1 files changed, 45 insertions, 0 deletions
diff --git a/dom/vr/XRReferenceSpace.cpp b/dom/vr/XRReferenceSpace.cpp
new file mode 100644
index 0000000000..9ed73003cd
--- /dev/null
+++ b/dom/vr/XRReferenceSpace.cpp
@@ -0,0 +1,45 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/XRReferenceSpace.h"
+#include "mozilla/dom/XRRigidTransform.h"
+#include "VRDisplayClient.h"
+
+namespace mozilla::dom {
+
+XRReferenceSpace::XRReferenceSpace(nsIGlobalObject* aParent,
+                                   XRSession* aSession,
+                                   XRNativeOrigin* aNativeOrigin,
+                                   XRReferenceSpaceType aType)
+    : XRSpace(aParent, aSession, aNativeOrigin), mType(aType) {}
+
+already_AddRefed<XRReferenceSpace> XRReferenceSpace::GetOffsetReferenceSpace(
+    const XRRigidTransform& aOriginOffset) {
+  RefPtr<XRReferenceSpace> offsetReferenceSpace =
+      new XRReferenceSpace(GetParentObject(), mSession, mNativeOrigin, mType);
+
+  // https://immersive-web.github.io/webxr/#multiply-transforms
+  // An XRRigidTransform is essentially a rotation followed by a translation
+  gfx::QuaternionDouble otherOrientation = aOriginOffset.RawOrientation();
+  // The resulting rotation is the two combined
+  offsetReferenceSpace->mOriginOffsetOrientation =
+      mOriginOffsetOrientation * otherOrientation;
+  // We first apply the rotation of aOriginOffset to
+  // mOriginOffsetPosition offset, then translate by the offset of
+  // aOriginOffset
+  offsetReferenceSpace->mOriginOffsetPosition =
+      otherOrientation.RotatePoint(mOriginOffsetPosition) +
+      aOriginOffset.RawPosition();
+
+  return offsetReferenceSpace.forget();
+}
+
+JSObject* XRReferenceSpace::WrapObject(JSContext* aCx,
+                                       JS::Handle<JSObject*> aGivenProto) {
+  return XRReferenceSpace_Binding::Wrap(aCx, this, aGivenProto);
+}
+
+}  // namespace mozilla::dom