Multi-Device

A BindingTable<TAction> supports more than one player through profile, a ProfileId everywhere its methods default to default (profile 0). Two players sharing a keyboard by key range (WASD vs. arrow keys) need nothing more than two BindAxis2D calls at different profiles, see Input. Two players each on their own physical keyboard need one more step: telling each profile which device is actually theirs.

Why profiles need device assignment

var bindings = new BindingTable<PlayerAction>()
    .BindAxis2D(profile: new ProfileId(0), PlayerAction.Move, SDL.Scancode.W, SDL.Scancode.S, SDL.Scancode.A, SDL.Scancode.D)
    .BindAxis2D(profile: new ProfileId(1), PlayerAction.Move, SDL.Scancode.W, SDL.Scancode.S, SDL.Scancode.A, SDL.Scancode.D);

Both profiles bind the same keys. Left unassigned, a profile merges every connected device of the relevant kind, so either keyboard pressing W satisfies both profiles at once, not what two separate keyboards are supposed to mean.

Assigning devices

bindings.AssignDevice(profile: new ProfileId(0), deviceId: firstKeyboardId)
        .AssignDevice(profile: new ProfileId(1), deviceId: secondKeyboardId);

Once a profile has an assigned device, it only reads from that device, or devices, AssignDevice is additive, call it again to also track a mouse alongside a keyboard for the same profile. UnassignDevice(profile) clears it back to merging every connected device.

Note

Where does a deviceId come from? Usually a DeviceChange.Connected event’s DeviceId (see Platform), captured during a “press a key to join” flow rather than hardcoded.

Reading per-profile state

Input.TryGet(PlayerAction.Move, out var player1Move, profile: new ProfileId(0));
Input.TryGet(PlayerAction.Move, out var player2Move, profile: new ProfileId(1));

Hot-plug during play

A disconnect clears that device’s held keys immediately, before the next tick resolves any action, a device dropping mid-press can’t leave an action stuck held. IntentSystem<TAction> handles this for every profile automatically, reacting to the disconnect itself (pausing, showing a reconnect prompt) still means reading DeviceChange yourself, see Platform.

Next

Remapping for saving player-customized bindings, device assignments aren’t part of what gets saved.