Flock
Get the daft flock home. A sheep-crossing arcade game built on hardware sprites — steer one sheep at a time across the lane and the stream, fill the fold, and mind the duck.
What You’ll Build
A farmyard arcade game in the lane-crossing tradition of Frogger and Freeway. One dim sheep at a time, you steer up from the field, across a lane of tractors and hay carts, over the stream by footbridge or hay bale, and into a pen in the fold. Fill every pen and the level is won. Lose a sheep — squashed, drowned, or carried off by the current — and the flock thins.
The road and the river play by opposite rules, and that opposition is the game: on the lane, touching a sprite kills you; on the stream, not touching one drowns you. Avoid, then ride. Same hardware, two meanings.
Why This Game?
Flock is built on the Amiga’s hardware sprites — the chip draws and moves your characters for free, no bitplane redrawing, no erasing. The sheep is a sprite. The tractor is a sprite. The hay bale you ride is a sprite. And the question every crossing turns on — did the sheep touch that? — is answered by hardware collision detection, the custom chipset feature this game teaches from both sides:
- Avoid-mode —
CLXDATsays sheep met tractor: she’s lost. - Ride-mode —
CLXDATsays sheep stands on bale: she’s safe, and the bale carries her.
Around that core the game layers everything a real arcade game needs, one unit at a time: joystick steering, sprite animation, deterministic traffic you learn to read, lives, score, a fold to fill, Paula sound, a title screen — and a rare black sheep worth risking everything for.
Skills You’ll Master
- Hardware sprites — data, position and control words, sprite DMA
- Sprite collision —
CLXCON/CLXDAT, in avoid and ride modes - Copper playfield composition — bands and per-band recolouring
- Joystick input — grid-step movement
- Deterministic hazards — lane choreography you read and time
- Game structure — lives, score, levels, state machine, Paula SFX
Prerequisites
The Meet the Machine primer — the 68000, the Copper, and the bitplane display. Flock picks up exactly where it left off.
You’ll need an emulator (FS-UAE, WinUAE or Emu198x), an assembler (vasm), and disk tools (amitools).
Unit roadmap
Arc 1 — Cross the Lane
A complete road-crossing game: the farmyard, a steerable sprite, deterministic traffic, avoid-mode collision, lives, the fold, score and sound.
Arc 2 — The River and the Flock
The rule flips: ride-mode collision on the stream, the diving duck, the cow, the black sheep, the nervous clock, and the finished game.