Use C++ <cmath> instead of <math.h>

Including math.h can pollute the default namespace, and break
some compilers if cmath versions of the method are declared as using.

Switching to C++ math functions also greatly simplifies handling of
float qreal as C++ automatically chooses the right method.

[ChangeLog][QtCore][QtMath] qmath.h no longer includes math.h, so any
sources depending on that indirect inclusion may fail to build.

Change-Id: I4d0e331dafba354ec05dc5052e61ef4ff8d387fe
Reviewed-by: Rafael Roquetto <rafael.roquetto@kdab.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/examples/widgets/graphicsview/boxes/trackball.cpp b/examples/widgets/graphicsview/boxes/trackball.cpp
index 2267636fa4..b1159b4989 100644
--- a/examples/widgets/graphicsview/boxes/trackball.cpp
+++ b/examples/widgets/graphicsview/boxes/trackball.cpp
@@ -33,6 +33,7 @@
 
 #include "trackball.h"
 #include "scene.h"
+#include <cmath>
 
 //============================================================================//
 //                                  TrackBall                                 //
@@ -94,19 +95,19 @@ void TrackBall::move(const QPointF& p, const QQuaternion &transformation)
             QVector3D lastPos3D = QVector3D(m_lastPos.x(), m_lastPos.y(), 0.0f);
             float sqrZ = 1 - QVector3D::dotProduct(lastPos3D, lastPos3D);
             if (sqrZ > 0)
-                lastPos3D.setZ(sqrt(sqrZ));
+                lastPos3D.setZ(std::sqrt(sqrZ));
             else
                 lastPos3D.normalize();
 
             QVector3D currentPos3D = QVector3D(p.x(), p.y(), 0.0f);
             sqrZ = 1 - QVector3D::dotProduct(currentPos3D, currentPos3D);
             if (sqrZ > 0)
-                currentPos3D.setZ(sqrt(sqrZ));
+                currentPos3D.setZ(std::sqrt(sqrZ));
             else
                 currentPos3D.normalize();
 
             m_axis = QVector3D::crossProduct(lastPos3D, currentPos3D);
-            float angle = 180 / PI * asin(sqrt(QVector3D::dotProduct(m_axis, m_axis)));
+            float angle = 180 / PI * std::asin(std::sqrt(QVector3D::dotProduct(m_axis, m_axis)));
 
             m_angularVelocity = angle / msecs;
             m_axis.normalize();