gecko-dev/dom/vr/VRDisplay.cpp

/* -*- 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 "nsWrapperCache.h"

#include "mozilla/dom/Element.h"
#include "mozilla/dom/ElementBinding.h"
#include "mozilla/dom/Promise.h"
#include "mozilla/dom/UserActivation.h"
#include "mozilla/dom/VRDisplay.h"
#include "mozilla/dom/VRDisplayBinding.h"
#include "mozilla/HoldDropJSObjects.h"
#include "mozilla/Base64.h"
#include "mozilla/StaticPrefs_dom.h"
#include "mozilla/gfx/DataSurfaceHelpers.h"
#include "Navigator.h"
#include "gfxUtils.h"
#include "gfxVR.h"
#include "VRDisplayClient.h"
#include "VRManagerChild.h"
#include "VRDisplayPresentation.h"
#include "nsIObserverService.h"
#include "nsIFrame.h"
#include "nsISupportsPrimitives.h"

using namespace mozilla::gfx;

namespace mozilla {
namespace dom {

VRFieldOfView::VRFieldOfView(nsISupports* aParent, double aUpDegrees,
                             double aRightDegrees, double aDownDegrees,
                             double aLeftDegrees)
    : mParent(aParent),
      mUpDegrees(aUpDegrees),
      mRightDegrees(aRightDegrees),
      mDownDegrees(aDownDegrees),
      mLeftDegrees(aLeftDegrees) {}

VRFieldOfView::VRFieldOfView(nsISupports* aParent,
                             const gfx::VRFieldOfView& aSrc)
    : mParent(aParent),
      mUpDegrees(aSrc.upDegrees),
      mRightDegrees(aSrc.rightDegrees),
      mDownDegrees(aSrc.downDegrees),
      mLeftDegrees(aSrc.leftDegrees) {}

bool VRDisplayCapabilities::HasPosition() const {
  return bool(mFlags & gfx::VRDisplayCapabilityFlags::Cap_Position);
}

bool VRDisplayCapabilities::HasOrientation() const {
  return bool(mFlags & gfx::VRDisplayCapabilityFlags::Cap_Orientation);
}

bool VRDisplayCapabilities::HasExternalDisplay() const {
  return bool(mFlags & gfx::VRDisplayCapabilityFlags::Cap_External);
}

bool VRDisplayCapabilities::CanPresent() const {
  return bool(mFlags & gfx::VRDisplayCapabilityFlags::Cap_Present);
}

uint32_t VRDisplayCapabilities::MaxLayers() const {
  return CanPresent() ? 1 : 0;
}

void VRDisplay::UpdateDisplayClient(
    already_AddRefed<gfx::VRDisplayClient> aClient) {
  mClient = std::move(aClient);
}

/*static*/
bool VRDisplay::RefreshVRDisplays(uint64_t aWindowId) {
  gfx::VRManagerChild* vm = gfx::VRManagerChild::Get();
  return vm && vm->RefreshVRDisplaysWithCallback(aWindowId);
}

/*static*/
void VRDisplay::UpdateVRDisplays(nsTArray<RefPtr<VRDisplay>>& aDisplays,
                                 nsPIDOMWindowInner* aWindow) {
  nsTArray<RefPtr<VRDisplay>> displays;

  gfx::VRManagerChild* vm = gfx::VRManagerChild::Get();
  nsTArray<RefPtr<gfx::VRDisplayClient>> updatedDisplays;
  if (vm) {
    vm->GetVRDisplays(updatedDisplays);
    for (size_t i = 0; i < updatedDisplays.Length(); i++) {
      RefPtr<gfx::VRDisplayClient> display = updatedDisplays[i];
      bool isNewDisplay = true;
      for (size_t j = 0; j < aDisplays.Length(); j++) {
        if (aDisplays[j]->GetClient()->GetDisplayInfo().GetDisplayID() ==
            display->GetDisplayInfo().GetDisplayID()) {
          displays.AppendElement(aDisplays[j]);
          isNewDisplay = false;
        } else {
          RefPtr<gfx::VRDisplayClient> ref = display;
          aDisplays[j]->UpdateDisplayClient(do_AddRef(display));
          displays.AppendElement(aDisplays[j]);
          isNewDisplay = false;
        }
      }

      if (isNewDisplay) {
        displays.AppendElement(new VRDisplay(aWindow, display));
      }
    }
  }

  aDisplays = displays;
}

NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(VRFieldOfView, mParent)
NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(VRFieldOfView, AddRef)
NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(VRFieldOfView, Release)

JSObject* VRFieldOfView::WrapObject(JSContext* aCx,
                                    JS::Handle<JSObject*> aGivenProto) {
  return VRFieldOfView_Binding::Wrap(aCx, this, aGivenProto);
}

NS_IMPL_CYCLE_COLLECTION_CLASS(VREyeParameters)

NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(VREyeParameters)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mParent, mFOV)
  NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
  tmp->mOffset = nullptr;
NS_IMPL_CYCLE_COLLECTION_UNLINK_END

NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(VREyeParameters)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mParent, mFOV)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(VREyeParameters)
  NS_IMPL_CYCLE_COLLECTION_TRACE_PRESERVED_WRAPPER
  NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mOffset)
NS_IMPL_CYCLE_COLLECTION_TRACE_END

NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(VREyeParameters, AddRef)
NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(VREyeParameters, Release)

VREyeParameters::VREyeParameters(nsISupports* aParent,
                                 const gfx::Point3D& aEyeTranslation,
                                 const gfx::VRFieldOfView& aFOV,
                                 const gfx::IntSize& aRenderSize)
    : mParent(aParent),
      mEyeTranslation(aEyeTranslation),
      mRenderSize(aRenderSize) {
  mFOV = new VRFieldOfView(aParent, aFOV);
  mozilla::HoldJSObjects(this);
}

VREyeParameters::~VREyeParameters() { mozilla::DropJSObjects(this); }

VRFieldOfView* VREyeParameters::FieldOfView() { return mFOV; }

void VREyeParameters::GetOffset(JSContext* aCx,
                                JS::MutableHandle<JSObject*> aRetval,
                                ErrorResult& aRv) {
  if (!mOffset) {
    // Lazily create the Float32Array
    mOffset =
        dom::Float32Array::Create(aCx, this, 3, mEyeTranslation.components);
    if (!mOffset) {
      aRv.NoteJSContextException(aCx);
      return;
    }
  }
  aRetval.set(mOffset);
}

JSObject* VREyeParameters::WrapObject(JSContext* aCx,
                                      JS::Handle<JSObject*> aGivenProto) {
  return VREyeParameters_Binding::Wrap(aCx, this, aGivenProto);
}

VRStageParameters::VRStageParameters(
    nsISupports* aParent, const gfx::Matrix4x4& aSittingToStandingTransform,
    const gfx::Size& aSize)
    : mParent(aParent),
      mSittingToStandingTransform(aSittingToStandingTransform),
      mSittingToStandingTransformArray(nullptr),
      mSize(aSize) {
  mozilla::HoldJSObjects(this);
}

VRStageParameters::~VRStageParameters() { mozilla::DropJSObjects(this); }

JSObject* VRStageParameters::WrapObject(JSContext* aCx,
                                        JS::Handle<JSObject*> aGivenProto) {
  return VRStageParameters_Binding::Wrap(aCx, this, aGivenProto);
}

NS_IMPL_CYCLE_COLLECTION_CLASS(VRStageParameters)

NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(VRStageParameters)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mParent)
  NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
  tmp->mSittingToStandingTransformArray = nullptr;
NS_IMPL_CYCLE_COLLECTION_UNLINK_END

NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(VRStageParameters)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mParent)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(VRStageParameters)
  NS_IMPL_CYCLE_COLLECTION_TRACE_PRESERVED_WRAPPER
  NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(
      mSittingToStandingTransformArray)
NS_IMPL_CYCLE_COLLECTION_TRACE_END

NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(VRStageParameters, AddRef)
NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(VRStageParameters, Release)

void VRStageParameters::GetSittingToStandingTransform(
    JSContext* aCx, JS::MutableHandle<JSObject*> aRetval, ErrorResult& aRv) {
  if (!mSittingToStandingTransformArray) {
    // Lazily create the Float32Array
    mSittingToStandingTransformArray = dom::Float32Array::Create(
        aCx, this, 16, mSittingToStandingTransform.components);
    if (!mSittingToStandingTransformArray) {
      aRv.NoteJSContextException(aCx);
      return;
    }
  }
  aRetval.set(mSittingToStandingTransformArray);
}

NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(VRDisplayCapabilities, mParent)
NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(VRDisplayCapabilities, AddRef)
NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(VRDisplayCapabilities, Release)

JSObject* VRDisplayCapabilities::WrapObject(JSContext* aCx,
                                            JS::Handle<JSObject*> aGivenProto) {
  return VRDisplayCapabilities_Binding::Wrap(aCx, this, aGivenProto);
}

VRPose::VRPose(nsISupports* aParent, const gfx::VRHMDSensorState& aState)
    : Pose(aParent), mVRState(aState) {
  mozilla::HoldJSObjects(this);
}

VRPose::VRPose(nsISupports* aParent) : Pose(aParent) {
  mVRState.inputFrameID = 0;
  mVRState.timestamp = 0.0;
  mVRState.flags = gfx::VRDisplayCapabilityFlags::Cap_None;
  mozilla::HoldJSObjects(this);
}

VRPose::~VRPose() { mozilla::DropJSObjects(this); }

void VRPose::GetPosition(JSContext* aCx, JS::MutableHandle<JSObject*> aRetval,
                         ErrorResult& aRv) {
  const bool valid =
      bool(mVRState.flags & gfx::VRDisplayCapabilityFlags::Cap_Position) ||
      bool(mVRState.flags &
           gfx::VRDisplayCapabilityFlags::Cap_PositionEmulated);
  SetFloat32Array(aCx, this, aRetval, mPosition,
                  valid ? mVRState.pose.position : nullptr, 3, aRv);
}

void VRPose::GetLinearVelocity(JSContext* aCx,
                               JS::MutableHandle<JSObject*> aRetval,
                               ErrorResult& aRv) {
  const bool valid =
      bool(mVRState.flags & gfx::VRDisplayCapabilityFlags::Cap_Position);
  SetFloat32Array(aCx, this, aRetval, mLinearVelocity,
                  valid ? mVRState.pose.linearVelocity : nullptr, 3, aRv);
}

void VRPose::GetLinearAcceleration(JSContext* aCx,
                                   JS::MutableHandle<JSObject*> aRetval,
                                   ErrorResult& aRv) {
  const bool valid = bool(
      mVRState.flags & gfx::VRDisplayCapabilityFlags::Cap_LinearAcceleration);
  SetFloat32Array(aCx, this, aRetval, mLinearAcceleration,
                  valid ? mVRState.pose.linearAcceleration : nullptr, 3, aRv);
}

void VRPose::GetOrientation(JSContext* aCx,
                            JS::MutableHandle<JSObject*> aRetval,
                            ErrorResult& aRv) {
  const bool valid =
      bool(mVRState.flags & gfx::VRDisplayCapabilityFlags::Cap_Orientation);
  SetFloat32Array(aCx, this, aRetval, mOrientation,
                  valid ? mVRState.pose.orientation : nullptr, 4, aRv);
}

void VRPose::GetAngularVelocity(JSContext* aCx,
                                JS::MutableHandle<JSObject*> aRetval,
                                ErrorResult& aRv) {
  const bool valid =
      bool(mVRState.flags & gfx::VRDisplayCapabilityFlags::Cap_Orientation);
  SetFloat32Array(aCx, this, aRetval, mAngularVelocity,
                  valid ? mVRState.pose.angularVelocity : nullptr, 3, aRv);
}

void VRPose::GetAngularAcceleration(JSContext* aCx,
                                    JS::MutableHandle<JSObject*> aRetval,
                                    ErrorResult& aRv) {
  const bool valid = bool(
      mVRState.flags & gfx::VRDisplayCapabilityFlags::Cap_AngularAcceleration);
  SetFloat32Array(aCx, this, aRetval, mAngularAcceleration,
                  valid ? mVRState.pose.angularAcceleration : nullptr, 3, aRv);
}

void VRPose::Update(const gfx::VRHMDSensorState& aState) { mVRState = aState; }

JSObject* VRPose::WrapObject(JSContext* aCx,
                             JS::Handle<JSObject*> aGivenProto) {
  return VRPose_Binding::Wrap(aCx, this, aGivenProto);
}

/* virtual */
JSObject* VRDisplay::WrapObject(JSContext* aCx,
                                JS::Handle<JSObject*> aGivenProto) {
  return VRDisplay_Binding::Wrap(aCx, this, aGivenProto);
}

VRDisplay::VRDisplay(nsPIDOMWindowInner* aWindow, gfx::VRDisplayClient* aClient)
    : DOMEventTargetHelper(aWindow),
      mClient(aClient),
      mDepthNear(0.01f)  // Default value from WebVR Spec
      ,
      mDepthFar(10000.0f)  // Default value from WebVR Spec
      ,
      mVRNavigationEventDepth(0),
      mShutdown(false) {
  const gfx::VRDisplayInfo& info = aClient->GetDisplayInfo();
  mCapabilities = new VRDisplayCapabilities(aWindow, info.GetCapabilities());
  if (info.GetCapabilities() &
      gfx::VRDisplayCapabilityFlags::Cap_StageParameters) {
    mStageParameters = new VRStageParameters(
        aWindow, info.GetSittingToStandingTransform(), info.GetStageSize());
  }
  mozilla::HoldJSObjects(this);
  nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
  if (MOZ_LIKELY(obs)) {
    obs->AddObserver(this, "inner-window-destroyed", false);
  }
}

VRDisplay::~VRDisplay() {
  MOZ_ASSERT(mShutdown);
  mozilla::DropJSObjects(this);
}

void VRDisplay::LastRelease() {
  // We don't want to wait for the CC to free up the presentation
  // for use in other documents, so we do this in LastRelease().
  Shutdown();
}

already_AddRefed<VREyeParameters> VRDisplay::GetEyeParameters(VREye aEye) {
  gfx::VRDisplayState::Eye eye = aEye == VREye::Left
                                     ? gfx::VRDisplayState::Eye_Left
                                     : gfx::VRDisplayState::Eye_Right;
  RefPtr<VREyeParameters> params = new VREyeParameters(
      GetParentObject(), mClient->GetDisplayInfo().GetEyeTranslation(eye),
      mClient->GetDisplayInfo().GetEyeFOV(eye),
      mClient->GetDisplayInfo().SuggestedEyeResolution());
  return params.forget();
}

VRDisplayCapabilities* VRDisplay::Capabilities() { return mCapabilities; }

VRStageParameters* VRDisplay::GetStageParameters() { return mStageParameters; }

uint32_t VRDisplay::DisplayId() const {
  const gfx::VRDisplayInfo& info = mClient->GetDisplayInfo();
  return info.GetDisplayID();
}

void VRDisplay::GetDisplayName(nsAString& aDisplayName) const {
  const gfx::VRDisplayInfo& info = mClient->GetDisplayInfo();
  aDisplayName = NS_ConvertUTF8toUTF16(info.GetDisplayName());
}

void VRDisplay::UpdateFrameInfo() {
  /**
   * The WebVR 1.1 spec Requires that VRDisplay.getPose and
   * VRDisplay.getFrameData must return the same values until the next
   * VRDisplay.submitFrame.
   *
   * mFrameInfo is marked dirty at the end of the frame or start of a new
   * composition and lazily created here in order to receive mid-frame
   * pose-prediction updates while still ensuring conformance to the WebVR spec
   * requirements.
   *
   * If we are not presenting WebVR content, the frame will never end and we
   * should return the latest frame data always.
   */
  mFrameInfo.Clear();

  if ((mFrameInfo.IsDirty() && IsPresenting()) ||
      mClient->GetDisplayInfo().GetPresentingGroups() == 0) {
    const gfx::VRHMDSensorState& state = mClient->GetSensorState();
    const gfx::VRDisplayInfo& info = mClient->GetDisplayInfo();
    mFrameInfo.Update(info, state, mDepthNear, mDepthFar);
  }
}

bool VRDisplay::GetFrameData(VRFrameData& aFrameData) {
  UpdateFrameInfo();
  if (!(mFrameInfo.mVRState.flags &
        gfx::VRDisplayCapabilityFlags::Cap_Orientation)) {
    // We must have at minimum Cap_Orientation for a valid pose.
    return false;
  }
  aFrameData.Update(mFrameInfo);
  return true;
}

already_AddRefed<VRPose> VRDisplay::GetPose() {
  UpdateFrameInfo();
  RefPtr<VRPose> obj = new VRPose(GetParentObject(), mFrameInfo.mVRState);

  return obj.forget();
}

void VRDisplay::ResetPose() {
  // ResetPose is deprecated and unimplemented
  // We must keep this stub function around as its referenced by
  // VRDisplay.webidl. Not asserting here, as that could break existing web
  // content.
}

void VRDisplay::StartVRNavigation() { mClient->StartVRNavigation(); }

void VRDisplay::StartHandlingVRNavigationEvent() {
  mHandlingVRNavigationEventStart = TimeStamp::Now();
  ++mVRNavigationEventDepth;
  TimeDuration timeout =
      TimeDuration::FromMilliseconds(StaticPrefs::dom_vr_navigation_timeout());
  // A 0 or negative TimeDuration indicates that content may take
  // as long as it wishes to respond to the event, as long as
  // it happens before the event exits.
  if (timeout.ToMilliseconds() > 0) {
    mClient->StopVRNavigation(timeout);
  }
}

void VRDisplay::StopHandlingVRNavigationEvent() {
  MOZ_ASSERT(mVRNavigationEventDepth > 0);
  --mVRNavigationEventDepth;
  if (mVRNavigationEventDepth == 0) {
    mClient->StopVRNavigation(TimeDuration::FromMilliseconds(0));
  }
}

bool VRDisplay::IsHandlingVRNavigationEvent() {
  if (mVRNavigationEventDepth == 0) {
    return false;
  }
  if (mHandlingVRNavigationEventStart.IsNull()) {
    return false;
  }
  TimeDuration timeout =
      TimeDuration::FromMilliseconds(StaticPrefs::dom_vr_navigation_timeout());
  return timeout.ToMilliseconds() <= 0 ||
         (TimeStamp::Now() - mHandlingVRNavigationEventStart) <= timeout;
}

void VRDisplay::OnPresentationGenerationChanged() { ExitPresentInternal(); }

already_AddRefed<Promise> VRDisplay::RequestPresent(
    const nsTArray<VRLayer>& aLayers, CallerType aCallerType,
    ErrorResult& aRv) {
  nsCOMPtr<nsIGlobalObject> global = GetParentObject();
  if (!global) {
    aRv.Throw(NS_ERROR_FAILURE);
    return nullptr;
  }

  RefPtr<Promise> promise = Promise::Create(global, aRv);
  NS_ENSURE_TRUE(!aRv.Failed(), nullptr);

  bool isChromePresentation = aCallerType == CallerType::System;
  uint32_t presentationGroup =
      isChromePresentation ? gfx::kVRGroupChrome : gfx::kVRGroupContent;

  mClient->SetXRAPIMode(gfx::VRAPIMode::WebVR);
  if (!UserActivation::IsHandlingUserInput() && !isChromePresentation &&
      !IsHandlingVRNavigationEvent() && StaticPrefs::dom_vr_require_gesture() &&
      !IsPresenting()) {
    // The WebVR API states that if called outside of a user gesture, the
    // promise must be rejected.  We allow VR presentations to start within
    // trusted events such as vrdisplayactivate, which triggers in response to
    // HMD proximity sensors and when navigating within a VR presentation.
    // This user gesture requirement is not enforced for chrome/system code.
    promise->MaybeRejectWithUndefined();
  } else if (!IsPresenting() && IsAnyPresenting(presentationGroup)) {
    // Only one presentation allowed per VRDisplay on a
    // first-come-first-serve basis.
    // If this Javascript context is presenting, then we can replace our
    // presentation with a new one containing new layers but we should never
    // replace the presentation of another context.
    // Simultaneous presentations in other groups are allowed in separate
    // Javascript contexts to enable browser UI from chrome/system contexts.
    // Eventually, this restriction will be loosened to enable multitasking
    // use cases.
    promise->MaybeRejectWithUndefined();
  } else {
    if (mPresentation) {
      mPresentation->UpdateLayers(aLayers);
    } else {
      mPresentation = mClient->BeginPresentation(aLayers, presentationGroup);
    }
    mFrameInfo.Clear();
    promise->MaybeResolve(JS::UndefinedHandleValue);
  }
  return promise.forget();
}

NS_IMETHODIMP
VRDisplay::Observe(nsISupports* aSubject, const char* aTopic,
                   const char16_t* aData) {
  MOZ_ASSERT(NS_IsMainThread());

  if (strcmp(aTopic, "inner-window-destroyed") == 0) {
    nsCOMPtr<nsISupportsPRUint64> wrapper = do_QueryInterface(aSubject);
    NS_ENSURE_TRUE(wrapper, NS_ERROR_FAILURE);

    uint64_t innerID;
    nsresult rv = wrapper->GetData(&innerID);
    NS_ENSURE_SUCCESS(rv, rv);

    if (!GetOwner() || GetOwner()->WindowID() == innerID) {
      Shutdown();
    }

    return NS_OK;
  }

  // This should not happen.
  return NS_ERROR_FAILURE;
}

already_AddRefed<Promise> VRDisplay::ExitPresent(ErrorResult& aRv) {
  nsCOMPtr<nsIGlobalObject> global = GetParentObject();
  if (!global) {
    aRv.Throw(NS_ERROR_FAILURE);
    return nullptr;
  }

  RefPtr<Promise> promise = Promise::Create(global, aRv);
  NS_ENSURE_TRUE(!aRv.Failed(), nullptr);

  if (!IsPresenting()) {
    // We can not exit a presentation outside of the context that
    // started the presentation.
    promise->MaybeRejectWithUndefined();
  } else {
    promise->MaybeResolve(JS::UndefinedHandleValue);
    ExitPresentInternal();
  }

  return promise.forget();
}

void VRDisplay::ExitPresentInternal() { mPresentation = nullptr; }

void VRDisplay::Shutdown() {
  mShutdown = true;
  ExitPresentInternal();
  nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
  if (MOZ_LIKELY(obs)) {
    obs->RemoveObserver(this, "inner-window-destroyed");
  }
}

void VRDisplay::GetLayers(nsTArray<VRLayer>& result) {
  if (mPresentation) {
    mPresentation->GetDOMLayers(result);
  } else {
    result = nsTArray<VRLayer>();
  }
}

void VRDisplay::SubmitFrame() {
  AUTO_PROFILER_TRACING_MARKER("VR", "SubmitFrameAtVRDisplay", OTHER);

  if (mClient && !mClient->IsPresentationGenerationCurrent()) {
    mPresentation = nullptr;
    mClient->MakePresentationGenerationCurrent();
  }

  if (mPresentation) {
    mPresentation->SubmitFrame();
  }
  mFrameInfo.Clear();
}

int32_t VRDisplay::RequestAnimationFrame(FrameRequestCallback& aCallback,
                                         ErrorResult& aError) {
  if (mShutdown) {
    return 0;
  }

  gfx::VRManagerChild* vm = gfx::VRManagerChild::Get();

  int32_t handle;
  aError = vm->ScheduleFrameRequestCallback(aCallback, &handle);
  return handle;
}

void VRDisplay::CancelAnimationFrame(int32_t aHandle, ErrorResult& aError) {
  gfx::VRManagerChild* vm = gfx::VRManagerChild::Get();
  vm->CancelFrameRequestCallback(aHandle);
}

bool VRDisplay::IsPresenting() const {
  // IsPresenting returns true only if this Javascript context is presenting
  // and will return false if another context is presenting.
  return mPresentation != nullptr;
}

bool VRDisplay::IsAnyPresenting(uint32_t aGroupMask) const {
  // IsAnyPresenting returns true if either this VRDisplay object or any other
  // from anther Javascript context is presenting with a group matching
  // aGroupMask.
  if (mPresentation && (mPresentation->GetGroup() & aGroupMask)) {
    return true;
  }
  if (mClient->GetDisplayInfo().GetPresentingGroups() & aGroupMask) {
    return true;
  }
  return false;
}

bool VRDisplay::IsConnected() const { return mClient->GetIsConnected(); }

uint32_t VRDisplay::PresentingGroups() const {
  return mClient->GetDisplayInfo().GetPresentingGroups();
}

uint32_t VRDisplay::GroupMask() const {
  return mClient->GetDisplayInfo().GetGroupMask();
}

void VRDisplay::SetGroupMask(const uint32_t& aGroupMask) {
  mClient->SetGroupMask(aGroupMask);
}

NS_IMPL_CYCLE_COLLECTION_INHERITED(VRDisplay, DOMEventTargetHelper,
                                   mCapabilities, mStageParameters)

NS_IMPL_ADDREF_INHERITED(VRDisplay, DOMEventTargetHelper)
NS_IMPL_RELEASE_INHERITED(VRDisplay, DOMEventTargetHelper)

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(VRDisplay)
  NS_INTERFACE_MAP_ENTRY(nsIObserver)
  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, DOMEventTargetHelper)
NS_INTERFACE_MAP_END_INHERITING(DOMEventTargetHelper)

NS_IMPL_CYCLE_COLLECTION_CLASS(VRFrameData)

NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(VRFrameData)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mParent, mPose)
  NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
  tmp->mLeftProjectionMatrix = nullptr;
  tmp->mLeftViewMatrix = nullptr;
  tmp->mRightProjectionMatrix = nullptr;
  tmp->mRightViewMatrix = nullptr;
NS_IMPL_CYCLE_COLLECTION_UNLINK_END

NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(VRFrameData)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mParent, mPose)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(VRFrameData)
  NS_IMPL_CYCLE_COLLECTION_TRACE_PRESERVED_WRAPPER
  NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mLeftProjectionMatrix)
  NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mLeftViewMatrix)
  NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mRightProjectionMatrix)
  NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mRightViewMatrix)
NS_IMPL_CYCLE_COLLECTION_TRACE_END

NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(VRFrameData, AddRef)
NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(VRFrameData, Release)

VRFrameData::VRFrameData(nsISupports* aParent)
    : mParent(aParent),
      mLeftProjectionMatrix(nullptr),
      mLeftViewMatrix(nullptr),
      mRightProjectionMatrix(nullptr),
      mRightViewMatrix(nullptr) {
  mozilla::HoldJSObjects(this);
  mPose = new VRPose(aParent);
}

VRFrameData::~VRFrameData() { mozilla::DropJSObjects(this); }

/* static */
already_AddRefed<VRFrameData> VRFrameData::Constructor(
    const GlobalObject& aGlobal) {
  RefPtr<VRFrameData> obj = new VRFrameData(aGlobal.GetAsSupports());
  return obj.forget();
}

JSObject* VRFrameData::WrapObject(JSContext* aCx,
                                  JS::Handle<JSObject*> aGivenProto) {
  return VRFrameData_Binding::Wrap(aCx, this, aGivenProto);
}

VRPose* VRFrameData::Pose() { return mPose; }

double VRFrameData::Timestamp() const {
  // Converting from seconds to milliseconds
  return mFrameInfo.mVRState.timestamp * 1000.0f;
}

void VRFrameData::GetLeftProjectionMatrix(JSContext* aCx,
                                          JS::MutableHandle<JSObject*> aRetval,
                                          ErrorResult& aRv) {
  Pose::SetFloat32Array(aCx, this, aRetval, mLeftProjectionMatrix,
                        mFrameInfo.mLeftProjection.components, 16, aRv);
}

void VRFrameData::GetLeftViewMatrix(JSContext* aCx,
                                    JS::MutableHandle<JSObject*> aRetval,
                                    ErrorResult& aRv) {
  Pose::SetFloat32Array(aCx, this, aRetval, mLeftViewMatrix,
                        mFrameInfo.mLeftView.components, 16, aRv);
}

void VRFrameData::GetRightProjectionMatrix(JSContext* aCx,
                                           JS::MutableHandle<JSObject*> aRetval,
                                           ErrorResult& aRv) {
  Pose::SetFloat32Array(aCx, this, aRetval, mRightProjectionMatrix,
                        mFrameInfo.mRightProjection.components, 16, aRv);
}

void VRFrameData::GetRightViewMatrix(JSContext* aCx,
                                     JS::MutableHandle<JSObject*> aRetval,
                                     ErrorResult& aRv) {
  Pose::SetFloat32Array(aCx, this, aRetval, mRightViewMatrix,
                        mFrameInfo.mRightView.components, 16, aRv);
}

void VRFrameData::Update(const VRFrameInfo& aFrameInfo) {
  mFrameInfo = aFrameInfo;
  mPose->Update(mFrameInfo.mVRState);
}

void VRFrameInfo::Update(const gfx::VRDisplayInfo& aInfo,
                         const gfx::VRHMDSensorState& aState, float aDepthNear,
                         float aDepthFar) {
  mVRState = aState;
  if (mTimeStampOffset == 0.0f) {
    /**
     * A mTimeStampOffset value of 0.0f indicates that this is the first
     * iteration and an offset has not yet been set.
     *
     * Generate a value for mTimeStampOffset such that if aState.timestamp is
     * monotonically increasing, aState.timestamp + mTimeStampOffset will never
     * be a negative number and will start at a pseudo-random offset
     * between 1000.0f and 11000.0f seconds.
     *
     * We use a pseudo random offset rather than 0.0f just to discourage users
     * from making the assumption that the timestamp returned in the WebVR API
     * has a base of 0, which is not necessarily true in all UA's.
     */
    mTimeStampOffset =
        float(rand()) / float(RAND_MAX) * 10000.0f + 1000.0f - aState.timestamp;
  }
  mVRState.timestamp = aState.timestamp + mTimeStampOffset;

  // Avoid division by zero within ConstructProjectionMatrix
  const float kEpsilon = 0.00001f;
  if (fabs(aDepthFar - aDepthNear) < kEpsilon) {
    aDepthFar = aDepthNear + kEpsilon;
  }

  const gfx::VRFieldOfView leftFOV =
      aInfo.mDisplayState.eyeFOV[gfx::VRDisplayState::Eye_Left];
  mLeftProjection =
      leftFOV.ConstructProjectionMatrix(aDepthNear, aDepthFar, true);
  const gfx::VRFieldOfView rightFOV =
      aInfo.mDisplayState.eyeFOV[gfx::VRDisplayState::Eye_Right];
  mRightProjection =
      rightFOV.ConstructProjectionMatrix(aDepthNear, aDepthFar, true);
  memcpy(mLeftView.components, aState.leftViewMatrix,
         sizeof(aState.leftViewMatrix));
  memcpy(mRightView.components, aState.rightViewMatrix,
         sizeof(aState.rightViewMatrix));
}

VRFrameInfo::VRFrameInfo() : mTimeStampOffset(0.0f) {
  mVRState.inputFrameID = 0;
  mVRState.timestamp = 0.0;
  mVRState.flags = gfx::VRDisplayCapabilityFlags::Cap_None;
}

bool VRFrameInfo::IsDirty() { return mVRState.timestamp == 0; }

void VRFrameInfo::Clear() { mVRState.Clear(); }

}  // namespace dom
}  // namespace mozilla