[mythtv] OpenGL questions

Peter Bennett pb.mythtv at gmail.com
Sun Mar 31 18:41:11 UTC 2019

On 3/31/19 5:56 AM, Mark Kendall wrote:

Hi Mark

Thank you for the detailed reply.

I am building and testing some of the sample OpenGL programs., and I am 
using apitrace to see what is going on.

One interesting thing I found - A sample program that uses QOpenGLWidget 
to display a window with just a triangle does hundreds of OpenGL calls 
that are not generated by the user code. Apart from displaying the 
triangle, it uses two textures and hundreds of other calls, plus some 
extra shaders that are not in the user code.

On the other hand a sample that uses QWindow and QOpenGLFunctions to 
display a triangle does not create any extra textures or shaders and 
seems to only generate the OpenGL code that is requested by the user code.

I have not yet tried QOpenGLWindow, I don't know how it compares to 
QWindow or OpenGLWidget.


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