Copyright and Opensource 'clones'

[benpage26]

[Not sure if this is in the relevant forum, so sorry if it isn't]

Hi,
Can anyone give me advice on the legality of Open-source (or closed-source) 'clones' of commercial software?

For example Frozen Bubble is very similar to Puzzle Bobble / Bust-a-move. Are there any legal issues there?

There are lots of other OS games that have taken inspiration from commercial (or at least copyrighted) games. I would think that the people who wrote/designed the original wouldn't be too happy.

Can anyone clear this up?

[ruy_lopez]

Copyright doesn't really apply to program features. It applies to line-by-line similarity, exactly the way copyright applies to literary works. You cannot copyright a story, only the unique combination of words that makes up the story.

Things like the program's name, it's avatar characters etc. are covered by trademark law, which is relatively easy to workaround.

When the mechanisms underying a program's features resemble another program's, it's Patent Law that applies. Patents are the hardest to get around, primarily because many patents haven't been tested in court. When large patent troll companies threaten lawsuits, other parties tend to settle to avoid a costly, protracted lawsuit.

To answer your question, the commercial software you are thinking about probably uses techniques which are already in the public domain. That would rule out a patent infringement, which only leaves trademark. Copyright wouldn't apply because open-source programmers don't have access to closed-source code (you can't copy if you can't see). Unless they inadvertently created the same code, line-by-line, by sheer chance (which is improbable, and copyright allows for a certain amount of accidental similarity).

[benpage26]

Thanks for explaining that :D

[pmasiar]

Also be careful to use original artwork, not to copy art from commercial game.

Don't worry about patents too much, chances that someone sues you are nil, because you don't have enough assets to pay fine even if you lose. Patents are dangerous for companies, who are worth to sue.