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Messages - nesrocks

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Programming / Re: [Help] Repositioning a single sprite.
« on: September 16, 2019, 10:38:47 am »
The multiplicative inverse of x^32 for CRC32 is always = cbf1acda.
I imagine that is the case when considering CRC32's default polynomial (which is my case, fortunately). So "inverse(x32)" in this case is just a constant. Wow... Thank you!

Programming / Re: [Help] Repositioning a single sprite.
« on: September 15, 2019, 10:38:18 pm »
Glad that was the thing :) I'm sorry to maybe hijack the thread, but since I'm not using C or anything common really, I would love an explanation of the math behind step "four" of this tutorial. Any such luck?

edit: that checksum manipulator is incredible, it might be the second best thing other than knowing the math behind step 4 of the tutorial, so thank you very much for that.
edit2: you may have led me to learn that GM allows external programs to be run with args through a code. I'll need to test this.
edit3: I see your edit. Yes, I had already seen that but it doesn't explain much. Inverse(x32) make it sound like he is flipping the most significant bit (32 from the right) which obviously isn't it. Another thing he said is that this means shifting "P" 32 times to the right which also can't be true because that would always give zero as a result. I'm going to call this solved for now and use the command line program, thanks!

Someone is remaking/fixing the SF1 game as a version for the Mega Drive:

Programming / Re: [Help] Repositioning a single sprite.
« on: September 15, 2019, 08:48:57 pm »
If virtuanes does the check through CRC I've got this EXACT same problem and would appreciate to know if you managed to do the reverse CRC and how.

Newcomer's Board / Re: Mega Man - Restore Weapon Energy after Death
« on: September 13, 2019, 11:54:09 am »
Doesn't the game already have code that refills all weapons when using a continue? I don't remember exactly.

Has anyone here ever done rom hacking for the odyssey 2 system? The most popular (and only?) O2 emulator seems to change the game's speed to ultra slow if it doesn't recognize the ROM file as a known O2 game. I suspect it does this through a CRC check. I was wondering if anyone knows what's going on.

edit: it turns out the emulator o2em uses a lot of internal hacks for compatibility and it detects the ROM by a crc32 check. So my only option is make it so the rom keeps the crc32 after modification...

I have not tested, approved or endorse this, but a quick google search for "hex editor find in files" resulted in for example this

ROM Hacking Discussion / Re: [mk1] and [(S)SFIIxx] modifiers
« on: August 30, 2019, 08:56:56 am »
Doesn't this belong in the ideas thread?

This is fantastic.

Sorry, hadn't seen it. :) Wow, now you can zoom the entire program! Finally!

Link please? Geocities has ended.

That's incredible how did you mofidy it?

For this type of tasks, a tool that helps me a lot is DjinnMapper v1.5.0.0

Hummm, it looks like's prg editor. I'll check it out!

edit: the link you provided has a rar inside a zip that asks for a password. This link
edit2: yep, it is better than prgeditor! For one it auto loads the chr from the rom itself, among other useful features. Nice, thanks! :)

Gaming Discussion / Re: A Cool NES Handheld From China...
« on: August 25, 2019, 12:47:02 am »
You got that right. I was researching this subject today due to this thread and it is just sad. Some systems actually look nice (the plastic), and the screens are colorful, etc, but yikes. Screen tearing is ugly.

Gaming Discussion / Re: A Cool NES Handheld From China...
« on: August 24, 2019, 04:42:27 pm »
It's certainly got to do with the costs, but I've yet to see one of these dedicated bootleg handhelds that has a proper screen for the system it is emulating. The pixels are rarely 1:1 and often cropped. It hurts my eyes.

Glad that people are finding it useful!
But yes, abw, I wished so much for a real time nametable drawing tool that I started to develop my own. I had to stop so I can finish my PC game, but I will probably work on it after it's done. I got to the point where I can import the PPU dump from fceux and it will load it all automatically (no need to split). I even made a change to fceux to export OAM in the same file so I can import sprites too! That way they come assembled and it should be easier to edit the CHR graphics. It also has a rudimentary 2x2 metatile generator from NAM with automatic no repeats (no export yet).

edit: I wanted to contact the yy-chr's developer for improvements to yy-chr but he seems to not want contact regarding that tool (due to his dead page and no contact links), so one more reason I started writing my own.

It's yy-chr's nam editor (it's the BG Set button). This method's main advantage is that you can edit existing game's background graphics without having to work the CHR like a puzzle. The dumped nametable data helps you find in the CHR where each tile is.

This is the result after you do all the steps I described. Right click any tile and it will locate the tile on the CHR table. And you can also quickly see results when you edit the CHR by looking at the nam editor.

I don't recall seeing anyone use this for hacking. I discovered PPUSplit when hacking Super Pitfall and I use it all the time.
Note that this is only for help on editing the CHR. You can edit the nametable on yy-chr but it is for previews only, there's no easy way to put that into the game unless the game uses a full screen of uncompressed nametable data which is rare.

For uncompressed screens I use a dump of PPU memory and yy-chr for this kind of thing. Open the game on fceux, get to the screen, look in the nametable viewer in the debugger to make sure it doesn't use mid frame changes (so that this method works), then open the hex editor, dump the ppu memory to a file. Then open the file using PPU-SPLIT, it will generate a CHR, a NAM and a PAL. Rename the PAL to DAT, then open the rom on yy-chr, open the DAT. Then open the nametable editor, load the nam, and done! Sounds more complicated than it is, but now you have it so you can edit tiles and see what they do, or right click the nam editor to find a tile in the chr table.

Help Wanted Ads / Re: Deadpool last changes
« on: June 03, 2019, 02:00:27 pm »
Backwards speed is in 0x7D911.

Forward is in 0x201C3

Help Wanted Ads / Re: Deadpool last changes
« on: June 03, 2019, 01:31:38 pm »
It seems to be 0x1EF05: change 00 to 01.

You can also change 0x1EEFC to 02 to make walking faster and forward jumping faster.

Actually modifying both these values to 02 would make for a pretty sick simple NG hack :D

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