Emulators available for commercial use?

[DaMadFiddler]

I have a couple of friends who have expressed interest in NES development. However, since cartridges are a large overhead expense for a very niche market, there is also an interest in releasing other versions of any games they might produce.

The easiest way to do this would just be to wrap the ROM in an NES emulator for the other platforms, and release it as a budget title to help fund the cartridge version. That would also make it easy to bring these games to a wide variety of platforms (e.g., Dreamcast). However, most of the emulators out there are not free for commercial use, and most of the good ones would be nearly impossible even to work out a paid license, given GPL and other proprietary licensing complications that stem from collaborative software development.

Does anyone know of a good NES emulator that would be legal to use for commercial projects? Preferably (long shot) one with an existing DC port?

[|darc|]

Most of the emulators are under GPLv2, which most people know as just "GPL." GPLv2 does not require any special provisions to be made in obtaining a "paid license." GPLv2 is completely compatible with a commercial software distribution model with one caveat: any modifications made to the source code must be released. So if they tailor the emulator code specifically to run their NES ROM (e.g. tweaking for maximum compatibility, tweaking the menu for perfect presentation of their game, etc.), they would have to release the code of all their changes. Which, I don't see why it would be a problem for them.

They shouldn't have to release the code for the NES ROM itself, with which I could see them having a problem.

[BlueCrab]

Most of the emulators are under GPLv2, which most people know as just "GPL." GPLv2 does not require any special provisions to be made in obtaining a "paid license." GPLv2 is completely compatible with a commercial software distribution model with one caveat: any modifications made to the source code must be released. So if they tailor the emulator code specifically to run their NES ROM (e.g. tweaking for maximum compatibility, tweaking the menu for perfect presentation of their game, etc.), they would have to release the code of all their changes. Which, I don't see why it would be a problem for them.

They shouldn't have to release the code for the NES ROM itself, with which I could see them having a problem.

Actually, it's not just any modifications must be released -- the source code of the entire emulator must be made available by the person selling it, regardless of if any changes were made.

The easiest way to comply with the GPLv2 in that case would be to just include the full source code of the emulator (with any relevant changes included, of course) on the disc with the binaries, of course.

As you said, the ROM itself would not have to have its source released, as long as the ROM is not embedded into the emulator directly and is just distributed alongside it as a separate file.

[|darc|]

Actually, it's not just any modifications must be released -- the source code of the entire emulator must be made available by the person selling it, regardless of if any changes were made.

Right, I was just saying that their changes would have to be released because the changes are what they would care about. To clarify, yes, the entire GPLed work in its entirety would have to be made available to anyone who wants it via postal mail, though I doubt anyone would order it that way if the code is present on the disc and you can charge a fee to mail it.

But in short, yea, any GPLed emulator should meet their needs just fine with very, very minimal concessions needed.