 3: map shapes, character sets, and moon icons.

Map Shapes

There are three files containing map tiles, two of which have been added by the U3 Upgrade.

• SHAPES.ULT - CGA shapes
• SHAPES.EGA - EGA shapes (U3 Upgrade)
• SHAPES.VGA - VGA shapes (U3 Upgrade)

There are 80 tiles in the file and each tile is 16x16 pixels. The only difference between each shapes file is the length of a pixel:

• CGA - 2 bits (4 pixels per byte)
• EGA - 4 bits (2 pixels per byte)
• VGA - 8 bits (1 pixel per byte)

Each row of a tile is stored sequentially. For example, if we indexed each pixel in the file, it would be organized in the following pattern:

tile 0, row 0 - 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
tile 0, row 1 - 10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F
tile 0, row 2 - 20 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E 2F
tile 0, row 3 - 30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F
tile 0, row 4 - 40 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F
tile 0, row 5 - 50 51 52 53 54 55 56 57 58 59 5A 5B 5C 5D 5E 5F
tile 0, row 6 - 60 61 62 63 64 65 66 67 68 69 6A 6B 6C 6D 6E 6F
tile 0, row 7 - 70 71 72 73 74 75 76 77 78 79 7A 7B 7C 7D 7E 7F
tile 1, row 0 - 80 81 82 83 84 85 86 87 88 89 8A 8B 8C 8D 8E 8F
tile 1, row 1 - 90 91 92 93 94 95 96 97 98 99 9A 9B 9C 9D 9E 9F
...

And so on. Since VGA has 1 pixel per byte, this is also the byte index into a VGA shapes file. The data is compacted in CGA and EGA because the size of each pixel is smaller.

The tiles and their description are as follows:

Character Sets

There are three files containing character sets, two of which have been added by the U3 Upgrade.

• CHARSET.ULT - CGA character set
• CHARSET.EGA - EGA character set (U3 Upgrade)
• CHARSET.VGA - VGA character set (U3 Upgrade)

There are 128 tiles in the file and each tile is 8x8 pixels. Otherwise, the byte organization is largely the same as the map shapes files. (see above)

Each row of a tile is stored sequentially. For example, if we indexed each pixel in the file, it would be organized in the following pattern:

tile 0, row 0 - 00 01 02 03 04 05 06 07
tile 0, row 1 - 08 09 0A 0B 0C 0D 0E 0F
tile 0, row 2 - 10 11 12 13 14 15 16 17
tile 0, row 3 - 18 19 1A 1B 1C 1D 1E 1F
tile 0, row 4 - 20 21 22 23 24 25 26 27
tile 0, row 5 - 28 29 2A 2B 2C 2D 2E 2F
tile 0, row 6 - 30 31 32 33 34 35 36 37
tile 0, row 7 - 38 39 3A 3B 3C 3D 3E 3F
tile 1, row 0 - 40 41 42 43 44 45 46 47
tile 1, row 1 - 48 49 4A 4B 4C 4D 4E 4F
...

And so on.

Each tile index corresponds mostly to an MS-DOS character code with some exceptions as follows:

Moon Icons

There are three files containing moon icons, all of which have been added by the U3 Upgrade.

• MOONS.ULT - CGA moon icons (U3 Upgrade)
• MOONS.EGA - EGA moon icons (U3 Upgrade)
• MOONS.VGA - VGA moon icons (U3 Upgrade)

There are 8 tiles in the file and each tile is 8x8 pixels. Otherwise, the byte organization is exactly the same as the charset files. (see above)

The U3 Upgrade added the MOONS.* files to store the moon phases that appear above the game window. Without the upgrade or with this feature disabled, the game uses characters 0-7 from the CHARSET.* files to display the moon phases.