Doom Spectrum 128

Doom Spectrum 128 is an AI assisted port of Kweepa's excellent Commodore 64 Doom demake to the Spectrum 128k.

Play through all 8 levels of Shareware Doom. Built for the Spectrum 128 family and compatibles, but plays nicely with accelerated Z80 CPUs.

Controls

Action	Keys
Movement	W, A, S, D
Turning	J, L
Shoot	Space
Select weapon	1, 2, 3, 4, 5
Interact	K
Map	M
Cheats	IDKFA, IDDQD, IDCLEV

Technical 
To adapt Doom64 to the Spectrum some compromises were required, no text mode character map means every 8x8 character block needs to be copied to the screen, and no sprites mean weapon animation is tied to the 3D render-rate. The viewport is necessarily a little smaller (32 x 24) vs (40 x 25), and the lack of a 'brown' makes the games colours a little Spectrum-y.

The extra space that the 128k Spectrum provides allows for some more graphics, music, and Z80 centric lookup tables that keep the game ticking along at a decent pace. The bitmap screen also allows for some sub-block graphics (4x4) for billboards objects, and the sky background has been ported.

One trick that's used is that only the changed portions of the view are drawn to the screen, because a lot of the screen content is the same between frames, this saves a lot of pixel copying especially in corridors! 

A 48k version is possible but would require cutting both content and game/render logic and would require loading between each level.

Credits
Game assets and logic are entirely from Doom64 by Kweepa. The distant mip maps were slightly edited to make them more readable on the Spectrum. Music is converted from the original Doom shareware via Autosiril. Embedded PT3 player by S V Bulba.  ZX0 compression by Einar Saukas. Generative AI was used to port the splash screen and crater map images from the original Doom.

In memory of Alan and Thomas Smith.

If you enjoyed this, and wanted to contribute, please make a donation to Kweepa's tip-jar project.

Sourcecode
Github: https://github.com/CordySmith/DoomSpectrum128k