[SecureContext, Exposed=Window] interface XR : EventTarget {
  // Methods
  Promise<XRDevice?> requestDevice();

  // Events
  attribute EventHandler ondevicechange;
};

[SecureContext]
partial interface Navigator {
  [SameObject] readonly attribute XR xr;
};

[SecureContext, Exposed=Window] interface XRDevice : EventTarget {
  // Methods
  Promise<void> supportsSession(optional XRSessionCreationOptions options);
  Promise<XRSession> requestSession(optional XRSessionCreationOptions options);
};

dictionary XRSessionCreationOptions {
  boolean exclusive = false;
  XRPresentationContext outputContext;
};

[SecureContext, Exposed=Window] interface XRSession : EventTarget {
  // Attributes
  readonly attribute XRDevice device;
  readonly attribute boolean exclusive;
  readonly attribute XRPresentationContext outputContext;

  attribute double depthNear;
  attribute double depthFar;
  attribute XRLayer baseLayer;

  // Methods
  Promise<XRFrameOfReference> requestFrameOfReference(XRFrameOfReferenceType type, optional XRFrameOfReferenceOptions options);

  long requestAnimationFrame(XRFrameRequestCallback callback);
  void cancelAnimationFrame(long handle);

  Promise<void> end();

  // Events
  attribute EventHandler onblur;
  attribute EventHandler onfocus;
  attribute EventHandler onresetpose;
  attribute EventHandler onend;
};

callback XRFrameRequestCallback = void (DOMHighResTimeStamp time, XRPresentationFrame frame);

[SecureContext, Exposed=Window] interface XRPresentationFrame {
  readonly attribute FrozenArray<XRView> views;

  XRDevicePose? getDevicePose(XRCoordinateSystem coordinateSystem);
};

[SecureContext, Exposed=Window] interface XRCoordinateSystem : EventTarget {
  Float32Array? getTransformTo(XRCoordinateSystem other);
};

enum XRFrameOfReferenceType {
  "headModel",
  "eyeLevel",
  "stage",
};

dictionary XRFrameOfReferenceOptions {
  boolean disableStageEmulation = false;
  double stageEmulationHeight = 0.0;
};

[SecureContext, Exposed=Window] interface XRFrameOfReference : XRCoordinateSystem {
  readonly attribute XRStageBounds? bounds;
  readonly attribute double emulatedHeight;

  attribute EventHandler onboundschange;
};

[SecureContext, Exposed=Window] interface XRStageBounds {
  readonly attribute FrozenArray<XRStageBoundsPoint> geometry;
};

[SecureContext, Exposed=Window] interface XRStageBoundsPoint {
  readonly attribute double x;
  readonly attribute double z;
};

enum XREye {
  "left",
  "right"
};

[SecureContext, Exposed=Window] interface XRView {
  readonly attribute XREye eye;
  readonly attribute Float32Array projectionMatrix;
};

[SecureContext, Exposed=Window] interface XRViewport {
  readonly attribute long x;
  readonly attribute long y;
  readonly attribute long width;
  readonly attribute long height;
};

[SecureContext, Exposed=Window] interface XRDevicePose {
  readonly attribute Float32Array poseModelMatrix;

  Float32Array getViewMatrix(XRView view);
};

[SecureContext, Exposed=Window] interface XRLayer {};

typedef (WebGLRenderingContext or
         WebGL2RenderingContext) XRWebGLRenderingContext;

dictionary XRWebGLLayerInit {
  boolean antialias = true;
  boolean depth = false;
  boolean stencil = false;
  boolean alpha = true;
  boolean multiview = false;
  double framebufferScaleFactor;
};

[SecureContext, Exposed=Window, Constructor(XRSession session,
             XRWebGLRenderingContext context,
             optional XRWebGLLayerInit layerInit)]
interface XRWebGLLayer : XRLayer {
  // Attributes
  readonly attribute XRWebGLRenderingContext context;

  readonly attribute boolean antialias;
  readonly attribute boolean depth;
  readonly attribute boolean stencil;
  readonly attribute boolean alpha;
  readonly attribute boolean multiview;

  readonly attribute WebGLFramebuffer framebuffer;
  readonly attribute unsigned long framebufferWidth;
  readonly attribute unsigned long framebufferHeight;

  // Methods
  XRViewport? getViewport(XRView view);
  void requestViewportScaling(double viewportScaleFactor);
};

partial dictionary WebGLContextAttributes {
    XRDevice compatibleXRDevice = null;
};

partial interface mixin WebGLRenderingContextBase {
    Promise<void> setCompatibleXRDevice(XRDevice device);
};

[SecureContext, Exposed=Window] interface XRPresentationContext {
  readonly attribute HTMLCanvasElement canvas;
};

[SecureContext, Exposed=Window, Constructor(DOMString type, XRSessionEventInit eventInitDict)]
interface XRSessionEvent : Event {
  readonly attribute XRSession session;
};

dictionary XRSessionEventInit : EventInit {
  required XRSession session;
};

[SecureContext, Exposed=Window, Constructor(DOMString type, XRCoordinateSystemEventInit eventInitDict)]
interface XRCoordinateSystemEvent : Event {
  readonly attribute XRCoordinateSystem coordinateSystem;
};

dictionary XRCoordinateSystemEventInit : EventInit {
  required XRCoordinateSystem coordinateSystem;
};