src/lib/commands/sona.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.
 *
 *  ---
 *
 *  sona.c: Sonar from a sub (or other sonar-equipped ship)
 * 
 *  Known contributors to this file:
 *     Jim Griffith, 1989
 *     Ken Stevens, 1995
 */

#include <config.h>

#include "commands.h"
#include "map.h"
#include "optlist.h"
#include "path.h"
#include "plane.h"
#include "retreat.h"
#include "ship.h"

static int blankrow(char *);

int
sona(void)
{
    struct nstr_item ni, nit;
    struct sctstr sect;
    struct shpstr ship;
    struct shpstr targ;
    struct natstr *natp;
    struct mchrstr *mcp;
    struct mchrstr *tmcp;
    struct nstr_sect ns;
    int range;
    int pingrange;
    int srange;
    int vrange;
    int dist;
    int x, y;
    int cx, cy;
    int changed = 0;
    int row;
    /* Where these are used are non-re-entrant, so we keep 'em around */
    static char **rad = NULL;
    static char *radbuf = NULL;
    static signed char **vis = NULL;
    static signed char *visbuf = NULL;

    if (!snxtitem(&ni, EF_SHIP, player->argp[1]))
        return RET_SYN;
    if (!radbuf)
        radbuf = malloc((WORLD_Y * (WORLD_X + 1)));
    if (!visbuf)
        visbuf = malloc((WORLD_Y * (WORLD_X + 1)));
    if (!rad && radbuf) {
        rad = malloc(WORLD_Y * sizeof(char *));
        if (rad) {
            for (x = 0; x < WORLD_Y; x++) {
                rad[x] = &radbuf[(WORLD_X + 1) * x];
            }
        }
    }
    if (!vis && visbuf) {
        vis = malloc(WORLD_Y * sizeof(signed char *));
        if (vis) {
            for (x = 0; x < WORLD_Y; x++) {
                vis[x] = &visbuf[(WORLD_X + 1) * x];
            }
        }
    }
    if (!radbuf || !visbuf || !rad || !vis) {
        pr("Memory error, tell the deity.\n");
        logerror("malloc failed in sona\n");
        return RET_FAIL;
    }
    while (nxtitem(&ni, &ship)) {
        if (!player->owner)
            continue;
        mcp = &mchr[(int)ship.shp_type];
        if (!(mcp->m_flags & M_SONAR))
            continue;
        getsect(ship.shp_x, ship.shp_y, &sect);
        if (sect.sct_type != SCT_WATER)
            continue;
        range = (int)techfact(ship.shp_tech, mcp->m_vrnge);
        srange = MIN(7, 7 * range * ship.shp_effic / 200);
        pr("%s at %s efficiency %d%%, max range %d\n",
           prship(&ship),
           xyas(ship.shp_x, ship.shp_y, player->cnum),
           ship.shp_effic, srange);
        snxtsct_dist(&ns, ship.shp_x, ship.shp_y, srange);
        blankfill(radbuf, &ns.range, 1);
        while (nxtsct(&ns, &sect)) {
            if (player->owner || sect.sct_type == SCT_WATER)
                rad[ns.dy][ns.dx] = dchr[sect.sct_type].d_mnem;
            else {
                rad[ns.dy][ns.dx] = '?';
            }
        }
        snxtsct_dist(&ns, ship.shp_x, ship.shp_y, srange);
        cx = deltax(ship.shp_x, ns.range.lx);
        cy = deltay(ship.shp_y, ns.range.ly);
        while (nxtsct(&ns, &sect)) {
            if (!line_of_sight(rad, cx, cy, ns.dx, ns.dy)) {
                rad[ns.dy][ns.dx] = ' ';
                continue;
            }
            if (ship.shp_tech >= 310 && sect.sct_type == SCT_WATER) {
                if (sect.sct_mines) {
                    pr("Sonar detects %d mines in %s!\n",
                       sect.sct_mines,
                       xyas(sect.sct_x, sect.sct_y, player->cnum));
                    rad[ns.dy][ns.dx] = 'X';
                }
            }
            changed |= map_set(player->cnum, sect.sct_x, sect.sct_y,
                               rad[ns.dy][ns.dx], 0);

        }
        memset(visbuf, 0, (WORLD_Y * (WORLD_X + 1)));
        snxtitem_dist(&nit, EF_SHIP, ship.shp_x, ship.shp_y, range);
        while (nxtitem(&nit, &targ)) {
            if (targ.shp_own == player->cnum || targ.shp_own == 0)
                continue;
            tmcp = &mchr[(int)targ.shp_type];
            pingrange = MIN(7, MAX(targ.shp_visib, 10) * range / 10);
            vrange = pingrange * ship.shp_effic / 200;
            dist = mapdist(targ.shp_x, targ.shp_y, ship.shp_x, ship.shp_y);
            pingrange = (MAX(pingrange, 2) * targ.shp_effic) / 100;
            if (dist > pingrange)
                continue;
            if (tmcp->m_flags & M_SONAR && targ.shp_own) {
                natp = getnatp(targ.shp_own);
                if (natp->nat_flags & NF_SONAR)
                    wu(0, targ.shp_own,
                       "Sonar ping from %s detected by %s!\n",
                       xyas(ship.shp_x, ship.shp_y,
                            targ.shp_own), prship(&targ));
                if (targ.shp_rflags & RET_SONARED) {
                    retreat_ship(&targ, 's');
                    putship(targ.shp_uid, &targ);
                }
            }
            if (dist > vrange)
                continue;
            x = deltx(&ns.range, (int)targ.shp_x);
            y = delty(&ns.range, (int)targ.shp_y);
            if (rad[y][x] != dchr[SCT_WATER].d_mnem && rad[y][x] != 'X')
                continue;
            if (tmcp->m_flags & M_SUB &&
                getrel(getnatp(targ.shp_own), player->cnum) < FRIENDLY) {
                if (mcp->m_vrnge + targ.shp_visib < 8)
                    pr("Sonar detects sub #%d @ %s\n",
                       targ.shp_uid,
                       xyas(targ.shp_x, targ.shp_y, player->cnum));
                else if (mcp->m_vrnge + targ.shp_visib < 10)
                    pr("Sonar detects %s @ %s\n",
                       prship(&targ),
                       xyas(targ.shp_x, targ.shp_y, player->cnum));
                else
                    pr("Sonar detects %s %s @ %s\n",
                       cname(targ.shp_own), prship(&targ),
                       xyas(targ.shp_x, targ.shp_y, player->cnum));
            } else
                pr("Sonar detects %s %s @ %s\n",
                   cname(targ.shp_own), prship(&targ),
                   xyas(targ.shp_x, targ.shp_y, player->cnum));

            if (targ.shp_visib > vis[y][x]) {
                vis[y][x] = targ.shp_visib;
                /* &~0x20 makes it a cap letter */
                rad[y][x] = (*mchr[(int)targ.shp_type].m_name) & ~0x20;
            }
        }
        if (!player->argp[2]) {
            rad[cy][cx] = '0';
            for (row = 0; row < ns.range.height; row++)
                if (!blankrow(rad[row]))
                    pr("%s\n", rad[row]);
        }
        pr("\n");

    }
    if (changed)
        writemap(player->cnum);
    return RET_OK;
}

void
plane_sona(struct emp_qelem *plane_list, int x, int y,
           struct shiplist **head)
{
    struct plnstr *pp;
    struct plchrstr *pcp;
    struct mchrstr *tmcp;
    struct shpstr *targ, s;
    struct natstr *natp;
    struct emp_qelem *qp;
    struct emp_qelem *next;
    struct plist *ip;
    struct sctstr sect;
    int found = 0;
    int range, i;
    int pingrange;
    int vrange;
    int dist;

    getsect(x, y, &sect);
    if ((sect.sct_type != SCT_WATER) && (sect.sct_type != SCT_HARBR))
        return;
    for (qp = plane_list->q_forw; qp != plane_list; qp = next) {
        next = qp->q_forw;
        ip = (struct plist *)qp;
        pp = &ip->plane;
        pcp = ip->pcp;
        if (!(pcp->pl_flags & P_A))     /* if it isn't an ASW plane */
            continue;
        range = (int)techfact(pp->pln_tech, (100.0 - pp->pln_acc) / 10.0);
        for (i = 0; getship(i, &s); i++) {
            targ = &s;
            if (targ->shp_own == pp->pln_own || targ->shp_own == 0)
                continue;
            if (on_shiplist(targ->shp_uid, *head))
                continue;
            tmcp = &mchr[(int)targ->shp_type];
            if (!(tmcp->m_flags & M_SUB))
                continue;
            if (roll(100) > pln_identchance(pp, shp_hardtarget(targ),
                                            EF_SHIP))
                continue;
            pingrange = MAX(targ->shp_visib, 10) * range / 10;
            vrange = pingrange * (pp->pln_effic / 200.0);
            dist = mapdist(targ->shp_x, targ->shp_y, x, y);
            pingrange = (MAX(pingrange, 2) * targ->shp_effic);
            pingrange = roundavg(pingrange / 100.0);
            if (dist > pingrange)
                continue;
            if (tmcp->m_flags & M_SONAR && targ->shp_own) {
                natp = getnatp(targ->shp_own);
                if (natp->nat_flags & NF_SONAR)
                    wu(0, targ->shp_own,
                       "Sonar ping from %s detected by %s!\n",
                       xyas(x, y, targ->shp_own), prship(targ));
            }
            if ((dist > vrange))
                continue;
            add_shiplist(targ->shp_uid, head);
            if (!found) {
                mpr(pp->pln_own,
                    "\nSonar contact in %s\n", xyas(x, y, pp->pln_own));
                found = 1;
            }
            if (getrel(getnatp(targ->shp_own), pp->pln_own) < FRIENDLY &&
                roll(100) > pln_identchance(pp, shp_hardtarget(targ),
                                            EF_SHIP))
                if (roll(100) > pln_identchance(pp, shp_hardtarget(targ),
                                                EF_SHIP))
                    mpr(pp->pln_own, "sub #%d %s\n", targ->shp_uid,
                        xyas(targ->shp_x, targ->shp_y, pp->pln_own));
                else
                    mpr(pp->pln_own, "%s %s\n",
                        prship(targ),
                        xyas(targ->shp_x, targ->shp_y, pp->pln_own));
            else
                mpr(pp->pln_own, "%s %s @ %s\n",
                    cname(targ->shp_own), prship(targ),
                    xyas(targ->shp_x, targ->shp_y, pp->pln_own));
        }
    }
}

/* 
 * line_of_sight() - is there a "straight" all water path from (x,y) to (tx,ty)
 * Ken & Irina Stevens, 1995
 */

#define DOT(ax,ay,bx,by) ((ax)*(bx) + (ay)*(by))
#define LEN(x,y) ((x)*(x) + (y)*(y))
#define DIST(ax,ay,bx,by) LEN(bx - ax, by -ay)

int
line_of_sight(char **rad, int ax, int ay, int bx, int by)
{
    int dxn = XNORM(bx - ax);
    int dyn = YNORM(by - ay);
    int dx = dxn > WORLD_X / 2 ? dxn - WORLD_X : dxn;
    int dy = dyn > WORLD_Y / 2 ? dyn - WORLD_Y : dyn;
    int dlen = LEN(dx, dy);
    int n;
    int cx = 0;
    int cy = 0;
    int tx, ty;                 /* test point */
    double cd_dist = dlen;      /* closest distance from c to vector d */
    double md_dist;             /* minimum distance from t to vector d */
    double td_dist;             /* distance from t to vector d */
    double td_proj;             /* the projection of t onto vector d */
    int closest;                /* index of closest */
    int blocked = 0;
    struct sctstr *sectp;

    while (cd_dist) {
        if (blocked)
            return 0;
        md_dist = 100;          /* will always be <= 2 */
        closest = -1;
        for (n = 1; n <= 6; ++n) {      /* Directions */
            tx = cx + diroff[n][0];
            ty = cy + diroff[n][1];
            if (DIST(tx, ty, dx, dy) >= cd_dist)
                continue;
            td_proj = (double)DOT(tx, ty, dx, dy) / dlen;
            td_dist = DIST(tx, ty, td_proj * dx, td_proj * dy);
            if (td_dist < md_dist) {
                md_dist = td_dist;
                closest = n;
            }
        }
        if (CANT_HAPPEN(closest < 0))
            return 0;
        cx = cx + diroff[closest][0];
        cy = cy + diroff[closest][1];
        if (rad) {
            blocked = (rad[YNORM(ay + cy)][XNORM(ax + cx)]
                       != dchr[SCT_WATER].d_mnem);
        } else {
            sectp = getsectp((ax + cx), (ay + cy));
            if (sectp) {
                if (sectp->sct_type == SCT_WATER ||
                    sectp->sct_type == SCT_BSPAN) {
                    blocked = 0;
                } else {
                    blocked = 1;
                }
            }
        }
        cd_dist = DIST(cx, cy, dx, dy);
    }
    return 1;
}

static int
blankrow(char *s)
{
    while (*s) {
        if (*s != ' ')
            return 0;
        ++s;
    }
    return 1;
}

---