[Interest] Replacement for Qt4 QMatrix4x4?

[Christian Gagneraud]

On Tue, 26 Feb 2019 at 05:37, Jason H <jhihn at gmx.com> wrote:
>
> > Sent: Friday, February 22, 2019 at 4:27 AM
> > From: "Christian Gagneraud" <chgans at gmail.com>
> > Would you consider making arm v8 the minimum requirement for Qt6?
>
> You might anger the raspberry pi people who still use ARM11 in the Pi Zero, and other embedded users. I don't see 32bit arm cores going away any time soon, particularly in embedded designs. It may be acceptable to cap these at a Qt5 version. Since ARM v8 is only 7 years old (about the same age of Qt5), I would hesitate to leave 32-bit arm out.

It was more a question than a suggestion. The rational is that
qreal=float only make sense on low-end/old processors, so if ARMv8 is
the minimum required, you can completely get rid of qreal.
Our code base is built with qreal=float on ARM and qreal=double on x86
Linux/Windows. It's actually a pain if you enable certain
-Wconversion.
How to you assign a literal to a qreal? You cannot, there's no qreal
literal, only float and double.
This code:
qreal a = 0.1f;
qreal b = 0.1;
Will cause a warning in both cases:
qreal=double: implicit conversion of a increases floating-point precision
qreal=float: implicit conversion of b looses floating-point precision

Chris