secrets

Hitbox script updates

http://code.google.com/p/mame-rr/source/detail?r=161

It's been so long I almost forgot what I set out to do:

• Get garou-hitboxes.lua to use FBA-rr 0.0.7's new emu.registerexec and emu.registerwrite Lua functions for breakpoints. I also used bps to remove the dodgy pseudo-disassembly for vulnerability checks and to avoid messing with the memory banking to get box data. This meant I had to go back through that maze.
• Re-fix the other scripts to draw breakpoint-triggered boxes on the correct frames. It's important not to set FBA's audio to mute or the frame sync will be off.

Breakpoints/watchpoints in FBA

FBA-rr 0.0.7 implements some new Lua functions:

memory.registerexec	trigger a function when a given code is executed
memory.registerread	trigger a function when given memory is accessed
memory.registerwrite
memory.getregister	read from and write to the CPU registers
memory.setregister

This effectively makes breakpoints and watchpoints available from within Lua. You can thank mz for these developments.

Most of the scripts have been updated to use these functions where applicable. In particular, if you want to see the CPS2 and Marvel throwboxes without messing around with MAME-rr, now you can.

In fact, the old method of piggybacking on the MAME-rr debugger has been removed, because I oppose writing to memory when the script is supposed to be read-only. So you have to use FBA for the bp/wp functionality now, but MAME still works for everything else.

The exceptions are garou-hitboxes.lua, since FBA's Lua can't control the NeoGeo's bank switching, and cps3-hitboxes.lua, since the new functions don't support the SH2 processor, although it's only one breakpoint at stake there. (It may be possible to get garou working in FBA by getting to script to read the box parameters exactly when the game's program does, which would obviate bank switching.)

The overhaul process was unexpectedly painstaking:

WarZard/Red Earth hitboxes

Added Warzard, or Red Earth as it was called in its limited distribution outside Japan, to the CPS3 script. The object handling and hitbox system has almost nothing in common with the Street Fighter III series, and I had to work from scratch to get it out.

Improved 3rd Strike hitboxes

I worked over the 3S hitbox script of c_cube, which had in turn been modified from the script mz made from LennethEX's custom MAME build. It's completely functional now. Get it from the SVN repo.

Here are the noticeable changes:

• Now showing pushboxes.
• Now showing throw and throwability boxes.
• Now showing the center axis of individual boxes.
• The usual hotkey functions are working.
• The usual customization settings are at the top.
• The vulnerability boxes that come out when the character is extending a limb during an attack are now the same blue as the regular vulnboxes, since the user has no reason to distinguish them. (Unless hitting them gives a counterhit bonus or something?) You can make the colors different if desired by editing the "ext. vulnerability" value.
• Removed all the debug stuff, such as infinite super and the membrowser drawn on screen.

It works great with mz's test build of FBA-rr 0.0.6. And, FBA comes with built-in background removal in Video > Graphics layers. By the way, you can put multiple versions of FBA in the same folder as long as the EXEs have different names. They'll use different INIs but share everything else.

KoF '94-'95 throwboxes

Though '96–2002 were already covered, the first two games don't write throws to RAM and needed breakpoints to bring them out. The throwability checks are also improved for the whole series. (disassembly / local copy) Nothing revolutionary here, but this is now done.

Some differences from the later games:

• Special and DM throws grab the opponent's axis, and the range of some of those depend on the opponent.
• Ground throwability boxes have no defined height.
• Air throwability height varies widely between characters. Width can change between grounded and air state.
• Air throws have no height: turning the character axis off and the box axis on can make them easier to see.

I've also brought the wiki page up to date and made all the scripts conform to my current, hopefully more readable than ever coding style. These things shouldn't make any difference to the user, but it closes up the last of my unfinished business with these scripts.

---

Was "Super Arabian Burglary Backbreaker" coined by KoF? It sounds like a typical name for a pro wrestling move but I haven't seen it anywhere else.

Also, has anyone noticed SNK puts the surnames of the Chinese and Korean fighters first, but does the Japanese names Western style?

garou-hitboxes.lua

Finally, work is more or less complete on the Fatal Fury series hitboxes, now including RBS, RB2 and MotW. Due to the significant differences from the KoF series, the script has been split into a new file. Some of the relevant disassembly can be found here (local copy). As usual, this script works with both parents and clones.

Marvel hitboxes updated

The Marvel script has been brought up to the same level of rigor as the other CPS-2 games.

In particular, if you put in the breakpoints provided, throwboxes will appear on the correct frames, and pushboxes don't flicker or fail to disappear on inactive frames. It also compensates for laggy stages (Onslaught, Apocalypse, Manhattan, and MSH Blackheart) and replaces hacky validity checks with the real deal. Since everything was basically working before, there's not much new to show, but it's a better tool now.

Only problem I noticed is in COTA, some chars show the throwbox for any normal attack, even if no directions are held or if it's a non-throw button. I guess the range is checked before the inputs in that game.

If you don't want to deal with BPs or want throwboxes to appear all the time like they used to, increase the fill and outline values of the "potential throw" boxtype at the top of the script. One of the changes to all the scripts has been to make it more clear what the user is and isn't supposed to edit. Another has been to make hotkey confirmations appear on the game screen instead of the Lua console.

Also, the index page on the MAME-rr wiki has been updated to reflect the recent upgrades. Some of the SF2 and CPS-2 screenshots have been improved.

And in related news, I got tired of waiting for Pugsy to update the mamecheat pack and reassembled all the BG removal codes, this time in a spreadsheet form.

CPS2 throwboxes

The CPS2 hitbox script can now show throwboxes for all its supported games with the help of breakpoints. Throwability boxes have also been added, which as usual are enabled with hotkey 5.

The third user-relevant change is that the validity checks that determine when to not draw the boxes have been made more accurate for all the box types. So for example, the blue boxes in vsav will disappear exactly when the opponent can no longer be juggled, and white boxes won't reappear until exactly the frame when the opponent can be thrown again.

This was achieved by studying trace after trace of asm dumps, sometimes using breakpoints or watchpoints to manipulate branch results, rather than my old guess & check methods. In some cases the solution dropped in easily, but some required swathes of new code to handle correctly. Once again I found that newer games are more systematic, while older games do everything the hard way.

BPs are applied in the same manner as described in the random SF2 damage post. That means most throws can only show up in MAME-rr with the debugger active. However, you can continue to use the new version normally in FBA-rr or without the debugger and still get all the rest of the functionality.

The actual breakpoint command to put in is printed in the Lua console when the game starts. Just copy it in and hit enter. To make it less tedious for the user, it's set up so that all BPs are merged into a single line. The BP addresses vary between different romsets (parents and clones), but the script is set to automatically adjust to whatever version you are running. Occasionally the game may glitch up as the BPs are entered, but this only happens once. Reset or load a savestate to proceed.

Be sure to enter bpc or bpclear before quitting or running a new game or MAME-rr will crash. If you want to run MAME with the debugger without having to launch from a command prompt window every time, you can create a batch file with the launch command in it and then just double click the .bat file.

Since these breakpoints work by scrawling some data into RAM where Lua can read it, it's possible they can interfere with the normal operation of the game if that RAM space is used for something else. It's difficult to confirm for certain there's no interference going on. (Ideally BPs would pass the info directly to the script. And ideally the user wouldn't have to deal with any of this.)

As was done with SF2, throws are inserted one frame ahead in the framebuffer so that they'll be drawn on the exact frame(s) they are attempted and not one frame too late. If the boxes aren't showing up at all, sometimes ground throws don't get attempted unless the opponent is on the ground, and likewise for air.

Below I'll discuss some findings for each game.

Samurai Shodown & Last Blade BG removal

In honor of Mauve's recent hitbox work and recognizing that someone might want to systematically catalog the hitboxes, I've developed background removal codes for the later Samurai Shodowns and the Last Blade games. (Only ss5sp has a hitbox script right now.)

These are of course also useful for general sprite ripping. As with all NeoGeo games, you can adjust the background color by editing one value.

http://www.mamecheat.co.uk/forums/viewtopic.php?p=13476#p13476

Random damage in SF2

Everyone knows there are random elements in the SF2 engine, including the amount of damage and stun done by most attacks. But what kind of randomness, exactly? Here are the general rules:

attack type	random dizzy	random damage	lifebar scaling*
non-throws	yes	yes	yes
normal throws	yes	no	yes
multi-hit throws	yes*	no	yes
command throws	yes	depends*	yes

• I didn't examine lifebar scaling in depth, but a little testing can confirm T.Akiba's findings. Just set the opponent's life to 30 and see the difference.
• Some holds like Blanka's and Balrog's always do no dizzy.
• Throws do fixed damage except the following:
  • Gief's SPD (SSF2 and SSF2T versions only)
  • Gief's close 360+K, 2nd hit
  • Gief's far 360+K
  • Gief's super, 3rd hit
  • Hawk's super, 2nd hit
  • Vega's super, 3rd hit
  • Honda's oicho, both hits

Now for the details. To reveal the exact damage and dizzy formula for all attacks and help compile more accurate attack data, I developed the following breakpoints for use in the MAME debugger:

breakpoints	helper Lua script
(local copy)	(local copy)

You run MAME with the -debug switch on, then copypaste each of the bp lines for your game into the console. Then anytime either player gets attacked, the damage and stun info is displayed there. Since the FBA/MAME-rr Lua implementation doesn't support breakpoints, there's no pure-Lua way to get the formulas. What the helper script does is it prints out damage/stun/timeout dealt whenever someone gets hurt. You can use it to more easily verify that the formulas jive with the real figures.

(There's supposed to be a way to enter multiple commands at once, but it doesn't work. Also, these will only work on the current parent ROMs, not clones. However, every ROM address is given relative to the breakpoint address, the pc, so getting these to work with a clone should only require offsetting the bp by a constant value.)

How random damage works: there's a base damage for every hit, then a random value is added. The random values are looked up from a table of 32 possibilities, with the actual one selected determined by the output of a pseudorandom number generator. The sum is then scaled down by a certain factor and rounded up to produce the final damage.

The lookup table is dependent on the attack, and all the relevant random number tables are included in the bp file. The scale factor, however, is dependent on the opponent: it's a defense rating.