openrct2 source code

[jessicajones]

Hi

 

Can anybody explain me how the source code of rollercoaster tycoon 2 was obtained to make openrct2?

Rollercoaster tycoon 2 was a commercial game and not open source. So I don't understand where the source code comes from.

Did Chris Sawyer donated the source code to openrct2?

 

thx

[X7123M3-256]

OpenRCT2 was written by reverse engineering the original game executable and reimplementing it in C (and later C++). The original RCT2 source code was never available to the OpenRCT2 developers; they worked only from the binary.

For the first two years of its existence, the OpenRCT2 code would call into the RCT2 binary for any functions that had not yet been rewritten, allowing the game to be reimplemented piece by piece while retaining full functionality. By the end of 2016, all the original code had been replaced. OpenRCT2 is now completely independent of the RCT2 code, but still uses the assets from the vanilla game.

Edited February 14, 2020 by X7123M3-256

[jessicajones]

- is this not crossing the "illegal" border because the original game was a commercial game?

 

- what tools were used to reverse engineer the game executable? I'm interested to know the background of this!

[jessicajones]

Are there plans to make complete free assets so the game does NOT use the original game's data anymore?

An example is OpenTTD which can use the original game's data OR completely free data: https://www.openttd.org/

[X7123M3-256]

1 hour ago, jessicajones said:

- what tools were used to reverse engineer the game executable? I'm interested to know the background of this!

Disassemblers are the tools used for this kind of reverse engineering. The OpenRCT2 wiki mentions both IDA and OllyDbg, so I assume these were the main tools used. I wasn't involved with the reverse engineering so I don't know the details. (I did start disassembling some code but stopped when I realized it wasn't the one I wanted. IIRC the code I was actually after was among the last to be decompiled).
 

1 hour ago, jessicajones said:

Are there plans to make complete free assets so the game does NOT use the original game's data anymore?

Anyone could do it. So far, nobody has done. There exists an OpenGraphics repository, but it only contains four rides and hasn't been updated in three years. There's over a hundred thousand sprites in g1.dat alone, so this would be a big project.