mirror of
https://github.com/odamex/odamex
synced 2026-08-19 02:23:09 -04:00
311 lines
8.3 KiB
C++
311 lines
8.3 KiB
C++
// Emacs style mode select -*- C++ -*-
|
|
//-----------------------------------------------------------------------------
|
|
//
|
|
// $Id$
|
|
//
|
|
// Copyright (C) 1993-1996 by id Software, Inc.
|
|
// Copyright (C) 2006-2026 by The Odamex Team.
|
|
//
|
|
// 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.
|
|
//
|
|
// 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 "odamex.h"
|
|
|
|
#include <time.h>
|
|
|
|
#include "m_random.h"
|
|
#include "farchive.h"
|
|
|
|
//
|
|
// M_Random
|
|
// Returns a 0-255 number
|
|
//
|
|
|
|
// [Dash|RD] -- Make random number generation use the original random number chart.
|
|
// The way we pick numbers from this chart is NOT the way the original
|
|
// game does it, but that's hardly relevant. We aren't trying to play back
|
|
// demos afterall. More work may need to be done on this.
|
|
//
|
|
// Why did I do it? With this chart the game appears to pick consistently higher
|
|
// numbers. This should address the reports that the SSG (and various other weapons)
|
|
// do less damage in ZDaemon.
|
|
//
|
|
// SSG damage statistics, 20 shot survey.
|
|
// PrBoom -- Max: 245 Min: 165 Median: 210 Average: 206.5 Total: 4,130
|
|
// ZDaemon -- Max: 215 Min: 155 Median: 195 Average: 194.5 Total: 3,890
|
|
// This Code -- Max: 245 Min: 155 Median: 205 Average: 202.75 Total: 4,055
|
|
//
|
|
// Obviously you want to give a bit of room for randomness, but has is definitely been my experience that
|
|
// this code statistically gives off higher `random' numbers. Other shotgun guru's have also claimed that
|
|
// this code fixes their issues with weapon damage.
|
|
//
|
|
|
|
static constexpr 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
|
|
};
|
|
|
|
unsigned char rndindex, prndindex;
|
|
|
|
extern bool step_mode;
|
|
|
|
//
|
|
// denis - Every actor has a random number generator so they can be sync'ed
|
|
// across the network without knowledge of other actors
|
|
//
|
|
int P_Random (AActor *actor)
|
|
{
|
|
if(!actor || demoplayback || step_mode)
|
|
return P_Random ();
|
|
|
|
return (rndtable[++actor->rndindex]);
|
|
}
|
|
|
|
int P_RandomDiff (AActor *actor)
|
|
{
|
|
int a = P_Random (actor);
|
|
int b = P_Random (actor);
|
|
|
|
return a - b;
|
|
}
|
|
|
|
int P_Random ()
|
|
{
|
|
return (rndtable[++prndindex]);
|
|
}
|
|
|
|
int P_RandomDiff ()
|
|
{
|
|
int a = P_Random ();
|
|
int b = P_Random ();
|
|
|
|
return a - b;
|
|
}
|
|
|
|
int M_Random()
|
|
{
|
|
return (rndtable[++rndindex]);
|
|
}
|
|
|
|
//
|
|
// A PRNG commonly known as "Jenkins Small Fast" by Bob Jenkins.
|
|
// Released into the public domain.
|
|
// http://burtleburtle.net/bob/rand/talksmall.html
|
|
//
|
|
|
|
struct jsf32ctx_t
|
|
{
|
|
uint32_t a;
|
|
uint32_t b;
|
|
uint32_t c;
|
|
uint32_t d;
|
|
};
|
|
|
|
static jsf32ctx_t g_rngState;
|
|
static jsf32ctx_t g_prngState;
|
|
|
|
#define ROT32(x, k) (((x) << (k)) | ((x) >> (32 - (k))))
|
|
|
|
/**
|
|
* @brief Run one iteration of JSF32.
|
|
*/
|
|
static uint32_t JSF32(jsf32ctx_t* x)
|
|
{
|
|
const uint32_t e = x->a - ROT32(x->b, 27);
|
|
x->a = x->b ^ ROT32(x->c, 17);
|
|
x->b = x->c + x->d;
|
|
x->c = x->d + e;
|
|
x->d = e + x->a;
|
|
return x->d;
|
|
}
|
|
|
|
/**
|
|
* @brief Seed the JSF state.
|
|
*/
|
|
static void JSF32Seed(jsf32ctx_t* x, const uint32_t seed)
|
|
{
|
|
x->a = 0xf1ea5eed, x->b = x->c = x->d = seed;
|
|
for (uint32_t i = 0; i < 20; i++)
|
|
{
|
|
(void)JSF32(x);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @brief Return a random integer that is not tied to game state.
|
|
*
|
|
* @param range One past the maximum number you want to roll.
|
|
* @return A random integer in the given range.
|
|
*/
|
|
uint32_t M_RandomInt(const uint32_t range)
|
|
{
|
|
const uint32_t t = (0U - range) % range;
|
|
for (;;)
|
|
{
|
|
const uint32_t r = JSF32(&::g_rngState);
|
|
if (r >= t)
|
|
{
|
|
return r % range;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @brief Return a random integer that is tied to game state.
|
|
*
|
|
* @param range One past the maximum number you want to roll.
|
|
* @return A random integer in the given range.
|
|
*/
|
|
uint32_t P_RandomInt(const uint32_t range)
|
|
{
|
|
const uint32_t t = (0U - range) % range;
|
|
for (;;)
|
|
{
|
|
const uint32_t r = JSF32(&::g_prngState);
|
|
if (r >= t)
|
|
{
|
|
return r % range;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @brief Return a random floating point number that is not tied to game state.
|
|
*
|
|
* @return A random float in the half-open range of [0.0, 1.0).
|
|
*/
|
|
float M_RandomFloat()
|
|
{
|
|
const uint32_t n = JSF32(&::g_rngState);
|
|
return static_cast<float>(n) / (static_cast<float>(0xFFFFFFFFU) + 1.0f);
|
|
}
|
|
|
|
/**
|
|
* @brief Return a random floating point number that is tied to game state.
|
|
*
|
|
* @return A random float in the half-open range of [0.0, 1.0).
|
|
*/
|
|
float P_RandomFloat()
|
|
{
|
|
const uint32_t n = JSF32(&::g_prngState);
|
|
return static_cast<float>(n) / (static_cast<float>(0xFFFFFFFFU) + 1.0f);
|
|
}
|
|
|
|
// 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()
|
|
{
|
|
static bool firsttime = true;
|
|
|
|
::prndindex = 0;
|
|
|
|
// Odamex's release date.
|
|
JSF32Seed(&::g_prngState, 20071801U);
|
|
|
|
// Only init M_Random values once.
|
|
if (firsttime)
|
|
{
|
|
firsttime = false;
|
|
::rndindex = ::prndindex;
|
|
|
|
// [AM] Make non-playsim random unpredictable.
|
|
uint32_t seed = static_cast<uint32_t>(time(NULL));
|
|
JSF32Seed(&::g_rngState, seed);
|
|
}
|
|
}
|
|
|
|
void P_SerializeRNGState(FArchive& arc)
|
|
{
|
|
if (arc.IsStoring())
|
|
{
|
|
arc << ::prndindex << ::g_prngState.a << ::g_prngState.b << ::g_prngState.c
|
|
<< ::g_prngState.d;
|
|
}
|
|
else
|
|
{
|
|
arc >> ::prndindex >> ::g_prngState.a >> ::g_prngState.b >> ::g_prngState.c >>
|
|
::g_prngState.d;
|
|
}
|
|
}
|
|
|
|
//
|
|
// P_RandomHitscanAngle
|
|
// Outputs a random angle between (-spread, spread), as an int ('cause it can be
|
|
// negative).
|
|
// spread: Maximum angle (degrees, in fixed point -- not BAM!)
|
|
//
|
|
int P_RandomHitscanAngle(fixed_t spread)
|
|
{
|
|
int t;
|
|
uint64_t spread_bam;
|
|
|
|
// FixedToAngle doesn't work for negative numbers,
|
|
// so for convenience take just the absolute value.
|
|
spread_bam = (spread < 0 ? FixedToAngle(-spread) : FixedToAngle(spread));
|
|
t = P_Random();
|
|
return (int)((spread_bam * (t - P_Random())) / 255);
|
|
}
|
|
|
|
//
|
|
// P_RandomHitscanSlope
|
|
// Outputs a random angle between (-spread, spread), converted to values used for slope
|
|
// spread: Maximum vertical angle (degrees, in fixed point -- not BAM!)
|
|
//
|
|
int P_RandomHitscanSlope(fixed_t spread)
|
|
{
|
|
int angle;
|
|
|
|
angle = P_RandomHitscanAngle(spread);
|
|
|
|
// clamp it, yo
|
|
if (angle > ANG90)
|
|
return finetangent[0];
|
|
else if (-angle > ANG90)
|
|
return finetangent[FINEANGLES / 2 - 1];
|
|
else
|
|
return finetangent[(ANG90 - angle) >> ANGLETOFINESHIFT];
|
|
}
|
|
|
|
VERSION_CONTROL (m_random_cpp, "$Id$")
|
|
|