Enable scrolling of UI elements.

chrome/browser/android/vr_shell/vr_shell_gl.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/android/vr_shell/vr_shell_gl.h"
 
 #include <limits>
 #include <utility>
 
 #include "base/android/jni_android.h"
@@ skipping 487 matching lines @@
   target_point_ = GetRayPoint(origin, forward, distance);
   gvr::Vec3f eye_to_target = target_point_;
   NormalizeVector(eye_to_target);
 
   // Determine which UI element (if any) intersects the line between the eyes
   // and the controller target position.
   float closest_element_distance = std::numeric_limits<float>::infinity();
   int pixel_x = 0;
   int pixel_y = 0;
   target_element_ = nullptr;
-  InputTarget input_target = InputTarget::NONE;
 
   for (const auto& plane : scene_->GetUiElements()) {
     if (!plane->IsHitTestable())
       continue;
 
     float distance_to_plane = plane->GetRayDistance(kOrigin, eye_to_target);
     gvr::Vec3f plane_intersection_point =
         GetRayPoint(kOrigin, eye_to_target, distance_to_plane);
 
     gvr::Vec3f rect_2d_point =
         MatrixVectorMul(plane->transform.from_world, plane_intersection_point);
-    if (distance_to_plane > 0 && distance_to_plane < closest_element_distance) {
-      float x = rect_2d_point.x + 0.5f;
-      float y = 0.5f - rect_2d_point.y;
-      bool is_inside = x >= 0.0f && x < 1.0f && y >= 0.0f && y < 1.0f;
-      if (!is_inside)
-        continue;
+    if (distance_to_plane < 0 ||
+        distance_to_plane >= closest_element_distance) {
+      continue;
+    }
 
-      closest_element_distance = distance_to_plane;
-      Rectf pixel_rect;
-      if (plane->fill == Fill::CONTENT) {
-        pixel_rect = {0, 0, content_tex_css_width_, content_tex_css_height_};
-      } else {
-        pixel_rect = {plane->copy_rect.x, plane->copy_rect.y,
-                      plane->copy_rect.width, plane->copy_rect.height};
-      }
-      pixel_x = pixel_rect.width * x + pixel_rect.x;
-      pixel_y = pixel_rect.height * y + pixel_rect.y;
+    float x = rect_2d_point.x + 0.5f;
+    float y = 0.5f - rect_2d_point.y;
+    bool is_inside = x >= 0.0f && x < 1.0f && y >= 0.0f && y < 1.0f;
+    if (!is_inside)
+      continue;
 
-      target_point_ = plane_intersection_point;
-      target_element_ = plane.get();
-      input_target = (plane->fill == Fill::CONTENT) ? InputTarget::CONTENT
-                                                    : InputTarget::UI;
+    closest_element_distance = distance_to_plane;
+    Rectf pixel_rect;
+    if (plane->fill == Fill::CONTENT) {
+      pixel_rect = {0, 0, content_tex_css_width_, content_tex_css_height_};
+    } else {
+      pixel_rect = {plane->copy_rect.x, plane->copy_rect.y,
+                    plane->copy_rect.width, plane->copy_rect.height};
+    }
+    pixel_x = pixel_rect.width * x + pixel_rect.x;
+    pixel_y = pixel_rect.height * y + pixel_rect.y;
+
+    target_point_ = plane_intersection_point;
+    target_element_ = plane.get();
+  }
+
+  // Treat UI elements, which do not show web content, as NONE input
+  // targets since they cannot make use of the input anyway.
+  InputTarget input_target = InputTarget::NONE;
+  if (target_element_ != nullptr) {
+    switch (target_element_->fill) {
+      case Fill::CONTENT:
+        input_target = InputTarget::CONTENT;
+        break;
+      case Fill::SPRITE:
+        input_target = InputTarget::UI;
+        break;
+      default:
+        input_target = InputTarget::NONE;
+        break;
     }
   }
   SendEventsToTarget(input_target, pixel_x, pixel_y);
 }
 
 void VrShellGl::SendEventsToTarget(InputTarget input_target,
                                    int pixel_x,
                                    int pixel_y) {
   std::vector<std::unique_ptr<WebGestureEvent>> gesture_list =
       controller_->DetectGestures();
   double timestamp = gesture_list.front()->timeStampSeconds();
 
   if (touch_pending_) {
     touch_pending_ = false;
     std::unique_ptr<WebGestureEvent> event(new WebGestureEvent(
         WebInputEvent::GestureTapDown, WebInputEvent::NoModifiers, timestamp));
     event->sourceDevice = blink::WebGestureDeviceTouchpad;
     event->x = pixel_x;
     event->y = pixel_y;
     gesture_list.push_back(std::move(event));
   }
 
-  for (const auto& gesture : gesture_list) {
+  for (auto& gesture : gesture_list) {
+    gesture->x = pixel_x;
+    gesture->y = pixel_y;
+    auto movableGesture = base::MakeUnique<WebGestureEvent>(*gesture);
+
     switch (gesture->type()) {
+      // Once the user starts scrolling send all the scroll events to this
+      // element until the scrolling stops.
       case WebInputEvent::GestureScrollBegin:
+        current_scroll_target = input_target;
+        if (current_scroll_target != InputTarget::NONE) {
+          SendGesture(current_scroll_target, std::move(movableGesture));
+        }
+        break;
+      case WebInputEvent::GestureScrollEnd:
+        if (current_scroll_target != InputTarget::NONE) {
+          SendGesture(current_scroll_target, std::move(movableGesture));
+        }
+        current_scroll_target = InputTarget::NONE;
+        break;
       case WebInputEvent::GestureScrollUpdate:
-      case WebInputEvent::GestureScrollEnd:
       case WebInputEvent::GestureFlingCancel:
       case WebInputEvent::GestureFlingStart:
-        SendGesture(InputTarget::CONTENT,
-                    base::WrapUnique(new WebGestureEvent(*gesture)));
+        if (current_scroll_target != InputTarget::NONE) {
+          SendGesture(current_scroll_target, std::move(movableGesture));
+        }
         break;
       case WebInputEvent::GestureTapDown:
-        gesture->x = pixel_x;
-        gesture->y = pixel_y;
-        if (input_target != InputTarget::NONE)
-          SendGesture(input_target,
-                      base::WrapUnique(new WebGestureEvent(*gesture)));
+        if (input_target != InputTarget::NONE) {
+          SendGesture(input_target, std::move(movableGesture));
+        }
         break;
       case WebInputEvent::Undefined:
         break;
       default:
         NOTREACHED();
     }
   }
 
   // Hover support
   bool new_target = input_target != current_input_target_;
@@ skipping 502 matching lines @@
     const base::Callback<void(device::mojom::VRDisplayInfoPtr)>& callback,
     uint32_t device_id) {
   device::mojom::VRDisplayInfoPtr info = VrShell::CreateVRDisplayInfo(
       gvr_api_.get(), content_tex_physical_size_, device_id);
   main_thread_task_runner_->PostTask(
       FROM_HERE,
       base::Bind(&RunVRDisplayInfoCallback, callback, base::Passed(&info)));
 }
 
 }  // namespace vr_shell