Applying shaders to a slideshow

Hi
I am creating a code of image slideshow and applying some shaders to it.
When shaders are getting applied the effect is only seen for the transition from 1st image to 2nd and it is absent for transition from 2nd to 3rd image and again it is getting applied for transition from 3rd to 4th image.
How to get the effect applied for transition from 2nd to 3rd image?



https://github.com/Immature29/CINDER_TEST/tree/Test_app