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147 lines
5.5 KiB
C
147 lines
5.5 KiB
C
/* Emacs style mode select -*- C++ -*-
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*-----------------------------------------------------------------------------
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*
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*
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* PrBoom: a Doom port merged with LxDoom and LSDLDoom
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* based on BOOM, a modified and improved DOOM engine
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* Copyright (C) 1999 by
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* id Software, Chi Hoang, Lee Killough, Jim Flynn, Rand Phares, Ty Halderman
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* Copyright (C) 1999-2000 by
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* Jess Haas, Nicolas Kalkhof, Colin Phipps, Florian Schulze
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* Copyright 2005, 2006 by
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* Florian Schulze, Colin Phipps, Neil Stevens, Andrey Budko
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
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* 02111-1307, USA.
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*
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* DESCRIPTION:
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* Random number LUT.
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*
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* 1/19/98 killough: Rewrote random number generator for better randomness,
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* while at the same time maintaining demo sync and backward compatibility.
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*
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* 2/16/98 killough: Made each RNG local to each control-equivalent block,
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* to reduce the chances of demo sync problems.
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*
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*-----------------------------------------------------------------------------*/
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#include "doomstat.h"
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#include "m_random.h"
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#include "lprintf.h"
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//
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// M_Random
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// Returns a 0-255 number
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//
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static const unsigned char rndtable[256] = { // 1/19/98 killough -- made const
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0, 8, 109, 220, 222, 241, 149, 107, 75, 248, 254, 140, 16, 66 ,
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74, 21, 211, 47, 80, 242, 154, 27, 205, 128, 161, 89, 77, 36 ,
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95, 110, 85, 48, 212, 140, 211, 249, 22, 79, 200, 50, 28, 188 ,
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52, 140, 202, 120, 68, 145, 62, 70, 184, 190, 91, 197, 152, 224 ,
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149, 104, 25, 178, 252, 182, 202, 182, 141, 197, 4, 81, 181, 242 ,
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145, 42, 39, 227, 156, 198, 225, 193, 219, 93, 122, 175, 249, 0 ,
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175, 143, 70, 239, 46, 246, 163, 53, 163, 109, 168, 135, 2, 235 ,
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25, 92, 20, 145, 138, 77, 69, 166, 78, 176, 173, 212, 166, 113 ,
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94, 161, 41, 50, 239, 49, 111, 164, 70, 60, 2, 37, 171, 75 ,
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136, 156, 11, 56, 42, 146, 138, 229, 73, 146, 77, 61, 98, 196 ,
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135, 106, 63, 197, 195, 86, 96, 203, 113, 101, 170, 247, 181, 113 ,
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80, 250, 108, 7, 255, 237, 129, 226, 79, 107, 112, 166, 103, 241 ,
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24, 223, 239, 120, 198, 58, 60, 82, 128, 3, 184, 66, 143, 224 ,
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145, 224, 81, 206, 163, 45, 63, 90, 168, 114, 59, 33, 159, 95 ,
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28, 139, 123, 98, 125, 196, 15, 70, 194, 253, 54, 14, 109, 226 ,
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71, 17, 161, 93, 186, 87, 244, 138, 20, 52, 123, 251, 26, 36 ,
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17, 46, 52, 231, 232, 76, 31, 221, 84, 37, 216, 165, 212, 106 ,
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197, 242, 98, 43, 39, 175, 254, 145, 190, 84, 118, 222, 187, 136 ,
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120, 163, 236, 249
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};
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rng_t rng; // the random number state
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unsigned long rngseed = 1993; // killough 3/26/98: The seed
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int (P_Random)(pr_class_t pr_class
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#ifdef INSTRUMENTED
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, const char *file, int line
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#endif
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)
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{
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// killough 2/16/98: We always update both sets of random number
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// generators, to ensure repeatability if the demo_compatibility
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// flag is changed while the program is running. Changing the
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// demo_compatibility flag does not change the sequences generated,
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// only which one is selected from.
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//
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// All of this RNG stuff is tricky as far as demo sync goes --
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// it's like playing with explosives :) Lee
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#ifdef INSTRUMENTED
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//lprintf(LO_DEBUG, "%.10d: %.10d - %s:%.5d\n", gametic, pr_class, file, line);
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#endif
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int compat = pr_class == pr_misc ?
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(rng.prndindex = (rng.prndindex + 1) & 255) :
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(rng. rndindex = (rng. rndindex + 1) & 255) ;
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unsigned long boom;
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// killough 3/31/98:
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// If demo sync insurance is not requested, use
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// much more unstable method by putting everything
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// except pr_misc into pr_all_in_one
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if (pr_class != pr_misc && !demo_insurance) // killough 3/31/98
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pr_class = pr_all_in_one;
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boom = rng.seed[pr_class];
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// killough 3/26/98: add pr_class*2 to addend
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rng.seed[pr_class] = boom * 1664525ul + 221297ul + pr_class*2;
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if (demo_compatibility)
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return rndtable[compat];
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boom >>= 20;
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/* killough 3/30/98: use gametic-levelstarttic to shuffle RNG
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* killough 3/31/98: but only if demo insurance requested,
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* since it's unnecessary for random shuffling otherwise
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* killough 9/29/98: but use basetic now instead of levelstarttic
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* cph - DEMOSYNC - this change makes MBF demos work,
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* but does it break Boom ones?
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*/
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if (demo_insurance)
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boom += (gametic-basetic)*7;
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return boom & 255;
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}
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// Initialize all the seeds
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//
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// This initialization method is critical to maintaining demo sync.
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// Each seed is initialized according to its class, so if new classes
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// are added they must be added to end of pr_class_t list. killough
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//
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void M_ClearRandom (void)
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{
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int i;
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unsigned long seed = rngseed*2+1; // add 3/26/98: add rngseed
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for (i=0; i<NUMPRCLASS; i++) // go through each pr_class and set
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rng.seed[i] = seed *= 69069ul; // each starting seed differently
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rng.prndindex = rng.rndindex = 0; // clear two compatibility indices
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}
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