Rattler Race (Entertainment Pack, snake.exe)
lib/apps.js id snake. It is GDI-only: every drawing operation is a
GetDC + PatBlt/BitBlt + ReleaseDC, with no DirectDraw and no frame
boundary.
Steering, by A/B (2026-10-10)
--tick-ms-per-batch=20, default budget. F2 at batch 100 shows the "ROOM 01"
card, and the field is live by 303. The snake enters at the bottom heading
up, toward a red bar.
Two runs of one command differ only in a Left press (keydown:37) at batch
420. Captures up to 420 are byte-identical.
- Run A: the snake turns left under the bar and is alive at 520.
- Run B: it runs into the bar, a life is lost, and "ROOM 01" is back by 520.
Step counter
One movement step is one tail-erase PatBlt (returns to 0x01002a18). There
are 39 in 2.34 guest-s at both a 20 ms and a 10 ms tick, so 16.7 steps per
guest-second is the game's own clock. The head BitBlt (0x01003be2) and
GetDC counts change with the tick (they are redraws), so do not count those.
The erase is skipped while the snake is still growing, so the count runs a
little low right after a (re)spawn.
Evidence: scratch/runs/20261010T0630Z-snake-control-steps.