how can i Transparent background to show .png( RGBA ) images, i try to change "mBgColor" ,and use
glClearColor(0,0,0,0); , but the background turned black, still no transparent， can you help me to fix this?

thanks...

Multiple instances of startTimer(0), slows down the GUI for some reasons. If you trigger the command for 4-5 times, GUI gets really slow. Can use threads for the same operation

Hi
the build under Ubuntu 16.04 failed with this .pro file.

/usr/bin/ld: cqtopencvviewergl.o: undefined reference to symbol '_ZN2cv8cvtColorERKNS_11_InputArrayERKNS_12_OutputArrayEii'
//usr/lib/x86_64-linux-gnu/libopencv_imgproc.so.2.4: error adding symbols: DSO missing from command

You have to add the opencv_imgproc library.

LIBS +=
-L$$LIBS_PATH
-lopencv_imgproc
-lopencv_highgui
-lopencv_core
}

Hello,

I have tried your source code in my Qt 5.4.1 OpenGL ES 2.0 and I got below issues.

protected QOpenGLFunctions_2_0 - Not working (this file included but not this line gives me error)

Following function says 'was not declared in this scope'
glMatrixMode
glLoadIdentity
glOrtho
glPushMatrix
glRasterPos2i
glDrawPixels
glPopMatrix

Will guide me what should I do to resolve all these errors.

Thanks

Tushar Kachhadiya

When using the widget stand-alone, if the widget window is resized by the user manually, the program crashes.