// Emacs style mode select -*- C++ -*- //----------------------------------------------------------------------------- // // $Id: M_RANDOM.C,v 1.1 2000/04/09 18:00:47 proff_fs Exp $ // // PRBOOM/GLBOOM (C) Florian 'Proff' Schulze (florian.proff.schulze@gmx.net) // based on // BOOM, a modified and improved DOOM engine // Copyright (C) 1999 by // id Software, Chi Hoang, Lee Killough, Jim Flynn, Rand Phares, Ty Halderman // // 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. // // You should have received a copy of the GNU General Public License // along with this program; if not, write to the Free Software // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA // 02111-1307, USA. // // 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. // //----------------------------------------------------------------------------- static const char rcsid[] = "$Id: M_RANDOM.C,v 1.1 2000/04/09 18:00:47 proff_fs Exp $"; #include "doomstat.h" #include "m_random.h" // // M_Random // Returns a 0-255 number // static const unsigned char rndtable[256] = { // 1/19/98 killough -- made const 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 demo_insurance=0, default_demo_insurance=0; // killough 3/31/98 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; // 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; 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; if (demo_compatibility) return rndtable[compat]; 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 // killough 9/29/98: but use basetic now instead of levelstarttic if (demo_insurance) boom += (gametic-basetic)*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