Programmer Gets Wolfenstein 3D Working on a Game Boy Color

A Swedish programmer, Anders Granlund, has managed to run Wolfenstein 3D on the Game Boy Color. For this he had to design a cartridge himself with a separate coprocessor, but the Game Boy did not have to be modified.

The separate system board is equipped with a KE04 processor with an ARM Cortex-M0 core that runs at 48MHz. Furthermore, the device has 128kB of flash memory and 16kB of ram. The KE04 works closely with the Game Boy’s own processor, the Z80. This itself is not fast enough to run the game, but it is to perform the necessary calculations for the interface.

The 3D images are rendered by the KE04 processor, which it does at a resolution of 160×96 pixels. The rest of the Game Boy’s 160×144-pixel screen is filled by the interface. For colors, the Game Boy divides its screen into tiles of 8×8 pixels. Within the tiles, only one color palette of four colors can be used. A total of eight different palettes can be stored. That is why the game is mainly rendered in shades of gray, with a highlight here and there in a color.

The game is now at an advanced stage. The creator has incorporated a menu, three different enemies and all ten levels from Episode 1 into the game. This consumes 123kB of the rom, so a lot does not fit anymore. The creator has already designed a sticker and box for the game, giving the impression that it was originally made for the console.