[Qt-interest] How to optimize QGLWidget render buffers

[Chen, Zhenqiang]

Hi All, 
 
GL render buffers take lots of memory for each app. 

By default, QGLFormat is:
 QGL::DoubleBuffer | QGL::DepthBuffer | QGL::Rgba | QGL::DirectRendering
| QGL::StencilBuffer | QGL::DeprecatedFunctions;

Due to the memory limitation on handset,
Can the app change config to clear stencil, depth buffer or others
when the app is in the background or minimized? 

Or use singlebuffer? 

How to optimize the buffers for QT-4.7.1?

Thanks!
-Zhenqiang