Methods ROM hacking

1 methods

1.1 hex editing
1.2 graphics editing
1.3 palette editing
1.4 level editing
1.5 data editing
1.6 assembly hacking
1.7 music hacking
1.8 rom expansion

methods

having been created many different programmers or programming teams, rom data can diverse.

hex editing

a hex editor 1 of fundamental tools in rom hacker s repertoire. hex editors used editing text, , editing other data structure known (for example, item properties), , assembly hacking.

editing text 1 of basic forms of hacking. many games not store text in ascii form, , because of this, specialized hex editors have been developed, can told byte values correspond letter(s) of alphabet, facilitate text editing; file defines these byte=letter relationships called table file. other games use simple text compression techniques (such byte pair encoding, called dual tile encoding or dte, in combinations of 2 or more letters encoded 1 byte) suitably equipped hex editor can facilitate editing.

a hex editor tool of choice editing things such character/item properties, if structure , location of data known , there no game-specific editor game can edit information. intrepid hackers perform level editing hex editor, extremely difficult (except on games level storage format closely resembles how presented in hex editor).

graphics editing

another basic hacking skill graphics hacking, changing appearance of game s environments, characters, fonts, or other such things. format of graphics data varies console console, of ones (nes, super nes, game boy, etc.) store graphics in tiles, 8x8-pixel units of data, arranged on-screen produce desired result. editing these tiles possible hex editor, accomplished tile editor (such tile layer or tile molester), can display rom data in graphical way, finding , editing tiles.

graphics hacks can range simple edits (such giving mario afro) porting characters 1 game another, full-blown thematic changes (usually accompanying palette changes; see below).

more sophisticated graphics hacking involves changing more tiles , colors, way in tiles arranged, or tile groups generated, giving more flexibility , control on final appearance. accomplished through hex editing or specialized tool (either specific game or specific system). example of graphics hack uncompleted pokémon torzach, hack attempted add whole new generation of pokémon , tiles game. hack has since been discontinued, still serves example on can achieved tools available.

palette editing

another common form of hacking palette hacking, color values modified change colors player sees in game (this goes hand-in-hand graphics hacking); palette values commonly stored in hex. easy nes games, graphics of use pre-defined set of colors among game selects; palette hacking in case entails changing of colors selected. matter more complicated super nes games , games other systems, store absolute rgb color values. palette editors simple , level editors, or game specific graphics editors.

level editing

one of popular forms of rom hacking, level editing entails modifying or redesigning game s levels or maps. exclusively done editor specially tailored particular game (called level editor). level edits can done make game more challenging, alter flow of game s plot, or give new old game. combined extensive graphics hacking, game can take on different , feel.

data editing

a core component of many hacks (especially of role-playing video games) editing data such character, item, , enemy properties. done either hand (with hex editor) if location , structure of data known, or game-specific editor has functionality. through this, hacker can alter how weapons work, how strong enemies or how act, etc. can done make game easier or harder, or create new scenarios player face.

assembly hacking

the powerful, , arguably difficult, hacking technique editing game s actual code, process called asm hacking ( asm means assembly , referring type of programming language used video games). there no set pattern asm hacking, code varies game game, skilled asm hackers either use emulator equipped built-in debugger or tracer, or run rom through disassembler, analyze code , modify using hex editor or assembler according needs. while quite challenging compared relatively simple methods listed above, possible asm hacking (of course, within limits of hardware/software of gaming platform), ranging altering enemy ai changing how graphics generated. (of course, possibilities still limited hacker s ability comprehend , modify existing code.)

if developers used typed language, hacker may able compile own code game in same language if have access proper compiler. 1 such example using c hack nintendo 64 games, since mips-gcc can compile code nintendo 64.

music hacking

music hacks relatively rare, due wide variety of ways games store music data (hence difficulty in locating , modifying data) , difficulties in composing new music (or porting music game). music cracking uncommon, many hacks not have ported/composed music added in. program saptapper can used hack game boy advance music data, however, many game boy advance games use m4a engine (also called sappy driver ) music. various other utilities created work engine such sappy 2006. instance of same engine being used between games on nintendo 64, in games use same format; although use different sound banks, expected. utility known n64 midi tool created edit sequences majority of nintendo 64 games use, though not cover first-party n64 titles use different engine, such super mario 64.

rom expansion

generally speaking, rom hacker cannot add content game, merely change existing content. limit can overcome through rom expansion, whereby total size of rom image increased, making room more content, , larger game. difficulty in doing varies depending on system game made. example, expanding nes rom may difficult or impossible due mapper used game. example, if mapper allows 16 rom banks , of them used, expanding rom further impossible without somehow converting game mapper, easy or extremely difficult. on other hand, expanding snes game (relatively) straightforward. utilize added space, parts of game code have modified or re-written (see assembly hacking above) game knows look. type of rom expansion easy game boy advance roms. roms small, memory space available exceeds multiples of 17.