I'm a noob--is this possible?

[cajones]

Hi, I'm quite the noob when it comes to the subject of Megadrive programming (have read a little on how to hack ROMs, but not done anything with it).
I'm wanting to develop a program that can interpret the visual things on screen and potentially output something--maybe audio--to represent it.
I know it would be extremely difficult to try and get everything that can be seen easily interpreted. For now, I'm just wanting to focus on something that can tell about where sprites are, maybe how big they are, things like that.

Problem is, I don't really know where to start. I'd greatly appreciate it if someone could point me in the right direction. (I can program in java... and know full well that this is useless for what I want to do. )

[andlabs]

...what exactly is your program going to accomplish? I don't get what you're doing from the description.

[cajones]

The idea is an accessibility tool for visually challenged players. There are games designed with VI players in mind, but as I'm sure you can imagine, the experience is very different from classic console games.
This idea actually got started when I made an audio version of Mario that seemed to work pretty well, and someone suggested it'd be easier to develop a program to interpret ROMs rather than rebuild games from scratch.

[KanedaFr]

Very interesting.....
I once saw a "joypad" for people who can only use their eyes...I can't retrieve the url...

You should give us a video/sound sample of what your "sound mario" is. It will help us to understand and help you I think...

[cajones]

Well, here's an MP3 of the first level: http://dl.dropbox.com/u/16520690/mario1-1.mp3
It's designed more specifically for Mario. Upcoming barriers, platforms, dropoffs and enemies make sound, there's sound for walking/landing/hitting things, and there's a "camera" that gives more specific sounds for individual objects.
It would be difficult to make something like that to be more universal, though, since every game is different.
It seems like it should be possible to find sprites and play sound that indicates the position and size, though. If I can get that to work, I might try something more detailed.

Recently, someone started a project to collect the most VI-accessible emulators and games and I believe a launcher for them. So there's definitely interest among VI gamers. (Gens and K Fusion were among the emulators in the collection).

[KanedaFr]

So, the FX you hear is the FX you COULD hear if you make the correct move
ex: If Mario is under a block with flower, you launch the "flower taking" fx ?

It would be hard to make a generic way to handle this....
The emulator should know what kind of action could be done and play a specific song for this....

My first thought would be to record the game (using GMV for example) and to convert them to something specifix......but you'll have to do it for each game....and only for not random game...and it doesn't solve all the problem like coming back, etc... (sorry, I'm thinking while typing)
....

[cajones]

So, the FX you hear is the FX you COULD hear if you make the correct move
ex: If Mario is under a block with flower, you launch the "flower taking" fx ?

Not exactly, but the idea is similar.


It'd be helpful if one could mod a game to use stereo to show where an object is, but I don't think the MD sound system works that way... does it?
An additional program that could locate objects would have that ability, though. The problem would be making something generic, and making it possible to identify the objects.
I think this wouldn't be too big of a problem for some games.
Ex, in Sonic, rings are smaller than most enemies, some enemies move, Etc. If a companion program could make a sound for the size of the sprites and use stereo to show location, one could find them by sound alone.

I don't know how this could show the shape of the track and platforms in a game like Sonic, but it's a start.

[KanedaFr]

In the genny, there is a sprite list when you can check if a sprite is 8x8 or 32x32...

The good news is so an emulator know where each sprite is
the bad news is it doesn't know if it's a small one, a sprite used to draw background, a big sprite using severel smaller one, etc...

[cajones]

Well, it sounds like a good place to start.

Hmm. There's a program called the vOICe that makes sounds to represent images. It's not good for anything useful, but I'm wondering if it wouldn't be better to set up an emulator to send its video to a program like that. It'd be a confusing mess if the user didn't disable certain layers (and then there's no telling if it would work), but I wonder if this wouldn't work better than trying to get at the information directly...

[cajones]

I'm still working with this. Just not getting very far. ^^

I think I'm going to try to come up with an approach that works for individual games, and see if I can expand from there.

Right now, I'm trying to get a program to read save states as its source of information. Never minding the annoyance this is bound to cause on the user end (it's the easiest way to test right now, I think).

I'm primarily using Fusion as my emulator, here, and I haven't been able to find a guide as to what data is saved where in a Fusion save state. Does anyone have / know where I can find this information?

[Chilly Willy]

I'm primarily using Fusion as my emulator, here, and I haven't been able to find a guide as to what data is saved where in a Fusion save state. Does anyone have / know where I can find this information?

There isn't any - FUSION is a closed source emulator. I'd suggest using an open source one like Gens, KGen, or Gens/GS. With open source emulators, you can refer directly to the source to see how the save states are stored since there won't be any docs on that anywhere.