Add XRSpace::get_viewer_pose()

4 files changed, 103 insertions, 0 deletions

diff --git a/components/script/dom/xrreferencespace.rs b/components/script/dom/xrreferencespace.rs
index a24ab48d0c1..1c137d575ce 100644
--- a/components/script/dom/xrreferencespace.rs
+++ b/components/script/dom/xrreferencespace.rs
@@ -4,6 +4,7 @@
 
 use crate::dom::bindings::codegen::Bindings::XRReferenceSpaceBinding;
 use crate::dom::bindings::codegen::Bindings::XRReferenceSpaceBinding::XRReferenceSpaceMethods;
+use crate::dom::bindings::inheritance::Castable;
 use crate::dom::bindings::reflector::reflect_dom_object;
 use crate::dom::bindings::root::{DomRoot, MutDom};
 use crate::dom::dompointreadonly::DOMPointReadOnly;
@@ -11,7 +12,10 @@ use crate::dom::window::Window;
 use crate::dom::xrrigidtransform::XRRigidTransform;
 use crate::dom::xrsession::XRSession;
 use crate::dom::xrspace::XRSpace;
+use crate::dom::xrstationaryreferencespace::XRStationaryReferenceSpace;
 use dom_struct::dom_struct;
+use euclid::Transform3D;
+use webvr_traits::WebVRFrameData;
 
 #[dom_struct]
 pub struct XRReferenceSpace {
@@ -64,3 +68,33 @@ impl XRReferenceSpaceMethods for XRReferenceSpace {
         self.transform.get()
     }
 }
+
+impl XRReferenceSpace {
+    /// Gets viewer pose represented by this space
+    pub fn get_viewer_pose(&self, base_pose: &WebVRFrameData) -> Transform3D<f64> {
+        let pose = self.get_pose(base_pose);
+
+        // This may change, see https://github.com/immersive-web/webxr/issues/567
+        let offset = self.transform.get().matrix();
+        // XXXManishearth we can directly compute the inverse from the transform parameters
+        // (and perhaps cache it)
+        // XXXManishearth we can also optimize for the unset/identity offset case
+        let inverse = offset
+            .inverse()
+            .expect("rigid transforms are always invertible");
+        inverse.pre_mul(&pose)
+    }
+
+    /// Gets pose represented by this space
+    ///
+    /// Does not apply originOffset, use get_viewer_pose instead if you need it
+    pub fn get_pose(&self, base_pose: &WebVRFrameData) -> Transform3D<f64> {
+        if let Some(stationary) = self.downcast::<XRStationaryReferenceSpace>() {
+            stationary.get_pose(base_pose)
+        } else {
+            // non-subclassed XRReferenceSpaces exist, obtained via the "identity"
+            // type. The pose does not depend on the base pose.
+            Transform3D::identity()
+        }
+    }
+}
diff --git a/components/script/dom/xrrigidtransform.rs b/components/script/dom/xrrigidtransform.rs
index 3f726475517..2999ce7a1b1 100644
--- a/components/script/dom/xrrigidtransform.rs
+++ b/components/script/dom/xrrigidtransform.rs
@@ -3,6 +3,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
 use crate::dom::bindings::codegen::Bindings::DOMPointBinding::DOMPointInit;
+use crate::dom::bindings::codegen::Bindings::DOMPointReadOnlyBinding::DOMPointReadOnlyBinding::DOMPointReadOnlyMethods;
 use crate::dom::bindings::codegen::Bindings::XRRigidTransformBinding;
 use crate::dom::bindings::codegen::Bindings::XRRigidTransformBinding::XRRigidTransformMethods;
 use crate::dom::bindings::error::Fallible;
@@ -12,6 +13,7 @@ use crate::dom::bindings::root::{Dom, DomRoot};
 use crate::dom::dompointreadonly::DOMPointReadOnly;
 use crate::dom::window::Window;
 use dom_struct::dom_struct;
+use euclid::{Rotation3D, Transform3D};
 
 #[dom_struct]
 pub struct XRRigidTransform {
@@ -65,6 +67,7 @@ impl XRRigidTransform {
     ) -> Fallible<DomRoot<Self>> {
         let global = window.global();
         let position = DOMPointReadOnly::new_from_init(&global, &position);
+        // XXXManishearth normalize this
         let orientation = DOMPointReadOnly::new_from_init(&global, &orientation);
         Ok(XRRigidTransform::new(window, &position, &orientation))
     }
@@ -80,3 +83,21 @@ impl XRRigidTransformMethods for XRRigidTransform {
         DomRoot::from_ref(&self.orientation)
     }
 }
+
+impl XRRigidTransform {
+    pub fn matrix(&self) -> Transform3D<f64> {
+        // XXXManishearth compute this during initialization
+        let translate = Transform3D::create_translation(
+            self.position.X(),
+            self.position.Y(),
+            self.position.Z(),
+        );
+        let rotation = Rotation3D::unit_quaternion(
+            self.orientation.X(),
+            self.orientation.Y(),
+            self.orientation.Z(),
+            self.orientation.W(),
+        );
+        translate.pre_mul(&rotation.to_transform())
+    }
+}
diff --git a/components/script/dom/xrspace.rs b/components/script/dom/xrspace.rs
index e0d4ce75cf3..95ebb2625b3 100644
--- a/components/script/dom/xrspace.rs
+++ b/components/script/dom/xrspace.rs
@@ -3,12 +3,16 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
 use crate::dom::bindings::codegen::Bindings::XRSpaceBinding;
+use crate::dom::bindings::inheritance::Castable;
 use crate::dom::bindings::reflector::reflect_dom_object;
 use crate::dom::bindings::root::{Dom, DomRoot};
 use crate::dom::eventtarget::EventTarget;
 use crate::dom::globalscope::GlobalScope;
+use crate::dom::xrreferencespace::XRReferenceSpace;
 use crate::dom::xrsession::XRSession;
 use dom_struct::dom_struct;
+use euclid::Transform3D;
+use webvr_traits::WebVRFrameData;
 
 #[dom_struct]
 pub struct XRSpace {
@@ -33,3 +37,25 @@ impl XRSpace {
         )
     }
 }
+
+impl XRSpace {
+    /// Gets viewer pose represented by this space
+    pub fn get_viewer_pose(&self, base_pose: &WebVRFrameData) -> Transform3D<f64> {
+        if let Some(reference) = self.downcast::<XRReferenceSpace>() {
+            reference.get_viewer_pose(base_pose)
+        } else {
+            unreachable!()
+        }
+    }
+
+    /// Gets pose represented by this space
+    ///
+    /// Does not apply originOffset, use get_viewer_pose instead if you need it
+    pub fn get_pose(&self, base_pose: &WebVRFrameData) -> Transform3D<f64> {
+        if let Some(reference) = self.downcast::<XRReferenceSpace>() {
+            reference.get_pose(base_pose)
+        } else {
+            unreachable!()
+        }
+    }
+}
diff --git a/components/script/dom/xrstationaryreferencespace.rs b/components/script/dom/xrstationaryreferencespace.rs
index 33d96f1488f..e8349ef3581 100644
--- a/components/script/dom/xrstationaryreferencespace.rs
+++ b/components/script/dom/xrstationaryreferencespace.rs
@@ -11,6 +11,8 @@ use crate::dom::xrreferencespace::XRReferenceSpace;
 use crate::dom::xrrigidtransform::XRRigidTransform;
 use crate::dom::xrsession::XRSession;
 use dom_struct::dom_struct;
+use euclid::{Rotation3D, Transform3D};
+use webvr_traits::WebVRFrameData;
 
 #[dom_struct]
 pub struct XRStationaryReferenceSpace {
@@ -46,3 +48,23 @@ impl XRStationaryReferenceSpace {
         )
     }
 }
+
+impl XRStationaryReferenceSpace {
+    /// Gets pose represented by this space
+    ///
+    /// Does not apply originOffset, use get_viewer_pose instead
+    pub fn get_pose(&self, base_pose: &WebVRFrameData) -> Transform3D<f64> {
+        // XXXManishearth add floor-level transform for floor-level and disable position in position-disabled
+        let pos = base_pose.pose.position.unwrap_or([0., 0., 0.]);
+        let translation =
+            Transform3D::create_translation(pos[0] as f64, pos[1] as f64, pos[2] as f64);
+        let orient = base_pose.pose.orientation.unwrap_or([0., 0., 0., 0.]);
+        let rotation = Rotation3D::quaternion(
+            orient[0] as f64,
+            orient[1] as f64,
+            orient[2] as f64,
+            orient[3] as f64,
+        );
+        translation.pre_mul(&rotation.to_transform())
+    }
+}