Specify that getViewerPose throws an error unless the frame come from a rAF call.

toji · toji · commit bef9369e0755 · 2019-02-22T15:42:35.000-08:00
diff --git a/index.bs b/index.bs
@@ -573,6 +573,7 @@ When an {{XRSession}} |session| receives updated [=viewer=] state from the [=/XR
   1. Let |callbacks| be a list of the entries in |session|'s [=list of animation frame callback=], in the order in which they were added to the list.
   1. Set |session|'s [=list of animation frame callbacks=] to the empty list.
   1. Set |frame|'s [=active=] boolean to <code>true</code>.
+  1. Set |frame|'s [=animationFrame=] boolean to <code>true</code>.
   1. For each entry in |callbacks|, in order:
     1. If the entry's [=cancelled=] boolean is <code>true</code>, continue to the next entry.
     1. [=Invoke the Web IDL callback function=], passing |now| and |frame| as the  arguments
@@ -636,7 +637,7 @@ An {{XRFrame}} represents a snapshot of the state of all of the tracked objects
 };
 </pre>
 
-Each {{XRFrame}} has a <dfn for="XRFrame">active</dfn> boolean which is initially set to <code>false</code>.
+Each {{XRFrame}} has a <dfn for="XRFrame">active</dfn> boolean which is initially set to <code>false</code>, and an <dfn for="XRFrame">animationFrame</dfn> boolean which is initially set to <code>false</code>.
 
 The <dfn attribute for="XRFrame">session</dfn> attribute returns the {{XRSession}} that produced the {{XRFrame}}.
 
@@ -645,6 +646,7 @@ The <dfn attribute for="XRFrame">session</dfn> attribute returns the {{XRSession
 When the <dfn method for="XRFrame">getViewerPose(|referenceSpace|)</dfn> method is invoked, the user agent MUST run the following steps:
 
   1. If the {{XRFrame}}'s [=active=] boolean is <code>false</code>, throw a {{InvalidStateError}} and abort these steps.
+  1. If the {{XRFrame}}'s [=animationFrame=] boolean is <code>false</code>, throw a {{InvalidStateError}} and abort these steps.
   1. Let |session| be the {{XRFrame}}'s {{XRFrame/session}} object.
   1. If |referenceSpace|'s [=XRSpace/session=] does not equal |session|, throw a {{InvalidStateError}} and abort these steps.
   1. If the [=viewer=]'s pose cannot be determined relative to |referenceSpace|, return <code>null</code>
diff --git a/input-explainer.md b/input-explainer.md
@@ -87,7 +87,7 @@ function onSessionStarted(session) {
 }
 ```
 
-All three events are `XRInputSourceEvent` events. When fired the event's `inputSource` attribute will contain the `XRInputSource` that produced the event. The event's `frame` attribute will contain a valid `XRFrame` that can be used to call `getPose()` at the time the selection event occurred. The frame's `getViewerPose()` function will return null.
+All three events are `XRInputSourceEvent` events. When fired the event's `inputSource` attribute will contain the `XRInputSource` that produced the event. The event's `frame` attribute will contain a valid `XRFrame` that can be used to call `getPose()` at the time the selection event occurred. Calling the frame's `getViewerPose()` method will throw an `InvalidState` error. (The viewer's pose can still be queried by passing the `XRSession`'s `viewerSpace` to `XRFrame.getPose()`.)
 
 ### Transient input sources
 Some input sources are only be added to the list of input sources while an action is occurring. For example, those with an `targetRayMode` of 'screen' or those with `targetRayMode` of 'gaze' which are triggered by a voice command. In these cases, `XRInputSource` is only present in the array returned by `getInputSources()` during the lifetime of the action. In this circumstance, the order of events is as follows:

Original file line number	Diff line number	Diff line change
`@@ -87,7 +87,7 @@ function onSessionStarted(session) {`
`87`	`87`	`}`
`88`	`88`	```
`89`	`89`
`90`		-All three events are `XRInputSourceEvent` events. When fired the event's `inputSource` attribute will contain the `XRInputSource` that produced the event. The event's `frame` attribute will contain a valid `XRFrame` that can be used to call `getPose()` at the time the selection event occurred. The frame's `getViewerPose()` function will return null.
	`90`	+All three events are `XRInputSourceEvent` events. When fired the event's `inputSource` attribute will contain the `XRInputSource` that produced the event. The event's `frame` attribute will contain a valid `XRFrame` that can be used to call `getPose()` at the time the selection event occurred. Calling the frame's `getViewerPose()` method will throw an `InvalidState` error. (The viewer's pose can still be queried by passing the `XRSession`'s `viewerSpace` to `XRFrame.getPose()`.)
`91`	`91`
`92`	`92`	`### Transient input sources`
`93`	`93`	Some input sources are only be added to the list of input sources while an action is occurring. For example, those with an `targetRayMode` of 'screen' or those with `targetRayMode` of 'gaze' which are triggered by a voice command. In these cases, `XRInputSource` is only present in the array returned by `getInputSources()` during the lifetime of the action. In this circumstance, the order of events is as follows: