trackable-pointer.md 3.3KB
TrackablePointer
A trackable that represents a pointer tracked by a PointerTracker.
A pointer is an abstraction that represents an instance of user input that targets one or more coordinates on a screen. For example, each point of contact between fingers and a multitouch screen generate a pointer. Devices such as a mouse and a pen/stylus also generate pointers.
Pointers are located in the viewport. Their positions are given in space units. By default, space units are normalized units, which range from -1 to +1. In normalized space, the center of the viewport is at (0,0). The top right corner is at (1,1). The bottom left corner is at (-1,-1).
Since: 0.4.0
Properties
id
pointer.id: number, read-only
A unique identifier assigned to this pointer.
phase
pointer.phase: string, read-only
The phase of the pointer. It’s one of the following strings:
"began": the tracking began in this frame (e.g., a finger has just touched the screen)"stationary": the user did not move the pointer in this frame"moved": the user moved the pointer in this frame"ended": the tracking ended in this frame (e.g., a finger has just been lifted from the screen)"canceled": the tracking was canceled in this frame (e.g., the page has just lost focus)
position
pointer.position: Vector2, read-only
The current position of the pointer, given in space units. See also: PointerTracker.space, Viewer.raycast, Viewport.convertToPixels.
initialPosition
pointer.initialPosition: Vector2, read-only
The position of the pointer when its tracking began.
deltaPosition
pointer.deltaPosition: Vector2, read-only
The difference between the position of the pointer in this and in the previous frame.
velocity
pointer.velocity: Vector2, read-only
The current velocity of the pointer, given in space units per second. You can get the current speed of motion by calculating the magnitude of this vector.
duration
pointer.duration: number, read-only
The elapsed time, in seconds, since the tracking of this pointer began. You can check if this pointer represents a tap by comparing its duration to a threshold at the "ended" phase. Example: isTap = pointer.phase == "ended" && pointer.duration < 0.25.
movementLength
pointer.movementLength: number, read-only
How much this pointer has moved, in space units, since its tracking began. You can get the average speed of motion by calculating the ratio movementLength / duration.
movementDuration
pointer.movementDuration: number, read-only
The total time, in seconds, in which this pointer has moved. You can get the average speed of motion, excluding the times in which this pointer remained stationary, by calculating the ratio movementLength / movementDuration.
isPrimary
pointer.isPrimary: boolean, read-only
Whether or not this is the primary pointer among all pointers of this kind. A typical primary pointer is that of a finger that touches the screen when no other fingers are touching it.
kind
pointer.kind: string, read-only
The kind of device that originated this pointer. Typically "touch", "mouse" or "pen".