controller.rs — Gamepad Input

Runs a background listener for gamepad input using the gilrs library, translating button and axis events into UDP packets sent to the rover. All dispatching is gated on the current mode (drive vs. pickup) and whether the relevant manual mode is active. 
 Modes 
 The controller operates in one of two top-level modes, toggled with the Start button: 
 Mode Active when Controls Drive pickup_mode = false Left stick (forward/turn), triggers (brake) Pickup pickup_mode = true Both sticks (X/Y/rotate/flick), D-pad (Z), triggers (gripper) 
 Within each mode, the Select button toggles the relevant manual mode ( drive_manual_mode or arm_manual_mode ). Commands are silently suppressed when the associated manual mode is inactive. 
 Threads 
 Three concurrent threads are spawned on startup: 
 start_controller_listener() — Entry point. Spawns all threads and owns the shared CommandState . 
 Event thread — Polls gilrs at ~125 Hz (8 ms sleep) and routes each Event to the appropriate handler. Holds the shared mutex only for the duration of each state update. 
 Heartbeat thread — Wakes every 2 seconds and re-sends the current state (drive axes + brake, or arm + brake). Ensures the rover never silently drifts from its commanded state if packets are dropped. 
 Ramp threads — Spawned on demand when a ramped button (D-pad up/down, left/right trigger in pickup mode) is pressed. Ticks at ~60 Hz and increments the axis value from 0.0 toward ±1.0 over RAMP_DURATION_SECS (1.0 s). The thread exits when the direction is set back to 0.0 on button release. 
 Button mapping 
 Button Drive mode Pickup mode Start Toggle pickup mode Toggle pickup mode Select Toggle drive_manual_mode Toggle arm_manual_mode Left trigger (LB) Toggle latching brake Ramp gripper speed → close (−1.0) Right trigger (RB) — Ramp gripper speed → open (+1.0) Left trigger 2 (LT) Toggle latching brake — Right trigger 2 (RT) Momentary brake (hold) — D-pad up — Ramp Z → up (+1.0) D-pad down — Ramp Z → down (−1.0) 
 Axis mapping 
 Axis Drive mode Pickup mode Left stick Y Forward / backward Flick Left stick X Turn Rotate Right stick X — End effector X (left/right) Right stick Y — End effector Y (forward/backward) 
 All analog axes pass through a deadzone ( ±0.05 ) and are only dispatched when the change from the last-sent value exceeds AXIS_CHANGE_THRESHOLD (0.05). Z and gripper speed are not axis-driven — they are ramped from button presses. 
 Packets sent 
 Packet When BasestationManualDrive Drive mode, on axis change or heartbeat BasestationManualBrake Drive mode, on brake toggle/press/release or heartbeat; also sent continuously (engaged) during pickup heartbeat BasestationManualArmMovement Pickup mode, on any arm state change or heartbeat 
 All values are scaled from [−1.0, 1.0] to the full sint32 range before transmission. 
 Constants 
 Constant Value Purpose AXIS_CHANGE_THRESHOLD 0.05 Deadzone boundary and minimum delta before a packet is sent HEARTBEAT_INTERVAL 2 s How often state is re-sent without an input event RAMP_DURATION_SECS 1.0 s Time for a ramped axis to travel from 0.0 to ±1.0 RAMP_TICK_MS 16 ms Ramp thread tick interval (~60 Hz) MOMENTARY_BRAKE_DURATION 500 ms Defined but unused — auto-release was commented out