BSH

It is the file format used to store Textures used by the game. It is usually packed using the Chunks format, but always as a standalone file (missed opportunity), and has either a .bsh or .zei file ending. .zei files contain characters and signs, the name probably stems from the German word Zeichen meaning sign.

The Chunk Header identifier is either BSH or ZEI. This depends on the file suffix.

After the Chunk Header comes an Index of offsets to the Textures in the file. Different index positions can use the same byte offset, to avoid storing duplicate textures. This is prominently used in STADTFLD.BSH in the KE version.

And after that the Textures is using a basic form of bitmap (8-bit indexed with RLE-like compression and custom header ??)

The BSH file doesn’t contain the Color Palette. See COL

Format Structure

Texture Index

List of 4byte/32bit unsigned integer Texture offsets. The Texture is at 20(Chunk Header) + offset absolute file position.

Texture

Starts with a Header:

Bytes	Use
4	Width of the Texture
4	Height of the Texture
4	Num of the Texture (??)
4	Length of the Texture in bytes

Followed by the RLE-ish compressed image data. The Texture starts in the upper left corner, is read line wise, and can be interpreted in the following loop:

• if the next byte is 0xFF the image has reached it’s end.
• if the next byte is 0xFE the current pixel line has reached it’s end.
• else it’s an Texture Chunk

Texture Chunk layout:

Bytes	Use
1	number of pixels to skip / number of transparent pixels
1	number of pixels that follow
up to 255	pixels to insert at current position

Notes

Since there is no length of the Texture Index, one can use the offset of the first Texture as an Texture Index delimiter.

Main source of information: Sir Henry’s Grafx Source.