content/browser/device_sensors/sensor_manager_chromeos.cc

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "content/browser/device_sensors/sensor_manager_chromeos.h"
   6
   7 #include <math.h>
   8
   9 #include "chromeos/accelerometer/accelerometer_reader.h"
  10 #include "chromeos/accelerometer/accelerometer_types.h"
  11 #include "content/browser/device_sensors/inertial_sensor_consts.h"
  12 #include "ui/gfx/geometry/vector3d_f.h"
  13
  14 namespace {
  15 // Conversion ratio from radians to degrees.
  16 const double kRad2deg = 180.0 / M_PI;
  17 }
  18
  19 namespace content {
  20
  21 SensorManagerChromeOS::SensorManagerChromeOS()
  22     : motion_buffer_(nullptr), orientation_buffer_(nullptr) {
  23 }
  24
  25 SensorManagerChromeOS::~SensorManagerChromeOS() {
  26 }
  27
  28 void SensorManagerChromeOS::StartFetchingDeviceMotionData(
  29     DeviceMotionHardwareBuffer* buffer) {
  30   DCHECK(thread_checker_.CalledOnValidThread());
  31   DCHECK(!motion_buffer_);
  32   motion_buffer_ = buffer;
  33
  34   motion_buffer_->seqlock.WriteBegin();
  35   // The interval between updates is the longer of the rate set on the buffer,
  36   // and the rate at which AccelerometerReader polls the sensor.
  37   motion_buffer_->data.interval =
  38       std::max(kInertialSensorIntervalMicroseconds / 1000,
  39                chromeos::AccelerometerReader::kDelayBetweenReadsMs);
  40   motion_buffer_->seqlock.WriteEnd();
  41
  42   if (!orientation_buffer_)
  43     StartObservingAccelerometer();
  44 }
  45
  46 bool SensorManagerChromeOS::StopFetchingDeviceMotionData() {
  47   DCHECK(thread_checker_.CalledOnValidThread());
  48   if (!motion_buffer_)
  49     return false;
  50
  51   // Make sure to indicate that the sensor data is no longer available.
  52   motion_buffer_->seqlock.WriteBegin();
  53   motion_buffer_->data.allAvailableSensorsAreActive = false;
  54   motion_buffer_->seqlock.WriteEnd();
  55
  56   motion_buffer_ = nullptr;
  57
  58   if (!orientation_buffer_)
  59     StopObservingAccelerometer();
  60   return true;
  61 }
  62
  63 void SensorManagerChromeOS::StartFetchingDeviceOrientationData(
  64     DeviceOrientationHardwareBuffer* buffer) {
  65   DCHECK(thread_checker_.CalledOnValidThread());
  66   DCHECK(!orientation_buffer_);
  67   orientation_buffer_ = buffer;
  68
  69   // No compass information, so we cannot provide absolute orientation.
  70   orientation_buffer_->seqlock.WriteBegin();
  71   orientation_buffer_->data.absolute = false;
  72   orientation_buffer_->data.hasAbsolute = true;
  73   orientation_buffer_->seqlock.WriteEnd();
  74
  75   if (!motion_buffer_)
  76     StartObservingAccelerometer();
  77 }
  78
  79 bool SensorManagerChromeOS::StopFetchingDeviceOrientationData() {
  80   DCHECK(thread_checker_.CalledOnValidThread());
  81   if (!orientation_buffer_)
  82     return false;
  83   // Make sure to indicate that the sensor data is no longer available.
  84   orientation_buffer_->seqlock.WriteBegin();
  85   orientation_buffer_->data.allAvailableSensorsAreActive = false;
  86   orientation_buffer_->seqlock.WriteEnd();
  87   orientation_buffer_ = nullptr;
  88
  89   if (!motion_buffer_)
  90     StopObservingAccelerometer();
  91   return true;
  92 }
  93
  94 void SensorManagerChromeOS::OnAccelerometerUpdated(
  95     scoped_refptr<const chromeos::AccelerometerUpdate> update) {
  96   DCHECK(thread_checker_.CalledOnValidThread());
  97   chromeos::AccelerometerSource source;
  98   if (update->has(chromeos::ACCELEROMETER_SOURCE_SCREEN))
  99     source = chromeos::ACCELEROMETER_SOURCE_SCREEN;
 100   else if (update->has(chromeos::ACCELEROMETER_SOURCE_ATTACHED_KEYBOARD))
 101     source = chromeos::ACCELEROMETER_SOURCE_ATTACHED_KEYBOARD;
 102   else
 103     return;
 104
 105   double x = update->get(source).x;
 106   double y = update->get(source).y;
 107   double z = update->get(source).z;
 108
 109   GenerateMotionEvent(x, y, z);
 110   GenerateOrientationEvent(x, y, z);
 111 }
 112
 113 void SensorManagerChromeOS::StartObservingAccelerometer() {
 114   chromeos::AccelerometerReader::GetInstance()->AddObserver(this);
 115 }
 116
 117 void SensorManagerChromeOS::StopObservingAccelerometer() {
 118   chromeos::AccelerometerReader::GetInstance()->RemoveObserver(this);
 119 }
 120
 121 void SensorManagerChromeOS::GenerateMotionEvent(double x, double y, double z) {
 122   if (!motion_buffer_)
 123     return;
 124
 125   motion_buffer_->seqlock.WriteBegin();
 126   motion_buffer_->data.accelerationIncludingGravityX = x;
 127   motion_buffer_->data.hasAccelerationIncludingGravityX = true;
 128   motion_buffer_->data.accelerationIncludingGravityY = y;
 129   motion_buffer_->data.hasAccelerationIncludingGravityY = true;
 130   motion_buffer_->data.accelerationIncludingGravityZ = z;
 131   motion_buffer_->data.hasAccelerationIncludingGravityZ = true;
 132   motion_buffer_->data.allAvailableSensorsAreActive = true;
 133   motion_buffer_->seqlock.WriteEnd();
 134 }
 135
 136 void SensorManagerChromeOS::GenerateOrientationEvent(double x,
 137                                                      double y,
 138                                                      double z) {
 139   if (!orientation_buffer_)
 140     return;
 141
 142   // Create a unit vector for trigonometry
 143   gfx::Vector3dF data(x, y, z);
 144   data.Scale(1.0f / data.Length());
 145
 146   // Transform accelerometer to W3C angles, using the Z-X-Y Eulerangles matrix.
 147   // x = sin(gamma)
 148   // y = -cos(gamma) * sin(beta)
 149   // z = cos(beta) * cos(gamma)
 150   // With only accelerometer alpha cannot be provided.
 151   double beta = kRad2deg * atan2(data.y(), data.z());
 152   double gamma = kRad2deg * asin(-data.x());
 153
 154   // Convert beta and gamma to fit the intervals in the specification. Beta is
 155   // [-180, 180) and gamma is [-90, 90).
 156   if (beta >= 180.0f)
 157     beta = -180.0f;
 158   if (gamma >= 90.0f)
 159     gamma = -90.0f;
 160   orientation_buffer_->seqlock.WriteBegin();
 161   orientation_buffer_->data.beta = beta;
 162   orientation_buffer_->data.hasBeta = true;
 163   orientation_buffer_->data.gamma = gamma;
 164   orientation_buffer_->data.hasGamma = true;
 165   orientation_buffer_->data.allAvailableSensorsAreActive = true;
 166   orientation_buffer_->seqlock.WriteEnd();
 167 }
 168
 169 }  // namespace content