Look this site Here do you think this code may work with fx file for construct?
The code would work, but wouldn't help much. He is faking a transition, by simply evaluating the grey value of every frame of an already existing transition video (where a transition effect was applied between a black and a white image). So, the hard work (the transition itself) is not coded. All the effect would do in Construct is to look at the red channel of the pixel colors, and if it is below 127 a pixel of the old layout is shown, and if the red channel of a pixel's color is above 127, a pixel of the new layout is shown. The result would be a noisy intermediate, non-transitioning image.
If you find some real transition code (XNA, HLSL) you like to use, just drop me a line, I'll convert it for you.