XRRigidTransform()

The XRRigidTransform() constructor creates a new XRRigidTransform object, representing the position and orientation of a point or object. Among other things, XRRigidTransform is used when providing a transform to translate between coordinate systems across spaces.

Syntax

new XRRigidTransform()
new XRRigidTransform(position)
new XRRigidTransform(position, orientation)

Parameters

position Optional

An object which specifies the coordinates at which the point or object is located. These dimensions are specified in meters. If this parameter is left out or is invalid,  the position used is assumed to be {x: 0, y: 0, z: 0, w: 1}. w must always be 1.

orientation Optional

An object which specifies the direction in which the object is facing. The default value for orientation is {x: 0, y: 0, z: 0, w: 1}. The specified orientation gets normalized if it's not already.

Return value

A new XRRigidTransform object which has been initialized to represent a transform matrix that would adjust the position and orientation of an object from the origin to the specified position and facing in the direction indicated by orientation.

Exceptions

TypeError

The value of the w coordinate in the specified position is not 1.0.

Examples

In this example, the beginning of the animation of a scene is shown, starting with a request for a reference space of a given type, then shifting the coordinate system based on a transform before requesting the first animation frame.

let animationFrameRequestID = 0;

xrSession.requestReferenceSpace("local-floor")
.then((refSpace) => {
  xrReferenceSpace = refSpace.getOffsetReferenceSpace(
        new XRRigidTransform(viewerPosition, viewerOrientation));
  animationFrameRequestID = xrSession.requestAnimationFrame(drawFrame);
});

After requesting a reference space of type local-floor, the returned promise is eventually resolved, at which time we receive a new reference space object, refSpace. After creating an XRRigidTransform from the viewer's initial position and orientation, we pass the new transform into getOffsetReferenceSpace() to create another reference space, now offset so that its origin is located at the same place in space as the coordinates given by viewerPosition, with the orientation also revised in the same fashion.

Then requestAnimationFrame() is called to ask for a new animation frame to draw into. The drawFrame() callback will be executed when the system is ready to draw the next frame.

You can find more examples in Movement, orientation, and motion.

Specifications

Specification
WebXR Device API
# dom-xrrigidtransform-xrrigidtransform

Browser compatibility

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