1 files changed, 44 insertions, 0 deletions
diff --git a/dom/vr/XRNativeOriginLocalFloor.cpp b/dom/vr/XRNativeOriginLocalFloor.cpp
new file mode 100644
index 0000000000..3d4c3c4ace
--- /dev/null
+++ b/dom/vr/XRNativeOriginLocalFloor.cpp
@@ -0,0 +1,44 @@
+/* -*- 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 "XRNativeOriginLocalFloor.h"
+#include "VRDisplayClient.h"
+
+namespace mozilla {
+namespace dom {
+
+XRNativeOriginLocalFloor::XRNativeOriginLocalFloor(
+    gfx::VRDisplayClient* aDisplay)
+    : mDisplay(aDisplay), mInitialPositionValid(false) {
+  MOZ_ASSERT(aDisplay);
+
+  // To avoid fingerprinting, we offset the floor height by 5cm.
+  // This will always result in the floor being lower than the
+  // real floor in order to avoid breaking content that expects
+  // you to pick objects up off the floor.
+  //
+  // TODO (Bug 1616394) - Convert this constant to a pref.
+  const double kFloorFuzz = 0.05f;  // Meters
+  mFloorRandom = double(rand()) / double(RAND_MAX) * kFloorFuzz;
+}
+
+gfx::PointDouble3D XRNativeOriginLocalFloor::GetPosition() {
+  // Keep returning {0,-fuzz,0} until a position can be found
+  const auto standing =
+      mDisplay->GetDisplayInfo().GetSittingToStandingTransform();
+  if (!mInitialPositionValid || standing != mStandingTransform) {
+    const gfx::VRHMDSensorState& sensorState = mDisplay->GetSensorState();
+    mInitialPosition.x = sensorState.pose.position[0];
+    mInitialPosition.y = -mFloorRandom - standing._42;
+    mInitialPosition.z = sensorState.pose.position[2];
+    mInitialPositionValid = true;
+    mStandingTransform = standing;
+  }
+  return mInitialPosition;
+}
+
+}  // namespace dom
+}  // namespace mozilla