Fix QAudioEngine constructors

From API review:

- QObject *parent always comes _last_, any additional ctor arguments
  go in front

Also make the default ctor non-explicit (so = {} works to invoke it).

Change-Id: I5db7c1bcbda023edb781757648c0e46eb0e4d3af
Reviewed-by: Lars Knoll <lars.knoll@gmail.com>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
(cherry picked from commit 18d1b7b8ce632d131286cfec3ffe6d047eb52d9d)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

2 files changed, 17 insertions, 8 deletions

diff --git a/src/spatialaudio/qaudioengine.cpp b/src/spatialaudio/qaudioengine.cpp
index fdf3864f8..e4bff71a4 100644
--- a/src/spatialaudio/qaudioengine.cpp
+++ b/src/spatialaudio/qaudioengine.cpp
@@ -323,15 +323,22 @@ QVector3D QAudioEnginePrivate::listenerPosition() const
 */
 
 /*!
-    Constructs a spatial audio engine with \a parent.
+    \fn QAudioEngine::QAudioEngine()
+    \fn QAudioEngine::QAudioEngine(QObject *parent)
+    \fn QAudioEngine::QAudioEngine(int sampleRate, QObject *parent = nullptr)
 
-    The engine will operate with a sample rate given by \a sampleRate. Sound content that is
-    not provided at that sample rate will automatically get resampled to \a sampleRate when
-    being processed by the engine. The default sample rate is fine in most cases, but you can define
-    a different rate if most of your sound files are sampled with a different rate, and avoid some
-    CPU overhead for resampling.
+    Constructs a spatial audio engine with \a parent, if any.
+
+    The engine will operate with a sample rate given by \a sampleRate. The
+    default sample rate, if none is provided, is 44100 (44.1kHz).
+
+    Sound content that is not provided at that sample rate will automatically
+    get resampled to \a sampleRate when being processed by the engine. The
+    default sample rate is fine in most cases, but you can define a different
+    rate if most of your sound files are sampled with a different rate, and
+    avoid some CPU overhead for resampling.
  */
-QAudioEngine::QAudioEngine(QObject *parent, int sampleRate)
+QAudioEngine::QAudioEngine(int sampleRate, QObject *parent)
     : QObject(parent)
     , d(new QAudioEnginePrivate)
 {
diff --git a/src/spatialaudio/qaudioengine.h b/src/spatialaudio/qaudioengine.h
index a88967cc1..da83c9a88 100644
--- a/src/spatialaudio/qaudioengine.h
+++ b/src/spatialaudio/qaudioengine.h
@@ -21,7 +21,9 @@ class Q_SPATIALAUDIO_EXPORT QAudioEngine : public QObject
     Q_PROPERTY(bool paused READ paused WRITE setPaused NOTIFY pausedChanged)
     Q_PROPERTY(float distanceScale READ distanceScale WRITE setDistanceScale NOTIFY distanceScaleChanged)
 public:
-    explicit QAudioEngine(QObject *parent = nullptr, int sampleRate = 44100);
+    QAudioEngine() : QAudioEngine(nullptr) {};
+    explicit QAudioEngine(QObject *parent) : QAudioEngine(44100, parent) {}
+    explicit QAudioEngine(int sampleRate, QObject *parent = nullptr);
     ~QAudioEngine();
 
     enum OutputMode {