Basically, hex editing is editing the hexadecimal value of a given property in the ROM. For example, you can change names of spells and other things by changing hexadecimal values stored at specific positions in the ROM. Allow me to demonstrate.
I'm brushing up on my tech editing knowledge with jsondag's tech editor, but his tech editor currently doesn't change spell names (or at least the version I was using before the Obama Campaign didn't have this feature yet). So, I've got these really sweet looking spells for Magus now, and I want the names to be changed thus:
*Lightning2 > Thor Hammer
*Ice2 > Maelstrom
*Fire2 > Doom Blaze
*Magic Wall > Curse
First thing to do is look up where the heck the spell names are stored in an unheadered ROM. That info has handily been recorded in the
Compendium Encyclopedia, under Modification.Look at "offsets pertinent to techs" specifically. An "offset" is just a fancy name for a certain position in the ROM. Tech names start at offset 0x0C15CF, which is simply hexidecimal notation for saying that tech names begin with the 792,015th byte in an unheadered CT ROM. Tech names are 11 bytes each, and as is often the case in videogames, a "relative alphabet" is used. That means each byte is interpreted by the game engine as a specific letter, number or special character. The relative alphabet used for CT techs is
here. Think of the relative alphabet as a Rosetta Stone that helps us translate hexadecimal into English.
Now, let's say I'm impatient and don't want to go through the trouble of finding out the pointer to a specific tech name (pointers, by the way, are hexadecimal values that tell the game engine where other data are stored). I can just use the relative alphabet to search for the names already in the ROM!
*Lightning2, according to the relative alphabet, is 2F AB C2 C0 C1 CD C7 C2 C7 C0 D6. We find that in two places, the second at 0x0C17DF being Magus' *Lightning2. Tech names in CT are a constant length of 11 characters in the ROM, with the hex value 0xFF representing blank space.
I go ahead and overwrite the spell names for *Lightning2, *Ice2, *Fire2, and *Magic Wall with the desired values in the Relative Alphabet. I'll upload a video of Magus owning Dalton with his spiffy new techs in
Prophet's Guile later.
Oh yeah, and you really don't have to go through all that -- Geiger has made it so you can just edit tech names in Temporal Flux.
But it's a good exercise in hex editing.
