Sonic Metatiles

What language is your exporting tool written in? I can help you with calculating the palette data to be more accurate.

 

Techokami's assistancy could be handy. He's really good with metatile ripping.

 

4 days ago I was assigned "build an application of your choice on the stuff you've learned so far" as homework for school, and I finished my project today, (do by Tuesday)

So I was trying to think of something to make, but nothing came to mind, and I was searching through the forums like I usually do, and seen this thread and it clicked, "I'll use these tiles for a level viewer".

And so I did that.


This probably has absolutely no use to anyone but I figured I'd share my app with the Sonic community.

With out further ado...

The Sonic Level Viewer:
(hope the image isn't too big, I have a really high resolution)


This doesn't read through ROM files, the layouts were dumped into bin files and are loaded from hard drive, then it loads the Metatiles created by Mercury.

Everything you need is in the zip(so you don't need anything)
Download

Enjoy.

EDIT: I forgot to mention that it requires .net 2.0.

EDIT2: oh and the code is a mess, and the way I rendered it is shitty and probably lags for some people.

 

If you have to write an image file in the good old binary way I don't recommend you to do so with a PNG file, because the format is a bitch (it's compressed and filled of checksums everywhere). I'd rather write a PCX file, which is billions of times easier. The palettes would be correct and sorted, though you won't be able to add transparency. Not a big deal, you can batch convert the files from 8-bit PCX to 8-bit PNG (making sure to use a converter that preserves palette indexes) and then massively add the "tRNS" chunk to the PNG, since it will always be the same for all the files as the transparent palette indexes are always the same (0, 16, 32, 48 iirc). Brutally adding a chunk to a PNG doesn't affect the checksums so you can totally do it. I'm up to help if you want.

 

Oh. I've been using PHP, because the GD libraries are actually quite handy, and work with paletted APNG images.
I should really update my tool to spit out priority-based images as well. But I should also figure out why the hell I can't get 16x16 tiles to properly transform with Sonic 1... mind helping me out with that? The wiki is useless in that regard. (transform in this case means the flip X/Y bits)

In the meantime, here's some code for calculating a Genesis palette entry. It's in PHP, but I'm sure that you can port it to GML:

Code (Text):

1. $color = getByte($source);
2. $color2 = getByte($source);
3. // Genesis pallete entries are words - 0B GR
4. $red = 17 * ($color2 % 16);
5. $green = 17 * floor($color2 / 16);
6. $blue = 17 * ($color % 16);

 

Yes, that's correct according to what we know.

 

Actually, IIRC GerbilSoft later told me that the answer in that thread is not the correct one.

 

You mean this?

 

He told me on IRC I think, but yeah.

 

You're right, Sonic 1 (and Sonic CD) uses different flags than the other Sonic games. (I remember that it took me a while to figure them out.)
Sonic 1 uses bit 4 (0x10) for vertical flipping and bit 3 (0x08) for horizontal flipping.

 

So I tried updating my Sonic 2/3K tool to export metatiles with priority, like Mercury is doing. The Wikis say the 8x8 tile data is PCCY XAAA AAAA AAAA, with P being the priority bit... so if I do a test to see if $tile & 0x8000, that should tell me if a tile has priority or not! Let's give it a spin and see what...

Well that ain't right.

 

Again, if you want I already have a lot of the code written in C++ for Chaotix. All that would really be needed would be to change the addresses and data loading, use the proper decompression formats, and then write a new for loop to write out the images, converting the palettes in the process (IF Qt allows that, which is why I've delayed — haven't checked).

 

Yes, PCX is really simple, but I don't see a reason to deal with compression at all (even if it's the simple RLE implementation used by the PCX format - unless you actually want PCX to be the final delivery format) when you could just export uncompressed BMPs. Since all the images for a given game have the same dimensions, you could even save "template images" from MS Paint (one that's 128x128 and another that's 256x256) and copy their headers directly, so that during export you just have to worry about writing the palettes and the image itself, one pixel at a time without having to bother compressing anything. These BMPs should compress well when archived, or you could convert them to PNG later. The only weird thing about BMP is that they are stored from the bottom up, so the first row in the file is the last row of the image.

 

Well one, yes there is a command line version of PHP you can install. But I don't use it, I run my scripts in the browser via my own webserver running on my computer.
And two, there's a fair amount of binary file functions, as well as a powerful image library called GD. While GD was made to have dynamically generated images for websites, or to watermark a photo that gets uploaded, or to generate thumbnails from a large image, it can also be used to, well, rip graphics from games!

Okay. Will it change anything?

Sonic 1 hates me.

 

Doesn't the image prove otherwise then?

 

That was the output from my upgraded script on a Sonic 1 savestate of Green Hill Zone, after getting help from both ValleyBell and Mercury. The shuttle loop isn't supposed to look like that, you know.

 

No, what I'm saying is doesn't this mean that it actually IS the same as other Sonic games?

Also if someone wants to dick around and get this working with not only other Sonic games but also outputting proper palette images of individual blocks...