Add VR gradient and grid background to non-WebVR scene.

- Add the floor, ceiling and grid quads.
- Add the content backplane to avoid reticle jumping around the edges.
- Configure the scene reticle distance limit based on content.

BUG=715573
TEST=Verified background on regular page; no background in WebVR.

Review-Url: https://codereview.chromium.org/2844313002
Cr-Commit-Position: refs/heads/master@{#467814}

chrome/browser/android/vr_shell/ui_elements/ui_element.h

@@ -113,9 +113,6 @@ struct UiElement : public WorldRectangle {
   // Valid IDs are non-negative.
   int id = -1;
 
-  // Name string for debugging and testing purposes.
-  std::string name;
-
   // If a non-negative parent ID is specified, applicable transformations
   // are applied relative to the parent, rather than absolutely.
   int parent_id = -1;

chrome/browser/android/vr_shell/ui_scene.cc

@@ -146,10 +146,18 @@ bool UiScene::HasVisibleHeadLockedElements() const {
   return !GetHeadLockedElements().empty();
 }
 
+void UiScene::SetBackgroundColor(const vr::Colorf& color) {
+  background_color_ = color;
+}
+
 const vr::Colorf& UiScene::GetBackgroundColor() const {
   return background_color_;
 }
 
+void UiScene::SetBackgroundDistance(float distance) {
+  background_distance_ = distance;
+}
+
 float UiScene::GetBackgroundDistance() const {
   return background_distance_;
 }

chrome/browser/android/vr_shell/ui_scene.h

@@ -62,8 +62,11 @@ class UiScene {
   std::vector<const UiElement*> GetHeadLockedElements() const;
   bool HasVisibleHeadLockedElements() const;
 
+  void SetBackgroundColor(const vr::Colorf& color);
   const vr::Colorf& GetBackgroundColor() const;
+  void SetBackgroundDistance(float distance);
   float GetBackgroundDistance() const;
+
   bool GetWebVrRenderingEnabled() const;
 
   void OnGLInitialized();

chrome/browser/android/vr_shell/ui_scene_manager.cc

@@ -19,16 +19,26 @@ namespace {
 static constexpr int kWarningTimeoutSeconds = 30;
 static constexpr float kWarningDistance = 0.7;
 static constexpr float kWarningAngleRadians = 16.3 * M_PI / 180.0;
-
 static constexpr float kPermanentWarningHeight = 0.226;
 static constexpr float kPermanentWarningWidth = 0.078;
 static constexpr float kTransientWarningHeight = 0.512;
 static constexpr float kTransientWarningWidth = 0.160;
 
-static constexpr float kContentHeight = 2.4;
-static constexpr float kContentWidth = 1.6;
+static constexpr float kContentWidth = 2.4;
+static constexpr float kContentHeight = 1.6;
 static constexpr float kContentDistance = 2.5;
 static constexpr float kContentVerticalOffset = -0.26;
+static constexpr float kBackplaneSize = 1000.0;
+static constexpr float kBackgroundDistanceMultiplier = 1.414;
+
+static constexpr float kSceneSize = 25.0;
+static constexpr float kSceneHeight = 4.0;
+static constexpr int kFloorGridlineCount = 40;
+static constexpr vr::Colorf kBackgroundHorizonColor = {0.57, 0.57, 0.57, 1.0};
+static constexpr vr::Colorf kBackgroundCenterColor = {0.48, 0.48, 0.48, 1.0};
+
+// Tiny distance to offset textures that should appear in the same plane.
+static constexpr float kTextureOffset = 0.01;
 
 }  // namespace
 
@@ -36,15 +46,20 @@ UiSceneManager::UiSceneManager(UiScene* scene)
     : scene_(scene), weak_ptr_factory_(this) {
   std::unique_ptr<UiElement> element;
 
-  // For now, use an ID range that does not conflict with the HTML UI.
-  int id = 1000;
+  CreateBackground();
+  CreateContentQuad();
+  CreateSecurityWarnings();
+}
+
+UiSceneManager::~UiSceneManager() {}
+
+void UiSceneManager::CreateSecurityWarnings() {
+  std::unique_ptr<UiElement> element;
 
-  // Permanent WebVR security warning.
   // TODO(mthiesse): Programatically compute the proper texture size for these
   // textured UI elements.
   element = base::MakeUnique<PermanentSecurityWarning>(512);
-  element->id = id++;
-  element->name = "Permanent security warning";
+  element->id = AllocateId();
   element->fill = vr_shell::Fill::NONE;
   element->size = {kPermanentWarningWidth, kPermanentWarningHeight, 1};
   element->scale = {kWarningDistance, kWarningDistance, 1};
@@ -57,10 +72,8 @@ UiSceneManager::UiSceneManager(UiScene* scene)
   permanent_security_warning_ = element.get();
   scene_->AddUiElement(std::move(element));
 
-  // Transient WebVR security warning.
   element = base::MakeUnique<TransientSecurityWarning>(1024);
-  element->id = id++;
-  element->name = "Transient security warning";
+  element->id = AllocateId();
   element->fill = vr_shell::Fill::NONE;
   element->size = {kTransientWarningWidth, kTransientWarningHeight, 1};
   element->scale = {kWarningDistance, kWarningDistance, 1};
@@ -70,20 +83,86 @@ UiSceneManager::UiSceneManager(UiScene* scene)
   element->lock_to_fov = true;
   transient_security_warning_ = element.get();
   scene_->AddUiElement(std::move(element));
+}
+
+void UiSceneManager::CreateContentQuad() {
+  std::unique_ptr<UiElement> element;
 
-  // Main web content quad.
   element = base::MakeUnique<UiElement>();
-  element->id = id++;
-  element->name = "Content";
+  element->id = AllocateId();
   element->fill = vr_shell::Fill::CONTENT;
   element->size = {kContentWidth, kContentHeight, 1};
   element->translation = {0, kContentVerticalOffset, -kContentDistance};
   element->visible = false;
   main_content_ = element.get();
+  browser_ui_elements_.push_back(element.get());
+  scene_->AddUiElement(std::move(element));
+
+  // Place an invisible but hittable plane behind the content quad, to keep the
+  // reticle roughly planar with the content if near content.
+  element = base::MakeUnique<UiElement>();
+  element->id = AllocateId();
+  element->fill = vr_shell::Fill::NONE;
+  element->size = {kBackplaneSize, kBackplaneSize, 1.0};
+  element->translation = {0.0, 0.0, -kTextureOffset};
+  element->parent_id = main_content_->id;
+  browser_ui_elements_.push_back(element.get());
   scene_->AddUiElement(std::move(element));
+
+  // Limit reticle distance to a sphere based on content distance.
+  scene_->SetBackgroundDistance(main_content_->translation.z() *
+                                -kBackgroundDistanceMultiplier);
 }
 
-UiSceneManager::~UiSceneManager() {}
+void UiSceneManager::CreateBackground() {
+  std::unique_ptr<UiElement> element;
+
+  // Floor.
+  element = base::MakeUnique<UiElement>();
+  element->id = AllocateId();
+  element->size = {kSceneSize, kSceneSize, 1.0};
+  element->translation = {0.0, -kSceneHeight / 2, 0.0};
+  element->rotation = {1.0, 0.0, 0.0, -M_PI / 2.0};
+  element->fill = vr_shell::Fill::OPAQUE_GRADIENT;
+  element->edge_color = kBackgroundHorizonColor;
+  element->center_color = kBackgroundCenterColor;
+  element->draw_phase = 0;
+  browser_ui_elements_.push_back(element.get());
+  scene_->AddUiElement(std::move(element));
+
+  // Ceiling.
+  element = base::MakeUnique<UiElement>();
+  element->id = AllocateId();
+  element->fill = vr_shell::Fill::OPAQUE_GRADIENT;
+  element->size = {kSceneSize, kSceneSize, 1.0};
+  element->translation = {0.0, kSceneHeight / 2, 0.0};
+  element->rotation = {1.0, 0.0, 0.0, M_PI / 2};
+  element->fill = vr_shell::Fill::OPAQUE_GRADIENT;
+  element->edge_color = kBackgroundHorizonColor;
+  element->center_color = kBackgroundCenterColor;
+  element->draw_phase = 0;
+  browser_ui_elements_.push_back(element.get());
+  scene_->AddUiElement(std::move(element));
+
+  // Floor grid.
+  element = base::MakeUnique<UiElement>();
+  element->id = AllocateId();
+  element->fill = vr_shell::Fill::GRID_GRADIENT;
+  element->size = {kSceneSize, kSceneSize, 1.0};
+  element->translation = {0.0, -kSceneHeight / 2 + kTextureOffset, 0.0};
+  element->rotation = {1.0, 0.0, 0.0, -M_PI / 2};
+  element->fill = vr_shell::Fill::GRID_GRADIENT;
+  element->center_color = kBackgroundHorizonColor;
+  vr::Colorf edge_color = kBackgroundHorizonColor;
+  edge_color.a = 0.0;
+  element->edge_color = edge_color;
+  element->gridline_count = kFloorGridlineCount;
+  element->draw_phase = 0;
+  browser_ui_elements_.push_back(element.get());
+  scene_->AddUiElement(std::move(element));
+
+  scene_->SetBackgroundColor(kBackgroundHorizonColor);
+}
 
 base::WeakPtr<UiSceneManager> UiSceneManager::GetWeakPtr() {
   return weak_ptr_factory_.GetWeakPtr();
@@ -91,7 +170,12 @@ base::WeakPtr<UiSceneManager> UiSceneManager::GetWeakPtr() {
 
 void UiSceneManager::SetWebVRMode(bool web_vr) {
   web_vr_mode_ = web_vr;
-  main_content_->visible = !web_vr_mode_;
+
+  // Make all VR scene UI elements visible if not in WebVR.
+  for (UiElement* element : browser_ui_elements_) {
+    element->visible = !web_vr_mode_;
+  }
+
   ConfigureSecurityWarnings();
 }
 
@@ -117,4 +201,8 @@ void UiSceneManager::OnSecurityWarningTimer() {
   transient_security_warning_->visible = false;
 }
 
+int UiSceneManager::AllocateId() {
+  return next_available_id_++;
+}
+
 }  // namespace vr_shell

chrome/browser/android/vr_shell/ui_scene_manager.h

@@ -26,9 +26,13 @@ class UiSceneManager {
   void SetWebVRMode(bool web_vr);
 
  private:
+  void CreateSecurityWarnings();
+  void CreateContentQuad();
+  void CreateBackground();
+
   void ConfigureSecurityWarnings();
   void OnSecurityWarningTimer();
-  void OnGLInitialized();
+  int AllocateId();
 
   UiScene* scene_;
 
@@ -40,6 +44,10 @@ class UiSceneManager {
   bool web_vr_mode_ = false;
   bool secure_origin_ = false;
 
+  int next_available_id_ = 1;
+
+  std::vector<UiElement*> browser_ui_elements_;
+
   base::OneShotTimer security_warning_timer_;
 
   base::WeakPtrFactory<UiSceneManager> weak_ptr_factory_;