WebVR: add angular velocity estimate to pose

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/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"
 
 namespace vr_shell {
 
 namespace {
 
 constexpr float kDisplacementScaleFactor = 300.0f;
 
 // A slop represents a small rectangular region around the first touch point of
@@ skipping 77 matching lines @@
   if (controller_api_)
     controller_api_->Pause();
 }
 
 device::GvrGamepadData VrController::GetGamepadData() {
   device::GvrGamepadData pad;
 
   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);
   pad.right_handed = handedness_ == GVR_CONTROLLER_RIGHT_HANDED;
 
   return pad;
 }
 
 bool VrController::IsTouching() {
   return controller_state_->IsTouching();
@@ skipping 74 matching lines @@
       gvr::GvrApi::GetTimePointNow().monotonic_system_time_nanos;
 }
 
 void VrController::Initialize(gvr_context* gvr_context) {
   CHECK(gvr_context != nullptr) << "invalid gvr_context";
   controller_api_.reset(new gvr::ControllerApi);
   controller_state_.reset(new gvr::ControllerState);
 
   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));
 
   std::unique_ptr<gvr::GvrApi> gvr = gvr::GvrApi::WrapNonOwned(gvr_context);
   // TODO(bajones): Monitor changes to the controller handedness.
   handedness_ = gvr->GetUserPrefs().GetControllerHandedness();
 
   // Work around an obscure link error in component build.
   // third_party/gvr-android-sdk/libgvr_shim_static_arm.a needs
   // __aeabi_f2lz (float to int64_t static cast implementation) for
@@ skipping 205 matching lines @@
   gvr::Vec2f velocity = Vector::ScalarMult(displacement, 1 / duration);
 
   float weight = duration / (kRC + duration);
 
   overall_velocity_ =
       Vector::Add(Vector::ScalarMult(overall_velocity_, 1 - weight),
                   Vector::ScalarMult(velocity, weight));
 }
 
 }  // namespace vr_shell