Rand / SeedRnd between B+ / B3D

I seem to recall there being an intrinsic change between the way B+ does random number sequences and B3D, to such an extent that given seed X, Blitz3D and Blitz+ will not generate the same sequence of random numbers. Simple experimentation bears this out.

I also seem to recall that someone (Mark perhaps?) posted a way to SeedRnd in such a way that you could get them to work together again.

Assuming I'm not getting my threads mixed up (which I probably am), does anyone remember what needed to happen to the value one passes SeedRnd, and in which environment, to get the two sequences to match up?

I remember it too, but can't spot it. Remind me to update the online docs when we do though...

If you want random numbers to match between versions then you should write your own generator.

There *is* a way to make B+ random numbers consistent with those generated from Blitz2d / 3d. I think you have to mask out the first 8 bits or something - i.e. SeedRnd $FFFF & MilliSecs(). Or something.

However, to guarantee the same random numbers across all PCs, you *do* have to roll your own generator - the random number generator will generate different results on different PCs, regardless of whether you apply the above tweak (should we ever find it again...).