VR: Use more accurate timestamps for input events.

chrome/browser/android/vr_shell/vr_controller.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_controller.h"
 
 #include <algorithm>
 #include <cmath>
 #include <utility>
 
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
-#include "base/time/time.h"
 #include "cc/base/math_util.h"
 #include "chrome/browser/android/vr_shell/elbow_model.h"
 #include "third_party/WebKit/public/platform/WebGestureEvent.h"
 #include "third_party/WebKit/public/platform/WebInputEvent.h"
 #include "third_party/gvr-android-sdk/src/libraries/headers/vr/gvr/capi/include/gvr.h"
 #include "third_party/gvr-android-sdk/src/libraries/headers/vr/gvr/capi/include/gvr_controller.h"
 #include "ui/gfx/transform.h"
 
 namespace vr_shell {
 
@@ skipping 18 matching lines @@
 
 constexpr float kCutoffHz = 10.0f;
 constexpr float kRC = static_cast<float>(1.0 / (2.0 * M_PI * kCutoffHz));
 constexpr float kNanoSecondsPerSecond = 1.0e9f;
 
 constexpr int kMaxNumOfExtrapolations = 2;
 
 // Distance from the center of the controller to start rendering the laser.
 constexpr float kLaserStartDisplacement = 0.045;
 
+constexpr float microsPerNano = 1000.0;

[cjgrant, 2017/06/16 16:19:00]

Why use a float?  The types used with this are integer.

[mthiesse, 2017/06/16 17:24:11]

Done.

+
 void ClampTouchpadPosition(gfx::Vector2dF* position) {
   position->set_x(cc::MathUtil::ClampToRange(position->x(), 0.0f, 1.0f));
   position->set_y(cc::MathUtil::ClampToRange(position->y(), 0.0f, 1.0f));
 }
 
 float DeltaTimeSeconds(int64_t last_timestamp_nanos) {
   return (gvr::GvrApi::GetTimePointNow().monotonic_system_time_nanos -
           last_timestamp_nanos) /
          kNanoSecondsPerSecond;
 }
@@ skipping 72 matching lines @@
 }
 
 float VrController::TouchPosX() {
   return controller_state_->GetTouchPos().x;
 }
 
 float VrController::TouchPosY() {
   return controller_state_->GetTouchPos().y;
 }
 
+base::TimeTicks VrController::GetLastOrientationTimestamp() const {
+  return base::TimeTicks::FromInternalValue(
+      controller_state_->GetLastOrientationTimestamp() / microsPerNano);
+}
+
+base::TimeTicks VrController::GetLastTouchTimestamp() const {
+  return base::TimeTicks::FromInternalValue(
+      controller_state_->GetLastTouchTimestamp() / microsPerNano);
+}
+
+base::TimeTicks VrController::GetLastButtonTimestamp() const {
+  return base::TimeTicks::FromInternalValue(
+      controller_state_->GetLastButtonTimestamp() / microsPerNano);
+}
+
 gfx::Quaternion VrController::Orientation() const {
   const gvr::Quatf& orientation = controller_state_->GetOrientation();
   return gfx::Quaternion(orientation.qx, orientation.qy, orientation.qz,
                          orientation.qw);
 }
 
 void VrController::GetTransform(gfx::Transform* out) const {
   *out = gfx::Transform(elbow_model_->GetControllerRotation());
   gfx::Point3F p = elbow_model_->GetControllerPosition();
   out->matrix().postTranslate(p.x(), p.y(), p.z());
@@ skipping 129 matching lines @@
       gesture_list->push_back(std::move(fling));
     }
     Reset();
   }
 
   return gesture_list;
 }
 
 void VrController::UpdateGestureFromTouchInfo(blink::WebGestureEvent* gesture) {
   gesture->SetTimeStampSeconds(
-      (base::TimeTicks::Now() - base::TimeTicks()).InSecondsF());
+      (GetLastTouchTimestamp() - base::TimeTicks()).InSecondsF());
   switch (state_) {
     // User has not put finger on touch pad.
     case WAITING:
       HandleWaitingState(gesture);
       break;
     // User has not started a gesture (by moving out of slop).
     case TOUCHING:
       HandleDetectingState(gesture);
       break;
     // User is scrolling on touchpad
@@ skipping 132 matching lines @@
 
   const gfx::Vector2dF& velocity = ScaleVector2d(displacement, (1 / duration));
 
   float weight = duration / (kRC + duration);
 
   overall_velocity_ = ScaleVector2d(overall_velocity_, (1 - weight)) +
                       ScaleVector2d(velocity, weight);
 }
 
 }  // namespace vr_shell