After familiarizing ourselves with the Atari 800’s graphics capabilities last week, today we’ll start to put it to use, implementing the “single-shot” version of the shooting gallery program we built for the Atari 2600. This should give us an apples-to-apples comparison for how the challenges we face change as we move from the Atari 2600 to its successor.
This implementation splits neatly into three parts, each corresponding to part of the graphics capabilities that both systems share: the playfield (rendering the score, the terrain, and the divider line between the score and the main play area), the players (the blaster and the targets), and the missiles (the player’s shot). Put all together, we get a pretty familiar scene:
It will make the most sense to tackle these three elements in that order; each of them uses the previous step as a reference for where things should go. This week we’ll focus on the playfield, with a particular eye to how playfield programming on the Atari 800 is an evolution of the way we programmed the playfield on the 2600. We’ve looked at both text and bitmap graphics on the Atari 800 before, but that was from the perspective of adapting a display from an old IBM PC program to the Commodore 64 and the Atari 800. Instead of treating it as a competitor to the C64, like last time, this time we will consider it more explicitly as a successor to the 2600.