Yeah. Just as I feared. This is why DOOM had "pseudo randomness" in that the "random" numbers were actually fixed and any time the game required a random value, it just picked the next one in sequence and looped around. This allowed two different computers to be more in sync.
How does Minecraft handle randomness with its generator? Does Java have a more predictable Random number generator across platforms? Since you can use a seed on any platform and always get the same world on Windows, OS X and Linux.
I think in a game this simple you could just pre-generate and hard-code a long list of random numbers and use the same method as DOOM used.
Alternatively, if you're having a networked game that's only networked, you could have the server do the random number returning, but then A) you'd still be restricted to whatever platform the server is running on and B) you'd be requesting network data every time you need a random number. Then again, you could also have the server generate a random string of numbers at game initialization, have it send that string of numbers to each player and that way they'd all have the same numbers.
Code: Select all
// Emacs style mode select -*- C++ -*-
//-----------------------------------------------------------------------------
//
// $Id:$
//
// Copyright (C) 1993-1996 by id Software, Inc.
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// $Log:$
//
// DESCRIPTION:
// Random number LUT.
//
//-----------------------------------------------------------------------------
static const char rcsid[] = "$Id: m_random.c,v 1.1 1997/02/03 22:45:11 b1 Exp $";
//
// M_Random
// Returns a 0-255 number
//
unsigned char rndtable[256] = {
0, 8, 109, 220, 222, 241, 149, 107, 75, 248, 254, 140, 16, 66 ,
74, 21, 211, 47, 80, 242, 154, 27, 205, 128, 161, 89, 77, 36 ,
95, 110, 85, 48, 212, 140, 211, 249, 22, 79, 200, 50, 28, 188 ,
52, 140, 202, 120, 68, 145, 62, 70, 184, 190, 91, 197, 152, 224 ,
149, 104, 25, 178, 252, 182, 202, 182, 141, 197, 4, 81, 181, 242 ,
145, 42, 39, 227, 156, 198, 225, 193, 219, 93, 122, 175, 249, 0 ,
175, 143, 70, 239, 46, 246, 163, 53, 163, 109, 168, 135, 2, 235 ,
25, 92, 20, 145, 138, 77, 69, 166, 78, 176, 173, 212, 166, 113 ,
94, 161, 41, 50, 239, 49, 111, 164, 70, 60, 2, 37, 171, 75 ,
136, 156, 11, 56, 42, 146, 138, 229, 73, 146, 77, 61, 98, 196 ,
135, 106, 63, 197, 195, 86, 96, 203, 113, 101, 170, 247, 181, 113 ,
80, 250, 108, 7, 255, 237, 129, 226, 79, 107, 112, 166, 103, 241 ,
24, 223, 239, 120, 198, 58, 60, 82, 128, 3, 184, 66, 143, 224 ,
145, 224, 81, 206, 163, 45, 63, 90, 168, 114, 59, 33, 159, 95 ,
28, 139, 123, 98, 125, 196, 15, 70, 194, 253, 54, 14, 109, 226 ,
71, 17, 161, 93, 186, 87, 244, 138, 20, 52, 123, 251, 26, 36 ,
17, 46, 52, 231, 232, 76, 31, 221, 84, 37, 216, 165, 212, 106 ,
197, 242, 98, 43, 39, 175, 254, 145, 190, 84, 118, 222, 187, 136 ,
120, 163, 236, 249
};
int rndindex = 0;
int prndindex = 0;
// Which one is deterministic?
int P_Random (void)
{
prndindex = (prndindex+1)&0xff;
return rndtable[prndindex];
}
int M_Random (void)
{
rndindex = (rndindex+1)&0xff;
return rndtable[rndindex];
}
void M_ClearRandom (void)
{
rndindex = prndindex = 0;
}
