Entry 62

Kite's stumbles: a round DualSense stick against a DualShock 2's threshold

2026-09-23uitest

Filescrates/piney-game/src/input.rscrates/piney-game/src/main.rs

The user played Mac Anu with a DualSense and reported:

• Kite's running breaks while the camera turns;
• he stalls and then keeps moving;
• it happens when the stick is pushed fully north-west.

Ruling out the game logic

A probe fed stick bytes through piney-input's ccPad::Read into the world:

• Clean input. A steady full north-west (0, 0), with or without the camera turning at full speed, runs steadily for every frame.
• Noisy input. The same with a few units of noise, but at (30, 30) instead of the corner: Kite switched between the run act (5) and the walk act (6) nearly every frame. pow_l wobbled between 211 and 238, across the run threshold, and the speed stayed 27.5 throughout.

So the logic, which the eemu checks already match to the game, does what the game does. The input it was given was the problem.

The cause

• The game's scale. SetAnalogStick measures the stick's strength as 255 over 80 steps past its dead zone, and the run/walk choice sits high on that scale.
• How a DualShock 2 reports. Its pots saturate before its round gate stops the stick, so a full push, diagonals included, reads at or near both axes' ends.
• How a DualSense reports. A modern round stick pushed fully diagonal reaches only about 0.7 per axis. That is (38, 38) as bytes, a strength on or below the threshold, so small movements, like the thumb shifting as the other thumb turns the camera, tip it between walking and running.
• gilrs made it worse. Its default filters apply a radial dead zone that rescales both axes, drop changes under 0.01, and can insert a zero for one axis on their own. The game applies its own dead zone after them.

The fix

• The stick's radius. input::square_stick carries the stick's radius to the square: the vector is scaled so that its larger axis equals its length, at most 1. A full push in any direction then reaches the corner, as on a DualShock 2. Straight pushes, half pushes along an axis and the centre are unchanged.
• No gilrs filters. gilrs is built with its default filters off. The stick values are raw, and only the game's dead zone applies.
• A diagnostic. --pad-log FILE writes every gamepad gilrs sees, then one line per game frame: the chosen pad's axes as gilrs gives them, the bytes passed on, the decoded direction and strength, and the mode's status. In The World the status now includes Kite's act and speed.

Checked

• Unit test. a_full_diagonal_reaches_the_corner: a round stick at full north-west becomes bytes (0, 0) and strength 255, while straight pushes, half pushes and the centre keep their values.
• The rest. piney-game has 11 tests, all passing; clippy and fmt are clean.
• Not yet on the controller. It is not confirmed on the user's DualSense; the pad log is there for that.