sev wrote:It's extremely difficult, especially when there is no source code. For illustration, Gobliiins engine, the smallest one in ScummVM took about a half year of devotion from Ivan Dubrov. Adding Inherit the Earth support from a well-suited ground, i.e. we had working intro and original source code, took over a year from a team of 3 developers. So you may guess by yourself.
Of course, even in the case where we do have source code to work from it also depends on what shape that source code is in, and how freely we are allowed to use it. I wasn't directly involved with Beneath a Steel Sky
but I know it took a lot of time since the original was written in assembly.
On the other hand, the Broken Sword 2
code that was first committed to the ScummVM repository, not long after we received it, ran straight away. It didn't actually draw
anything to screen or play any sounds, but that was just a relatively small matter of rewriting a bunch of Windows-specific functions, and they were clearly separated from the rest of the code. Of course, since then there has been quite a bit of work in an attempt to make it endian-safe, alignment-safe, 64-bit safe, etc. (Since I don't have access to that kind of hardware, I can't say for sure how well that has succeeded, but the lack of bug reports is encouraging.)
Some parts of it are still a bit of a mess, but that's being taken care of. Slowly. Any year now.