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// Copyright 2014 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 "data_fetcher_shared_memory.h"
#include "base/logging.h"
#include "base/metrics/histogram.h"
#include "third_party/sudden_motion_sensor/sudden_motion_sensor_mac.h"
namespace {
const double kMeanGravity = 9.80665;
void FetchMotion(SuddenMotionSensor* sensor,
content::DeviceMotionHardwareBuffer* buffer) {
DCHECK(buffer);
float axis_value[3];
if (!sensor->ReadSensorValues(axis_value))
return;
buffer->seqlock.WriteBegin();
buffer->data.accelerationIncludingGravityX = axis_value[0] * kMeanGravity;
buffer->data.hasAccelerationIncludingGravityX = true;
buffer->data.accelerationIncludingGravityY = axis_value[1] * kMeanGravity;
buffer->data.hasAccelerationIncludingGravityY = true;
buffer->data.accelerationIncludingGravityZ = axis_value[2] * kMeanGravity;
buffer->data.hasAccelerationIncludingGravityZ = true;
buffer->data.allAvailableSensorsAreActive = true;
buffer->seqlock.WriteEnd();
}
void FetchOrientation(SuddenMotionSensor* sensor,
content::DeviceOrientationHardwareBuffer* buffer) {
DCHECK(buffer);
// Retrieve per-axis calibrated values.
float axis_value[3];
if (!sensor->ReadSensorValues(axis_value))
return;
// Transform the accelerometer values to W3C draft angles.
//
// Accelerometer values are just dot products of the sensor axes
// by the gravity vector 'g' with the result for the z axis inverted.
//
// To understand this transformation calculate the 3rd row of the z-x-y
// Euler angles rotation matrix (because of the 'g' vector, only 3rd row
// affects to the result). Note that z-x-y matrix means R = Ry * Rx * Rz.
// Then, assume alpha = 0 and you get this:
//
// x_acc = sin(gamma)
// y_acc = - cos(gamma) * sin(beta)
// z_acc = cos(beta) * cos(gamma)
//
// After that the rest is just a bit of trigonometry.
//
// Also note that alpha can't be provided but it's assumed to be always zero.
// This is necessary in order to provide enough information to solve
// the equations.
//
const double kRad2deg = 180.0 / M_PI;
double beta = kRad2deg * atan2(-axis_value[1], axis_value[2]);
double gamma = kRad2deg * asin(axis_value[0]);
// Make sure that the interval boundaries comply with the specification. At
// this point, beta is [-180, 180] and gamma is [-90, 90], but the spec has
// the upper bound open on both.
if (beta == 180.0)
beta = -180; // -180 == 180 (upside-down)
if (gamma == 90.0)
gamma = nextafter(90, 0);
// At this point, DCHECKing is paranoia. Never hurts.
DCHECK_GE(beta, -180.0);
DCHECK_LT(beta, 180.0);
DCHECK_GE(gamma, -90.0);
DCHECK_LT(gamma, 90.0);
buffer->seqlock.WriteBegin();
buffer->data.beta = beta;
buffer->data.hasBeta = true;
buffer->data.gamma = gamma;
buffer->data.hasGamma = true;
buffer->data.allAvailableSensorsAreActive = true;
buffer->seqlock.WriteEnd();
}
} // namespace
namespace content {
DataFetcherSharedMemory::DataFetcherSharedMemory() {
}
DataFetcherSharedMemory::~DataFetcherSharedMemory() {
}
void DataFetcherSharedMemory::Fetch(unsigned consumer_bitmask) {
DCHECK(base::MessageLoop::current() == GetPollingMessageLoop());
DCHECK(sudden_motion_sensor_);
DCHECK(consumer_bitmask & CONSUMER_TYPE_ORIENTATION ||
consumer_bitmask & CONSUMER_TYPE_MOTION);
if (consumer_bitmask & CONSUMER_TYPE_ORIENTATION)
FetchOrientation(sudden_motion_sensor_.get(), orientation_buffer_);
if (consumer_bitmask & CONSUMER_TYPE_MOTION)
FetchMotion(sudden_motion_sensor_.get(), motion_buffer_);
}
DataFetcherSharedMemory::FetcherType DataFetcherSharedMemory::GetType() const {
return FETCHER_TYPE_POLLING_CALLBACK;
}
bool DataFetcherSharedMemory::Start(ConsumerType consumer_type, void* buffer) {
DCHECK(base::MessageLoop::current() == GetPollingMessageLoop());
DCHECK(buffer);
if (!sudden_motion_sensor_)
sudden_motion_sensor_.reset(SuddenMotionSensor::Create());
bool sudden_motion_sensor_available = sudden_motion_sensor_.get() != NULL;
switch (consumer_type) {
case CONSUMER_TYPE_MOTION:
motion_buffer_ = static_cast<DeviceMotionHardwareBuffer*>(buffer);
UMA_HISTOGRAM_BOOLEAN("InertialSensor.MotionMacAvailable",
sudden_motion_sensor_available);
if (!sudden_motion_sensor_available) {
// No motion sensor available, fire an all-null event.
motion_buffer_->seqlock.WriteBegin();
motion_buffer_->data.allAvailableSensorsAreActive = true;
motion_buffer_->seqlock.WriteEnd();
}
return sudden_motion_sensor_available;
case CONSUMER_TYPE_ORIENTATION:
orientation_buffer_ =
static_cast<DeviceOrientationHardwareBuffer*>(buffer);
UMA_HISTOGRAM_BOOLEAN("InertialSensor.OrientationMacAvailable",
sudden_motion_sensor_available);
if (sudden_motion_sensor_available) {
// On Mac we cannot provide absolute orientation.
orientation_buffer_->seqlock.WriteBegin();
orientation_buffer_->data.absolute = false;
orientation_buffer_->data.hasAbsolute = true;
orientation_buffer_->seqlock.WriteEnd();
} else {
// No motion sensor available, fire an all-null event.
orientation_buffer_->seqlock.WriteBegin();
orientation_buffer_->data.allAvailableSensorsAreActive = true;
orientation_buffer_->seqlock.WriteEnd();
}
return sudden_motion_sensor_available;
default:
NOTREACHED();
}
return false;
}
bool DataFetcherSharedMemory::Stop(ConsumerType consumer_type) {
DCHECK(base::MessageLoop::current() == GetPollingMessageLoop());
switch (consumer_type) {
case CONSUMER_TYPE_MOTION:
if (motion_buffer_) {
motion_buffer_->seqlock.WriteBegin();
motion_buffer_->data.allAvailableSensorsAreActive = false;
motion_buffer_->seqlock.WriteEnd();
motion_buffer_ = NULL;
}
return true;
case CONSUMER_TYPE_ORIENTATION:
if (orientation_buffer_) {
orientation_buffer_->seqlock.WriteBegin();
orientation_buffer_->data.allAvailableSensorsAreActive = false;
orientation_buffer_->seqlock.WriteEnd();
orientation_buffer_ = NULL;
}
return true;
default:
NOTREACHED();
}
return false;
}
} // namespace content
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