Because Qt 3D most likely misses a few multiplications by devicePixelRatio(). Probably easy to correct.
See http://www.qtdeveloperdays.com/sites/default/files/presentation_pdf/AgocsLaszlo_opengl_enablers_news.pdf#26 Best regards, Laszlo From: interest-bounces+laszlo.agocs=theqtcompany....@qt-project.org [mailto:interest-bounces+laszlo.agocs=theqtcompany....@qt-project.org] On Behalf Of Till Oliver Knoll Sent: 24. mars 2015 15:06 To: Qt Project Subject: Re: [Interest] High-dpi fixing for Qt 5.5 Am 24.03.2015 um 14:39 schrieb Eddie Sutton <edsut...@gmail.com<mailto:edsut...@gmail.com>>: >My knowledge of available "HiDPI" APIs is currently based on your (excellent) >blog post, which does not seem to mention that use case: >http://blog.qt.io/blog/2013/04/25/retina-display-support-for-mac-os-ios-and-x11/ Thanks for posting the excellent link. It may help me find a work-around for a Qt3D windows scaling issue that affects OS X and iOS as well. This, plus the Apple Developer docs may help as well, see "Enable OpenGL for High-Resolution Drawing" https://developer.apple.com/library/mac/documentation/GraphicsAnimation/Conceptual/HighResolutionOSX/CapturingScreenContents/CapturingScreenContents.html#//apple_ref/doc/uid/TP40012302-CH10-SW1 "OpenGL is a pixel-based API. The NSOpenGLView class does not provide high-resolution surfaces by default. Because adding more pixels to renderbuffers has performance implications, you must explicitly opt in to support high-resolution screens. You can opt in to high resolution by calling the method setWantsBestResolutionOpenGLSurface: when you initialize the view, and supplying YES as an argument: [self setWantsBestResolutionOpenGLSurface:YES]; If you don't opt in, the system magnifies the rendered results." /quote Basically the docs say that OpenGL is a pixel-based drawing system, so any conversions between "points" and "pixels" needs to be done explicitly by the application itself, e.g. when resizing a window. And that you have to explicitly enable the "HiDPI" mode for the OpenGL context first. How much that helps you to fix problems with the Qt3D module I can't say, but it is generally something you have to keep in mind when developing your own OpenGL based application (under OS X - on other OSes similar rules probably apply, too). Cheers, Oliver
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