Skeetendo

’Cause all games were better on the GBC

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#1 2013-09-08 18:59:22

cambaby
New member
Registered: 2013-09-08
Post 1/5

[HELP NEEDED] Offsets of pre-TitleScreen intro sprites

Alright, so I've tried doing this myself, but I was wondering if anyone could help me find the answer.

In the pre-Title Screen intro, the sprites of the three johto starters appear. The neat thing to notice is that the sprites are different in Gold and in Silver. This is because, I am assuming, the title sequence points to the in game sprites for these three Pokemon.

What I am trying to do is change the three starter pokemon to show the three Kanto starter Pokemon instead. Ive used this:
http://datacrystal.romhacking.net/wiki/ … ld:ROM_map
as a reference. However, I've only been able to find the graphics for the title sequence and the title screen, NOT the actually assembly routine and the assumed pointers that need to be change.

Getting to the point, I was wondering if anyone on here had any insight or solution to this problem I thought was going to be easy.

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#2 2013-09-08 21:16:10

comet
Member
Registered: 2012-04-09
Post 296/675

Re: [HELP NEEDED] Offsets of pre-TitleScreen intro sprites

if you arent already, use bgb.

pressing esc will open a debugger. check out the tiles section of the vram viewer and set an access breakpoint on writes to wherever the pokemon graphic ends up

if it works out, youll get thrown into the decompression routine. you can follow the program flow using the stack (the list of addresses on the right). the code you're looking for should be at the one that's highlighted

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#3 2013-09-08 22:25:15

cambaby
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Registered: 2013-09-08
Post 2/5

Re: [HELP NEEDED] Offsets of pre-TitleScreen intro sprites

I gave it a go, but sadly, I do not fully understand how assembly works... I could get the breakpoints to stop when it was writting to a vram address and step by step it through the assembly, but I'm clueless on how to track down the address of the pointer to the Chikorita sprite

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#4 2013-09-08 23:46:35

comet
Member
Registered: 2012-04-09
Post 297/675

Re: [HELP NEEDED] Offsets of pre-TitleScreen intro sprites

setting an access breakpoint on address 8100 (vram) breaks at 0xb77, in the middle of decompression:

6KXfVIe.png

the highlighted address in the stack to the right is where the program will return to after the decompression is done. you can see whats at this address with ctrl+g 523a

since you know from the rom map that intro stuff is in bank 0x39, we're already in the right bank (see 'rom= 39' at the top right). if you were in a different bank you would do ctrl+g 39:523a to bring it up

bgb will let you edit whats there in real time and save the changes too, so its really convenient for this sort of stuff

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#5 2013-09-09 01:22:56

cambaby
New member
Registered: 2013-09-08
Post 4/5

Re: [HELP NEEDED] Offsets of pre-TitleScreen intro sprites

Alright! I got the sprites to change! Now comes the part of getting the palettes for each one to load properly.

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#6 2013-09-13 00:49:45

cambaby
New member
Registered: 2013-09-08
Post 5/5

Re: [HELP NEEDED] Offsets of pre-TitleScreen intro sprites

Ive hit a road block and seem unable to change the palettes that get loaded. It loads the sprite fo the Johto starters. Anyone have any ideas? Help much appreciated.

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#7 2013-09-13 08:13:52

AtecainCorp.
Member
Registered: 2013-04-14
Post 596/627

Re: [HELP NEEDED] Offsets of pre-TitleScreen intro sprites

BGB Is great. It help me a lot in making MIDIS from KTD.


http://hax.iimarck.us/topic/3435/ - Pokemon Ruby GEN V GRAPHIC hack Thread
http://hax.iimarck.us/topic/3476/ - Unused Music Midi Thread
http://hax.iimarck.us/topic/3579/ - Some info about region Thonsu

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