Mission Genocide, originally titled ZTB (for Zap the Bastards and later Badstars ) and still named thusly on the loading screen and elsewhere, is a game by Paul Shirley (a.k.a. Rotovision) for the old generation of CPCs, released on both tape and disc and compatible with all models.
The game is mentioned fairly often for its smooth and pixel-perfect vertical scrolling, which is done in hardware using the CRTC. It is also notable in using a very fast method of plotting sprites, which takes advantage of the 16 colours of graphical Mode 0 by using 3 for sprites, Ink 0 for transparency, and the remaining 12 as 3 duplicate sets of 4 colours for the background: the roles of these Inks are arranged according to binary logic so that sprites can be ORd onto the background and ANDed to remove them, a method that is much faster and more memory-efficient than storing a sprite and a masking table and then performing all the relevant masking operations between these and the background. The name Rotovision has been used to refer to either of these techniques, but this seems actually to be an alias of the game’s programmer Paul Shirley: different ROMs of the game display one of these two names.
Shirley later ported Mission Genocide from the CPC to the Commodore 64, although he says that version is “not worth the tape it's saved on”, unlike the “technically impressive” original version.
- Mission genocide (Firebird Software) (199 Silver Range) (1987) (Standard Jewel Case).cdt.zip (CDT for Emulators)
- Amstrad Computer User July of 1987:
- Amstrad Action October of 1987: Pages 40-41