“The real key was not to write the game first and then try to compress it, but rather to write the game in compressed form right from the word go. I knew the landscape graphics would take up a lot of memory, so the first couple of weeks were spent writing routines that used a specially modified form of run length encoding and decoding for these graphics, as well as some utilities in BASIC that would enable me to interface with a graphics tablet and automatically scale and then manually touch up the landscape features I had drawn.”
Singleton was adamant that the game was not to be about merely wandering around and admiring the scenery. Much thought went into creating the characters and creatures to support the over-arching concept. Small details would prove to be significant once the player was submerged into the game world. “The data that the map had to store included landscape features, armies, place names, magical objects and creatures such as wolves, dragons, wild horses, skulkrin and trolls. Each of these was encoded with the absolute minimum number of bits,” explains Singleton. “The creatures, for instance, were stored in just one bit per cell. That bit said whether there were creatures there or not. Then a number-scrambling routine told you which type of creature it was by scrunching up the map coordinates of the cell. Likewise, all the text in the game was tokenised using a one- or two-byte code per word, and the words referred to were further compressed by using only five bits per character.”
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