[Machenstein]

It worked for Green Hill Zone, but it gave me an "ILLEGAL INSTRUCTION$000077E0" for Marble Zone.

EDIT: I just thought of a different idea on how to manage acts for my hack, so no further assistance is needed. Thanks for the advice anyway.

This post has been edited by Machenstein: 23 November 2011 - 07:07 PM

[flarn2006]

Sometimes I want to explore a level in debug in S3&K, figuring out where things are and trying to mess up the sequence, but it can get hard to try things with those annoying level boundaries in the way. You know, like when you try to go left or right during a boss or something, but it won't let you as if it was the beginning of the level? I do know sometimes there's even some stuff before the "beginning" of the level, such as in Mushroom Hill Zone in plain Sonic & Knuckles (I.e. no Sonic 3.) Does anyone know of a code to do this, or barring that, a (preferably simple) hex edit? Thanks.

[Tiddles]

For most situations you can use PAR codes similar to these:

FFEE12:0F20 - unlock bottom
FFEE14:0000 - unlock left
FFEE16:7EC0 - unlock right
FFEE18:0000 - unlock top

They won't work everywhere; a few places use a different locking mechanism, or constantly reset the lock in the event scripts. Also bear in mind that some events will not occur at all with these enabled as they depend on a specific screen lock (e.g. the LRZ boss).

[Sambo]

How do you change the order of the levels in Sonic 2?

[FraGag]

Sambo, on 26 November 2011 - 03:38 PM, said:

How do you change the order of the levels in Sonic 2?

Edit the values at LevelOrder (or WrdArr_LevelOrder, or word_142F8, depending on your version of the disassembly) in s2.asm.

[Nostalgia Ninja]

Is there a way to change the color of a current zone (ie: by breaking a monitor, the stages pallete changes) to another pallete that was customly made for the stage. (Green Hill Day -> Green Hill Night)

[Elektro-Omega]

I have a few more questions:

1) I understand that porting objects doesn't mean just copy and pasting the code but what would I need to do to, say, port an object from S3K to S1 or S2?

2) How do you create a palette cycle or create an object that has a cycling palette in S2?

3) How do you create animations for an object? How do you ensure that when the object is present it cycles through the frames correctly and are the frames stored in a single file or split across multiple? (S2 again)

Also, I have literally no idea how to do music for hacks (porting or programming) so could someone give me a rough outline as how it is done.

I have a little ASM knowledge but I am in no way asking for anyone to hold my hand through every step, just kind of detailed roughness XD. I am honestly trying to learn my way around.

[FraGag]

Elektro-Omega, on 28 November 2011 - 03:26 PM, said:

1) I understand that porting objects doesn't mean just copy and pasting the code but what would I need to do to, say, port an object from S3K to S1 or S2?

You'll have to find the equivalent of RAM addresses, SST offsets and subroutines in S1 or S2. If there's no equivalent for a subroutine, you'll have to port it yourself. If the object is trying to use a RAM area that's used for a feature that's not available in the target game, you'll have to either port the feature (if you have enough available RAM) or drop the feature from the object.

Elektro-Omega, on 28 November 2011 - 03:26 PM, said:

2) How do you create a palette cycle or create an object that has a cycling palette in S2?

PalCycle_Load runs the palette cycles. Since there are only 4 palettes of 16 colors, you can't really make a palette cycle local to a specific object without risking affecting something else unless you plan ahead. PalCycle_Load is run once per frame and has code specific to each act to animate the palette. If you want an object to have a cycling palette, just reference the palette entries that are animated.

Elektro-Omega, on 28 November 2011 - 03:26 PM, said:

3) How do you create animations for an object? How do you ensure that when the object is present it cycles through the frames correctly and are the frames stored in a single file or split across multiple? (S2 again)

Many objects use a simple animation script to define what frames to use and the duration of each step. The format is very simple: the first byte is the duration in frames, minus 1, that each step will last; subsequent bytes are frame indices in the sprite mappings; the script ends with a command ($Fx) which describes what happens when the script ends (repeat, play a different animation, etc.). The AnimateSprite subroutine animates an object according to an animation script.

Elektro-Omega, on 28 November 2011 - 03:26 PM, said:

Also, I have literally no idea how to do music for hacks (porting or programming) so could someone give me a rough outline as how it is done.

Porting music between MD games can be troublesome because each game has a different engine with different features. Even between games that use the same base engine (e.g. SMPS), you'll usually see more features in later games. There are tools that try to accommodate this fact, but it's not always perfect. If you want to import custom music, I think your best bet is to use a tool like xm4smps. Either way, you'll have to add/edit an entry in the music list to be able to use it in game.

[E-122-Psi]

I've been trying to edit the Sonic 2 titles, so far I've managed to edit the sprites but changing what displays is a little more complex. So far I've managed to get to this:



Uploaded with ImageShack.us

Basically I'm trying to edit it so only the (former) Tails sprite appears. I've managed to code out Sonic's hand but can't figure out Sonic's coding. I've gotten to a similar level on the separate coding when you press the Start button.

This post has been edited by E-122-Psi: 30 November 2011 - 08:11 PM

[BetaTwizzler]

I posted something in here before...but I don't remember exactly what, haha. I think it had something to do with the Path Swappers in Sonic 2, which I have another question about.

The hack I'm making has loops, lots of loops, and unfortunately they're loops that end with different tiles or continue on with different ones. What I wanna know is if it's possible for a loop to work like this or like this, and if so, what Path Swapper would I use to make them work? I know for normal loops the Swapper in the center is 03 91 00 and the one on the outside is (I think) usually 03 11 00, but the latter doesn't work for my loops. Stupid Pathswappers, there's just so many.

[Irixion]

Actually you'll have to make sure the collision is properly set on your tiles—You're using the right swappers though. 03 91 00 and 03 12 00 (12 is bigger than 11, I usually use it)

[iojnekns]

BetaTwizzler, on 01 December 2011 - 11:13 PM, said:

I posted something in here before...but I don't remember exactly what, haha. I think it had something to do with the Path Swappers in Sonic 2, which I have another question about.

The hack I'm making has loops, lots of loops, and unfortunately they're loops that end with different tiles or continue on with different ones. What I wanna know is if it's possible for a loop to work like this or like this, and if so, what Path Swapper would I use to make them work? I know for normal loops the Swapper in the center is 03 91 00 and the one on the outside is (I think) usually 03 11 00, but the latter doesn't work for my loops. Stupid Pathswappers, there's just so many.

If you're struggling with pathswappers, the absolute best thing you can do is to download Thorn's object definitions for SonED2 (thread), which will significantly demystify them. With the definitions installed, a sure fire way to test your collision and planes is to use the W and E keys to toggle between viewing Path 0 and Path 1 of collision and the Y and U keys to toggle the High and Low Planes. It is a pretty simple case of tracing along the level with your finger and toggling the view when you hit a pathswapper to confirm the correct change is being made.

Some examples -

00 will force Sonic into Path 0 and Below High plane no matter which way you pass through it
01 will change Sonic from Path 0 to Path 1 from left to right, but will force him into Below High no matter which way you pass through it
10 will change Sonic from Path 1 to Path 0 from left to right, but will force him into Below High no matter which way you pass through it
00 will force Sonic into Path 0 no matter which way he passes through it but will change Sonic from Below High to Above High from left to right
01 will change Sonic from Path 0 to Path 1 from left to right, and will move him from Above High to Below High from left to right.
11 will force Sonic into Path 1 and Above High plane no matter which way you pass through it
And so on...

As you can see it is fairly intuitive. Using the definitions you can see the size, orientation amd characteristics of a pathswapper at a glance. There are some other nuances to bear in mind - the list restarts at 03 80 00, but require sonic to be on the ground to activate them - ie: running, walking or rolling. More advanced tricks can be used too. If I recall correctly, mirroring the pathswapper causes it to act solely as a planeswapper and disables the path swapping aspect.

There is a more exhaustive reference guide which uses the proper object numbers can be found here.

This post has been edited by iojnekns: 04 December 2011 - 10:05 AM

[Selbi]

Ok, quick question: In my game, I want to change a specific color in the palette without touching the others. However, I don't know how to modify specific positions in the CRAM without touching anything else, so right now I can only do this by cheating myself to the position I want, which looks like this:

		lea	($C00000).l,a5			; load VDP data port address to a5
		lea	($C00004).l,a6			; load VDP address port address to a6
		move.l	#$C0000000,(a6)			; set VDP address to C-Ram
		lea	(Palette_Main).l,a1		; load palette array in a1
		move.w	(a1)+,(a5)			; dump colors
		move.w	(a1)+,(a5)			; dump colors
		....
		move.w	#$0EEE,(a5)			; finally dump color the color I want

And it's silly. How would I do this properly?

This post has been edited by Selbi: 04 December 2011 - 01:41 PM

[FraGag]

Selbi, on 04 December 2011 - 01:41 PM, said:

Ok, quick question: In my game, I want to change a specific color in the palette without touching the others. However, I don't know how to modify specific positions in the CRAM without touching anything else, so right now I can only do this by cheating myself to the position I want, which looks like this:

		lea	($C00000).l,a5			; load VDP data port address to a5
		lea	($C00004).l,a6			; load VDP address port address to a6
		move.l	#$C0000000,(a6)			; set VDP address to C-Ram
		lea	(Palette_Main).l,a1		; load palette array in a1
		move.w	(a1)+,(a5)			; dump colors
		move.w	(a1)+,(a5)			; dump colors
		....
		move.w	#$0EEE,(a5)			; finally dump color the color I want

And it's silly. How would I do this properly?

The format of long commands is described in genvdp.txt, section 7, under "Accessing VDP RAM":

    CD1 CD0 A13 A12 A11 A10 A09 A08     (D31-D24)
    A07 A06 A05 A04 A03 A02 A01 A00     (D23-D16)
     ?   ?   ?   ?   ?   ?   ?   ?      (D15-D8)
    CD5 CD4 CD3 CD2  ?   ?  A15 A14     (D7-D0)

    CDx = VDP code (0-3F)
    Axx = VDP address (00-FFFF)

This format is annoying, because related bits are not all consecutive. The Sonic 2 disassembly has a vdpComm function to help, but it only works with AS.

What you want to do is a CRAM write to some address. CRAM has 4 palettes of 16 colors, and each color takes a word, so addresses range from 0 to $7F; therefore, you can start with the base CRAM write command ($C0000000) and just change the A06-A00 bits, which are all consecutive. For example, to do a CRAM write to $3C, the command would be $C03C0000.

[E-122-Psi]

Is there any way to have the SONIC AND MILES TAILS PROWER IN screen skipped in the Sonic 2 intro?