[Qt-interest] QGLWidget Vs "-graphicssystem opengl"

[Oliver Demetz]

Hmm okay,
this is clear.
But the difference that I would be interested in is using

A) -graphicssystem opengl

versus

B) setting a QGLWidget as viewport of my QGraphicsScene

In case A, will a standard QGraphicsScene (without explicit QGLWidget) 
still be opengl powered? Where are the advantages? And downsides?

Thanks,
Oliver

Nathan Carter schrieb:
> Amit,
> 
> It depends on what you want to show in your application.
> 
> If you want to show widgets, the stuff that Qt is built to draw for  
> you, then you just build a UI using the usual Qt tools and you may  
> choose to render it with -graphicssystem opengl or not.  But what gets  
> shown are Qt widgets.
> 
> If you want to show a 3D architectural model, or a 2D side-scroller  
> video game, or any of a host of other virtual worlds that you want to  
> write the OpenGL code to render, then you'll need an OpenGL context  
> and a place to put your initialization and rendering code; QGLWidget  
> provides you with those things.
> 
> Summary:
> 	For standard UI widgets, use Qt with or without -graphicssystem opengl.
> 	For standard OpenGL use cases (games, 3D models, etc.) use QGLWidget.
> 
> Nathan
> 
> 
> On Jul 15, 2009, at 7:45 AM, Amit Pundir wrote:
> 
>> Hi,
>>
>> Please help me in understanding the difference between QGLWidget and
>> "-graphicssystem opengl" switch.
>>
>> What will be the difference if I use QGLWidget for rendering OpenGL
>> graphics, and 2nd case, if I render normal widgets with opengl backend
>> using "-graphicssystem opengl" switch?
>>
>> What is a typical usage scenario for both the cases?
>>
>> I'm not a graphics expert so there are chances that this question may
>> sound stupid :)
>>
>> Thanks for your concern.
>> Regards
>> Amit Pundir
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