How to find the unfindable bug?

[Atomic_Sheep]

I write a program. Get everything to work... totally happy with the result. Now I need to write the exact same program but for it to load a different image. So I create a new class... copy all the code from the previous program, change the file path to the picture that I now want to display and guess what? Doesn't work... this is all OpenGL mind you... all I get is a window with a white square. If I copy paste the file location of the second image into the old working program, everything works as expected. How the heck???

[amleto]

"How the heck" - yes indeed. How the heck can we give any ideas when you give us no information except that you have copy and pasted some code.

Since that is all we have to go on, I will guess that you fail at copy & paste. A possible alternative is that you have some path handling that doesn't make sense from one place but does in the other.