From 2c55e121c22601d365aa353cfa39ee856770855c Mon Sep 17 00:00:00 2001 From: Giuseppe D'Angelo Date: Sun, 17 Jan 2021 19:19:39 +0100 Subject: QMatrix4x4: deprecate operator*(QVector3D, QMatrix4x4) The operation is sketchy for a number of reasons: 1) Mathematically, it doesn't make sense. The code interprets the QVector3D as a point, extending it with w=1, and uses it as a row vector. But similarly, the vector could be intepreted as a directional vector, with w=0. No semantic is "better" than the other. 2) QMatrix4x4 is not meant to be post-multiplied. Granted, one could use a QMatrix4x4 as arbitrary storage for 16 floats, but QMatrix4x4 builds itself to be always *pre* multiplied (e.g. translate changes the 4th column, not the 4th row). We can keep post multiplication for the general case if we do it against a QVector4D, but I don't feel that we should support it also for QVector3D. [ChangeLog][QtGui][QMatrix4x4] The multiplication operator (operator*) between a QVector3D and a QMatrix4x4 has been deprecated. User code needs to extend the QVector3D to a QVector4D first (by specifying the intended w coordinate), and then multiply the QVector4D by the matrix. Change-Id: I41b64d8ab7eb6126dc4c49fe29cf3f1b7afc7987 Reviewed-by: Edward Welbourne (cherry picked from commit 654a2164994974639e62f9d388408ed559b797a3) Reviewed-by: Qt Cherry-pick Bot --- src/gui/math3d/qmatrix4x4.cpp | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'src/gui/math3d/qmatrix4x4.cpp') diff --git a/src/gui/math3d/qmatrix4x4.cpp b/src/gui/math3d/qmatrix4x4.cpp index 591809df31..947af641d1 100644 --- a/src/gui/math3d/qmatrix4x4.cpp +++ b/src/gui/math3d/qmatrix4x4.cpp @@ -627,16 +627,18 @@ QMatrix4x4& QMatrix4x4::operator/=(float divisor) #ifndef QT_NO_VECTOR3D +#if QT_DEPRECATED_SINCE(6, 1) + /*! \fn QVector3D operator*(const QVector3D& vector, const QMatrix4x4& matrix) \relates QMatrix4x4 + \obsolete Convert the QVector3D to a QVector4D first, then multiply. + Returns the result of transforming \a vector according to \a matrix, - with the matrix applied post-vector. + with the matrix applied post-vector. The vector is transformed as a point. */ -#if QT_DEPRECATED_SINCE(6, 1) - /*! \fn QVector3D operator*(const QMatrix4x4& matrix, const QVector3D& vector) \relates QMatrix4x4 -- cgit v1.2.3