main/physics.c

   1 /* $Id: physics.c,v 1.8 2004-12-20 06:28:10 btb Exp $ */
   2 /*
   3 THE COMPUTER CODE CONTAINED HEREIN IS THE SOLE PROPERTY OF PARALLAX
   4 SOFTWARE CORPORATION ("PARALLAX").  PARALLAX, IN DISTRIBUTING THE CODE TO
   5 END-USERS, AND SUBJECT TO ALL OF THE TERMS AND CONDITIONS HEREIN, GRANTS A
   6 ROYALTY-FREE, PERPETUAL LICENSE TO SUCH END-USERS FOR USE BY SUCH END-USERS
   7 IN USING, DISPLAYING,  AND CREATING DERIVATIVE WORKS THEREOF, SO LONG AS
   8 SUCH USE, DISPLAY OR CREATION IS FOR NON-COMMERCIAL, ROYALTY OR REVENUE
   9 FREE PURPOSES.  IN NO EVENT SHALL THE END-USER USE THE COMPUTER CODE
  10 CONTAINED HEREIN FOR REVENUE-BEARING PURPOSES.  THE END-USER UNDERSTANDS
  11 AND AGREES TO THE TERMS HEREIN AND ACCEPTS THE SAME BY USE OF THIS FILE.
  12 COPYRIGHT 1993-1999 PARALLAX SOFTWARE CORPORATION.  ALL RIGHTS RESERVED.
  13 */
  14
  15 /*
  16  *
  17  * Code for flying through the mines
  18  *
  19  */
  20
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <conf.h>
  24 #endif
  25
  26 #ifdef RCS
  27 static char rcsid[] = "$Id: physics.c,v 1.8 2004-12-20 06:28:10 btb Exp $";
  28 #endif
  29
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32
  33 #include "joy.h"
  34 #include "mono.h"
  35 #include "error.h"
  36
  37 #include "inferno.h"
  38 #include "segment.h"
  39 #include "object.h"
  40 #include "physics.h"
  41 #include "key.h"
  42 #include "game.h"
  43 #include "collide.h"
  44 #include "fvi.h"
  45 #include "newdemo.h"
  46 #include "timer.h"
  47 #include "ai.h"
  48 #include "wall.h"
  49 #include "laser.h"
  50 #include "bm.h"
  51 #include "player.h"
  52
  53 #ifdef TACTILE
  54 #include "tactile.h"
  55 #endif
  56
  57 //Global variables for physics system
  58
  59 #define ROLL_RATE               0x2000
  60 #define DAMP_ANG                        0x400                  //min angle to bank
  61
  62 #define TURNROLL_SCALE  (0x4ec4/2)
  63
  64 #define MAX_OBJECT_VEL i2f(100)
  65
  66 #define BUMP_HACK       1               //if defined, bump player when he gets stuck
  67
  68 //--unused-- int mike_mode=0;
  69
  70 //check point against each side of segment. return bitmask, where bit
  71 //set means behind that side
  72
  73 int Physics_cheat_flag = 0;
  74 extern char BounceCheat;
  75
  76 //##//returns the distance of a point (checkp) from a plane (defined by norm & planep)
  77 //##fix dist_to_plane(vms_vector *checkp,vms_vector *norm,vms_vector *planep)
  78 //##{
  79 //##    vms_vector deltap;
  80 //##
  81 //##    vm_vec_sub(&deltap,checkp,planep);
  82 //##
  83 //##    return vm_vec_dot(&deltap,norm);
  84 //##}
  85
  86 //--unused-- int dpjm_old_joy_x, dpjm_old_joy_y;
  87
  88 int floor_levelling=0;
  89
  90 //--unused-- level_with_floor()
  91 //--unused-- {
  92 //--unused--    floor_levelling=1;
  93 //--unused-- }
  94
  95 //make sure matrix is orthogonal
  96 void check_and_fix_matrix(vms_matrix *m)
  97 {
  98         vms_matrix tempm;
  99
 100         vm_vector_2_matrix(&tempm,&m->fvec,&m->uvec,NULL);
 101         *m  = tempm;
 102 }
 103
 104
 105 void do_physics_align_object( object * obj )
 106 {
 107         vms_vector desired_upvec;
 108         fixang delta_ang,roll_ang;
 109         //vms_vector forvec = {0,0,f1_0};
 110         vms_matrix temp_matrix;
 111         fix d,largest_d=-f1_0;
 112         int i,best_side;
 113
 114         best_side=0;
 115         // bank player according to segment orientation
 116
 117         //find side of segment that player is most alligned with
 118
 119         for (i=0;i<6;i++) {
 120                 #ifdef COMPACT_SEGS
 121                         vms_vector _tv1;
 122                         get_side_normal( &Segments[obj->segnum], i, 0, &_tv1 );
 123                         d = vm_vec_dot(&_tv1,&obj->orient.uvec);
 124                 #else
 125                         d = vm_vec_dot(&Segments[obj->segnum].sides[i].normals[0],&obj->orient.uvec);
 126                 #endif
 127
 128                 if (d > largest_d) {largest_d = d; best_side=i;}
 129         }
 130
 131         if (floor_levelling) {
 132
 133                 // old way: used floor's normal as upvec
 134                 #ifdef COMPACT_SEGS
 135                         get_side_normal(&Segments[obj->segnum], 3, 0, &desired_upvec );
 136                 #else
 137                         desired_upvec = Segments[obj->segnum].sides[3].normals[0];
 138                 #endif
 139
 140         }
 141         else  // new player leveling code: use normal of side closest to our up vec
 142                 if (get_num_faces(&Segments[obj->segnum].sides[best_side])==2) {
 143                         #ifdef COMPACT_SEGS
 144                                 vms_vector normals[2];
 145                                 get_side_normals(&Segments[obj->segnum], best_side, &normals[0], &normals[1] );
 146
 147                                 desired_upvec.x = (normals[0].x + normals[1].x) / 2;
 148                                 desired_upvec.y = (normals[0].y + normals[1].y) / 2;
 149                                 desired_upvec.z = (normals[0].z + normals[1].z) / 2;
 150
 151                                 vm_vec_normalize(&desired_upvec);
 152                         #else
 153                                 side *s = &Segments[obj->segnum].sides[best_side];
 154                                 desired_upvec.x = (s->normals[0].x + s->normals[1].x) / 2;
 155                                 desired_upvec.y = (s->normals[0].y + s->normals[1].y) / 2;
 156                                 desired_upvec.z = (s->normals[0].z + s->normals[1].z) / 2;
 157
 158                                 vm_vec_normalize(&desired_upvec);
 159                         #endif
 160                 }
 161                 else
 162                         #ifdef COMPACT_SEGS
 163                                 get_side_normal(&Segments[obj->segnum], best_side, 0, &desired_upvec );
 164                         #else
 165                                 desired_upvec = Segments[obj->segnum].sides[best_side].normals[0];
 166                         #endif
 167
 168         if (labs(vm_vec_dot(&desired_upvec,&obj->orient.fvec)) < f1_0/2) {
 169                 fixang save_delta_ang;
 170                 vms_angvec tangles;
 171
 172                 vm_vector_2_matrix(&temp_matrix,&obj->orient.fvec,&desired_upvec,NULL);
 173
 174                 save_delta_ang = delta_ang = vm_vec_delta_ang(&obj->orient.uvec,&temp_matrix.uvec,&obj->orient.fvec);
 175
 176                 delta_ang += obj->mtype.phys_info.turnroll;
 177
 178                 if (abs(delta_ang) > DAMP_ANG) {
 179                         vms_matrix rotmat, new_pm;
 180
 181                         roll_ang = fixmul(FrameTime,ROLL_RATE);
 182
 183                         if (abs(delta_ang) < roll_ang) roll_ang = delta_ang;
 184                         else if (delta_ang<0) roll_ang = -roll_ang;
 185
 186                         tangles.p = tangles.h = 0;  tangles.b = roll_ang;
 187                         vm_angles_2_matrix(&rotmat,&tangles);
 188
 189                         vm_matrix_x_matrix(&new_pm,&obj->orient,&rotmat);
 190                         obj->orient = new_pm;
 191                 }
 192                 else floor_levelling=0;
 193         }
 194
 195 }
 196
 197 void set_object_turnroll(object *obj)
 198 {
 199         fixang desired_bank;
 200
 201         desired_bank = -fixmul(obj->mtype.phys_info.rotvel.y,TURNROLL_SCALE);
 202
 203         if (obj->mtype.phys_info.turnroll != desired_bank) {
 204                 fixang delta_ang,max_roll;
 205
 206                 max_roll = fixmul(ROLL_RATE,FrameTime);
 207
 208                 delta_ang = desired_bank - obj->mtype.phys_info.turnroll;
 209
 210                 if (labs(delta_ang) < max_roll)
 211                         max_roll = delta_ang;
 212                 else
 213                         if (delta_ang < 0)
 214                                 max_roll = -max_roll;
 215
 216                 obj->mtype.phys_info.turnroll += max_roll;
 217         }
 218
 219 }
 220
 221 //list of segments went through
 222 int phys_seglist[MAX_FVI_SEGS],n_phys_segs;
 223
 224
 225 #define MAX_IGNORE_OBJS 100
 226
 227 #ifndef NDEBUG
 228 #define EXTRA_DEBUG 1           //no extra debug when NDEBUG is on
 229 #endif
 230
 231 #ifdef EXTRA_DEBUG
 232 object *debug_obj=NULL;
 233 #endif
 234
 235 #define XYZ(v) (v)->x,(v)->y,(v)->z
 236
 237
 238 #ifndef NDEBUG
 239 int     Total_retries=0, Total_sims=0;
 240 int     Dont_move_ai_objects=0;
 241 #endif
 242
 243 #define FT (f1_0/64)
 244
 245 extern int disable_new_fvi_stuff;
 246 //      -----------------------------------------------------------------------------------------------------------
 247 // add rotational velocity & acceleration
 248 void do_physics_sim_rot(object *obj)
 249 {
 250         vms_angvec      tangles;
 251         vms_matrix      rotmat,new_orient;
 252         //fix                   rotdrag_scale;
 253         physics_info *pi;
 254
 255         Assert(FrameTime > 0);  //Get MATT if hit this!
 256
 257         pi = &obj->mtype.phys_info;
 258
 259         if (!(pi->rotvel.x || pi->rotvel.y || pi->rotvel.z || pi->rotthrust.x || pi->rotthrust.y || pi->rotthrust.z))
 260                 return;
 261
 262         if (obj->mtype.phys_info.drag) {
 263                 int count;
 264                 vms_vector accel;
 265                 fix drag,r,k;
 266
 267                 count = FrameTime / FT;
 268                 r = FrameTime % FT;
 269                 k = fixdiv(r,FT);
 270
 271                 drag = (obj->mtype.phys_info.drag*5)/2;
 272
 273                 if (obj->mtype.phys_info.flags & PF_USES_THRUST) {
 274
 275                         vm_vec_copy_scale(&accel,&obj->mtype.phys_info.rotthrust,fixdiv(f1_0,obj->mtype.phys_info.mass));
 276
 277                         while (count--) {
 278
 279                                 vm_vec_add2(&obj->mtype.phys_info.rotvel,&accel);
 280
 281                                 vm_vec_scale(&obj->mtype.phys_info.rotvel,f1_0-drag);
 282                         }
 283
 284                         //do linear scale on remaining bit of time
 285
 286                         vm_vec_scale_add2(&obj->mtype.phys_info.rotvel,&accel,k);
 287                         vm_vec_scale(&obj->mtype.phys_info.rotvel,f1_0-fixmul(k,drag));
 288                 }
 289                 else if (! (obj->mtype.phys_info.flags & PF_FREE_SPINNING)) {
 290                         fix total_drag=f1_0;
 291
 292                         while (count--)
 293                                 total_drag = fixmul(total_drag,f1_0-drag);
 294
 295                         //do linear scale on remaining bit of time
 296
 297                         total_drag = fixmul(total_drag,f1_0-fixmul(k,drag));
 298
 299                         vm_vec_scale(&obj->mtype.phys_info.rotvel,total_drag);
 300                 }
 301
 302         }
 303
 304         //mprintf( (0, "Rot vel = %.3f,%.3f,%.3f\n", f2fl(obj->mtype.phys_info.rotvel.x),f2fl(obj->mtype.phys_info.rotvel.y), f2fl(obj->mtype.phys_info.rotvel.z) ));
 305
 306         //now rotate object
 307
 308         //unrotate object for bank caused by turn
 309         if (obj->mtype.phys_info.turnroll) {
 310                 vms_matrix new_pm;
 311
 312                 tangles.p = tangles.h = 0;
 313                 tangles.b = -obj->mtype.phys_info.turnroll;
 314                 vm_angles_2_matrix(&rotmat,&tangles);
 315                 vm_matrix_x_matrix(&new_pm,&obj->orient,&rotmat);
 316                 obj->orient = new_pm;
 317         }
 318
 319         tangles.p = fixmul(obj->mtype.phys_info.rotvel.x,FrameTime);
 320         tangles.h = fixmul(obj->mtype.phys_info.rotvel.y,FrameTime);
 321         tangles.b  = fixmul(obj->mtype.phys_info.rotvel.z,FrameTime);
 322
 323         vm_angles_2_matrix(&rotmat,&tangles);
 324         vm_matrix_x_matrix(&new_orient,&obj->orient,&rotmat);
 325         obj->orient = new_orient;
 326
 327         if (obj->mtype.phys_info.flags & PF_TURNROLL)
 328                 set_object_turnroll(obj);
 329
 330         //re-rotate object for bank caused by turn
 331         if (obj->mtype.phys_info.turnroll) {
 332                 vms_matrix new_pm;
 333
 334                 tangles.p = tangles.h = 0;
 335                 tangles.b = obj->mtype.phys_info.turnroll;
 336                 vm_angles_2_matrix(&rotmat,&tangles);
 337                 vm_matrix_x_matrix(&new_pm,&obj->orient,&rotmat);
 338                 obj->orient = new_pm;
 339         }
 340
 341         check_and_fix_matrix(&obj->orient);
 342 }
 343
 344 //      -----------------------------------------------------------------------------------------------------------
 345 //Simulate a physics object for this frame
 346 void do_physics_sim(object *obj)
 347 {
 348         int ignore_obj_list[MAX_IGNORE_OBJS],n_ignore_objs;
 349         int iseg;
 350         int try_again;
 351         int fate;
 352         vms_vector frame_vec;                   //movement in this frame
 353         vms_vector new_pos,ipos;                //position after this frame
 354         int count=0;
 355         int objnum;
 356         int WallHitSeg, WallHitSide;
 357         fvi_info hit_info;
 358         fvi_query fq;
 359         vms_vector save_pos;
 360         int save_seg;
 361         fix drag;
 362         fix sim_time,old_sim_time;
 363         vms_vector start_pos;
 364         int obj_stopped=0;
 365         fix moved_time;                 //how long objected moved before hit something
 366         vms_vector save_p0,save_p1;
 367         physics_info *pi;
 368         int orig_segnum = obj->segnum;
 369         int bounced=0;
 370
 371         Assert(obj->type != OBJ_NONE);
 372         Assert(obj->movement_type == MT_PHYSICS);
 373
 374 #ifndef NDEBUG
 375 if (Dont_move_ai_objects)
 376         if (obj->control_type == CT_AI)
 377                 return;
 378 #endif
 379
 380         pi = &obj->mtype.phys_info;
 381
 382         do_physics_sim_rot(obj);
 383
 384         if (!(pi->velocity.x || pi->velocity.y || pi->velocity.z || pi->thrust.x || pi->thrust.y || pi->thrust.z))
 385                 return;
 386
 387         objnum = obj-Objects;
 388
 389         n_phys_segs = 0;
 390
 391         disable_new_fvi_stuff = (obj->type != OBJ_PLAYER);
 392
 393         sim_time = FrameTime;
 394
 395 //debug_obj = obj;
 396
 397         #ifdef EXTRA_DEBUG
 398         if (obj == debug_obj) {
 399                 printf("object %d:\n  start pos = %x %x %x\n",objnum,XYZ(&obj->pos));
 400                 printf("  thrust = %x %x %x\n",XYZ(&obj->mtype.phys_info.thrust));
 401                 printf("  sim_time = %x\n",sim_time);
 402         }
 403
 404         //check for correct object segment
 405         if(!get_seg_masks(&obj->pos, obj->segnum, 0, __FILE__, __LINE__).centermask == 0)
 406         {
 407                 #ifndef NDEBUG
 408                 mprintf((0,"Warning: object %d not in given seg!\n",objnum));
 409                 #endif
 410                 //Int3();  Removed by Rob 10/5/94
 411                 if (!update_object_seg(obj)) {
 412                         #ifndef NDEBUG
 413                         mprintf((0,"Warning: can't find seg for object %d - moving\n",objnum));
 414                         #endif
 415                         if (!(Game_mode & GM_MULTI))
 416                                 Int3();
 417                         compute_segment_center(&obj->pos,&Segments[obj->segnum]);
 418                         obj->pos.x += objnum;
 419                 }
 420         }
 421         #endif
 422
 423         start_pos = obj->pos;
 424
 425         n_ignore_objs = 0;
 426
 427         Assert(obj->mtype.phys_info.brakes==0);         //brakes not used anymore?
 428
 429                 //if uses thrust, cannot have zero drag
 430         Assert(!(obj->mtype.phys_info.flags&PF_USES_THRUST) || obj->mtype.phys_info.drag!=0);
 431
 432 //mprintf((0,"thrust=%x  speed=%x\n",vm_vec_mag(&obj->mtype.phys_info.thrust),vm_vec_mag(&obj->mtype.phys_info.velocity)));
 433
 434         //do thrust & drag
 435
 436         if ((drag = obj->mtype.phys_info.drag) != 0) {
 437
 438                 int count;
 439                 vms_vector accel;
 440                 fix r,k;
 441
 442                 count = sim_time / FT;
 443                 r = sim_time % FT;
 444                 k = fixdiv(r,FT);
 445
 446                 if (obj->mtype.phys_info.flags & PF_USES_THRUST) {
 447
 448                         vm_vec_copy_scale(&accel,&obj->mtype.phys_info.thrust,fixdiv(f1_0,obj->mtype.phys_info.mass));
 449
 450                         while (count--) {
 451
 452                                 vm_vec_add2(&obj->mtype.phys_info.velocity,&accel);
 453
 454                                 vm_vec_scale(&obj->mtype.phys_info.velocity,f1_0-drag);
 455                         }
 456
 457                         //do linear scale on remaining bit of time
 458
 459                         vm_vec_scale_add2(&obj->mtype.phys_info.velocity,&accel,k);
 460
 461                         vm_vec_scale(&obj->mtype.phys_info.velocity,f1_0-fixmul(k,drag));
 462                 }
 463                 else {
 464                         fix total_drag=f1_0;
 465
 466                         while (count--)
 467                                 total_drag = fixmul(total_drag,f1_0-drag);
 468
 469                         //do linear scale on remaining bit of time
 470
 471                         total_drag = fixmul(total_drag,f1_0-fixmul(k,drag));
 472
 473                         vm_vec_scale(&obj->mtype.phys_info.velocity,total_drag);
 474                 }
 475         }
 476
 477         #ifdef EXTRA_DEBUG
 478         if (obj == debug_obj)
 479                 printf("  velocity = %x %x %x\n",XYZ(&obj->mtype.phys_info.velocity));
 480         #endif
 481
 482         do {
 483                 try_again = 0;
 484
 485                 //Move the object
 486                 vm_vec_copy_scale(&frame_vec, &obj->mtype.phys_info.velocity, sim_time);
 487
 488                 #ifdef EXTRA_DEBUG
 489                 if (obj == debug_obj)
 490                         printf("  pass %d, frame_vec = %x %x %x\n",count,XYZ(&frame_vec));
 491                 #endif
 492
 493                 if ( (frame_vec.x==0) && (frame_vec.y==0) && (frame_vec.z==0) )
 494                         break;
 495
 496                 count++;
 497
 498                 //      If retry count is getting large, then we are trying to do something stupid.
 499                 if ( count > 3)         {
 500                         if (obj->type == OBJ_PLAYER) {
 501                                 if (count > 8)
 502                                         break;
 503                         } else
 504                                 break;
 505                 }
 506
 507                 vm_vec_add(&new_pos,&obj->pos,&frame_vec);
 508
 509                 #ifdef EXTRA_DEBUG
 510                 if (obj == debug_obj)
 511                         printf("   desired_pos  = %x %x %x\n",XYZ(&new_pos));
 512                 #endif
 513
 514                 ignore_obj_list[n_ignore_objs] = -1;
 515
 516                 #ifdef EXTRA_DEBUG
 517                 if (obj == debug_obj) {
 518                         printf("   FVI parms: p0 = %8x %8x %8x, segnum=%x, size=%x\n",XYZ(&obj->pos),obj->segnum,obj->size);
 519                         printf("              p1 = %8x %8x %8x\n",XYZ(&new_pos));
 520                 }
 521                 #endif
 522
 523                 fq.p0                                           = &obj->pos;
 524                 fq.startseg                             = obj->segnum;
 525                 fq.p1                                           = &new_pos;
 526                 fq.rad                                  = obj->size;
 527                 fq.thisobjnum                   = objnum;
 528                 fq.ignore_obj_list      = ignore_obj_list;
 529                 fq.flags                                        = FQ_CHECK_OBJS;
 530
 531                 if (obj->type == OBJ_WEAPON)
 532                         fq.flags |= FQ_TRANSPOINT;
 533
 534                 if (obj->type == OBJ_PLAYER)
 535                         fq.flags |= FQ_GET_SEGLIST;
 536
 537 //@@                    if (get_seg_masks(&obj->pos, obj->segnum, 0, __FILE__, __LINE__).centermask != 0)
 538 //@@                            Int3();
 539
 540 save_p0 = *fq.p0;
 541 save_p1 = *fq.p1;
 542
 543
 544                 fate = find_vector_intersection(&fq,&hit_info);
 545                 //      Matt: Mike's hack.
 546                 if (fate == HIT_OBJECT) {
 547                         object  *objp = &Objects[hit_info.hit_object];
 548
 549                         if ((objp->type == OBJ_WEAPON) && ((objp->id == PROXIMITY_ID) || (objp->id == SUPERPROX_ID)))
 550                                 count--;
 551                 }
 552
 553                 #ifndef NDEBUG
 554                 if (fate == HIT_BAD_P0) {
 555                         mprintf((0,"Warning: Bad p0 in physics!  Object = %i, type = %i [%s]\n", obj-Objects, obj->type, Object_type_names[obj->type]));
 556                         Int3();
 557                 }
 558                 #endif
 559
 560                 if (obj->type == OBJ_PLAYER) {
 561                         int i;
 562
 563                         if (n_phys_segs && phys_seglist[n_phys_segs-1]==hit_info.seglist[0])
 564                                 n_phys_segs--;
 565
 566                         for (i=0;(i<hit_info.n_segs) && (n_phys_segs<MAX_FVI_SEGS-1);  )
 567                                 phys_seglist[n_phys_segs++] = hit_info.seglist[i++];
 568                 }
 569
 570                 #ifdef EXTRA_DEBUG
 571                 if (obj == debug_obj)
 572                         printf("   fate  = %d, hit_pnt = %8x %8x %8x\n",fate,XYZ(&hit_info.hit_pnt));;
 573                 #endif
 574
 575                 ipos = hit_info.hit_pnt;
 576                 iseg = hit_info.hit_seg;
 577                 WallHitSide = hit_info.hit_side;
 578                 WallHitSeg = hit_info.hit_side_seg;
 579
 580                 if (iseg==-1) {         //some sort of horrible error
 581                         #ifndef NDEBUG
 582                         mprintf((1,"iseg==-1 in physics!  Object = %i, type = %i (%s)\n", obj-Objects, obj->type, Object_type_names[obj->type]));
 583                         #endif
 584                         //Int3();
 585                         //compute_segment_center(&ipos,&Segments[obj->segnum]);
 586                         //ipos.x += objnum;
 587                         //iseg = obj->segnum;
 588                         //fate = HIT_NONE;
 589                         if (obj->type == OBJ_WEAPON)
 590                                 obj->flags |= OF_SHOULD_BE_DEAD;
 591                         break;
 592                 }
 593
 594                 Assert(!((fate==HIT_WALL) && ((WallHitSeg == -1) || (WallHitSeg > Highest_segment_index))));
 595
 596                 //if(!get_seg_masks(&hit_info.hit_pnt, hit_info.hit_seg, 0, __FILE__, __LINE__).centermask == 0)
 597                 //      Int3();
 598
 599                 save_pos = obj->pos;                    //save the object's position
 600                 save_seg = obj->segnum;
 601
 602                 // update object's position and segment number
 603                 obj->pos = ipos;
 604
 605                 #ifdef EXTRA_DEBUG
 606                 if (obj == debug_obj)
 607                         printf("   new pos = %x %x %x\n",XYZ(&obj->pos));
 608                 #endif
 609
 610                 if ( iseg != obj->segnum )
 611                         obj_relink(objnum, iseg );
 612
 613                 //if start point not in segment, move object to center of segment
 614                 if (get_seg_masks(&obj->pos, obj->segnum, 0, __FILE__, __LINE__).centermask !=0 )
 615                 {
 616                         int n;
 617
 618                         if ((n=find_object_seg(obj))==-1) {
 619                                 //Int3();
 620                                 if (obj->type==OBJ_PLAYER && (n=find_point_seg(&obj->last_pos,obj->segnum))!=-1) {
 621                                         obj->pos = obj->last_pos;
 622                                         obj_relink(objnum, n );
 623                                 }
 624                                 else {
 625                                         compute_segment_center(&obj->pos,&Segments[obj->segnum]);
 626                                         obj->pos.x += objnum;
 627                                 }
 628                                 if (obj->type == OBJ_WEAPON)
 629                                         obj->flags |= OF_SHOULD_BE_DEAD;
 630                         }
 631                         return;
 632                 }
 633
 634                 //calulate new sim time
 635                 {
 636                         //vms_vector moved_vec;
 637                         vms_vector moved_vec_n;
 638                         fix attempted_dist,actual_dist;
 639
 640                         old_sim_time = sim_time;
 641
 642                         actual_dist = vm_vec_normalized_dir(&moved_vec_n,&obj->pos,&save_pos);
 643
 644                         if (fate==HIT_WALL && vm_vec_dot(&moved_vec_n,&frame_vec) < 0) {                //moved backwards
 645
 646                                 //don't change position or sim_time
 647
 648 //*******                                       mprintf((0,"Obj %d moved backwards\n",obj-Objects));
 649
 650                                 #ifdef EXTRA_DEBUG
 651                                 if (obj == debug_obj)
 652                                         printf("   Warning: moved backwards!\n");
 653                                 #endif
 654
 655                                 obj->pos = save_pos;
 656
 657                                 //iseg = obj->segnum;           //don't change segment
 658
 659                                 obj_relink(objnum, save_seg );
 660
 661                                 moved_time = 0;
 662                         }
 663                         else {
 664
 665                                 //if (obj == debug_obj)
 666                                 //      printf("   moved_vec = %x %x %x\n",XYZ(&moved_vec));
 667
 668                                 attempted_dist = vm_vec_mag(&frame_vec);
 669
 670                                 sim_time = fixmuldiv(sim_time,attempted_dist-actual_dist,attempted_dist);
 671
 672                                 moved_time = old_sim_time - sim_time;
 673
 674                                 if (sim_time < 0 || sim_time>old_sim_time) {
 675                                         #ifndef NDEBUG
 676                                         mprintf((0,"Bogus sim_time = %x, old = %x\n",sim_time,old_sim_time));
 677                                         if (obj == debug_obj)
 678                                                 printf("   Bogus sim_time = %x, old = %x, attempted_dist = %x, actual_dist = %x\n",sim_time,old_sim_time,attempted_dist,actual_dist);
 679                                         //Int3(); Removed by Rob
 680                                         #endif
 681                                         sim_time = old_sim_time;
 682                                         //WHY DOES THIS HAPPEN??
 683
 684                                         moved_time = 0;
 685                                 }
 686                         }
 687
 688                         #ifdef EXTRA_DEBUG
 689                         if (obj == debug_obj)
 690                                 printf("   new sim_time = %x\n",sim_time);
 691                         #endif
 692
 693                 }
 694
 695
 696                 switch( fate )          {
 697
 698                         case HIT_WALL:          {
 699                                 vms_vector moved_v;
 700                                 //@@fix total_d,moved_d;
 701                                 fix hit_speed,wall_part;
 702
 703                                 // Find hit speed
 704
 705                                 vm_vec_sub(&moved_v,&obj->pos,&save_pos);
 706
 707                                 wall_part = vm_vec_dot(&moved_v,&hit_info.hit_wallnorm);
 708
 709                                 if (wall_part != 0 && moved_time>0 && (hit_speed=-fixdiv(wall_part,moved_time))>0)
 710                                         collide_object_with_wall( obj, hit_speed, WallHitSeg, WallHitSide, &hit_info.hit_pnt );
 711                                 else
 712                                         scrape_object_on_wall(obj, WallHitSeg, WallHitSide, &hit_info.hit_pnt );
 713
 714                                 Assert( WallHitSeg > -1 );
 715                                 Assert( WallHitSide > -1 );
 716
 717                                 if ( !(obj->flags&OF_SHOULD_BE_DEAD) )  {
 718                                         int forcefield_bounce;          //bounce off a forcefield
 719
 720                                         Assert(BounceCheat || !(obj->mtype.phys_info.flags & PF_STICK && obj->mtype.phys_info.flags & PF_BOUNCE));      //can't be bounce and stick
 721
 722                                         forcefield_bounce = (TmapInfo[Segments[WallHitSeg].sides[WallHitSide].tmap_num].flags & TMI_FORCE_FIELD);
 723
 724                                         if (!forcefield_bounce && (obj->mtype.phys_info.flags & PF_STICK)) {            //stop moving
 725
 726                                                 // mprintf((0, "Object %i stuck at %i:%i\n", obj-Objects, WallHitSeg, WallHitSide));
 727                                                 add_stuck_object(obj, WallHitSeg, WallHitSide);
 728
 729                                                 vm_vec_zero(&obj->mtype.phys_info.velocity);
 730                                                 obj_stopped = 1;
 731                                                 try_again = 0;
 732                                         }
 733                                         else {                                  // Slide object along wall
 734                                                 int check_vel=0;
 735
 736                                                 //We're constrained by wall, so subtract wall part from
 737                                                 //velocity vector
 738
 739                                                 wall_part = vm_vec_dot(&hit_info.hit_wallnorm,&obj->mtype.phys_info.velocity);
 740
 741 //                                              mprintf((0, "%d", f2i(vm_vec_mag(&hit_info.hit_wallnorm)) ));
 742
 743                                                 if (forcefield_bounce || (obj->mtype.phys_info.flags & PF_BOUNCE)) {            //bounce off wall
 744                                                         wall_part *= 2; //Subtract out wall part twice to achieve bounce
 745
 746                                                         if (forcefield_bounce) {
 747                                                                 check_vel = 1;                          //check for max velocity
 748                                                                 if (obj->type == OBJ_PLAYER)
 749                                                                         wall_part *= 2;         //player bounce twice as much
 750                                                         }
 751
 752                                                         if ( obj->mtype.phys_info.flags & PF_BOUNCES_TWICE) {
 753                                                                 Assert(obj->mtype.phys_info.flags & PF_BOUNCE);
 754                                                                 if (obj->mtype.phys_info.flags & PF_BOUNCED_ONCE)
 755                                                                         obj->mtype.phys_info.flags &= ~(PF_BOUNCE+PF_BOUNCED_ONCE+PF_BOUNCES_TWICE);
 756                                                                 else
 757                                                                         obj->mtype.phys_info.flags |= PF_BOUNCED_ONCE;
 758                                                         }
 759
 760                                                         bounced = 1;            //this object bounced
 761                                                 }
 762
 763                                                 vm_vec_scale_add2(&obj->mtype.phys_info.velocity,&hit_info.hit_wallnorm,-wall_part);
 764
 765 //                                              mprintf((0, "Velocity at bounce time = %d\n", f2i(vm_vec_mag(&obj->mtype.phys_info.velocity))));
 766
 767 //if (obj==ConsoleObject)
 768 //      mprintf((0,"player vel = %x\n",vm_vec_mag_quick(&obj->mtype.phys_info.velocity)));
 769
 770                                                 if (check_vel) {
 771                                                         fix vel = vm_vec_mag_quick(&obj->mtype.phys_info.velocity);
 772
 773                                                         if (vel > MAX_OBJECT_VEL)
 774                                                                 vm_vec_scale(&obj->mtype.phys_info.velocity,fixdiv(MAX_OBJECT_VEL,vel));
 775                                                 }
 776
 777                                                 if (bounced && obj->type == OBJ_WEAPON)
 778                                                         vm_vector_2_matrix(&obj->orient,&obj->mtype.phys_info.velocity,&obj->orient.uvec,NULL);
 779
 780                                                 #ifdef EXTRA_DEBUG
 781                                                 if (obj == debug_obj) {
 782                                                         printf("   sliding - wall_norm %x %x %x %x\n",wall_part,XYZ(&hit_info.hit_wallnorm));
 783                                                         printf("   wall_part %x, new velocity = %x %x %x\n",wall_part,XYZ(&obj->mtype.phys_info.velocity));
 784                                                 }
 785                                                 #endif
 786
 787                                                 try_again = 1;
 788                                         }
 789                                 }
 790                                 break;
 791                         }
 792
 793                         case HIT_OBJECT:                {
 794                                 vms_vector old_vel;
 795
 796                                 // Mark the hit object so that on a retry the fvi code
 797                                 // ignores this object.
 798
 799                                 Assert(hit_info.hit_object != -1);
 800
 801                                 //      Calculcate the hit point between the two objects.
 802                                 {       vms_vector      *ppos0, *ppos1, pos_hit;
 803                                         fix                     size0, size1;
 804                                         ppos0 = &Objects[hit_info.hit_object].pos;
 805                                         ppos1 = &obj->pos;
 806                                         size0 = Objects[hit_info.hit_object].size;
 807                                         size1 = obj->size;
 808                                         Assert(size0+size1 != 0);       // Error, both sizes are 0, so how did they collide, anyway?!?
 809                                         //vm_vec_scale(vm_vec_sub(&pos_hit, ppos1, ppos0), fixdiv(size0, size0 + size1));
 810                                         //vm_vec_add2(&pos_hit, ppos0);
 811                                         vm_vec_sub(&pos_hit, ppos1, ppos0);
 812                                         vm_vec_scale_add(&pos_hit,ppos0,&pos_hit,fixdiv(size0, size0 + size1));
 813
 814                                         old_vel = obj->mtype.phys_info.velocity;
 815
 816                                         collide_two_objects( obj, &Objects[hit_info.hit_object], &pos_hit);
 817
 818                                 }
 819
 820                                 // Let object continue its movement
 821                                 if ( !(obj->flags&OF_SHOULD_BE_DEAD)  ) {
 822                                         //obj->pos = save_pos;
 823
 824                                         if (obj->mtype.phys_info.flags&PF_PERSISTENT || (old_vel.x == obj->mtype.phys_info.velocity.x && old_vel.y == obj->mtype.phys_info.velocity.y && old_vel.z == obj->mtype.phys_info.velocity.z)) {
 825                                                 //if (Objects[hit_info.hit_object].type == OBJ_POWERUP)
 826                                                         ignore_obj_list[n_ignore_objs++] = hit_info.hit_object;
 827                                                 try_again = 1;
 828                                         }
 829                                 }
 830
 831                                 break;
 832                         }
 833                         case HIT_NONE:
 834                         #ifdef TACTILE
 835                                 if (TactileStick && obj==ConsoleObject && !(FrameCount & 15))
 836                                  Tactile_Xvibrate_clear ();
 837                         #endif
 838                                 break;
 839
 840                         #ifndef NDEBUG
 841                         case HIT_BAD_P0:
 842                                 Int3();         // Unexpected collision type: start point not in specified segment.
 843                                 mprintf((0,"Warning: Bad p0 in physics!!!\n"));
 844                                 break;
 845                         default:
 846                                 // Unknown collision type returned from find_vector_intersection!!
 847                                 Int3();
 848                                 break;
 849                         #endif
 850                 }
 851
 852         } while ( try_again );
 853
 854         //      Pass retry count info to AI.
 855         if (obj->control_type == CT_AI) {
 856                 if (count > 0) {
 857                         Ai_local_info[objnum].retry_count = count-1;
 858                         #ifndef NDEBUG
 859                         Total_retries += count-1;
 860                         Total_sims++;
 861                         #endif
 862                 }
 863         }
 864
 865         //I'm not sure why we do this.  I wish there were a comment that
 866         //explained it.  I think maybe it only needs to be done if the object
 867         //is sliding, but I don't know
 868         if (!obj_stopped && !bounced)   {       //Set velocity from actual movement
 869                 vms_vector moved_vec;
 870
 871                 vm_vec_sub(&moved_vec,&obj->pos,&start_pos);
 872                 vm_vec_copy_scale(&obj->mtype.phys_info.velocity,&moved_vec,fixdiv(f1_0,FrameTime));
 873
 874                 #ifdef BUMP_HACK
 875                 if (obj==ConsoleObject && (obj->mtype.phys_info.velocity.x==0 && obj->mtype.phys_info.velocity.y==0 && obj->mtype.phys_info.velocity.z==0) &&
 876                           !(obj->mtype.phys_info.thrust.x==0 && obj->mtype.phys_info.thrust.y==0 && obj->mtype.phys_info.thrust.z==0)) {
 877                         vms_vector center,bump_vec;
 878
 879                         //bump player a little towards center of segment to unstick
 880
 881                         compute_segment_center(&center,&Segments[obj->segnum]);
 882                         vm_vec_normalized_dir_quick(&bump_vec,&center,&obj->pos);
 883
 884                         //don't bump player toward center of reactor segment
 885                         if (Segment2s[obj->segnum].special == SEGMENT_IS_CONTROLCEN)
 886                                 vm_vec_negate(&bump_vec);
 887
 888                         vm_vec_scale_add2(&obj->pos,&bump_vec,obj->size/5);
 889
 890                         //if moving away from seg, might move out of seg, so update
 891                         if (Segment2s[obj->segnum].special == SEGMENT_IS_CONTROLCEN)
 892                                 update_object_seg(obj);
 893                 }
 894                 #endif
 895         }
 896
 897         //Assert(check_point_in_seg(&obj->pos,obj->segnum,0).centermask==0);
 898
 899         //if (obj->control_type == CT_FLYING)
 900         if (obj->mtype.phys_info.flags & PF_LEVELLING)
 901                 do_physics_align_object( obj );
 902
 903
 904         //hack to keep player from going through closed doors
 905         if (obj->type==OBJ_PLAYER && obj->segnum!=orig_segnum && (Physics_cheat_flag!=0xBADA55) ) {
 906                 int sidenum;
 907
 908                 sidenum = find_connect_side(&Segments[obj->segnum],&Segments[orig_segnum]);
 909
 910                 if (sidenum != -1) {
 911
 912                         if (! (WALL_IS_DOORWAY(&Segments[orig_segnum],sidenum) & WID_FLY_FLAG)) {
 913                                 side *s;
 914                                 int vertnum,num_faces,i;
 915                                 fix dist;
 916                                 int vertex_list[6];
 917
 918                                 //bump object back
 919
 920                                 s = &Segments[orig_segnum].sides[sidenum];
 921
 922                                 if (orig_segnum==-1)
 923                                         Error("orig_segnum == -1 in physics");
 924
 925                                 create_abs_vertex_lists(&num_faces, vertex_list, orig_segnum, sidenum, __FILE__, __LINE__);
 926
 927                                 //let's pretend this wall is not triangulated
 928                                 vertnum = vertex_list[0];
 929                                 for (i=1;i<4;i++)
 930                                         if (vertex_list[i] < vertnum)
 931                                                 vertnum = vertex_list[i];
 932
 933                                 #ifdef COMPACT_SEGS
 934                                         {
 935                                         vms_vector _vn;
 936                                         get_side_normal(&Segments[orig_segnum], sidenum, 0, &_vn );
 937                                         dist = vm_dist_to_plane(&start_pos, &_vn, &Vertices[vertnum]);
 938                                         vm_vec_scale_add(&obj->pos,&start_pos,&_vn,obj->size-dist);
 939                                         }
 940                                 #else
 941                                         dist = vm_dist_to_plane(&start_pos, &s->normals[0], &Vertices[vertnum]);
 942                                         vm_vec_scale_add(&obj->pos,&start_pos,&s->normals[0],obj->size-dist);
 943                                 #endif
 944                                 update_object_seg(obj);
 945
 946                         }
 947                 }
 948         }
 949
 950 //--WE ALWYS WANT THIS IN, MATT AND MIKE DECISION ON 12/10/94, TWO MONTHS AFTER FINAL   #ifndef NDEBUG
 951         //if end point not in segment, move object to last pos, or segment center
 952         if (get_seg_masks(&obj->pos, obj->segnum, 0, __FILE__, __LINE__).centermask != 0)
 953         {
 954                 if (find_object_seg(obj)==-1) {
 955                         int n;
 956
 957                         //Int3();
 958                         if (obj->type==OBJ_PLAYER && (n=find_point_seg(&obj->last_pos,obj->segnum))!=-1) {
 959                                 obj->pos = obj->last_pos;
 960                                 obj_relink(objnum, n );
 961                         }
 962                         else {
 963                                 compute_segment_center(&obj->pos,&Segments[obj->segnum]);
 964                                 obj->pos.x += objnum;
 965                         }
 966                         if (obj->type == OBJ_WEAPON)
 967                                 obj->flags |= OF_SHOULD_BE_DEAD;
 968                 }
 969         }
 970 //--WE ALWYS WANT THIS IN, MATT AND MIKE DECISION ON 12/10/94, TWO MONTHS AFTER FINAL   #endif
 971
 972
 973 }
 974
 975 //--unused-- //tell us what the given object will do (as far as hiting walls) in
 976 //--unused-- //the given time (in seconds) t.  Igores acceleration (sorry)
 977 //--unused-- //if check_objects is set, check with objects, else just with walls
 978 //--unused-- //returns fate, fills in hit time.  If fate==HIT_NONE, hit_time undefined
 979 //--unused-- int physics_lookahead(object *obj,fix t,int fvi_flags,fix *hit_time, fvi_info *hit_info)
 980 //--unused-- {
 981 //--unused--    vms_vector new_pos;
 982 //--unused--    int objnum,fate;
 983 //--unused--    fvi_query fq;
 984 //--unused--
 985 //--unused--    Assert(obj->movement_type == MT_PHYSICS);
 986 //--unused--
 987 //--unused--    objnum = obj-Objects;
 988 //--unused--
 989 //--unused--    vm_vec_scale_add(&new_pos, &obj->pos, &obj->mtype.phys_info.velocity, t);
 990 //--unused--
 991 //--unused--    fq.p0                                           = &obj->pos;
 992 //--unused--    fq.startseg                             = obj->segnum;
 993 //--unused--    fq.p1                                           = &new_pos;
 994 //--unused--    fq.rad                                  = obj->size;
 995 //--unused--    fq.thisobjnum                   = objnum;
 996 //--unused--    fq.ignore_obj_list      = NULL;
 997 //--unused--    fq.flags                                        = fvi_flags;
 998 //--unused--
 999 //--unused--    fate = find_vector_intersection(&fq,hit_info);
1000 //--unused--
1001 //--unused--    if (fate != HIT_NONE) {
1002 //--unused--            fix dist,speed;
1003 //--unused--
1004 //--unused--            dist = vm_vec_dist(&obj->pos, &hit_info->hit_pnt);
1005 //--unused--
1006 //--unused--            speed = vm_vec_mag(&obj->mtype.phys_info.velocity);
1007 //--unused--
1008 //--unused--            *hit_time = fixdiv(dist,speed);
1009 //--unused--
1010 //--unused--    }
1011 //--unused--
1012 //--unused--    return fate;
1013 //--unused--
1014 //--unused-- }
1015
1016 //Applies an instantaneous force on an object, resulting in an instantaneous
1017 //change in velocity.
1018 void phys_apply_force(object *obj,vms_vector *force_vec)
1019 {
1020
1021         //      Put in by MK on 2/13/96 for force getting applied to Omega blobs, which have 0 mass,
1022         //      in collision with crazy reactor robot thing on d2levf-s.
1023         if (obj->mtype.phys_info.mass == 0)
1024                 return;
1025
1026         if (obj->movement_type != MT_PHYSICS)
1027                 return;
1028
1029 #ifdef TACTILE
1030    if (TactileStick && obj==&Objects[Players[Player_num].objnum])
1031                 Tactile_apply_force (force_vec,&obj->orient);
1032 #endif
1033
1034         //Add in acceleration due to force
1035         vm_vec_scale_add2(&obj->mtype.phys_info.velocity,force_vec,fixdiv(f1_0,obj->mtype.phys_info.mass));
1036
1037
1038 }
1039
1040 //      ----------------------------------------------------------------
1041 //      Do *dest = *delta unless:
1042 //                              *delta is pretty small
1043 //              and     they are of different signs.
1044 void physics_set_rotvel_and_saturate(fix *dest, fix delta)
1045 {
1046         if ((delta ^ *dest) < 0) {
1047                 if (abs(delta) < F1_0/8) {
1048                         // mprintf((0, "D"));
1049                         *dest = delta/4;
1050                 } else
1051                         // mprintf((0, "d"));
1052                         *dest = delta;
1053         } else {
1054                 // mprintf((0, "!"));
1055                 *dest = delta;
1056         }
1057 }
1058
1059 //      ------------------------------------------------------------------------------------------------------
1060 //      Note: This is the old ai_turn_towards_vector code.
1061 //      phys_apply_rot used to call ai_turn_towards_vector until I fixed it, which broke phys_apply_rot.
1062 void physics_turn_towards_vector(vms_vector *goal_vector, object *obj, fix rate)
1063 {
1064         vms_angvec      dest_angles, cur_angles;
1065         fix                     delta_p, delta_h;
1066         vms_vector      *rotvel_ptr = &obj->mtype.phys_info.rotvel;
1067
1068         // Make this object turn towards the goal_vector.  Changes orientation, doesn't change direction of movement.
1069         // If no one moves, will be facing goal_vector in 1 second.
1070
1071         //      Detect null vector.
1072         if ((goal_vector->x == 0) && (goal_vector->y == 0) && (goal_vector->z == 0))
1073                 return;
1074
1075         //      Make morph objects turn more slowly.
1076         if (obj->control_type == CT_MORPH)
1077                 rate *= 2;
1078
1079         vm_extract_angles_vector(&dest_angles, goal_vector);
1080         vm_extract_angles_vector(&cur_angles, &obj->orient.fvec);
1081
1082         delta_p = (dest_angles.p - cur_angles.p);
1083         delta_h = (dest_angles.h - cur_angles.h);
1084
1085         if (delta_p > F1_0/2) delta_p = dest_angles.p - cur_angles.p - F1_0;
1086         if (delta_p < -F1_0/2) delta_p = dest_angles.p - cur_angles.p + F1_0;
1087         if (delta_h > F1_0/2) delta_h = dest_angles.h - cur_angles.h - F1_0;
1088         if (delta_h < -F1_0/2) delta_h = dest_angles.h - cur_angles.h + F1_0;
1089
1090         delta_p = fixdiv(delta_p, rate);
1091         delta_h = fixdiv(delta_h, rate);
1092
1093         if (abs(delta_p) < F1_0/16) delta_p *= 4;
1094         if (abs(delta_h) < F1_0/16) delta_h *= 4;
1095
1096         physics_set_rotvel_and_saturate(&rotvel_ptr->x, delta_p);
1097         physics_set_rotvel_and_saturate(&rotvel_ptr->y, delta_h);
1098         rotvel_ptr->z = 0;
1099 }
1100
1101 //      -----------------------------------------------------------------------------
1102 //      Applies an instantaneous whack on an object, resulting in an instantaneous
1103 //      change in orientation.
1104 void phys_apply_rot(object *obj,vms_vector *force_vec)
1105 {
1106         fix     rate, vecmag;
1107
1108         if (obj->movement_type != MT_PHYSICS)
1109                 return;
1110
1111         vecmag = vm_vec_mag(force_vec)/8;
1112         if (vecmag < F1_0/256)
1113                 rate = 4*F1_0;
1114         else if (vecmag < obj->mtype.phys_info.mass >> 14)
1115                 rate = 4*F1_0;
1116         else {
1117                 rate = fixdiv(obj->mtype.phys_info.mass, vecmag);
1118                 if (obj->type == OBJ_ROBOT) {
1119                         if (rate < F1_0/4)
1120                                 rate = F1_0/4;
1121                         //      Changed by mk, 10/24/95, claw guys should not slow down when attacking!
1122                         if (!Robot_info[obj->id].thief && !Robot_info[obj->id].attack_type) {
1123                                 if (obj->ctype.ai_info.SKIP_AI_COUNT * FrameTime < 3*F1_0/4) {
1124                                         fix     tval = fixdiv(F1_0, 8*FrameTime);
1125                                         int     addval;
1126
1127                                         addval = f2i(tval);
1128
1129                                         if ( (d_rand() * 2) < (tval & 0xffff))
1130                                                 addval++;
1131                                         obj->ctype.ai_info.SKIP_AI_COUNT += addval;
1132                                         // -- mk: too much stuff making hard to see my debug messages...mprintf((0, "FrameTime = %7.3f, addval = %i\n", f2fl(FrameTime), addval));
1133                                 }
1134                         }
1135                 } else {
1136                         if (rate < F1_0/2)
1137                                 rate = F1_0/2;
1138                 }
1139         }
1140
1141         //      Turn amount inversely proportional to mass.  Third parameter is seconds to do 360 turn.
1142         physics_turn_towards_vector(force_vec, obj, rate);
1143
1144
1145 }
1146
1147
1148 //this routine will set the thrust for an object to a value that will
1149 //(hopefully) maintain the object's current velocity
1150 void set_thrust_from_velocity(object *obj)
1151 {
1152         fix k;
1153
1154         Assert(obj->movement_type == MT_PHYSICS);
1155
1156         k = fixmuldiv(obj->mtype.phys_info.mass,obj->mtype.phys_info.drag,(f1_0-obj->mtype.phys_info.drag));
1157
1158         vm_vec_copy_scale(&obj->mtype.phys_info.thrust,&obj->mtype.phys_info.velocity,k);
1159
1160 }
1161
1162