Input

Wyrd.Ecs.Input resolves physical keys and mouse buttons into named actions you define, strongly typed as your own enum. AddInput needs AddWindow called somewhere in the same chain, it reads events off PlatformSystem - but not necessarily first, construction order doesn’t matter.

Declaring actions and binding them

using Wyrd.Ecs.Input;
using SDL3;

public enum PlayerAction { Move, Jump }

var bindings = new BindingTable<PlayerAction>()
    .BindAxis2D(PlayerAction.Move, SDL.Scancode.W, SDL.Scancode.S, SDL.Scancode.A, SDL.Scancode.D)
    .Bind(PlayerAction.Jump, SDL.Scancode.Space);

var world = new WorldBuilder()
    .AddWindow("My Game", 1280, 720)
    .AddInput(bindings)
    .Build();

BindAxis2D composes four keys into one Vector2, each contributing +/-1 on its axis, clamped to unit length. Bind maps one or more keys or mouse buttons to a digital action. Both are additive across calls, Unbind removes a binding. An action is either digital or an axis, never both, binding it the other way throws until you Unbind first.

Note

Every Bind/BindAxis2D/Unbind overload above targets profile 0 by default. A profile parameter is there for more than one player, see Multi-Device.

Reading resolved state

public sealed partial class MovementSystem : QuerySystem
{
    [Resource] public IntentState<PlayerAction> Input { get; private set; }

    protected override IQuery DefineQuery(Query query) => query.With<Position>();

    public void Update(Time time, ref Position position)
    {
        if (Input.TryGet(PlayerAction.Move, out var move))
            position.X += move.Value.X * (float)time.Delta.TotalSeconds;
    }
}

IntentState<TAction> is a resource, IntentSystem<TAction> (registered by AddInput) republishes it fresh every tick. ActionState carries IsHeld, JustPressed, JustReleased, and Value (the resolved Vector2, UnitX for a held digital action, the composite for an axis). TryGet returns false for an action nothing ever bound, the indexer (Input[PlayerAction.Move]) throws instead, use whichever fits the call site.

Reading edges from a fixed-timestep system

JustPressed/JustReleased are recomputed fresh on every real world.Update() call, safe from a system running at the default cadence but not a [FixedTimestep] one, a fixed step doesn’t line up one-to-one with real calls, so it can miss an edge or double-count it. Use TickJustPressed/TickJustReleased instead, from a [FixedTimestep] system:

[FixedTimestep]
public sealed partial class JumpSystem : QuerySystem
{
    [Resource] public IntentState<PlayerAction> Input { get; private set; }

    protected override IQuery DefineQuery(Query query) => query.With<Velocity>();

    public void Update(Time time, ref Velocity velocity)
    {
        if (Input[PlayerAction.Jump].TickJustPressed) velocity.Y = JumpSpeed;
    }
}

They accumulate across however many real calls land inside one fixed step, then clear exactly once per step, so a fast frame’s burst of real calls before the next fixed step still registers the press.

Caution

Reading JustPressed/JustReleased from a [FixedTimestep] system is a compile error (WYRD011), naming TickJustPressed/TickJustReleased as the fix.

Mouse

Input.MousePosition;  // window coordinates, shared across every profile
Input.MouseDelta;     // this tick's movement, reset every tick
Input.WheelDelta;      // this tick's scroll, reset every tick

Read directly off IntentState<TAction>, not tied to any bound action.

Next

Audio for sound effects and music, Multi-Device for more than one keyboard or mouse, Remapping for saving player-customized bindings.