5 files changed, 30 insertions, 12 deletions
diff --git a/src/gui/math3d/qgenericmatrix.h b/src/gui/math3d/qgenericmatrix.h
index c08faaaa8b..19809056fd 100644
--- a/src/gui/math3d/qgenericmatrix.h
+++ b/src/gui/math3d/qgenericmatrix.h
@@ -57,7 +57,7 @@ public:
 
     void fill(T value);
 
-    QGenericMatrix<M, N, T> transposed() const;
+    QGenericMatrix<M, N, T> transposed() const Q_REQUIRED_RESULT;
 
     QGenericMatrix<N, M, T>& operator+=(const QGenericMatrix<N, M, T>& other);
     QGenericMatrix<N, M, T>& operator-=(const QGenericMatrix<N, M, T>& other);
diff --git a/src/gui/math3d/qquaternion.cpp b/src/gui/math3d/qquaternion.cpp
index 4b35ee4e79..0e73f79ac0 100644
--- a/src/gui/math3d/qquaternion.cpp
+++ b/src/gui/math3d/qquaternion.cpp
@@ -301,13 +301,21 @@ void QQuaternion::normalize()
 */
 
 /*!
-    \fn QQuaternion QQuaternion::conjugate() const
+    \fn QQuaternion QQuaternion::conjugated() const
+    \since 5.5
 
     Returns the conjugate of this quaternion, which is
     (-x, -y, -z, scalar).
 */
 
 /*!
+    \fn QQuaternion QQuaternion::conjugate() const
+    \obsolete
+
+    Use conjugated() instead.
+*/
+
+/*!
     Rotates \a vector with this quaternion to produce a new vector
     in 3D space.  The following code:
 
@@ -318,12 +326,12 @@ void QQuaternion::normalize()
     is equivalent to the following:
 
     \code
-    QVector3D result = (q * QQuaternion(0, vector) * q.conjugate()).vector();
+    QVector3D result = (q * QQuaternion(0, vector) * q.conjugated()).vector();
     \endcode
 */
 QVector3D QQuaternion::rotatedVector(const QVector3D& vector) const
 {
-    return (*this * QQuaternion(0, vector) * conjugate()).vector();
+    return (*this * QQuaternion(0, vector) * conjugated()).vector();
 }
 
 /*!
diff --git a/src/gui/math3d/qquaternion.h b/src/gui/math3d/qquaternion.h
index 52c717072d..5b0006ac56 100644
--- a/src/gui/math3d/qquaternion.h
+++ b/src/gui/math3d/qquaternion.h
@@ -83,12 +83,15 @@ public:
     float length() const;
     float lengthSquared() const;
 
-    QQuaternion normalized() const;
+    QQuaternion normalized() const Q_REQUIRED_RESULT;
     void normalize();
 
     inline QQuaternion inverted() const;
 
-    QQuaternion conjugate() const;
+    QQuaternion conjugated() const Q_REQUIRED_RESULT;
+#if QT_DEPRECATED_SINCE(5, 5)
+    QT_DEPRECATED QQuaternion conjugate() const Q_REQUIRED_RESULT;
+#endif
 
     QVector3D rotatedVector(const QVector3D& vector) const;
 
@@ -161,12 +164,12 @@ inline QQuaternion::QQuaternion(float aScalar, float xpos, float ypos, float zpo
 
 inline bool QQuaternion::isNull() const
 {
-    return qIsNull(xp) && qIsNull(yp) && qIsNull(zp) && qIsNull(wp);
+    return xp == 0.0f && yp == 0.0f && zp == 0.0f && wp == 0.0f;
 }
 
 inline bool QQuaternion::isIdentity() const
 {
-    return qIsNull(xp) && qIsNull(yp) && qIsNull(zp) && wp == 1.0f;
+    return xp == 0.0f && yp == 0.0f && zp == 0.0f && wp == 1.0f;
 }
 
 inline float QQuaternion::x() const { return xp; }
@@ -196,11 +199,18 @@ inline QQuaternion QQuaternion::inverted() const
     return QQuaternion(0.0f, 0.0f, 0.0f, 0.0f);
 }
 
-inline QQuaternion QQuaternion::conjugate() const
+inline QQuaternion QQuaternion::conjugated() const
 {
     return QQuaternion(wp, -xp, -yp, -zp);
 }
 
+#if QT_DEPRECATED_SINCE(5, 5)
+inline QQuaternion QQuaternion::conjugate() const
+{
+    return conjugated();
+}
+#endif
+
 inline QQuaternion &QQuaternion::operator+=(const QQuaternion &quaternion)
 {
     xp += quaternion.xp;
@@ -230,9 +240,9 @@ inline QQuaternion &QQuaternion::operator*=(float factor)
 
 inline const QQuaternion operator*(const QQuaternion &q1, const QQuaternion& q2)
 {
-    float ww = (q1.zp + q1.xp) * (q2.xp + q2.yp);
     float yy = (q1.wp - q1.yp) * (q2.wp + q2.zp);
     float zz = (q1.wp + q1.yp) * (q2.wp - q2.zp);
+    float ww = (q1.zp + q1.xp) * (q2.xp + q2.yp);
     float xx = ww + yy + zz;
     float qq = 0.5 * (xx + (q1.zp - q1.xp) * (q2.xp - q2.yp));
 
diff --git a/src/gui/math3d/qvector2d.h b/src/gui/math3d/qvector2d.h
index 20264fa84f..137142f381 100644
--- a/src/gui/math3d/qvector2d.h
+++ b/src/gui/math3d/qvector2d.h
@@ -75,7 +75,7 @@ public:
     float length() const;
     float lengthSquared() const; //In Qt 6 convert to inline and constexpr
 
-    QVector2D normalized() const;
+    QVector2D normalized() const Q_REQUIRED_RESULT;
     void normalize();
 
     float distanceToPoint(const QVector2D &point) const;
diff --git a/src/gui/math3d/qvector4d.h b/src/gui/math3d/qvector4d.h
index aa69104f55..72db8ac754 100644
--- a/src/gui/math3d/qvector4d.h
+++ b/src/gui/math3d/qvector4d.h
@@ -81,7 +81,7 @@ public:
     float length() const;
     float lengthSquared() const; //In Qt 6 convert to inline and constexpr
 
-    QVector4D normalized() const;
+    QVector4D normalized() const Q_REQUIRED_RESULT;
     void normalize();
 
     QVector4D &operator+=(const QVector4D &vector);