[Interest] Bad application rendering on Remote Desktop
Calogero Mauceri
mauceri at actgate.com
Wed Apr 29 12:32:38 CEST 2015
Interesting. Well in that case I think I'll need to modify my code to
use ANGLE, as you are suggesting.
That'll require quite an effort so for the time being I'll stay with
QGLWidget.
Thanks a lot for your hints.
Calogero
Il 4/29/2015 11:31 AM, Agocs Laszlo ha scritto:
> Hi Calogero,
>
> When adding a QOpenGLWidget or QQuickWidget into a widget hierarchy in a
> window, the entire window will be rendered differently: it is switched
> over to OpenGL-based compositing. This involves using OpenGL features not
> present in OpenGL 1.1.
>
> If you avoid adding (parenting) the QOpenGLWidget into the window, you
> will find that it becomes functional with GL 1.1 again. This is because
> you then use the traditional path without relying on GL.
>
> Note also that switching back and forth between the rendering models is
> not fully in place: making a QOpenGLWidget invisible or even removing it
> may not have any effect on how the window is rendered afterwards.
>
> Best regards,
> Laszlo
>
> On 29/04/15 10:26, "Calogero Mauceri" <mauceri at actgate.com> wrote:
>
>> Thanks Laszlo for your explanation.
>>
>> I still do not understand why the whole application is not properly
>> rendered, not only the OpenGL stuff.
>> The application we are developing is a quite complex one, having
>> multiple windows, and the OpenGL one is a small part of it.
>> Simply including just one instance of QOpenGLWidget in the application
>> causes the bad rendering, even if that widget is not even shown.
>>
>> Calogero
>>
>> Il 4/28/2015 8:54 PM, Agocs Laszlo ha scritto:
>>> Because when using remote desktop you are suddenly left with OpenGL 1.1
>>> (ouch) and so QOpenGLWidget and friends that rely on OpenGL 2.0 features
>>> (like framebuffer objects) cease to function.
>>>
>>> The solution is to rely on ANGLE or a software rasterizer (like Mesa
>>> llvmpipe) in this case.
>>>
>>> When using the dynamic OpenGL builds, the fallback to ANGLE will happen
>>> automatically when using remote desktop. I assume you are using the
>>> -opengl packages from 5.4.1 and that's why this is not in place. With
>>> 5.5
>>> this won't be an issue since desktop OpenGL packages will not be
>>> provided
>>> anymore.
>>>
>>> Best regards,
>>> Laszlo
>>>
>>>
>>> On 27/04/15 17:17, "Calogero Mauceri" <mauceri at actgate.com> wrote:
>>>
>>>> Hi all,
>>>>
>>>> switching my application from using QGLWidget to the new QOpenGLWidget
>>>> I
>>>> noticed a very weird problem when using the application through Remote
>>>> Desktop on Windows. The whole application is fully black, it is not
>>>> properly rendered, not only the QOpenGLWidget, but also the other
>>>> widgets in the application.
>>>>
>>>> I created a very simple example demonstrating my issue.
>>>>
>>>> MyWidget::MyWidget(QWidget* parent, Qt::WindowFlags fl)
>>>> : QWidget(parent, fl)
>>>> {
>>>> QVBoxLayout *vBoxLayout = new QVBoxLayout(this);
>>>> QHBoxLayout *hLayout = new QHBoxLayout;
>>>>
>>>> QLabel *myLabel = new QLabel("Test", this);
>>>> QPushButton *myButton = new QPushButton("Test", this);
>>>> hLayout->addWidget(myLabel);
>>>> hLayout->addWidget(myButton);
>>>>
>>>> QGLWidget *myOPenGLWidget = new QGLWidget(this);
>>>> // QOpenGLWidget *myOPenGLWidget = new QOpenGLWidget(this);// this
>>>> causes bad app rendering on Remote Desktop
>>>>
>>>> vBoxLayout->addItem(hLayout);
>>>> vBoxLayout->addWidget(myOPenGLWidget);
>>>> }
>>>>
>>>> When I use QGLWidget the widgets are properly rendered, as you can see
>>>> in the attached image. When I replace the QGLWidget with its counter
>>>> part QOpenGLWidget then the whole app is fully black when launched
>>>> through remote desktop (on Windows), no widget is rendered (see other
>>>> image attached). If I run the application on my local machine, then
>>>> everything is properly rendered.
>>>>
>>>> Am I doing something wrong? Or is this a limit/bug in Qt (I'm using
>>>> latest Qt version, 5.4.1)?
>>>>
>>>> This is my main
>>>>
>>>> int main( int argc, char *argv[] )
>>>> {
>>>> QApplication appMain(argc, argv);
>>>>
>>>> MyWidget *mainWin = new MyWidget;
>>>> mainWin->show();
>>>>
>>>> return appMain.exec();
>>>> }
>>>>
>>>> I enabled qt.qpa.gl debugging and this is the output of the application
>>>> in the two cases.
>>>>
>>>> Output in case of QGLWidget enabled:
>>>> [...]
>>>> qt.qpa.gl: QWindowsIntegration::createPlatformOpenGLContext
>>>> QSurfaceFormat(version 2.0, options QFlags(), depthBufferSize 1,
>>>> redBufferSize -1, greenBufferSize -1, blueBufferSize -1,
>>>> alphaBufferSize
>>>> -1, stencilBufferSize 1, samples -1, swapBehavior 2, swapInterval -1,
>>>> profile 0)
>>>> qt.qpa.gl: Qt: Using WGL and OpenGL from "opengl32.dll"
>>>> qt.qpa.gl: QOpenGLStaticContext::create OpenGL: "Microsoft
>>>> Corporation","GDI Generic" default ContextFormat: v1.1 profile: 0
>>>> options: QFlags(0x4)
>>>> Extensions: 3
>>>> qt.qpa.gl: QWindowsGLContext::QWindowsGLContext 0x6be850 GDI
>>>> requested: QSurfaceFormat(version 2.0, options QFlags(),
>>>> depthBufferSize 1, redBufferSize -1, greenBufferSize -1, blueBufferSize
>>>> -1, alphaBufferSize -1, stencilBufferSize 1, samples -1, swapBehavior
>>>> 2,
>>>> swapInterval -1, profile 0)
>>>> obtained # 8 GDI QSurfaceFormat(version 1.1, options QFlags(0x4),
>>>> depthBufferSize 16, redBufferSize 8, greenBufferSize 8, blueBufferSize
>>>> 8, alphaBufferSize 8, stencilBufferSize 8, samples -1, swapBehavior 2,
>>>> swapInterval 1, profile 0)
>>>> PIXELFORMATDESCRIPTOR dwFlags=0x465 PFD_DRAW_TO_WINDOW
>>>> PFD_SUPPORT_OPENGL PFD_GENERIC_FORMAT PFD_DOUBLEBUFFER iPixelType=0
>>>> cColorBits=32 cRedBits=8 cRedShift=16 cGreenBits=8 cGreenShift=8
>>>> cBlueBits=8 cBlueShift=0 cDepthBits=16 cStencilBits=8 iLayerType=0
>>>> cAlphaBits=8 cAlphaShift=0 cAccumBits=64 cAccumRedBits=16
>>>> cAccumGreenBits=16 cAccumBlueBits=16 cAccumAlphaBits=16 swap interval:
>>>> -1
>>>> default: ContextFormat: v1.1 profile: 0 options: QFlags(0x4)
>>>> HGLRC=0x20000
>>>> [...]
>>>>
>>>> Output in case of QOpenGLWidget enabled:
>>>> [...]
>>>> qt.qpa.gl: QWindowsIntegration::createPlatformOpenGLContext
>>>> QSurfaceFormat(version 2.0, options QFlags(), depthBufferSize -1,
>>>> redBufferSize -1, greenBufferSize -1, blueBufferSize -1,
>>>> alphaBufferSize
>>>> -1, stencilBufferSize -1, samples -1, swapBehavior 0, swapInterval 1,
>>>> profile 0)
>>>> qt.qpa.gl: Qt: Using WGL and OpenGL from "opengl32.dll"
>>>> qt.qpa.gl: QOpenGLStaticContext::create OpenGL: "Microsoft
>>>> Corporation","GDI Generic" default ContextFormat: v1.1 profile: 0
>>>> options: QFlags(0x4)
>>>> Extensions: 3
>>>> qt.qpa.gl: QWindowsGLContext::QWindowsGLContext 0x4c0e68 GDI
>>>> requested: QSurfaceFormat(version 2.0, options QFlags(),
>>>> depthBufferSize -1, redBufferSize -1, greenBufferSize -1,
>>>> blueBufferSize
>>>> -1, alphaBufferSize -1, stencilBufferSize -1, samples -1, swapBehavior
>>>> 0, swapInterval 1, profile 0)
>>>> obtained # 7 GDI QSurfaceFormat(version 1.1, options QFlags(0x4),
>>>> depthBufferSize 32, redBufferSize 8, greenBufferSize 8, blueBufferSize
>>>> 8, alphaBufferSize 8, stencilBufferSize 8, samples -1, swapBehavior 2,
>>>> swapInterval 1, profile 0)
>>>> PIXELFORMATDESCRIPTOR dwFlags=0x465 PFD_DRAW_TO_WINDOW
>>>> PFD_SUPPORT_OPENGL PFD_GENERIC_FORMAT PFD_DOUBLEBUFFER iPixelType=0
>>>> cColorBits=32 cRedBits=8 cRedShift=16 cGreenBits=8 cGreenShift=8
>>>> cBlueBits=8 cBlueShift=0 cDepthBits=32 cStencilBits=8 iLayerType=0
>>>> cAlphaBits=8 cAlphaShift=0 cAccumBits=64 cAccumRedBits=16
>>>> cAccumGreenBits=16 cAccumBlueBits=16 cAccumAlphaBits=16 swap interval:
>>>> -1
>>>> default: ContextFormat: v1.1 profile: 0 options: QFlags(0x4)
>>>> HGLRC=0x20000
>>>> QOpenGLShaderProgram: could not create shader program
>>>> QOpenGLShader: could not create shader
>>>> bool __thiscall QOpenGLTextureBlitter::create(void) Could not link
>>>> shader program:
>>>> ""
>>>> QOpenGLBuffer::bind(): buffer not created
>>>> QOpenGLBuffer::release(): buffer not created
>>>> QOpenGLBuffer::bind(): buffer not created
>>>> QOpenGLBuffer::release(): buffer not created
>>>> [...]
>>>>
>>>> Thanks in advance for your help!
>>>> Calogero
>>>>
>>>> --
>>>> Calogero Mauceri
>>>> Software Engineer
>>>>
>>>> Applied Coherent Technology Corporation (ACT)
>>>> www.actgate.com
>>>>
>> --
>> Calogero Mauceri
>> Software Engineer
>>
>> Applied Coherent Technology Corporation (ACT)
>> www.actgate.com
>>
>>
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--
Calogero Mauceri
Software Engineer
Applied Coherent Technology Corporation (ACT)
www.actgate.com
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