Text rendering bug with OpenGL ES?
If I build QUIt Coding's "5-in-a-row demo":http://quitcoding.com/?page=work with Qt 4.7.2 on a desktop, it displays all Text items correctly when using desktop OpenGL.
However, if I instead configure Qt with "-egl -opengl es2", only some of the text displays -- in particular, Text items show nothing with style: Text.Normal, but they do show the expected text if the style is Text.Raised, Text.Sunken or Text.Outline. (I see the same behavior in another application, which is what I really care about, but the 5-in-a-row demo makes it easy to reproduce.)
I see the same behavior with both the Mesa EGL/GLES2.x libraries and with Imagination Technologies' PVRVFrame libraries, which makes me think it is a problem in Qt or the application code rather than in the OpenGL ES stack.
Is this the intended behavior?
[EDIT: fixed link formatting, Volker]
There were some changes to QML text painting in 4.7.2, which is probably what is causing the issue. If you set the environmental variable QML_ENABLE_TEXT_IMAGE_CACHE=1 does it display correctly for you again?
Have you been able to reproduce the issue on a device, or only with the desktop es2 emulation?
The target device (with an SGX 530 core) does not show the problem.
Setting that environment variable does fix it on the desktop emulation, which I can live with. Thank you!
As an update: The target device did not show the problem before because I was not actually using QWS_DISPLAY=powervr. When Qt does use hardware acceleration on the target device, Text items show mostly corrupted without QML_ENABLE_TEXT_IMAGE_CACHE but show correctly with QML_ENABLE_TEXT_IMAGE_CACHE=1.
Okay, thanks for the update. If you decide QML_ENABLE_TEXT_IMAGE_CACHE isn't sufficient for your needs, I'd suggest filing a bug at http://bugreports.qt.nokia.com. You could possibly also try HEAD of 4.7 to see if things are fixed there (as there have been numerous QML fixes since 4.7.2).