Function: createUiInteractionEcsSystem()

createUiInteractionEcsSystem(pointerSource, renderContext): EcsSystem<[UiInteractableEcsComponent, RectTransformDefaultedOptions]>

Defined in: ui/systems/ui-interaction-system.ts:164

Creates a system that runs the pointer interaction state machine over every UiInteractableEcsComponent: hover enter/exit, a captured press (from a pointer-down edge on the element until its matching up edge, regardless of whether the pointer stays over it), drag start/move/end once the press exceeds dragThreshold, and onInvoke on a release inside that didn't turn into a drag.

State is derived fresh from each tick's facts (this tick's raycast hit, this tick's button edges) rather than advanced one transition at a time, so a pointer enter-and-press or press-and-release landing in the same tick - which a real pointer source can genuinely report, since edges are only ever sampled once per tick - still resolves correctly instead of silently dropping the click: an enter-and-press tick raises both onPointerEnter and onPointerDown and goes straight to a captured press without ever being observed as merely hovered, and a press-and-release tick still raises onInvoke because the down and up edges are read from separate per-tick sets rather than a single "is held" flag that a same-tick press-then-release would never show as true.

Also applies the canvas policy that the pointer hovering an interactable focuses it too (via setUiFocus), so the focus highlight follows the mouse the same way it follows gamepad navigation.

An element whose own interactable is true but sits under a CanvasGroupEcsComponent ancestor with interactable: false cannot begin a new press or gain focus by hover - see resolveCanvasGroupState

• the same way it couldn't if interactable were false on the element itself.

Must be registered after createUiRaycastEcsSystem (it reads CanvasEcsComponent.hoveredEntity).

Parameters

pointerSource

UiPointerSource

The pointer source driving this state machine.

renderContext

RenderContext

The render context canvases' cameras render through, used to convert the pointer position for drag-threshold checks.

Returns

EcsSystem<[UiInteractableEcsComponent, RectTransformDefaultedOptions]>

The UI interaction ECS system.