src/lib/update/nat.c

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/*
 *  Empire - A multi-player, client/server Internet based war game.
 *  Copyright (C) 1986-2007, Dave Pare, Jeff Bailey, Thomas Ruschak,
 *                           Ken Stevens, Steve McClure
 *
 *  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
 *
 *  ---
 *
 *  See files README, COPYING and CREDITS in the root of the source
 *  tree for related information and legal notices.  It is expected
 *  that future projects/authors will amend these files as needed.
 *
 *  ---
 *
 *  nat.c: Accumulate tech, edu, research and happiness.
 * 
 *  Known contributors to this file:
 *     Dave Pare, 1989
 *     Steve McClure, 1997
 */

#include <config.h>

#include <math.h>
#include "budg.h"
#include "game.h"
#include "item.h"
#include "update.h"

/*
 * hap and edu avg mean that the weight on current happiness is
 *  (cur_hap * hap_avg + hap_prod * etu) / (hap_avg + etu);
 * same for education.
 * right now, happiness has 1 day (48 etu) average, prod of 10 from
 * initial level of 0 yields (1) 1.42, (6) 6.03, (12) 8.42, (18) 9.37
 *
 * education has 4 day (192 etu) average, prod of 10 from initial
 * level of 0 yields (1) 0.4, (6) 2.2, (12) 3.9, (18) 5.2.
 */

static void share_incr(double *, double *);

/*
 * for values below the "easy level" values, production is
 * as normal.  For values above "easy", production gets harder
 * based on an equation in "limit_level()" in update/nat.c.
 * Basically, the smaller the the values for "level_log", the
 * smaller return on investment above level_easy[] values.
 */
/*
 * Damn! I hate this, but ...
 * The values here for tech are *not* the real ones.
 * They are changed later in the limit_level routine.
 */
                        /*tech   res   edu   hap */
static float level_easy[4] = { 0.75, 0.75, 5.00, 5.00 };
static float level_log[4] = { 1.75, 2.00, 4.00, 6.00 };

float levels[MAXNOC][4];

/*
 * technique to limit the sharpers who turn entire countries
 * into tech plants overnight...
 */

double
logx(double d, double base)
{
    if (base == 1.0)
        return d;
    return log10(d) / log10(base);
}

static double
limit_level(double level, int type, int flag)
{
    double above_easy;
    double above;
    double logbase;
    double easy;

/*
 * Begin ugly hack.
 */
    level_easy[0] = easy_tech;
    level_log[0] = tech_log_base;
/*
 * End ugly hack.
 */

    if (level > level_easy[type]) {
        logbase = level_log[type];
        easy = level_easy[type];
        above_easy = level - easy;
        if (flag)
            above = above_easy / logx(logbase + above_easy, logbase);
        else
            above = logx(above_easy + 1.0, logbase);
        if (above > 250)
            above = 250;
        return above < 0 ? easy : easy + above;
    } else
        return level;
}

void
prod_nat(int etu)
{
    struct natstr *np;
    float hap;
    float edu;
    float hap_edu;
    long pop;
    double rlev;
    double tlev;
    double tech[MAXNOC];
    double res[MAXNOC];
    double newvalue;
    natid n;
    int cn;
    struct natstr *cnp;

    for (n = 0; NULL != (np = getnatp(n)); n++) {
        grant_btus(np, game_reset_tick(&np->nat_access));
        if (np->nat_stat < STAT_ACTIVE)
            continue;
        /*
         * hap_edu: the more education people have, the
         * more happiness they want.
         */
        hap_edu = np->nat_level[NAT_ELEV];
        hap_edu = 1.5 - ((hap_edu + 10.0) / (hap_edu + 20.0));
        pop = pops[n] + 1;
        /*
         * get per-population happiness and education
         * see what the total per-civilian production is
         * for this time period.
         */
        hap = levels[n][NAT_HLEV] * hap_edu * hap_cons /
            ((float)pop * etu);
        edu = levels[n][NAT_ELEV] * edu_cons / ((float)pop * etu);
        wu((natid)0, n, "%3.0f happiness, %3.0f education produced\n",
           levels[n][NAT_HLEV], levels[n][NAT_ELEV]);
        hap = limit_level(hap, NAT_HLEV, 1);
        edu = limit_level(edu, NAT_ELEV, 1);
        /*
         * change the "moving average"...old happiness and
         * education levels are weighted heavier than current
         * production.
         */
        newvalue = (np->nat_level[NAT_HLEV] * hap_avg + hap * etu) /
            (hap_avg + etu);
        np->nat_level[NAT_HLEV] = newvalue;
        newvalue = (np->nat_level[NAT_ELEV] * edu_avg + edu * etu) /
            (edu_avg + etu);
        np->nat_level[NAT_ELEV] = newvalue;
        /*
         * limit tech/research production
         */
        levels[n][NAT_TLEV] =
            limit_level(levels[n][NAT_TLEV] / 1, NAT_TLEV, 0) * 1;
        levels[n][NAT_RLEV] =
            limit_level(levels[n][NAT_RLEV] / 1, NAT_RLEV, 0) * 1;
        wu((natid)0, n,
           "total pop was %ld, yielding %4.2f hap, %4.2f edu\n",
           pop - 1, hap, edu);
    }
    if (ally_factor > 0.0)
        share_incr(res, tech);
    else {
        memset(res, 0, sizeof(res));
        memset(tech, 0, sizeof(tech));
    }
    for (n = 0; NULL != (np = getnatp(n)); n++) {
        if (np->nat_stat < STAT_ACTIVE)
            continue;
        tlev = levels[n][NAT_TLEV];
        rlev = levels[n][NAT_RLEV];
        if (tech[n] != 0.0 || res[n] != 0.0) {
            wu((natid)0, n,
               "%5.4f technology (%5.4f + %5.4f), ",
               tlev + tech[n], tlev, tech[n]);
            wu((natid)0, n,
               "%5.4f research (%5.4f + %5.4f) produced\n",
               rlev + res[n], rlev, res[n]);
        } else
            wu((natid)0, n,
               "%5.4f tech, %5.4f research produced\n", tlev, rlev);
        rlev += res[n];
        tlev += tech[n];
        if (rlev != 0.0)
            np->nat_level[NAT_RLEV] += rlev;
        if (tlev != 0.0)
            np->nat_level[NAT_TLEV] += tlev;
        if ((sea_money[n] != 0) || (air_money[n] != 0) ||
            (lnd_money[n] != 0))
            wu((natid)0, n,
               "Army delta $%ld, Navy delta $%ld, Air force delta $%ld\n",
               lnd_money[n], sea_money[n], air_money[n]);
        wu((natid)0, n, "money delta was $%ld for this update\n",
           np->nat_money - money[n]);
        if (opt_LOSE_CONTACT) {
            for (cn = 1; cn < MAXNOC; cn++) {
                if ((cnp = getnatp(cn)) != NULL)
                    agecontact(cnp);
            }
        }
    }
}

/*
 * find out everyones increment
 */
static void
share_incr(double *res, double *tech)
{
    struct natstr *np;
    struct natstr *other;
    natid i;
    natid j;
    int rnc;
    int tnc;

    for (i = 0; NULL != (np = getnatp(i)); i++) {
        res[i] = tech[i] = 0.0;
        if (np->nat_stat < STAT_SANCT || np->nat_stat == STAT_GOD)
            continue;
        rnc = tnc = 0;
        for (j = 0; NULL != (other = getnatp(j)); j++) {
            if (j == i)
                continue;
            if (other->nat_stat != STAT_ACTIVE)
                continue;
            if (opt_HIDDEN) {
                if (!getcontact(np, j))
                    continue;
            }
            if (!opt_ALL_BLEED) {
                if (getrel(np, j) != ALLIED)
                    continue;
                if (getrel(other, i) != ALLIED)
                    continue;
                res[i] += levels[j][NAT_RLEV];
                tech[i] += levels[j][NAT_TLEV];
                rnc++;
                tnc++;
            } else {
                if (levels[j][NAT_TLEV] > 0.001) {
                    tech[i] += levels[j][NAT_TLEV];
                    tnc++;
                }
                if (levels[j][NAT_RLEV] > 0.001) {
                    res[i] += levels[j][NAT_RLEV];
                    rnc++;
                }
            }
        }
        if (rnc > 0) {
            res[i] /= rnc * ally_factor;
        }
        if (tnc > 0) {
            tech[i] /= tnc * ally_factor;
        }
/*              logerror("Country #%d gets %g res from %d allies, %g tech from %d allies", i, res[i], rnc, tech[i], tnc);*/
    }
}

---