WebVR: add angular velocity estimate to pose

chrome/browser/android/vr_shell/vr_controller.cc

Index: chrome/browser/android/vr_shell/vr_controller.cc
diff --git a/chrome/browser/android/vr_shell/vr_controller.cc b/chrome/browser/android/vr_shell/vr_controller.cc
index 0bcf10f6816befb5afa37c22ab11aa202c74688d..4405aa8819105815fa629f3e8da82e444a7cf280 100644
--- a/chrome/browser/android/vr_shell/vr_controller.cc
+++ b/chrome/browser/android/vr_shell/vr_controller.cc
@@ -10,6 +10,7 @@
 
 #include "base/logging.h"
 #include "base/time/time.h"
+#include "chrome/browser/android/vr_shell/vr_math.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"
 
@@ -107,8 +108,12 @@ device::GvrGamepadData VrController::GetGamepadData() {
   pad.timestamp = controller_state_->GetLastOrientationTimestamp();
   pad.touch_pos = controller_state_->GetTouchPos();
   pad.orientation = controller_state_->GetOrientation();
-  pad.accel = controller_state_->GetAccel();
-  pad.gyro = controller_state_->GetGyro();
+
+  // Use orientation to rotate acceleration/gyro into seated space.

[billorr, 2017/03/27 17:33:53]

nit: Accelerometer measurement or acceleration?  Is gravity included?

[klausw, 2017/03/27 17:55:42]

Acceleration and gravity are the same thing (blame Einstein), so it does include
(0, 9.81 m/s^2, 0) when used on Earth.

+  gvr::Mat4f pose_mat = QuatToMatrix(pad.orientation);
+  pad.accel = MatrixVectorMul(pose_mat, controller_state_->GetAccel());
+  pad.gyro = MatrixVectorMul(pose_mat, controller_state_->GetGyro());
+
   pad.is_touching = controller_state_->IsTouching();
   pad.controller_button_pressed =
       controller_state_->GetButtonState(GVR_CONTROLLER_BUTTON_CLICK);
@@ -203,9 +208,10 @@ void VrController::Initialize(gvr_context* gvr_context) {
 
   int32_t options = gvr::ControllerApi::DefaultOptions();
 
-  // Enable non-default options - WebVR needs gyro, and since VrShell
-  // implements GvrGamepadDataProvider we need this always.
+  // Enable non-default options - WebVR needs gyro and linear acceleration, and
+  // since VrShell implements GvrGamepadDataProvider we need this always.
   options |= GVR_CONTROLLER_ENABLE_GYRO;
+  options |= GVR_CONTROLLER_ENABLE_ACCEL;
 
   CHECK(controller_api_->Init(options, gvr_context));