games/trek/move.c

   1 /*-
   2  * Copyright (c) 1980, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * @(#)move.c   8.1 (Berkeley) 5/31/93
  30  * $FreeBSD: src/games/trek/move.c,v 1.6 1999/11/30 03:49:50 billf Exp $
  31  * $DragonFly: src/games/trek/move.c,v 1.3 2006/09/07 21:19:44 pavalos Exp $
  32  */
  33
  34 #include "trek.h"
  35
  36 /*
  37 **  Move Under Warp or Impulse Power
  38 **
  39 **      `Ramflag' is set if we are to be allowed to ram stars,
  40 **      Klingons, etc.  This is passed from warp(), which gets it from
  41 **      either play() or ram().  Course is the course (0 -> 360) at
  42 **      which we want to move.  `Speed' is the speed we
  43 **      want to go, and `p_time' is the expected time.  It
  44 **      can get cut short if a long range tractor beam is to occur.  We
  45 **      cut short the move so that the user doesn't get docked time and
  46 **      energy for distance which he didn't travel.
  47 **
  48 **      We check the course through the current quadrant to see that he
  49 **      doesn't run into anything.  After that, though, space sort of
  50 **      bends around him.  Note that this puts us in the awkward posi-
  51 **      tion of being able to be dropped into a sector which is com-
  52 **      pletely surrounded by stars.  Oh Well.
  53 **
  54 **      If the SINS (Space Inertial Navigation System) is out, we ran-
  55 **      domize the course accordingly before ever starting to move.
  56 **      We will still move in a straight line.
  57 **
  58 **      Note that if your computer is out, you ram things anyway.  In
  59 **      other words, if your computer and sins are both out, you're in
  60 **      potentially very bad shape.
  61 **
  62 **      Klingons get a chance to zap you as you leave the quadrant.
  63 **      By the way, they also try to follow you (heh heh).
  64 **
  65 **      Return value is the actual amount of time used.
  66 **
  67 **
  68 **      Uses trace flag 4.
  69 */
  70
  71 double
  72 move(int ramflag, int course, double p_time, double speed)
  73 {
  74         double                  angle;
  75         double                  x, y, dx, dy;
  76         int             ix, iy;
  77         double                  bigger;
  78         int                     n;
  79         int             i;
  80         double                  dist;
  81         double                  sectsize;
  82         double                  xn;
  83         double                  evtime;
  84
  85         ix = iy = 0;
  86 #ifdef xTRACE
  87         if (Trace)
  88                 printf("move: ramflag %d course %d time %.2f speed %.2f\n",
  89                         ramflag, course, p_time, speed);
  90 #endif
  91         sectsize = NSECTS;
  92         /* initialize delta factors for move */
  93         angle = course * 0.0174532925;
  94         if (damaged(SINS))
  95                 angle += Param.navigcrud[1] * (franf() - 0.5);
  96         else
  97                 if (Ship.sinsbad)
  98                         angle += Param.navigcrud[0] * (franf() - 0.5);
  99         dx = -cos(angle);
 100         dy = sin(angle);
 101         bigger = fabs(dx);
 102         dist = fabs(dy);
 103         if (dist > bigger)
 104                 bigger = dist;
 105         dx /= bigger;
 106         dy /= bigger;
 107
 108         /* check for long range tractor beams */
 109         /****  TEMPORARY CODE == DEBUGGING  ****/
 110         evtime = Now.eventptr[E_LRTB]->date - Now.date;
 111 #ifdef xTRACE
 112         if (Trace)
 113                 printf("E.ep = %p, ->evcode = %d, ->date = %.2f, evtime = %.2f\n",
 114                         (void *)Now.eventptr[E_LRTB],
 115                         Now.eventptr[E_LRTB]->evcode,
 116                         Now.eventptr[E_LRTB]->date, evtime);
 117 #endif
 118         if (p_time > evtime && Etc.nkling < 3) {
 119                 /* then we got a LRTB */
 120                 evtime += 0.005;
 121                 p_time = evtime;
 122         } else
 123                 evtime = -1.0e50;
 124         dist = p_time * speed;
 125
 126         /* move within quadrant */
 127         Sect[Ship.sectx][Ship.secty] = EMPTY;
 128         x = Ship.sectx + 0.5;
 129         y = Ship.secty + 0.5;
 130         xn = NSECTS * dist * bigger;
 131         n = xn + 0.5;
 132 #ifdef xTRACE
 133         if (Trace)
 134                 printf("dx = %.2f, dy = %.2f, xn = %.2f, n = %d\n", dx, dy, xn, n);
 135 #endif
 136         Move.free = 0;
 137
 138         for (i = 0; i < n; i++) {
 139                 ix = (x += dx);
 140                 iy = (y += dy);
 141 #ifdef xTRACE
 142                 if (Trace)
 143                         printf("ix = %d, x = %.2f, iy = %d, y = %.2f\n", ix, x, iy, y);
 144 #endif
 145                 if (x < 0.0 || y < 0.0 || x >= sectsize || y >= sectsize) {
 146                         /* enter new quadrant */
 147                         dx = Ship.quadx * NSECTS + Ship.sectx + dx * xn;
 148                         dy = Ship.quady * NSECTS + Ship.secty + dy * xn;
 149                         if (dx < 0.0)
 150                                 ix = -1;
 151                         else
 152                                 ix = dx + 0.5;
 153                         if (dy < 0.0)
 154                                 iy = -1;
 155                         else
 156                                 iy = dy + 0.5;
 157 #ifdef xTRACE
 158                         if (Trace)
 159                                 printf("New quad: ix = %d, iy = %d\n", ix, iy);
 160 #endif
 161                         Ship.sectx = x;
 162                         Ship.secty = y;
 163                         compkldist(0);
 164                         Move.newquad = 2;
 165                         attack(0);
 166                         checkcond();
 167                         Ship.quadx = ix / NSECTS;
 168                         Ship.quady = iy / NSECTS;
 169                         Ship.sectx = ix % NSECTS;
 170                         Ship.secty = iy % NSECTS;
 171                         if (ix < 0 || Ship.quadx >= NQUADS || iy < 0 ||
 172                             Ship.quady >= NQUADS) {
 173                                 if (!damaged(COMPUTER)) {
 174                                         dumpme(0);
 175                                 } else
 176                                         lose(L_NEGENB);
 177                         }
 178                         initquad(0);
 179                         n = 0;
 180                         break;
 181                 }
 182                 if (Sect[ix][iy] != EMPTY) {
 183                         /* we just hit something */
 184                         if (!damaged(COMPUTER) && ramflag <= 0) {
 185                                 ix = x - dx;
 186                                 iy = y - dy;
 187                                 printf("Computer reports navigation error; %s stopped at %d,%d\n",
 188                                         Ship.shipname, ix, iy);
 189                                 Ship.energy -= Param.stopengy * speed;
 190                                 break;
 191                         }
 192                         /* test for a black hole */
 193                         if (Sect[ix][iy] == HOLE) {
 194                                 /* get dumped elsewhere in the galaxy */
 195                                 dumpme(1);
 196                                 initquad(0);
 197                                 n = 0;
 198                                 break;
 199                         }
 200                         ram(ix, iy);
 201                         break;
 202                 }
 203         }
 204         if (n > 0) {
 205                 dx = Ship.sectx - ix;
 206                 dy = Ship.secty - iy;
 207                 dist = sqrt(dx * dx + dy * dy) / NSECTS;
 208                 p_time = dist / speed;
 209                 if (evtime > p_time)
 210                         p_time = evtime;                /* spring the LRTB trap */
 211                 Ship.sectx = ix;
 212                 Ship.secty = iy;
 213         }
 214         Sect[Ship.sectx][Ship.secty] = Ship.ship;
 215         compkldist(0);
 216         return (p_time);
 217 }