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Author Topic: How to find code for no clipping/walk thru walls?  (Read 5221 times)

Manaplayer

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How to find code for no clipping/walk thru walls?
« on: January 15, 2012, 01:15:16 pm »
Hi guys/girls!

My question is how to find by myself a code to walk on everywhere in a game.
Please don't say "use Google"
The games i want to code are Secret of Mana and Secret of Evermore.
For Mana there existed a code for the NTSC version, but not for the german PAL version.
I compared the "cheated" value with the "uncheated value from the NTSC version with the cheat searcher from ZSNES until
only a few adresses are left - The right adress was there!
If you walk in the game in different levels (If you walk through stairs),you can see that the value of this adress is changing.

Now comes my real question -
Why is this method not working in Secret of Evermore? There is a code for the NTSC version and i converted it with some help
of guys in this forum for the PAL/G version.But this code is a little bit buggy in both versions - Not only the player and dog can walk
everywhere, but the enemies and npcs.

Any ideas how i can get to just to player and dog walk trhu walls? With the method i used on Mana, every time walk on a different level
and search for changed values in cheat searcher doesn't work...

Auryn

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Re: How to find code for no clipping/walk thru walls?
« Reply #1 on: January 18, 2012, 02:56:27 am »
To get real no clip mode (apart that you can really find something on google) you need ASM knowledge and parse/modify the game code.
Every other way is probably buggy in someway.
Anyway it's a good way to make your game crash many times and probably not be able to continue at all because you will be "invisible" to triggers that make the game continue with the story.
I dont' really see why you are so fascinated with the no clip mode.

Manaplayer

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Re: How to find code for no clipping/walk thru walls?
« Reply #2 on: January 18, 2012, 04:04:30 am »
I think that ASM i too high for me :(
I know that with no clip the story and other things are no more in right order. I just want to walk on places where you can't
without no clip - Just to explore a "little more" of this old games...

MottZilla

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Re: How to find code for no clipping/walk thru walls?
« Reply #3 on: January 18, 2012, 03:57:55 pm »
If you are using an emulator you can modify RAM values that contain your position on the map to move into areas you cannot reach normally. The problem with your walk through walls codes is that you need to know exactly why the code allows that, which means you must understand the ASM code that is changed.

Manaplayer

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Re: How to find code for no clipping/walk thru walls?
« Reply #4 on: January 18, 2012, 04:18:53 pm »
Hm...Than it was just a accident that in Mana the code could be found with the cheat searcher?
Is there a good and little tool to disassamble a SNES game? I will search for it of course, but
if someone has a good tip for me, i'm very thankful :)

Jorpho

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Re: How to find code for no clipping/walk thru walls?
« Reply #5 on: January 18, 2012, 11:17:41 pm »
Is there a good and little tool to disassamble a SNES game?
The result of such a disassembly is raw 65c816 assembler code.  It ain't pretty.  There's a tip.  ;D
This signature is an illusion and is a trap devised by Satan. Go ahead dauntlessly! Make rapid progres!

Manaplayer

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Re: How to find code for no clipping/walk thru walls?
« Reply #6 on: January 19, 2012, 04:54:13 am »
Ok ok, i'm really a unlearned newbie...

henke37

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Re: How to find code for no clipping/walk thru walls?
« Reply #7 on: January 19, 2012, 05:56:40 pm »
There are two kinds of cheats, the ones who overwrites important data the game program uses and the ones that overwrites the game program itself.

Walk thru walls codes tend to be the later kind, literally changing the collision checking code to say "no collision" all the time.

Romsstar

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Re: How to find code for no clipping/walk thru walls?
« Reply #8 on: January 19, 2012, 07:43:49 pm »
Oh guys come on, ASM is not needen for everything.

At least not for such a simple task.

First of all figure out the coordinates of your character.

This can be done by a "search unknown value" on initial and then go some steps and look for increasement.
Then go some steps back and look for decreasement.

Narrow this down till you get X and Y, or X,Y,Z in 3D based games.

Colission Detection often happens on a basis of Walking = 1, Colission = 0.
Sometimes it's the other way around you gotta test that with the game.

So walk around and search for 1. Run into a wall. Search for a decreasement of 1.
Or just the other way around. 0 and then increasement.

Can work. I always write walk through wall codes for PSX games like that.
Never had any problems with them.

Two ways for writing the code:

1. pretty one: locate the clipping routines and replace them with nop operations.

2. ugly and fast one: freeze the colission detector value to constantly walking. (Running into a wall will be interpreted as walking)

Auryn

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Re: How to find code for no clipping/walk thru walls?
« Reply #9 on: January 21, 2012, 02:31:33 am »
Would you mind demonstrate your theory with either of this games please.

Romsstar

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Re: How to find code for no clipping/walk thru walls?
« Reply #10 on: January 21, 2012, 10:12:52 am »
Would you mind demonstrate your theory with either of this games please.

I never tried with SNES games and as you correctly state it is a theory. It worked for PSX Games for me, it is just the basic way to look for walk through wall codes.
I rather suggested the op to try this theory himself and see how far it gets him.
And well I'm kinda not in the mood to waste time to prove a theory. It doesn't feel significant enough.

I merely wanted to show the op a way without ASM.
Whether it works or not depends on the game.

Auryn

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Re: How to find code for no clipping/walk thru walls?
« Reply #11 on: January 21, 2012, 12:16:16 pm »
Well, it isn't working. I tried to expand the search to any value as well but more than glitches (random tiles appearing on screen while walking and sometimes they overwritten the background as well) and wrong codes, I found no no clip code.
I admit that with the code with the random tiles, I would get blocked in some points where i should not and some tiles appeared to have changed to be in front of the sprites but never got to any place outside the defined area.