Qt 5 - OpenGL Problem

ZapB · wrote on 10 Jan 2013, 09:16

Oh boy this really needs to go into an FAQ somewhere. Let me guess, you are using the pre-compiled Qt5 SDK on Windows? If so that is the cause of your problem. Let me explain.

The precompiled binary packages ship with Qt5 configured for OpenGL ES 2 and using the ANGLE layer which implements ES 2 on top of DirectX. This was done to ensure that QtQuick2 works on all windows machines, even those with crappy Intel OpenGL drivers.

To get access to glBegin() etc which are not part of OpenGL ES 2 you need to build your own Qt5 and pass in the -opengl desktop option to configure.

Qt 5.0.1 should hopefully also ship with such a pre-compiled Qt. Please go and vote for this bug https://bugreports.qt-project.org/browse/QTBUG-28715

DamianPrg · wrote on 10 Jan 2013, 19:35

[quote author="ZapB" date="1357809361"]Oh boy this really needs to go into an FAQ somewhere. Let me guess, you are using the pre-compiled Qt5 SDK on Windows? If so that is the cause of your problem. Let me explain.

The precompiled binary packages ship with Qt5 configured for OpenGL ES 2 and using the ANGLE layer which implements ES 2 on top of DirectX. This was done to ensure that QtQuick2 works on all windows machines, even those with crappy Intel OpenGL drivers.

To get access to glBegin() etc which are not part of OpenGL ES 2 you need to build your own Qt5 and pass in the -opengl desktop option to configure.

Qt 5.0.1 should hopefully also ship with such a pre-compiled Qt. Please go and vote for this bug https://bugreports.qt-project.org/browse/QTBUG-28715

[/quote]

Ok thanks, I will try to compile it by myself, Thank again :-)

utcenter · wrote on 10 Jan 2013, 20:12

People still use glBegin? Don't!!!

DamianPrg · wrote on 10 Jan 2013, 20:15

[quote author="utcenter" date="1357848726"]People still use glBegin? Don't!!![/quote]

Often I use modern opengl (3.2), but for simple 2d editor, I should be allright with VA and fixed OpenGL 2.1.

utcenter · wrote on 10 Jan 2013, 20:18

The fixed function pipeline is left only for the sake of backward compatibility, only for code that already exists, if you write new code, it is very counter-productive to use it. You don't really gain anything by using it, you lose out on many features that are beneficial even in 2d, and in many cases, performance is actually worse, plus you lose portability.

ZapB · wrote on 10 Jan 2013, 20:31

If you are writing new code then I would also recommend avoiding the old fixed function pipeline stuff. Note that some vendors (notably Apple) do not implement the compatibility profile. So if you need a 3.2 context on OS X you can only use the Core profile. Just something to bear in mind.

DamianPrg · wrote on 10 Jan 2013, 21:06

[quote author="ZapB" date="1357849860"]If you are writing new code then I would also recommend avoiding the old fixed function pipeline stuff. Note that some vendors (notably Apple) do not implement the compatibility profile. So if you need a 3.2 context on OS X you can only use the Core profile. Just something to bear in mind.[/quote]

Anyway if i want to use OpenGL 3.2+, i need compiile qt by myself.

mgonzalo · wrote on 16 Jan 2013, 12:20

Hi guys!

I've got exactly the same problem as DamianPrg.

Maybe this is a stupid question, but I am a very beginner, anyway : what do you mean by saying that you need to compile Qt by yourself ?

DamianPrg · wrote on 16 Jan 2013, 12:22

[quote author="mgonzalo" date="1358338826"]Hi guys!

I've got exactly the same problem as DamianPrg.

Maybe this is a stupid question, but I am a very beginner, anyway : what do you mean by saying that you need to compile Qt by yourself ?

[/quote]

You can compile it by yourself, I tried but didn't work. Some problem with configure.
Or you can wait for next release of Qt 5, and maybe there will be OpenGL desktop instead of GL ES 2.

Note: If you want compile it by yourself, it will take some time, on good machine about 1h :-)

ZapB · wrote on 16 Jan 2013, 12:24

Well, just that you need to compile your own build of the Qt libraries to enable Desktop OpenGL on windows at present. Helpful instructions can be found at http://qt-project.org/wiki/Building_Qt_5_from_Git

DamianPrg · wrote on 16 Jan 2013, 12:25

http://www.youtube.com/watch?v=K0O6mvD6uk4 - It also can help you :-)

sierdzio · wrote on 16 Jan 2013, 12:27

Qt is a set of libraries and tools. What you download from Qt Project web site is - most probably - a pack of precompiled libraries, ready to be used. Necessarily, this general package is compiled with default, fit-for-all settings.

However, Qt is a big project, and can be compiled in thousands of ways (by passing flags to configure script) and for some usages it's better to define those flags as you want to.

Qt Project is open sourced, you can download sources yourself and take a look ("link":http://qt-project.org/wiki/Building_Qt_5_from_Git).

EDIT whoosh, I was waaaay too slow on this one ;)

DamianPrg · wrote on 16 Jan 2013, 12:31

@

C:\qt5>configure -developer-build -opensource -opengl desktop -nomake examples -
nomake tests

C:/qt5/qtbase/configure -developer-build -opensource -opengl desktop -nomake e
xamples -nomake tests
'C:\qt5\qtbase\configure.exe' is not recognized as an internal or external comm
and,
operable program or batch file.
*** qtbase/configure exited with non-zero status.

C:\qt5>
@

This is what I get when I try to configure. Note that i have Perl, Python installed. Source code is downloaded from http://qt-project.org/downloads

sierdzio · wrote on 16 Jan 2013, 12:34

On Windows, you need to rdowload the .zip file, not tarball. Also, I think you need to run configure.exe, not the configure script. I'm using Linux, though, this info is second-hand at best ;)

ZapB · wrote on 16 Jan 2013, 12:35

Probably best to get a git clone as it is easier to get back to a clean state. Also it makes sure you have the same exact source tree as the Qt devs so it's easier to trouble shoot. The packaging may remove some files needed to do a fresh build. Does the configure.exe actually exist at that path?

DamianPrg · wrote on 16 Jan 2013, 12:39

[quote author="sierdzio" date="1358339671"]On Windows, you need to rdowload the .zip file, not tarball. Also, I think you need to run configure.exe, not the configure script. I'm using Linux, though, this info is second-hand at best ;)[/quote]

I tried ZIP, but it wont extract on my PC. Do you think thats problem? Because Tarball is often used on linux?

@ZapB - Does the configure.exe actually exist at that path?

No, just .bat and one with no extenstion.

sierdzio · wrote on 16 Jan 2013, 12:45

Qt packaging strips tarballs of things that are not needed on unix (so, Windows stuff is missing there), and uses unix line endings. So you need the .zip.

As ZapB mentioned, using git is a much better idea.

DamianPrg · wrote on 16 Jan 2013, 12:52

Ok thanks, guys. I will install from there.

DamianPrg · wrote on 16 Jan 2013, 14:20

Ok, i downloaded source from GitHub, and I have new problem.

@

C:\Users\Damian\Documents\GitHub\qt5>configure -developer-build -opensource -ope
ngl desktop -nomake examples -nomake tests

C:/Users/Damian/Documents/GitHub/qt5/qtbase/configure -developer-build -openso
urce -opengl desktop -nomake examples -nomake tests
Please wait while bootstrapping configure ...
<srcbase> = C:/Users/Damian/Documents/GitHub/qt5/qtbase
<outbase> = C:/Users/Damian/Documents/GitHub/qt5/qtbase
No suitable compiler found in PATH. Aborting.
*** qtbase/configure exited with non-zero status.

C:\Users\Damian\Documents\GitHub\qt5>
@

I have VS10 Pro, VS11 Pro, so why it says "No suitable compiler found in PATH", should I add VS to PATH, or what?

ZapB · wrote on 16 Jan 2013, 14:33

Run configure from a MS VS10 command prompt so that the environment variables are set up to find the compiler etc on the %PATH%