Question

I’ve got a lot of code that’s driving me really crazy right now.
I’m working with OpenGL, building a GUI framework which utilizes several different types of objects. I have Image classes which load *.png files and store image information in the form of a GLuint texture reference. I have Panel and Button classes with pointers to the image classes they should be displaying. I have a Hud class with std::vectors of Panel and Button pointers. Finally, I have an Engine class that contains one Hud class, all my Button and Panel classes, and Image pointers. When the constructor is run, each of the Image pointers is initialized using:

imgMy = new Image;

Once all the images have been initialized, I run my load functions:

imgMy->loadImage("imgMy.png");

Of course, I delete the Images when I close the program.

My problem is that some of the images are getting “crossed.” I have about thirty images right now, and a couple of the buttons are apparently pointing to the wrong images. I have checked my code thoroughly, and it appears to be solid. I believe this is a memory bug since the buttons which display the incorrect images are inconsistent. Sometimes they display the correct images, sometimes different buttons are displaying the wrong images. I wish I could show my code here, but it’s pretty massive.

The reason I’m using Image pointers in my Engine class instead of actual Image objects is that I’m afraid of the Buttons pointing to invalid memory if the Engine class is resized, or its memory rearranged. I suspect there’s a much better approach to what I’m trying to accomplish, and I’d appreciate any advice along those lines.

Answer 1

Use a debugger that lets you put a watchpoint on the relevant imgMys, and then the debugger will tell you where they’re being modified. That is probably the easiest way to track it down.

You may also want to try valgrind, but this doesn’t sound like the type of problem valgrind will find.