Thanks for the quick response. It is now QTBUG-21035. Keith
-----Original Message----- From: [email protected] [mailto:[email protected]] Sent: Friday, August 19, 2011 1:47 PM To: Keith Gardner Cc: [email protected] Subject: Re: [Qt5-feedback] Question about QVector2D, QVector3D, QVector4D, etc... On Aug 19, 2011, at 8:35 PM, ext Keith Gardner wrote: > I noticed that QVector2D, QVector3D, QVector4D, etc... use floats as the > storage type and I recognize that it was a performance decision to do it this > way. I am just wondering why the getters and setters for the structures use > qreal as the parameter type instead of floats. > > I know that on a mobile system qreal is a float, but on desktop systems qreal > is a double. I would like to use these data structures but the conversion > from double to float only to be accessed as a double again seems to be overly > expensive. > > In Qt5, would it be possible to have the function parameters take a floats > instead of a qreals? I think that is a very good idea. Could you make a suggestion about that on the Qt bugtracker? In general, we have discussed dropping the concept of qreal and sticking to the native C++ types. It is a pain to develop something on desktop and have the sizeof(qreal) change behind the scenes or to have an algorithm you developed suddenly become numerically unstable when ported to device. We've been thinking it is better to be explicit. For most of graphics floats is the "right" choice as it maps directly to OpenGL, is storage-wise efficient and quality-wise precise enough. Then for the cases where precision is very important, we should explicitly use double. best regards, Gunnar _______________________________________________ Qt5-feedback mailing list [email protected] http://lists.qt.nokia.com/mailman/listinfo/qt5-feedback
