1 files changed, 135 insertions, 0 deletions
diff --git a/components/script/dom/xrreferencespace.rs b/components/script/dom/xrreferencespace.rs
new file mode 100644
index 00000000000..fb4f890e766
--- /dev/null
+++ b/components/script/dom/xrreferencespace.rs
@@ -0,0 +1,135 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use crate::dom::bindings::codegen::Bindings::XRReferenceSpaceBinding::XRReferenceSpaceMethods;
+use crate::dom::bindings::codegen::Bindings::XRReferenceSpaceBinding::XRReferenceSpaceType;
+use crate::dom::bindings::inheritance::Castable;
+use crate::dom::bindings::reflector::{reflect_dom_object, DomObject};
+use crate::dom::bindings::root::{Dom, DomRoot};
+use crate::dom::globalscope::GlobalScope;
+use crate::dom::xrrigidtransform::XRRigidTransform;
+use crate::dom::xrsession::{cast_transform, ApiPose, BaseTransform, XRSession};
+use crate::dom::xrspace::XRSpace;
+use dom_struct::dom_struct;
+use euclid::RigidTransform3D;
+use webxr_api::{self, Frame, Space};
+
+#[dom_struct]
+pub struct XRReferenceSpace {
+    xrspace: XRSpace,
+    offset: Dom<XRRigidTransform>,
+    ty: XRReferenceSpaceType,
+}
+
+impl XRReferenceSpace {
+    pub fn new_inherited(
+        session: &XRSession,
+        offset: &XRRigidTransform,
+        ty: XRReferenceSpaceType,
+    ) -> XRReferenceSpace {
+        XRReferenceSpace {
+            xrspace: XRSpace::new_inherited(session),
+            offset: Dom::from_ref(offset),
+            ty,
+        }
+    }
+
+    #[allow(unused)]
+    pub fn new(
+        global: &GlobalScope,
+        session: &XRSession,
+        ty: XRReferenceSpaceType,
+    ) -> DomRoot<XRReferenceSpace> {
+        let offset = XRRigidTransform::identity(global);
+        Self::new_offset(global, session, ty, &offset)
+    }
+
+    #[allow(unused)]
+    pub fn new_offset(
+        global: &GlobalScope,
+        session: &XRSession,
+        ty: XRReferenceSpaceType,
+        offset: &XRRigidTransform,
+    ) -> DomRoot<XRReferenceSpace> {
+        reflect_dom_object(
+            Box::new(XRReferenceSpace::new_inherited(session, &offset, ty)),
+            global,
+        )
+    }
+
+    pub fn space(&self) -> Space {
+        let base = match self.ty {
+            XRReferenceSpaceType::Local => webxr_api::BaseSpace::Local,
+            XRReferenceSpaceType::Viewer => webxr_api::BaseSpace::Viewer,
+            XRReferenceSpaceType::Local_floor => webxr_api::BaseSpace::Floor,
+            _ => panic!("unsupported reference space found"),
+        };
+        let offset = self.offset.transform();
+        Space { base, offset }
+    }
+}
+
+impl XRReferenceSpaceMethods for XRReferenceSpace {
+    /// https://immersive-web.github.io/webxr/#dom-xrreferencespace-getoffsetreferencespace
+    fn GetOffsetReferenceSpace(&self, new: &XRRigidTransform) -> DomRoot<Self> {
+        let offset = self.offset.transform().pre_transform(&new.transform());
+        let offset = XRRigidTransform::new(&self.global(), offset);
+        Self::new_offset(
+            &self.global(),
+            self.upcast::<XRSpace>().session(),
+            self.ty,
+            &offset,
+        )
+    }
+}
+
+impl XRReferenceSpace {
+    /// Get a transform that can be used to locate the base space
+    ///
+    /// This is equivalent to `get_pose(self).inverse()` (in column vector notation),
+    /// but with better types
+    pub fn get_base_transform(&self, base_pose: &Frame) -> Option<BaseTransform> {
+        let pose = self.get_pose(base_pose)?;
+        Some(pose.inverse().cast_unit())
+    }
+
+    /// Gets pose represented by this space
+    ///
+    /// The reference origin used is common between all
+    /// get_pose calls for spaces from the same device, so this can be used to compare
+    /// with other spaces
+    pub fn get_pose(&self, base_pose: &Frame) -> Option<ApiPose> {
+        let pose = self.get_unoffset_pose(base_pose)?;
+        let offset = self.offset.transform();
+        // pose is a transform from the unoffset space to native space,
+        // offset is a transform from offset space to unoffset space,
+        // we want a transform from unoffset space to native space,
+        // which is pose * offset in column vector notation
+        Some(pose.pre_transform(&offset))
+    }
+
+    /// Gets pose represented by this space
+    ///
+    /// Does not apply originOffset, use get_viewer_pose instead if you need it
+    pub fn get_unoffset_pose(&self, base_pose: &Frame) -> Option<ApiPose> {
+        match self.ty {
+            XRReferenceSpaceType::Local => {
+                // The eye-level pose is basically whatever the headset pose was at t=0, which
+                // for most devices is (0, 0, 0)
+                Some(RigidTransform3D::identity())
+            },
+            XRReferenceSpaceType::Local_floor => {
+                let native_to_floor = self
+                    .upcast::<XRSpace>()
+                    .session()
+                    .with_session(|s| s.floor_transform())?;
+                Some(cast_transform(native_to_floor.inverse()))
+            },
+            XRReferenceSpaceType::Viewer => {
+                Some(cast_transform(base_pose.pose.as_ref()?.transform))
+            },
+            _ => unimplemented!(),
+        }
+    }
+}