rockbox/apps/plugins/doom/m_random.h

/* Emacs style mode select   -*- C++ -*-
 *-----------------------------------------------------------------------------
 *
 *
 *  PrBoom a Doom port merged with LxDoom and LSDLDoom
 *  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
 *  Copyright (C) 1999-2000 by
 *  Jess Haas, Nicolas Kalkhof, Colin Phipps, Florian Schulze
 *
 *  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:
 *  Functions to return random numbers.
 *
 *-----------------------------------------------------------------------------*/


#ifndef __M_RANDOM__
#define __M_RANDOM__

#include "doomtype.h"

// killough 1/19/98: rewritten to use to use a better random number generator
// in the new engine, although the old one is available for compatibility.

// killough 2/16/98:
//
// Make every random number generator local to each control-equivalent block.
// Critical for demo sync. Changing the order of this list breaks all previous
// versions' demos. The random number generators are made local to reduce the
// chances of sync problems. In Doom, if a single random number generator call
// was off, it would mess up all random number generators. This reduces the
// chances of it happening by making each RNG local to a control flow block.
//
// Notes to developers: if you want to reduce your demo sync hassles, follow
// this rule: for each call to P_Random you add, add a new class to the enum
// type below for each block of code which calls P_Random. If two calls to
// P_Random are not in "control-equivalent blocks", i.e. there are any cases
// where one is executed, and the other is not, put them in separate classes.
//
// Keep all current entries in this list the same, and in the order
// indicated by the #'s, because they're critical for preserving demo
// sync. Do not remove entries simply because they become unused later.

enum {
   pr_skullfly,                // #1
   pr_damage,                  // #2
   pr_crush,                   // #3
   pr_genlift,                 // #4
   pr_killtics,                // #5
   pr_damagemobj,              // #6
   pr_painchance,              // #7
   pr_lights,                  // #8
   pr_explode,                 // #9
   pr_respawn,                 // #10
   pr_lastlook,                // #11
   pr_spawnthing,              // #12
   pr_spawnpuff,               // #13
   pr_spawnblood,              // #14
   pr_missile,                 // #15
   pr_shadow,                  // #16
   pr_plats,                   // #17
   pr_punch,                   // #18
   pr_punchangle,              // #19
   pr_saw,                     // #20
   pr_plasma,                  // #21
   pr_gunshot,                 // #22
   pr_misfire,                 // #23
   pr_shotgun,                 // #24
   pr_bfg,                     // #25
   pr_slimehurt,               // #26
   pr_dmspawn,                 // #27
   pr_missrange,               // #28
   pr_trywalk,                 // #29
   pr_newchase,                // #30
   pr_newchasedir,             // #31
   pr_see,                     // #32
   pr_facetarget,              // #33
   pr_posattack,               // #34
   pr_sposattack,              // #35
   pr_cposattack,              // #36
   pr_spidrefire,              // #37
   pr_troopattack,             // #38
   pr_sargattack,              // #39
   pr_headattack,              // #40
   pr_bruisattack,             // #41
   pr_tracer,                  // #42
   pr_skelfist,                // #43
   pr_scream,                  // #44
   pr_brainscream,             // #45
   pr_cposrefire,              // #46
   pr_brainexp,                // #47
   pr_spawnfly,                // #48
   pr_misc,                    // #49
   pr_all_in_one,              // #50
   /* CPhipps - new entries from MBF, mostly unused for now */
   pr_opendoor,                // #51
   pr_targetsearch,            // #52
   pr_friends,                 // #53
   pr_threshold,               // #54
   pr_skiptarget,              // #55
   pr_enemystrafe,             // #56
   pr_avoidcrush,              // #57
   pr_stayonlift,              // #58
   pr_helpfriend,              // #59
   pr_dropoff,                 // #60
   pr_randomjump,              // #61
   pr_defect,                  // #62  // Start new entries -- add new entries below

   // End of new entries
   NUMPRCLASS               // MUST be last item in list
};
typedef unsigned pr_class_t;

// The random number generator's state.
typedef struct {
   unsigned long seed[NUMPRCLASS];      // Each block's random seed
   int rndindex, prndindex;             // For compatibility support
} rng_t;

extern rng_t rng;                      // The rng's state

extern unsigned long rngseed;          // The starting seed (not part of state)

// Returns a number from 0 to 255,
#define M_Random() P_Random(pr_misc)

// As M_Random, but used by the play simulation.
int P_Random(pr_class_t);

// Fix randoms for demos.
void M_ClearRandom(void);

#endif