Encode frame number in pixel data for pose sync

device/vr/android/gvr/gvr_device.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 "device/vr/android/gvr/gvr_device.h"
 
 #include <math.h>
 #include <algorithm>
 
 #include "base/time/time.h"
@@ skipping 116 matching lines @@
   return device;
 }
 
 VRPosePtr GvrDevice::GetPose() {
   TRACE_EVENT0("input", "GvrDevice::GetSensorState");
 
   VRPosePtr pose = VRPose::New();
 
   pose->timestamp = base::Time::Now().ToJsTime();
 
+  // Increment pose frame counter always, even if it's a faked pose.
+  pose->poseIndex = ++pose_index_;
+
   pose->orientation = mojo::Array<float>::New(4);
 
   gvr::GvrApi* gvr_api = GetGvrApi();
   if (!gvr_api) {
     // If we don't have a GvrApi instance return a static forward orientation.
     pose->orientation[0] = 0.0;
     pose->orientation[1] = 0.0;
     pose->orientation[2] = 0.0;
     pose->orientation[3] = 1.0;
 
@@ skipping 22 matching lines @@
     pose->orientation[1] = decomposed_transform.quaternion[1];
     pose->orientation[2] = decomposed_transform.quaternion[2];
     pose->orientation[3] = decomposed_transform.quaternion[3];
 
     pose->position = mojo::Array<float>::New(3);
     pose->position[0] = decomposed_transform.translate[0];
     pose->position[1] = decomposed_transform.translate[1];
     pose->position[2] = decomposed_transform.translate[2];
   }
 
+  // Save the underlying GVR pose for use by rendering. It can't use a
+  // VRPosePtr since that's a different data type.
+  delegate_->SetGvrPoseForWebVr(head_mat, pose_index_);
+
   return pose;
 }
 
 void GvrDevice::ResetPose() {
   gvr::GvrApi* gvr_api = GetGvrApi();
   if (gvr_api)
     gvr_api->ResetTracking();
 }
 
 bool GvrDevice::RequestPresent(bool secure_origin) {
@@ skipping 36 matching lines @@
 }
 
 gvr::GvrApi* GvrDevice::GetGvrApi() {
   if (!delegate_)
     return nullptr;
 
   return delegate_->gvr_api();
 }
 
 }  // namespace device