Support grip spaces in WebXR

components/script/dom/webidls/XRInputSource.webidl

@@ -21,6 +21,6 @@ interface XRInputSource {
   readonly attribute XRHandedness handedness;
   // [SameObject] readonly attribute XRTargetRayMode targetRayMode;
   [SameObject] readonly attribute XRSpace targetRaySpace;
-  // [SameObject] readonly attribute XRSpace? gripSpace;
+  [SameObject] readonly attribute XRSpace? gripSpace;
   // [SameObject] readonly attribute Gamepad? gamepad;
 };

components/script/dom/xrinputsource.rs

@@ -18,10 +18,12 @@ use webxr_api::{Handedness, InputId, InputSource};
 pub struct XRInputSource {
     reflector: Reflector,
     session: Dom<XRSession>,
-    #[ignore_malloc_size_of = "Defined in rust-webvr"]
+    #[ignore_malloc_size_of = "Defined in rust-webxr"]
     info: InputSource,
-    #[ignore_malloc_size_of = "Defined in rust-webvr"]
+    #[ignore_malloc_size_of = "Defined in rust-webxr"]
     target_ray_space: MutNullableDom<XRSpace>,
+    #[ignore_malloc_size_of = "Defined in rust-webxr"]
+    grip_space: MutNullableDom<XRSpace>,
 }
 
 impl XRInputSource {
@@ -31,6 +33,7 @@ impl XRInputSource {
             session: Dom::from_ref(session),
             info,
             target_ray_space: Default::default(),
+            grip_space: Default::default(),
         }
     }
 
@@ -65,7 +68,19 @@ impl XRInputSourceMethods for XRInputSource {
     fn TargetRaySpace(&self) -> DomRoot<XRSpace> {
         self.target_ray_space.or_init(|| {
             let global = self.global();
-            XRSpace::new_inputspace(&global, &self.session, &self)
+            XRSpace::new_inputspace(&global, &self.session, &self, false)
         })
     }
+
+    /// https://immersive-web.github.io/webxr/#dom-xrinputsource-gripspace
+    fn GetGripSpace(&self) -> Option<DomRoot<XRSpace>> {
+        if self.info.supports_grip {
+            Some(self.target_ray_space.or_init(|| {
+                let global = self.global();
+                XRSpace::new_inputspace(&global, &self.session, &self, true)
+            }))
+        } else {
+            None
+        }
+    }
 }

components/script/dom/xrspace.rs

@@ -19,6 +19,8 @@ pub struct XRSpace {
     eventtarget: EventTarget,
     session: Dom<XRSession>,
     input_source: MutNullableDom<XRInputSource>,
+    /// If we're an input space, are we an aim space or a grip space?
+    is_grip_space: bool,
 }
 
 impl XRSpace {
@@ -27,14 +29,20 @@ impl XRSpace {
             eventtarget: EventTarget::new_inherited(),
             session: Dom::from_ref(session),
             input_source: Default::default(),
+            is_grip_space: false,
         }
     }
 
-    fn new_inputspace_inner(session: &XRSession, input: &XRInputSource) -> XRSpace {
+    fn new_inputspace_inner(
+        session: &XRSession,
+        input: &XRInputSource,
+        is_grip_space: bool,
+    ) -> XRSpace {
         XRSpace {
             eventtarget: EventTarget::new_inherited(),
             session: Dom::from_ref(session),
             input_source: MutNullableDom::new(Some(input)),
+            is_grip_space,
         }
     }
 
@@ -42,9 +50,10 @@ impl XRSpace {
         global: &GlobalScope,
         session: &XRSession,
         input: &XRInputSource,
+        is_grip_space: bool,
     ) -> DomRoot<XRSpace> {
         reflect_dom_object(
-            Box::new(XRSpace::new_inputspace_inner(session, input)),
+            Box::new(XRSpace::new_inputspace_inner(session, input, is_grip_space)),
             global,
             XRSpaceBinding::Wrap,
         )
@@ -72,7 +81,11 @@ impl XRSpace {
                 .iter()
                 .find(|i| i.id == id)
                 .expect("no input found");
-            frame.target_ray_origin.map(cast_transform)
+            if self.is_grip_space {
+                frame.grip_origin.map(cast_transform)
+            } else {
+                frame.target_ray_origin.map(cast_transform)
+            }
         } else {
             unreachable!()
         }