Use qRadiansToDegrees() and qDegreesToRadians() more widely

They document intent more clearly than arithmetic with pi does.
Also eliminate some hand-rolled RADIANS_TO_DEGREES constants in
favor of calling qRadiansToDegrees().

Change-Id: I7ca5e876b3591433bf681b56ad51c4cb409ac59f
Reviewed-by: Lorn Potter <lorn.potter@gmail.com>

6 files changed, 23 insertions, 31 deletions

diff --git a/src/plugins/sensors/android/src/androidcompass.cpp b/src/plugins/sensors/android/src/androidcompass.cpp
index e98f0484..610dcde7 100644
--- a/src/plugins/sensors/android/src/androidcompass.cpp
+++ b/src/plugins/sensors/android/src/androidcompass.cpp
@@ -168,7 +168,6 @@ void AndroidCompass::testStuff()
         return;
     qreal azimuth = AndroidSensors::getCompassAzimuth(m_accelerometerListener->reading, m_magnetometerListener->reading);
 
-    azimuth = azimuth * 180.0 / M_PI;
-    m_reading.setAzimuth(azimuth);
+    m_reading.setAzimuth(qRadiansToDegrees(azimuth));
     newReadingAvailable();
 }
diff --git a/src/plugins/sensors/android/src/androidgyroscope.cpp b/src/plugins/sensors/android/src/androidgyroscope.cpp
index 623838db..c963761b 100644
--- a/src/plugins/sensors/android/src/androidgyroscope.cpp
+++ b/src/plugins/sensors/android/src/androidgyroscope.cpp
@@ -38,7 +38,7 @@
 ****************************************************************************/
 
 #include "androidgyroscope.h"
-#include <math.h>
+#include <QtCore/qmath.h>
 
 AndroidGyroscope::AndroidGyroscope(AndroidSensors::AndroidSensorType type, QSensor *sensor)
     : AndroidCommonSensor<QGyroscopeReading>(type, sensor)
@@ -50,9 +50,9 @@ void AndroidGyroscope::onSensorChanged(jlong timestamp, const jfloat *values, ui
         return;
     m_reader.setTimestamp(timestamp/1000);
     // check https://developer.android.com/reference/android/hardware/SensorEvent.html#values
-    m_reader.setX(values[0]*180/M_PI);
-    m_reader.setY(values[1]*180/M_PI);
-    m_reader.setZ(values[2]*180/M_PI);
+    m_reader.setX(qRadiansToDegrees(values[0]));
+    m_reader.setY(qRadiansToDegrees(values[1]));
+    m_reader.setZ(qRadiansToDegrees(values[2]));
     newReadingAvailable();
 }
 
diff --git a/src/plugins/sensors/android/src/androidrotation.cpp b/src/plugins/sensors/android/src/androidrotation.cpp
index dfe4f2ad..f7d02257 100644
--- a/src/plugins/sensors/android/src/androidrotation.cpp
+++ b/src/plugins/sensors/android/src/androidrotation.cpp
@@ -38,7 +38,7 @@
 ****************************************************************************/
 
 #include "androidrotation.h"
-#include <math.h>
+#include <QtCore/qmath.h>
 
 AndroidRotation::AndroidRotation(AndroidSensors::AndroidSensorType type, QSensor *sensor)
     : AndroidCommonSensor<QRotationReading>(type, sensor)
@@ -55,9 +55,9 @@ void AndroidRotation::onSensorChanged(jlong timestamp, const jfloat *values, uin
         return;
     m_reader.setTimestamp(timestamp/1000);
 
-    float rz = -values[0]*180/M_PI;
-    float rx = -values[1]*180/M_PI;
-    float ry = values[2]*180/M_PI;
+    float rz = -qRadiansToDegrees(values[0]);
+    float rx = -qRadiansToDegrees(values[1]);
+    float ry =  qRadiansToDegrees(values[2]);
     m_reader.setFromEuler(rx, ry, rz);
     newReadingAvailable();
 }
diff --git a/src/plugins/sensors/generic/genericrotationsensor.cpp b/src/plugins/sensors/generic/genericrotationsensor.cpp
index adf28e43..40768297 100644
--- a/src/plugins/sensors/generic/genericrotationsensor.cpp
+++ b/src/plugins/sensors/generic/genericrotationsensor.cpp
@@ -41,8 +41,6 @@
 #include <QDebug>
 #include <qmath.h>
 
-#define RADIANS_TO_DEGREES 57.2957795
-
 char const * const genericrotationsensor::id("generic.rotation");
 
 genericrotationsensor::genericrotationsensor(QSensor *sensor)
@@ -88,8 +86,8 @@ bool genericrotationsensor::filter(QSensorReading *reading)
 
     // Note that the formula used come from this document:
     // http://www.freescale.com/files/sensors/doc/app_note/AN3461.pdf
-    pitch = qAtan(y / qSqrt(x*x + z*z)) * RADIANS_TO_DEGREES;
-    roll = qAtan(x / qSqrt(y*y + z*z)) * RADIANS_TO_DEGREES;
+    pitch = qRadiansToDegrees(qAtan(y / qSqrt(x * x + z * z)));
+    roll  = qRadiansToDegrees(qAtan(x / qSqrt(y * y + z * z)));
     // Roll is a left-handed rotation but we need right-handed rotation
     roll = -roll;
 
@@ -98,7 +96,7 @@ bool genericrotationsensor::filter(QSensorReading *reading)
     // Note that theta is defined as the angle of the Z axis relative
     // to gravity (see referenced document). It's negative when the
     // face of the device points downward.
-    qreal theta = qAtan(qSqrt(x*x + y*y) / z) * RADIANS_TO_DEGREES;
+    qreal theta = qRadiansToDegrees(qAtan(qSqrt(x * x + y * y) / z));
     if (theta < 0) {
         if (roll > 0)
             roll = 180 - roll;
diff --git a/src/plugins/sensors/generic/generictiltsensor.cpp b/src/plugins/sensors/generic/generictiltsensor.cpp
index 831b03ec..a4ada7d8 100644
--- a/src/plugins/sensors/generic/generictiltsensor.cpp
+++ b/src/plugins/sensors/generic/generictiltsensor.cpp
@@ -39,14 +39,13 @@
 
 #include "generictiltsensor.h"
 #include <QDebug>
-#define _USE_MATH_DEFINES
 #include <qmath.h>
 
 char const * const GenericTiltSensor::id("generic.tilt");
 
 GenericTiltSensor::GenericTiltSensor(QSensor *sensor)
     : QSensorBackend(sensor)
-    , radAccuracy(M_PI / 180)
+    , radAccuracy(qDegreesToRadians(qreal(1)))
     , pitch(0)
     , roll(0)
     , calibratedPitch(0)
@@ -106,11 +105,6 @@ void GenericTiltSensor::calibrate()
     calibratedRoll = roll;
 }
 
-static qreal rad2deg(qreal rad)
-{
-    return rad / (2 * M_PI) * 360;
-}
-
 bool GenericTiltSensor::filter(QAccelerometerReading *reading)
 {
     /*
@@ -159,18 +153,18 @@ bool GenericTiltSensor::filter(QAccelerometerReading *reading)
     qDebug() << "new yrot: " << yrot;
     qDebug() << "----------------------------------";
 #endif
-    qreal dxrot = rad2deg(xrot) - xRotation;
-    qreal dyrot = rad2deg(yrot) - yRotation;
+    qreal dxrot = qRadiansToDegrees(xrot) - xRotation;
+    qreal dyrot = qRadiansToDegrees(yrot) - yRotation;
     if (dxrot < 0) dxrot = -dxrot;
     if (dyrot < 0) dyrot = -dyrot;
 
     bool setNewReading = false;
-    if (dxrot >= rad2deg(radAccuracy) || !sensor()->skipDuplicates()) {
-        xRotation = rad2deg(xrot);
+    if (dxrot >= qRadiansToDegrees(radAccuracy) || !sensor()->skipDuplicates()) {
+        xRotation = qRadiansToDegrees(xrot);
         setNewReading = true;
     }
-    if (dyrot >= rad2deg(radAccuracy) || !sensor()->skipDuplicates()) {
-        yRotation = rad2deg(yrot);
+    if (dyrot >= qRadiansToDegrees(radAccuracy) || !sensor()->skipDuplicates()) {
+        yRotation = qRadiansToDegrees(yrot);
         setNewReading = true;
     }
 
diff --git a/src/plugins/sensors/ios/iosgyroscope.mm b/src/plugins/sensors/ios/iosgyroscope.mm
index 0cd37aea..8155abac 100644
--- a/src/plugins/sensors/ios/iosgyroscope.mm
+++ b/src/plugins/sensors/ios/iosgyroscope.mm
@@ -41,6 +41,7 @@
 #include "iosgyroscope.h"
 
 #import <CoreMotion/CoreMotion.h>
+#import <QtCore/qmath.h>
 
 char const * const IOSGyroscope::id("ios.gyroscope");
 
@@ -89,9 +90,9 @@ void IOSGyroscope::timerEvent(QTimerEvent *)
     if (rate.x != rate.x || rate.y != rate.y || rate.z != rate.z)
         return;
     m_reading.setTimestamp(quint64(data.timestamp * 1e6));
-    m_reading.setX((qreal(rate.x) / M_PI) * 180);
-    m_reading.setY((qreal(rate.y) / M_PI) * 180);
-    m_reading.setZ((qreal(rate.z) / M_PI) * 180);
+    m_reading.setX(qRadiansToDegrees(qreal(rate.x)));
+    m_reading.setY(qRadiansToDegrees(qreal(rate.y)));
+    m_reading.setZ(qRadiansToDegrees(qreal(rate.z)));
     newReadingAvailable();
 }