dom/vr/XRNativeOriginLocalFloor.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "mozilla/StaticPrefs_dom.h"
   8 #include "XRNativeOriginLocalFloor.h"
   9 #include "VRDisplayClient.h"
  10
  11 namespace mozilla::dom {
  12
  13 XRNativeOriginLocalFloor::XRNativeOriginLocalFloor(
  14     gfx::VRDisplayClient* aDisplay)
  15     : mDisplay(aDisplay), mInitialPositionValid(false) {
  16   MOZ_ASSERT(aDisplay);
  17
  18   // To avoid fingerprinting, we offset the floor height.
  19   // This should result in the floor being higher than the
  20   // real floor in order to avoid breaking content that expects
  21   // you to pick objects up off the floor.
  22   const double kFloorFuzz = StaticPrefs::dom_vr_webxr_quantization();  // Meters
  23   mFloorRandom = double(rand()) / double(RAND_MAX) * kFloorFuzz;
  24 }
  25
  26 gfx::PointDouble3D XRNativeOriginLocalFloor::GetPosition() {
  27   // Keep returning {0,-fuzz,0} until a position can be found
  28   const auto standing =
  29       mDisplay->GetDisplayInfo().GetSittingToStandingTransform();
  30   if (!mInitialPositionValid || standing != mStandingTransform) {
  31     const gfx::VRHMDSensorState& sensorState = mDisplay->GetSensorState();
  32     mInitialPosition.x = sensorState.pose.position[0];
  33     mInitialPosition.y = -mFloorRandom - standing._42;
  34     mInitialPosition.z = sensorState.pose.position[2];
  35     mInitialPositionValid = true;
  36     mStandingTransform = standing;
  37   }
  38   return mInitialPosition;
  39 }
  40
  41 }  // namespace mozilla::dom