I was wondering what kind of checksum the Demo version of Q3A uses, and if it can be circumvented. And please don't tell me to just buy the game, I just wanted to see if it was possible, and to get a little more knowledge on checksums.
IIRC it's a simple CRC32, and yes, it can be circumvented by patching the exe. I'd recommend just using an alternative Q3 engine like ioquake3 instead of the original exe though. I think ioq3 already comes with CRC checks disabled, and even if not it's easy to do yourself. Or you could grab the source, look for the checksum the game expects and add random stuff to your PK3 until you get a match, but that'd be a colossal waste of time imho.
I understand there are alternatives, I am really interested in how checksums work. How would I go about changing the checksum?
Take ioquake3 source code because this is a fix version of q3 (without bug and with many extentions), then modify it. If you want I can do this week-end, it's not difficult. What is your OS ? (please tell me you run on gnu/linux)
Sorry for the delay, I were busy these last weeks. I test running demo's pak0.pk3 with latest ioquake3 executable in my gnu/linux, and the program run well so you can play demo maps with the last engine (without bugs) and with many added features. In your terminal you will just saw this kind of message: ************************************************** WARNING: pak0.pk3 is present but its checksum (2985612116) is not correct. Please re-install the point release ************************************************** Here checksum produce a warning message, nothing more.
