1 files changed, 151 insertions, 0 deletions
diff --git a/gfx/vr/ipc/VRLayerChild.cpp b/gfx/vr/ipc/VRLayerChild.cpp
new file mode 100644
index 0000000000..57f69f7d2b
--- /dev/null
+++ b/gfx/vr/ipc/VRLayerChild.cpp
@@ -0,0 +1,151 @@
+/* -*- 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 "VRLayerChild.h"
+
+#include "mozilla/dom/HTMLCanvasElement.h"
+#include "mozilla/layers/ImageBridgeChild.h"
+#include "mozilla/layers/LayersMessages.h"  // for TimedTexture
+#include "mozilla/layers/SyncObject.h"      // for SyncObjectClient
+#include "mozilla/StaticPrefs_dom.h"
+#include "mozilla/StaticPrefs_webgl.h"
+
+#include "ClientWebGLContext.h"
+#include "gfxPlatform.h"
+#include "GLContext.h"
+#include "GLScreenBuffer.h"
+#include "SharedSurface.h"    // for SharedSurface
+#include "SharedSurfaceGL.h"  // for SharedSurface
+
+namespace mozilla::gfx {
+
+VRLayerChild::VRLayerChild() { MOZ_COUNT_CTOR(VRLayerChild); }
+
+VRLayerChild::~VRLayerChild() {
+  ClearSurfaces();
+
+  MOZ_COUNT_DTOR(VRLayerChild);
+}
+
+void VRLayerChild::Initialize(dom::HTMLCanvasElement* aCanvasElement,
+                              const gfx::Rect& aLeftEyeRect,
+                              const gfx::Rect& aRightEyeRect) {
+  MOZ_ASSERT(aCanvasElement);
+  mLeftEyeRect = aLeftEyeRect;
+  mRightEyeRect = aRightEyeRect;
+  mCanvasElement = aCanvasElement;
+}
+
+void VRLayerChild::SetXRFramebuffer(WebGLFramebufferJS* fb) {
+  mFramebuffer = fb;
+}
+
+static constexpr bool kIsAndroid =
+#if defined(MOZ_WIDGET_ANDROID)
+    true;
+#else
+    false;
+#endif
+
+void VRLayerChild::SubmitFrame(const VRDisplayInfo& aDisplayInfo) {
+  uint64_t frameId = aDisplayInfo.GetFrameId();
+
+  // aFrameId will not increment unless the previuosly submitted
+  // frame was received by the VR thread and submitted to the VR
+  // compositor.  We early-exit here in the event that SubmitFrame
+  // was called twice for the same aFrameId.
+  if (!mCanvasElement || frameId == mLastSubmittedFrameId) {
+    return;
+  }
+
+  const auto& webgl = mCanvasElement->GetWebGLContext();
+  if (!webgl) return;
+
+  // Keep the SharedSurfaceTextureClient alive long enough for
+  // 1 extra frame, accomodating overlapped asynchronous rendering.
+  mLastFrameTextureDesc = mThisFrameTextureDesc;
+
+  bool getNewFrame = true;
+  if (kIsAndroid) {
+    /**
+     * Do not blit WebGL to a SurfaceTexture until the last submitted frame is
+     * already processed and the new frame poses are ready. SurfaceTextures need
+     * to be released in the VR render thread in order to allow to be used again
+     * in the WebGLContext GLScreenBuffer producer. Not doing so causes some
+     * freezes, crashes or other undefined behaviour.
+     */
+    getNewFrame = (!mThisFrameTextureDesc ||
+                   aDisplayInfo.mDisplayState.lastSubmittedFrameId ==
+                       mLastSubmittedFrameId);
+  }
+  if (getNewFrame) {
+    const RefPtr<layers::ImageBridgeChild> imageBridge =
+        layers::ImageBridgeChild::GetSingleton();
+
+    auto texType = layers::TextureType::Unknown;
+    if (imageBridge) {
+      texType = layers::PreferredCanvasTextureType(imageBridge);
+    }
+    if (kIsAndroid && StaticPrefs::webgl_enable_surface_texture()) {
+      texType = layers::TextureType::AndroidNativeWindow;
+    }
+
+    webgl->Present(mFramebuffer, texType, true);
+    mThisFrameTextureDesc = webgl->GetFrontBuffer(mFramebuffer, true);
+  }
+
+  mLastSubmittedFrameId = frameId;
+
+  if (!mThisFrameTextureDesc) {
+    gfxCriticalError() << "ToSurfaceDescriptor failed in "
+                          "VRLayerChild::SubmitFrame";
+    return;
+  }
+
+  SendSubmitFrame(*mThisFrameTextureDesc, frameId, mLeftEyeRect, mRightEyeRect);
+}
+
+bool VRLayerChild::IsIPCOpen() { return mIPCOpen; }
+
+void VRLayerChild::ClearSurfaces() {
+  mThisFrameTextureDesc = Nothing();
+  mLastFrameTextureDesc = Nothing();
+  const auto& webgl = mCanvasElement->GetWebGLContext();
+  if (!mFramebuffer && webgl) {
+    webgl->ClearVRSwapChain();
+  }
+}
+
+void VRLayerChild::ActorDestroy(ActorDestroyReason aWhy) { mIPCOpen = false; }
+
+// static
+PVRLayerChild* VRLayerChild::CreateIPDLActor() {
+  if (!StaticPrefs::dom_vr_enabled() && !StaticPrefs::dom_vr_webxr_enabled()) {
+    return nullptr;
+  }
+
+  VRLayerChild* c = new VRLayerChild();
+  c->AddIPDLReference();
+  return c;
+}
+
+// static
+bool VRLayerChild::DestroyIPDLActor(PVRLayerChild* actor) {
+  static_cast<VRLayerChild*>(actor)->ReleaseIPDLReference();
+  return true;
+}
+
+void VRLayerChild::AddIPDLReference() {
+  MOZ_ASSERT(mIPCOpen == false);
+  mIPCOpen = true;
+  AddRef();
+}
+void VRLayerChild::ReleaseIPDLReference() {
+  MOZ_ASSERT(mIPCOpen == false);
+  Release();
+}
+
+}  // namespace mozilla::gfx