Feeling a Little Silly

While I was working on refactoring isLayerCompatibleWith(), I started looking at FF4 layer numbers and noticed what is now some very obvious bit flags in local map layer numbers:

• Bits 1 and 0 are our two layer bits.
• Bit 2 is the bridge flag.
• Bit 3 is the save point flag.
• Bit 4 is the transition flag.

I could probably sort out bit flags in the 2-byte overworld tiles for things like which vehicles can pass through which squares and which can land in which squares, but for the moment I have no compelling reason to do so. I'll probably give it a shot when I try to sort out vehicles in FF5.

So the downside is that I looked dumb on the internet, although nobody's watching at the moment. The upside is I know a bit more about how mobility layers work, I got to simplify some important code, and may end up not needing to make isLayerCompatibleWith() game-specific. Yet. We still need to look for barriers between squares, but we can turn the check for that on and off with some configuration.

Oh, that's right, I didn't blog about that.

I've got a bunch of functions that just compare a location in the game's memory against a given value to see whether the game is in a certain state. isInCutscene(), isMoving(), and justOpenedTreasure() are a few examples. The logic for these functions will necessarily different for each game. We could build some C++ class that reads from a config file and interprets the logic needed for each method, and that would work, but I'd really rather not build a makeshift logic interpreter for this project, and it would slow down some functions that may actually need to run quickly.

Enter boost::function and boost::bind. Between FF4 and FF5, I really only need 3 operators for these functions: ==, !=, and <, and they're all comparing a named memory byte against a specific number. So I made three functions, one for each operator, used boost::bind to build a function with the memory key name and expected value from the config file, and saved that as a boost::function. It works great.