[Interest] Quick2 OpenGL inefficiency?

[Jani Tykka]

Thanks a lot for the info! Will check that out.

Jani

On Tue, Mar 8, 2016 at 9:40 AM, Filip Piechocki <fpiechocki at gmail.com>
wrote:

> I don't know how you produce the video frames, but check that the software
> you are using might be able to produce OpenGL texture directly (not the
> buffer data). If not then here are some useful links:
>
> http://stackoverflow.com/questions/9863969/updating-a-texture-in-opengl-with-glteximage2d
> http://www.gamedev.net/topic/641283-fastest-way-to-stream-video-to-texture/
>
> So basically you'll need to use glTexSubImage2D directly (and you probably
> do not need QImage at all) and for custom OpenGL rendering you can use
> QQuickFramebufferObject as your DisplayItem:
>
> http://blog.qt.io/blog/2015/05/11/integrating-custom-opengl-rendering-with-qt-quick-via-qquickframebufferobject/
>
> On Tue, Mar 8, 2016 at 7:00 AM, Jani Tykka <jtykka at broadsoft.com> wrote:
>
>> I'm creating the image from buffer which is unsigned char buffer
>> containing video frame data
>> QImage( buffer, width, height, QImage::Format_RGB32 );
>>
>>
>>
>> On Mon, Mar 7, 2016 at 10:05 PM, Filip Piechocki <fpiechocki at gmail.com>
>> wrote:
>> >
>> > How are you generating those images? What do they represent?
>> >
>> > On Mar 7, 2016 20:55, "Jani Tykka" <jtykka at broadsoft.com> wrote:
>> >>
>> >> Images are passed from another thread in rate 15-30 fps. Is there an
>> example available how to achieve Image to OpenGL texture and use it in
>> scene graph?
>> >>
>> >> On Mon, Mar 7, 2016 at 5:11 PM, Filip Piechocki <fpiechocki at gmail.com>
>> wrote:
>> >>>
>> >>> And where it comes from? How frequent it happens? Probably the best
>> thing here would be to generate this image as an OpenGL texture and then
>> use in the Qt's scene graph.
>> >>>
>> >>> On Mon, Mar 7, 2016 at 4:04 PM, Jani Tykka <jtykka at broadsoft.com>
>> wrote:
>> >>>>
>> >>>> Yes, the image is always changed when the update is invoked.
>> >>>>
>> >>>> On Mon, Mar 7, 2016 at 4:43 PM, Filip Piechocki <
>> fpiechocki at gmail.com> wrote:
>> >>>>>
>> >>>>> Hi,
>> >>>>>
>> >>>>> Why are you re-creating the texture on every node update? Does the
>> m_Renderer->getImage() really changes? My first guess would be that the
>> texture creation from image is the most costly part here (uploading the
>> texture to GPU?) and I would do this only if necessary (the image really
>> changes).
>> >>>>>
>> >>>>> BR,
>> >>>>> Filip
>> >>>>>
>> >>>>> On Mon, Mar 7, 2016 at 3:04 PM, Jani Tykka <jtykka at broadsoft.com>
>> wrote:
>> >>>>>>
>> >>>>>> Hi,
>> >>>>>>
>> >>>>>> We are rendering QImages on QQuickItem as following:
>> >>>>>>
>> >>>>>> QSGNode * DisplayItem::updatePaintNode( QSGNode * node,
>> UpdatePaintNodeData * /*data*/ )
>> >>>>>>
>> >>>>>> {
>> >>>>>>
>> >>>>>> QSGSimpleTextureNode * n = static_cast< QSGSimpleTextureNode* >(
>> node );
>> >>>>>>
>> >>>>>> if ( !n )
>> >>>>>>
>> >>>>>> n = new QSGSimpleTextureNode;
>> >>>>>>
>> >>>>>>
>> >>>>>> n->setRect( 0, 0, width(), height() );
>> >>>>>>
>> >>>>>>
>> >>>>>> delete m_Texture;
>> >>>>>>
>> >>>>>>
>> >>>>>> m_Texture = window()->createTextureFromImage(
>> m_Renderer->getImage() );
>> >>>>>>
>> >>>>>> n->setTexture( m_Texture );
>> >>>>>>
>> >>>>>>
>> >>>>>> return n;
>> >>>>>>
>> >>>>>> }
>> >>>>>>
>> >>>>>>
>> >>>>>>
>> >>>>>> It seems that computers with separate GPU there is a decent amount
>> of CPU utilised. We are running into problems if the machine lacks GPU,
>> then with large images the CPU usage grows drastically. Any suggestions how
>> to improve large image painting on QQuickItem? With Quick1 and painting
>> directly on HWND/CocoaWindow we didn't experience this high CPU usage.
>> >>>>>>
>> >>>>>>
>> >>>>>>
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>> >>>>
>> >>>>
>> >>>>
>> >>>> --
>> >>>> Jani Tykkä
>> >>>> Development Manager | BroadSoft, Inc. | +358 44 596 0587 |
>> jtykka at broadsoft.com
>> >>>>
>> >>>>
>> >>>> This email is intended solely for the person or entity to which it
>> is addressed and may contain confidential and/or privileged information. If
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>> please notify BroadSoft, Inc. immediately by replying to this message, and
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>> >>>
>> >>>
>> >>
>> >>
>> >>
>> >> --
>> >> Jani Tykkä
>> >> Development Manager | BroadSoft, Inc. | +358 44 596 0587 |
>> jtykka at broadsoft.com
>> >>
>> >>
>> >> This email is intended solely for the person or entity to which it is
>> addressed and may contain confidential and/or privileged information. If
>> you are not the intended recipient and have received this email in error,
>> please notify BroadSoft, Inc. immediately by replying to this message, and
>> destroy all copies of this message, along with any attachment, prior to
>> reading, distributing or copying it.
>>
>>
>>
>>
>> --
>> Jani Tykkä
>> Development Manager | BroadSoft, Inc. | +358 44 596 0587 |
>> jtykka at broadsoft.com
>>
>>
>> This email is intended solely for the person or entity to which it is
>> addressed and may contain confidential and/or privileged information. If
>> you are not the intended recipient and have received this email in error,
>> please notify BroadSoft, Inc. immediately by replying to this message, and
>> destroy all copies of this message, along with any attachment, prior to
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>>
>
>


-- 
*Jani Tykkä*
Development Manager | BroadSoft, Inc. | +358 44 596 0587 |
jtykka at broadsoft.com

-- 


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