mirror of
https://github.com/ZDoom/gzdoom.git
synced 2025-04-25 20:20:57 +00:00
126 lines
3.8 KiB
C
126 lines
3.8 KiB
C
// Emacs style mode select -*- C++ -*-
|
|
//-----------------------------------------------------------------------------
|
|
//
|
|
// $Id: m_random.c,v 1.6 1998/05/03 23:13:18 killough Exp $
|
|
//
|
|
// Copyright (C) 1993-1996 by id Software, Inc.
|
|
//
|
|
// This source is available for distribution and/or modification
|
|
// only under the terms of the DOOM Source Code License as
|
|
// published by id Software. All rights reserved.
|
|
//
|
|
// The source is distributed in the hope that it will be useful,
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// FITNESS FOR A PARTICULAR PURPOSE. See the DOOM Source Code License
|
|
// for more details.
|
|
//
|
|
//
|
|
// DESCRIPTION:
|
|
// Random number LUT.
|
|
//
|
|
// 1/19/98 killough: Rewrote random number generator for better randomness,
|
|
// while at the same time maintaining demo sync and backward compatibility.
|
|
//
|
|
// 2/16/98 killough: Made each RNG local to each control-equivalent block,
|
|
// to reduce the chances of demo sync problems.
|
|
//
|
|
//-----------------------------------------------------------------------------
|
|
|
|
|
|
#include "doomstat.h"
|
|
#include "m_random.h"
|
|
|
|
//
|
|
// M_Random
|
|
// Returns a 0-255 number
|
|
//
|
|
rng_t rng; // the random number state
|
|
|
|
unsigned long rngseed = 1993; // killough 3/26/98: The seed
|
|
|
|
int P_Random(pr_class_t pr_class)
|
|
{
|
|
// killough 2/16/98: We always update both sets of random number
|
|
// generators, to ensure repeatability if the demo_compatibility
|
|
// flag is changed while the program is running. Changing the
|
|
// demo_compatibility flag does not change the sequences generated,
|
|
// only which one is selected from.
|
|
//
|
|
// All of this RNG stuff is tricky as far as demo sync goes --
|
|
// it's like playing with explosives :) Lee
|
|
|
|
int compat = pr_class == pr_misc ?
|
|
(rng.prndindex = (rng.prndindex + 1) & 255) :
|
|
(rng. rndindex = (rng. rndindex + 1) & 255) ;
|
|
|
|
unsigned long boom;
|
|
|
|
#if 0 // [RH]
|
|
|
|
// killough 3/31/98:
|
|
// If demo sync insurance is not requested, use
|
|
// much more unstable method by putting everything
|
|
// except pr_misc into pr_all_in_one
|
|
|
|
if (pr_class != pr_misc && !demo_insurance) // killough 3/31/98
|
|
pr_class = pr_all_in_one;
|
|
|
|
#endif
|
|
|
|
boom = rng.seed[pr_class];
|
|
|
|
// killough 3/26/98: add pr_class*2 to addend
|
|
|
|
rng.seed[pr_class] = boom * 1664525ul + 221297ul + pr_class*2;
|
|
|
|
boom >>= 20;
|
|
|
|
// killough 3/30/98: use gametic-levelstarttic to shuffle RNG
|
|
// killough 3/31/98: but only if demo insurance requested,
|
|
// since it's unnecessary for random shuffling otherwise
|
|
// [RH] And it also seems to screws up netgame sync.
|
|
|
|
//if (demo_insurance)
|
|
// boom += (gametic-level.starttime)*7;
|
|
|
|
return boom & 255;
|
|
}
|
|
|
|
// Initialize all the seeds
|
|
//
|
|
// This initialization method is critical to maintaining demo sync.
|
|
// Each seed is initialized according to its class, so if new classes
|
|
// are added they must be added to end of pr_class_t list. killough
|
|
//
|
|
|
|
void M_ClearRandom (void)
|
|
{
|
|
int i;
|
|
unsigned long seed = rngseed*2+1; // add 3/26/98: add rngseed
|
|
for (i=0; i<NUMPRCLASS; i++) // go through each pr_class and set
|
|
rng.seed[i] = seed *= 69069ul; // each starting seed differently
|
|
rng.prndindex = rng.rndindex = 0; // clear two compatibility indices
|
|
}
|
|
|
|
//----------------------------------------------------------------------------
|
|
//
|
|
// $Log: m_random.c,v $
|
|
// Revision 1.6 1998/05/03 23:13:18 killough
|
|
// Fix #include
|
|
//
|
|
// Revision 1.5 1998/03/31 10:43:05 killough
|
|
// Fix (supposed) RNG problems, add new demo_insurance
|
|
//
|
|
// Revision 1.4 1998/03/28 17:56:05 killough
|
|
// Improve RNG by adding external seed
|
|
//
|
|
// Revision 1.3 1998/02/17 05:40:08 killough
|
|
// Make RNGs local to each calling block, for demo sync
|
|
//
|
|
// Revision 1.2 1998/01/26 19:23:51 phares
|
|
// First rev with no ^Ms
|
|
//
|
|
// Revision 1.1.1.1 1998/01/19 14:02:58 rand
|
|
// Lee's Jan 19 sources
|
|
//
|
|
//----------------------------------------------------------------------------
|