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[btb/d2x.git] / main / physics.c
1 /*
2 THE COMPUTER CODE CONTAINED HEREIN IS THE SOLE PROPERTY OF PARALLAX
3 SOFTWARE CORPORATION ("PARALLAX").  PARALLAX, IN DISTRIBUTING THE CODE TO
4 END-USERS, AND SUBJECT TO ALL OF THE TERMS AND CONDITIONS HEREIN, GRANTS A
5 ROYALTY-FREE, PERPETUAL LICENSE TO SUCH END-USERS FOR USE BY SUCH END-USERS
6 IN USING, DISPLAYING,  AND CREATING DERIVATIVE WORKS THEREOF, SO LONG AS
7 SUCH USE, DISPLAY OR CREATION IS FOR NON-COMMERCIAL, ROYALTY OR REVENUE
8 FREE PURPOSES.  IN NO EVENT SHALL THE END-USER USE THE COMPUTER CODE
9 CONTAINED HEREIN FOR REVENUE-BEARING PURPOSES.  THE END-USER UNDERSTANDS
10 AND AGREES TO THE TERMS HEREIN AND ACCEPTS THE SAME BY USE OF THIS FILE.  
11 COPYRIGHT 1993-1999 PARALLAX SOFTWARE CORPORATION.  ALL RIGHTS RESERVED.
12 */
13
14 #ifdef HAVE_CONFIG_H
15 #include <conf.h>
16 #endif
17
18 #ifdef RCS
19 static char rcsid[] = "$Id: physics.c,v 1.3 2001-01-31 15:17:57 bradleyb Exp $";
20 #endif
21
22 #include <stdio.h>
23 #include <stdlib.h>
24
25 #include "joy.h"
26 #include "mono.h"
27 #include "error.h"
28
29 #include "inferno.h"
30 #include "segment.h"
31 #include "object.h"
32 #include "physics.h"
33 #include "key.h"
34 #include "game.h"
35 #include "collide.h"
36 #include "fvi.h"
37 #include "newdemo.h"
38 #include "timer.h"
39 #include "ai.h"
40 #include "wall.h"
41 #include "laser.h"
42 #include "bm.h"
43 #include "player.h"
44
45 #ifdef TACTILE
46 #include "tactile.h"
47 #endif
48
49 //Global variables for physics system
50
51 #define ROLL_RATE               0x2000
52 #define DAMP_ANG                        0x400                  //min angle to bank
53
54 #define TURNROLL_SCALE  (0x4ec4/2)
55
56 #define MAX_OBJECT_VEL i2f(100)
57
58 #define BUMP_HACK       1               //if defined, bump player when he gets stuck
59
60 //--unused-- int mike_mode=0;
61
62 //check point against each side of segment. return bitmask, where bit
63 //set means behind that side
64
65 int Physics_cheat_flag = 0;
66 extern char BounceCheat;
67
68 //##//returns the distance of a point (checkp) from a plane (defined by norm & planep) 
69 //##fix dist_to_plane(vms_vector *checkp,vms_vector *norm,vms_vector *planep)
70 //##{
71 //##    vms_vector deltap;
72 //##
73 //##    vm_vec_sub(&deltap,checkp,planep);
74 //##
75 //##    return vm_vec_dot(&deltap,norm);
76 //##}
77  
78 //--unused-- int dpjm_old_joy_x, dpjm_old_joy_y;
79
80 int floor_levelling=0;
81
82 //--unused-- level_with_floor()
83 //--unused-- {
84 //--unused--    floor_levelling=1;
85 //--unused-- }
86
87 //make sure matrix is orthogonal
88 void check_and_fix_matrix(vms_matrix *m)
89 {
90         vms_matrix tempm;
91
92         vm_vector_2_matrix(&tempm,&m->fvec,&m->uvec,NULL);
93         *m  = tempm;
94 }
95
96
97 void do_physics_align_object( object * obj )
98 {
99         vms_vector desired_upvec;
100         fixang delta_ang,roll_ang;
101         //vms_vector forvec = {0,0,f1_0};
102         vms_matrix temp_matrix;
103         fix d,largest_d=-f1_0;
104         int i,best_side;
105
106         best_side=0;
107         // bank player according to segment orientation
108
109         //find side of segment that player is most alligned with
110
111         for (i=0;i<6;i++) {
112                 #ifdef COMPACT_SEGS
113                         vms_vector _tv1;
114                         get_side_normal( &Segments[obj->segnum], i, 0, &_tv1 );
115                         d = vm_vec_dot(&_tv1,&obj->orient.uvec);
116                 #else                                   
117                         d = vm_vec_dot(&Segments[obj->segnum].sides[i].normals[0],&obj->orient.uvec);
118                 #endif
119
120                 if (d > largest_d) {largest_d = d; best_side=i;}
121         }
122
123         if (floor_levelling) {
124
125                 // old way: used floor's normal as upvec
126                 #ifdef COMPACT_SEGS
127                         get_side_normal(&Segments[obj->segnum], 3, 0, &desired_upvec );                 
128                 #else
129                         desired_upvec = Segments[obj->segnum].sides[3].normals[0];
130                 #endif
131
132         }
133         else  // new player leveling code: use normal of side closest to our up vec
134                 if (get_num_faces(&Segments[obj->segnum].sides[best_side])==2) {
135                         #ifdef COMPACT_SEGS
136                                 vms_vector normals[2];
137                                 get_side_normals(&Segments[obj->segnum], best_side, &normals[0], &normals[1] );                 
138
139                                 desired_upvec.x = (normals[0].x + normals[1].x) / 2;
140                                 desired_upvec.y = (normals[0].y + normals[1].y) / 2;
141                                 desired_upvec.z = (normals[0].z + normals[1].z) / 2;
142
143                                 vm_vec_normalize(&desired_upvec);
144                         #else
145                                 side *s = &Segments[obj->segnum].sides[best_side];
146                                 desired_upvec.x = (s->normals[0].x + s->normals[1].x) / 2;
147                                 desired_upvec.y = (s->normals[0].y + s->normals[1].y) / 2;
148                                 desired_upvec.z = (s->normals[0].z + s->normals[1].z) / 2;
149                 
150                                 vm_vec_normalize(&desired_upvec);
151                         #endif
152                 }
153                 else
154                         #ifdef COMPACT_SEGS
155                                 get_side_normal(&Segments[obj->segnum], best_side, 0, &desired_upvec );                 
156                         #else
157                                 desired_upvec = Segments[obj->segnum].sides[best_side].normals[0];
158                         #endif
159
160         if (labs(vm_vec_dot(&desired_upvec,&obj->orient.fvec)) < f1_0/2) {
161                 fixang save_delta_ang;
162                 vms_angvec tangles;
163                 
164                 vm_vector_2_matrix(&temp_matrix,&obj->orient.fvec,&desired_upvec,NULL);
165
166                 save_delta_ang = delta_ang = vm_vec_delta_ang(&obj->orient.uvec,&temp_matrix.uvec,&obj->orient.fvec);
167
168                 delta_ang += obj->mtype.phys_info.turnroll;
169
170                 if (abs(delta_ang) > DAMP_ANG) {
171                         vms_matrix rotmat, new_pm;
172
173                         roll_ang = fixmul(FrameTime,ROLL_RATE);
174
175                         if (abs(delta_ang) < roll_ang) roll_ang = delta_ang;
176                         else if (delta_ang<0) roll_ang = -roll_ang;
177
178                         tangles.p = tangles.h = 0;  tangles.b = roll_ang;
179                         vm_angles_2_matrix(&rotmat,&tangles);
180
181                         vm_matrix_x_matrix(&new_pm,&obj->orient,&rotmat);
182                         obj->orient = new_pm;
183                 }
184                 else floor_levelling=0;
185         }
186
187 }
188
189 void set_object_turnroll(object *obj)
190 {
191         fixang desired_bank;
192
193         desired_bank = -fixmul(obj->mtype.phys_info.rotvel.y,TURNROLL_SCALE);
194
195         if (obj->mtype.phys_info.turnroll != desired_bank) {
196                 fixang delta_ang,max_roll;
197
198                 max_roll = fixmul(ROLL_RATE,FrameTime);
199
200                 delta_ang = desired_bank - obj->mtype.phys_info.turnroll;
201
202                 if (labs(delta_ang) < max_roll)
203                         max_roll = delta_ang;
204                 else
205                         if (delta_ang < 0)
206                                 max_roll = -max_roll;
207
208                 obj->mtype.phys_info.turnroll += max_roll;
209         }
210
211 }
212
213 //list of segments went through
214 int phys_seglist[MAX_FVI_SEGS],n_phys_segs;
215
216
217 #define MAX_IGNORE_OBJS 100
218
219 #ifndef NDEBUG
220 #define EXTRA_DEBUG 1           //no extra debug when NDEBUG is on
221 #endif
222
223 #ifdef EXTRA_DEBUG
224 object *debug_obj=NULL;
225 #endif
226
227 #define XYZ(v) (v)->x,(v)->y,(v)->z
228
229
230 #ifndef NDEBUG
231 int     Total_retries=0, Total_sims=0;
232 int     Dont_move_ai_objects=0;
233 #endif
234
235 #define FT (f1_0/64)
236
237 extern int disable_new_fvi_stuff;
238 //      -----------------------------------------------------------------------------------------------------------
239 // add rotational velocity & acceleration
240 void do_physics_sim_rot(object *obj)
241 {
242         vms_angvec      tangles;
243         vms_matrix      rotmat,new_orient;
244         //fix                   rotdrag_scale;
245         physics_info *pi;
246
247         Assert(FrameTime > 0);  //Get MATT if hit this!
248
249         pi = &obj->mtype.phys_info;
250
251         if (!(pi->rotvel.x || pi->rotvel.y || pi->rotvel.z || pi->rotthrust.x || pi->rotthrust.y || pi->rotthrust.z))
252                 return;
253
254         if (obj->mtype.phys_info.drag) {
255                 int count;
256                 vms_vector accel;
257                 fix drag,r,k;
258
259                 count = FrameTime / FT;
260                 r = FrameTime % FT;
261                 k = fixdiv(r,FT);
262
263                 drag = (obj->mtype.phys_info.drag*5)/2;
264
265                 if (obj->mtype.phys_info.flags & PF_USES_THRUST) {
266
267                         vm_vec_copy_scale(&accel,&obj->mtype.phys_info.rotthrust,fixdiv(f1_0,obj->mtype.phys_info.mass));
268
269                         while (count--) {
270
271                                 vm_vec_add2(&obj->mtype.phys_info.rotvel,&accel);
272
273                                 vm_vec_scale(&obj->mtype.phys_info.rotvel,f1_0-drag);
274                         }
275
276                         //do linear scale on remaining bit of time
277
278                         vm_vec_scale_add2(&obj->mtype.phys_info.rotvel,&accel,k);
279                         vm_vec_scale(&obj->mtype.phys_info.rotvel,f1_0-fixmul(k,drag));
280                 }
281                 else if (! (obj->mtype.phys_info.flags & PF_FREE_SPINNING)) {
282                         fix total_drag=f1_0;
283
284                         while (count--)
285                                 total_drag = fixmul(total_drag,f1_0-drag);
286
287                         //do linear scale on remaining bit of time
288
289                         total_drag = fixmul(total_drag,f1_0-fixmul(k,drag));
290
291                         vm_vec_scale(&obj->mtype.phys_info.rotvel,total_drag);
292                 }
293
294         }
295
296         //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) ));
297
298         //now rotate object 
299
300         //unrotate object for bank caused by turn
301         if (obj->mtype.phys_info.turnroll) {
302                 vms_matrix new_pm;
303
304                 tangles.p = tangles.h = 0;
305                 tangles.b = -obj->mtype.phys_info.turnroll;
306                 vm_angles_2_matrix(&rotmat,&tangles);
307                 vm_matrix_x_matrix(&new_pm,&obj->orient,&rotmat);
308                 obj->orient = new_pm;
309         }
310   
311         tangles.p = fixmul(obj->mtype.phys_info.rotvel.x,FrameTime);
312         tangles.h = fixmul(obj->mtype.phys_info.rotvel.y,FrameTime);
313         tangles.b  = fixmul(obj->mtype.phys_info.rotvel.z,FrameTime);
314
315         vm_angles_2_matrix(&rotmat,&tangles);
316         vm_matrix_x_matrix(&new_orient,&obj->orient,&rotmat);
317         obj->orient = new_orient;
318
319         if (obj->mtype.phys_info.flags & PF_TURNROLL)
320                 set_object_turnroll(obj);
321
322         //re-rotate object for bank caused by turn
323         if (obj->mtype.phys_info.turnroll) {
324                 vms_matrix new_pm;
325
326                 tangles.p = tangles.h = 0;
327                 tangles.b = obj->mtype.phys_info.turnroll;
328                 vm_angles_2_matrix(&rotmat,&tangles);
329                 vm_matrix_x_matrix(&new_pm,&obj->orient,&rotmat);
330                 obj->orient = new_pm;
331         }
332
333         check_and_fix_matrix(&obj->orient);
334 }
335
336 //      -----------------------------------------------------------------------------------------------------------
337 //Simulate a physics object for this frame
338 void do_physics_sim(object *obj)
339 {
340         int ignore_obj_list[MAX_IGNORE_OBJS],n_ignore_objs;
341         int iseg;
342         int try_again;
343         int fate;
344         vms_vector frame_vec;                   //movement in this frame
345         vms_vector new_pos,ipos;                //position after this frame
346         int count=0;
347         int objnum;
348         int WallHitSeg, WallHitSide;
349         fvi_info hit_info;
350         fvi_query fq;
351         vms_vector save_pos;
352         int save_seg;
353         fix drag;
354         fix sim_time,old_sim_time;
355         vms_vector start_pos;
356         int obj_stopped=0;
357         fix moved_time;                 //how long objected moved before hit something
358         vms_vector save_p0,save_p1;
359         physics_info *pi;
360         int orig_segnum = obj->segnum;
361         int bounced=0;
362
363         Assert(obj->type != OBJ_NONE);
364         Assert(obj->movement_type == MT_PHYSICS);
365
366 #ifndef NDEBUG
367 if (Dont_move_ai_objects)
368         if (obj->control_type == CT_AI)
369                 return;
370 #endif
371
372         pi = &obj->mtype.phys_info;
373
374         do_physics_sim_rot(obj);
375
376         if (!(pi->velocity.x || pi->velocity.y || pi->velocity.z || pi->thrust.x || pi->thrust.y || pi->thrust.z))
377                 return;
378
379         objnum = obj-Objects;
380
381         n_phys_segs = 0;
382
383         disable_new_fvi_stuff = (obj->type != OBJ_PLAYER);
384
385         sim_time = FrameTime;
386
387 //debug_obj = obj;
388
389         #ifdef EXTRA_DEBUG
390         if (obj == debug_obj) {
391                 printf("object %d:\n  start pos = %x %x %x\n",objnum,XYZ(&obj->pos));
392                 printf("  thrust = %x %x %x\n",XYZ(&obj->mtype.phys_info.thrust));
393                 printf("  sim_time = %x\n",sim_time);
394         }
395
396         //check for correct object segment 
397         if(!get_seg_masks(&obj->pos,obj->segnum,0).centermask==0) {
398                 #ifndef NDEBUG
399                 mprintf((0,"Warning: object %d not in given seg!\n",objnum));
400                 #endif
401                 //Int3();  Removed by Rob 10/5/94
402                 if (!update_object_seg(obj)) {
403                         #ifndef NDEBUG
404                         mprintf((0,"Warning: can't find seg for object %d - moving\n",objnum));
405                         #endif
406                         if (!(Game_mode & GM_MULTI))
407                                 Int3();
408                         compute_segment_center(&obj->pos,&Segments[obj->segnum]);
409                         obj->pos.x += objnum;
410                 }
411         }
412         #endif
413
414         start_pos = obj->pos;
415
416         n_ignore_objs = 0;
417
418         Assert(obj->mtype.phys_info.brakes==0);         //brakes not used anymore?
419
420                 //if uses thrust, cannot have zero drag
421         Assert(!(obj->mtype.phys_info.flags&PF_USES_THRUST) || obj->mtype.phys_info.drag!=0);
422
423 //mprintf((0,"thrust=%x  speed=%x\n",vm_vec_mag(&obj->mtype.phys_info.thrust),vm_vec_mag(&obj->mtype.phys_info.velocity)));
424
425         //do thrust & drag
426         
427         if ((drag = obj->mtype.phys_info.drag) != 0) {
428
429                 int count;
430                 vms_vector accel;
431                 fix r,k;
432
433                 count = sim_time / FT;
434                 r = sim_time % FT;
435                 k = fixdiv(r,FT);
436
437                 if (obj->mtype.phys_info.flags & PF_USES_THRUST) {
438
439                         vm_vec_copy_scale(&accel,&obj->mtype.phys_info.thrust,fixdiv(f1_0,obj->mtype.phys_info.mass));
440
441                         while (count--) {
442
443                                 vm_vec_add2(&obj->mtype.phys_info.velocity,&accel);
444
445                                 vm_vec_scale(&obj->mtype.phys_info.velocity,f1_0-drag);
446                         }
447
448                         //do linear scale on remaining bit of time
449
450                         vm_vec_scale_add2(&obj->mtype.phys_info.velocity,&accel,k);
451
452                         vm_vec_scale(&obj->mtype.phys_info.velocity,f1_0-fixmul(k,drag));
453                 }
454                 else {
455                         fix total_drag=f1_0;
456
457                         while (count--)
458                                 total_drag = fixmul(total_drag,f1_0-drag);
459
460                         //do linear scale on remaining bit of time
461
462                         total_drag = fixmul(total_drag,f1_0-fixmul(k,drag));
463
464                         vm_vec_scale(&obj->mtype.phys_info.velocity,total_drag);
465                 }
466         }
467
468         #ifdef EXTRA_DEBUG
469         if (obj == debug_obj)
470                 printf("  velocity = %x %x %x\n",XYZ(&obj->mtype.phys_info.velocity));
471         #endif
472
473         do {
474                 try_again = 0;
475
476                 //Move the object
477                 vm_vec_copy_scale(&frame_vec, &obj->mtype.phys_info.velocity, sim_time);
478
479                 #ifdef EXTRA_DEBUG
480                 if (obj == debug_obj)
481                         printf("  pass %d, frame_vec = %x %x %x\n",count,XYZ(&frame_vec));
482                 #endif
483
484                 if ( (frame_vec.x==0) && (frame_vec.y==0) && (frame_vec.z==0) ) 
485                         break;
486
487                 count++;
488
489                 //      If retry count is getting large, then we are trying to do something stupid.
490                 if ( count > 3)         {
491                         if (obj->type == OBJ_PLAYER) {
492                                 if (count > 8)
493                                         break;
494                         } else
495                                 break;
496                 }
497
498                 vm_vec_add(&new_pos,&obj->pos,&frame_vec);
499
500                 #ifdef EXTRA_DEBUG
501                 if (obj == debug_obj)
502                         printf("   desired_pos  = %x %x %x\n",XYZ(&new_pos));
503                 #endif
504
505                 ignore_obj_list[n_ignore_objs] = -1;
506
507                 #ifdef EXTRA_DEBUG
508                 if (obj == debug_obj) {
509                         printf("   FVI parms: p0 = %8x %8x %8x, segnum=%x, size=%x\n",XYZ(&obj->pos),obj->segnum,obj->size);
510                         printf("              p1 = %8x %8x %8x\n",XYZ(&new_pos));
511                 }
512                 #endif
513
514                 fq.p0                                           = &obj->pos;
515                 fq.startseg                             = obj->segnum;
516                 fq.p1                                           = &new_pos;
517                 fq.rad                                  = obj->size;
518                 fq.thisobjnum                   = objnum;
519                 fq.ignore_obj_list      = ignore_obj_list;
520                 fq.flags                                        = FQ_CHECK_OBJS;
521
522                 if (obj->type == OBJ_WEAPON)
523                         fq.flags |= FQ_TRANSPOINT;
524
525                 if (obj->type == OBJ_PLAYER)
526                         fq.flags |= FQ_GET_SEGLIST;
527
528 //@@                    if (get_seg_masks(&obj->pos,obj->segnum,0).centermask!=0)
529 //@@                            Int3();
530
531 save_p0 = *fq.p0;
532 save_p1 = *fq.p1;
533
534
535                 fate = find_vector_intersection(&fq,&hit_info);
536                 //      Matt: Mike's hack.
537                 if (fate == HIT_OBJECT) {
538                         object  *objp = &Objects[hit_info.hit_object];
539
540                         if ((objp->type == OBJ_WEAPON) && ((objp->id == PROXIMITY_ID) || (objp->id == SUPERPROX_ID)))
541                                 count--;
542                 }
543
544                 #ifndef NDEBUG
545                 if (fate == HIT_BAD_P0) {
546                         mprintf((0,"Warning: Bad p0 in physics!  Object = %i, type = %i [%s]\n", obj-Objects, obj->type, Object_type_names[obj->type]));
547                         Int3();
548                 }
549                 #endif
550
551                 if (obj->type == OBJ_PLAYER) {
552                         int i;
553
554                         if (n_phys_segs && phys_seglist[n_phys_segs-1]==hit_info.seglist[0])
555                                 n_phys_segs--;
556
557                         for (i=0;(i<hit_info.n_segs) && (n_phys_segs<MAX_FVI_SEGS-1);  )
558                                 phys_seglist[n_phys_segs++] = hit_info.seglist[i++];
559                 }
560
561                 #ifdef EXTRA_DEBUG
562                 if (obj == debug_obj)
563                         printf("   fate  = %d, hit_pnt = %8x %8x %8x\n",fate,XYZ(&hit_info.hit_pnt));;
564                 #endif
565
566                 ipos = hit_info.hit_pnt;
567                 iseg = hit_info.hit_seg;
568                 WallHitSide = hit_info.hit_side;
569                 WallHitSeg = hit_info.hit_side_seg;
570
571                 if (iseg==-1) {         //some sort of horrible error
572                         #ifndef NDEBUG
573                         mprintf((1,"iseg==-1 in physics!  Object = %i, type = %i (%s)\n", obj-Objects, obj->type, Object_type_names[obj->type]));
574                         #endif
575                         //Int3();
576                         //compute_segment_center(&ipos,&Segments[obj->segnum]);
577                         //ipos.x += objnum;
578                         //iseg = obj->segnum;
579                         //fate = HIT_NONE;
580                         if (obj->type == OBJ_WEAPON)
581                                 obj->flags |= OF_SHOULD_BE_DEAD;
582                         break;
583                 }
584
585                 Assert(!((fate==HIT_WALL) && ((WallHitSeg == -1) || (WallHitSeg > Highest_segment_index))));
586
587                 //if(!get_seg_masks(&hit_info.hit_pnt,hit_info.hit_seg,0).centermask==0)
588                 //      Int3();
589
590                 save_pos = obj->pos;                    //save the object's position
591                 save_seg = obj->segnum;
592
593                 // update object's position and segment number
594                 obj->pos = ipos;
595
596                 #ifdef EXTRA_DEBUG
597                 if (obj == debug_obj)
598                         printf("   new pos = %x %x %x\n",XYZ(&obj->pos));
599                 #endif
600
601                 if ( iseg != obj->segnum )
602                         obj_relink(objnum, iseg );
603
604                 //if start point not in segment, move object to center of segment
605                 if (get_seg_masks(&obj->pos,obj->segnum,0).centermask!=0) {
606                         int n;
607
608                         if ((n=find_object_seg(obj))==-1) {
609                                 //Int3();
610                                 if (obj->type==OBJ_PLAYER && (n=find_point_seg(&obj->last_pos,obj->segnum))!=-1) {
611                                         obj->pos = obj->last_pos;
612                                         obj_relink(objnum, n );
613                                 }
614                                 else {
615                                         compute_segment_center(&obj->pos,&Segments[obj->segnum]);
616                                         obj->pos.x += objnum;
617                                 }
618                                 if (obj->type == OBJ_WEAPON)
619                                         obj->flags |= OF_SHOULD_BE_DEAD;
620                         }
621                         return;
622                 }
623
624                 //calulate new sim time
625                 {
626                         //vms_vector moved_vec;
627                         vms_vector moved_vec_n;
628                         fix attempted_dist,actual_dist;
629
630                         old_sim_time = sim_time;
631
632                         actual_dist = vm_vec_normalized_dir(&moved_vec_n,&obj->pos,&save_pos);
633
634                         if (fate==HIT_WALL && vm_vec_dot(&moved_vec_n,&frame_vec) < 0) {                //moved backwards
635
636                                 //don't change position or sim_time
637
638 //*******                                       mprintf((0,"Obj %d moved backwards\n",obj-Objects));
639
640                                 #ifdef EXTRA_DEBUG
641                                 if (obj == debug_obj)
642                                         printf("   Warning: moved backwards!\n");
643                                 #endif
644
645                                 obj->pos = save_pos;
646                 
647                                 //iseg = obj->segnum;           //don't change segment
648
649                                 obj_relink(objnum, save_seg );
650
651                                 moved_time = 0;
652                         }
653                         else {
654
655                                 //if (obj == debug_obj)
656                                 //      printf("   moved_vec = %x %x %x\n",XYZ(&moved_vec));
657                         
658                                 attempted_dist = vm_vec_mag(&frame_vec);
659
660                                 sim_time = fixmuldiv(sim_time,attempted_dist-actual_dist,attempted_dist);
661
662                                 moved_time = old_sim_time - sim_time;
663
664                                 if (sim_time < 0 || sim_time>old_sim_time) {
665                                         #ifndef NDEBUG
666                                         mprintf((0,"Bogus sim_time = %x, old = %x\n",sim_time,old_sim_time));
667                                         if (obj == debug_obj)
668                                                 printf("   Bogus sim_time = %x, old = %x, attempted_dist = %x, actual_dist = %x\n",sim_time,old_sim_time,attempted_dist,actual_dist);
669                                         //Int3(); Removed by Rob
670                                         #endif
671                                         sim_time = old_sim_time;
672                                         //WHY DOES THIS HAPPEN??
673
674                                         moved_time = 0;
675                                 }
676                         }
677
678                         #ifdef EXTRA_DEBUG
679                         if (obj == debug_obj)
680                                 printf("   new sim_time = %x\n",sim_time);
681                         #endif
682
683                 }
684
685
686                 switch( fate )          {
687
688                         case HIT_WALL:          {
689                                 vms_vector moved_v;
690                                 //@@fix total_d,moved_d;
691                                 fix hit_speed,wall_part;
692         
693                                 // Find hit speed       
694
695                                 vm_vec_sub(&moved_v,&obj->pos,&save_pos);
696
697                                 wall_part = vm_vec_dot(&moved_v,&hit_info.hit_wallnorm);
698
699                                 if (wall_part != 0 && moved_time>0 && (hit_speed=-fixdiv(wall_part,moved_time))>0)
700                                         collide_object_with_wall( obj, hit_speed, WallHitSeg, WallHitSide, &hit_info.hit_pnt );
701                                 else
702                                         scrape_object_on_wall(obj, WallHitSeg, WallHitSide, &hit_info.hit_pnt );
703
704                                 Assert( WallHitSeg > -1 );
705                                 Assert( WallHitSide > -1 );
706
707                                 if ( !(obj->flags&OF_SHOULD_BE_DEAD) )  {
708                                         int forcefield_bounce;          //bounce off a forcefield
709
710                                         Assert(BounceCheat || !(obj->mtype.phys_info.flags & PF_STICK && obj->mtype.phys_info.flags & PF_BOUNCE));      //can't be bounce and stick
711
712                                         forcefield_bounce = (TmapInfo[Segments[WallHitSeg].sides[WallHitSide].tmap_num].flags & TMI_FORCE_FIELD);
713
714                                         if (!forcefield_bounce && (obj->mtype.phys_info.flags & PF_STICK)) {            //stop moving
715
716                                                 // mprintf((0, "Object %i stuck at %i:%i\n", obj-Objects, WallHitSeg, WallHitSide));
717                                                 add_stuck_object(obj, WallHitSeg, WallHitSide);
718
719                                                 vm_vec_zero(&obj->mtype.phys_info.velocity);
720                                                 obj_stopped = 1;
721                                                 try_again = 0;
722                                         }
723                                         else {                                  // Slide object along wall
724                                                 int check_vel=0;
725
726                                                 //We're constrained by wall, so subtract wall part from 
727                                                 //velocity vector
728
729                                                 wall_part = vm_vec_dot(&hit_info.hit_wallnorm,&obj->mtype.phys_info.velocity);
730
731 //                                              mprintf((0, "%d", f2i(vm_vec_mag(&hit_info.hit_wallnorm)) ));
732
733                                                 if (forcefield_bounce || (obj->mtype.phys_info.flags & PF_BOUNCE)) {            //bounce off wall
734                                                         wall_part *= 2; //Subtract out wall part twice to achieve bounce
735
736                                                         if (forcefield_bounce) {
737                                                                 check_vel = 1;                          //check for max velocity
738                                                                 if (obj->type == OBJ_PLAYER)
739                                                                         wall_part *= 2;         //player bounce twice as much
740                                                         }
741
742                                                         if ( obj->mtype.phys_info.flags & PF_BOUNCES_TWICE) {
743                                                                 Assert(obj->mtype.phys_info.flags & PF_BOUNCE);
744                                                                 if (obj->mtype.phys_info.flags & PF_BOUNCED_ONCE)
745                                                                         obj->mtype.phys_info.flags &= ~(PF_BOUNCE+PF_BOUNCED_ONCE+PF_BOUNCES_TWICE);
746                                                                 else
747                                                                         obj->mtype.phys_info.flags |= PF_BOUNCED_ONCE;
748                                                         }
749
750                                                         bounced = 1;            //this object bounced
751                                                 }
752
753                                                 vm_vec_scale_add2(&obj->mtype.phys_info.velocity,&hit_info.hit_wallnorm,-wall_part);
754
755 //                                              mprintf((0, "Velocity at bounce time = %d\n", f2i(vm_vec_mag(&obj->mtype.phys_info.velocity))));
756
757 //if (obj==ConsoleObject)
758 //      mprintf((0,"player vel = %x\n",vm_vec_mag_quick(&obj->mtype.phys_info.velocity)));
759
760                                                 if (check_vel) {
761                                                         fix vel = vm_vec_mag_quick(&obj->mtype.phys_info.velocity);
762
763                                                         if (vel > MAX_OBJECT_VEL)
764                                                                 vm_vec_scale(&obj->mtype.phys_info.velocity,fixdiv(MAX_OBJECT_VEL,vel));
765                                                 }
766
767                                                 if (bounced && obj->type == OBJ_WEAPON)
768                                                         vm_vector_2_matrix(&obj->orient,&obj->mtype.phys_info.velocity,&obj->orient.uvec,NULL);
769
770                                                 #ifdef EXTRA_DEBUG
771                                                 if (obj == debug_obj) {
772                                                         printf("   sliding - wall_norm %x %x %x %x\n",wall_part,XYZ(&hit_info.hit_wallnorm));
773                                                         printf("   wall_part %x, new velocity = %x %x %x\n",wall_part,XYZ(&obj->mtype.phys_info.velocity));
774                                                 }
775                                                 #endif
776
777                                                 try_again = 1;
778                                         }
779                                 }
780                                 break;
781                         }
782
783                         case HIT_OBJECT:                {
784                                 vms_vector old_vel;
785
786                                 // Mark the hit object so that on a retry the fvi code
787                                 // ignores this object.
788
789                                 Assert(hit_info.hit_object != -1);
790
791                                 //      Calculcate the hit point between the two objects.
792                                 {       vms_vector      *ppos0, *ppos1, pos_hit;
793                                         fix                     size0, size1;
794                                         ppos0 = &Objects[hit_info.hit_object].pos;
795                                         ppos1 = &obj->pos;
796                                         size0 = Objects[hit_info.hit_object].size;
797                                         size1 = obj->size;
798                                         Assert(size0+size1 != 0);       // Error, both sizes are 0, so how did they collide, anyway?!?
799                                         //vm_vec_scale(vm_vec_sub(&pos_hit, ppos1, ppos0), fixdiv(size0, size0 + size1));
800                                         //vm_vec_add2(&pos_hit, ppos0);
801                                         vm_vec_sub(&pos_hit, ppos1, ppos0);
802                                         vm_vec_scale_add(&pos_hit,ppos0,&pos_hit,fixdiv(size0, size0 + size1));
803
804                                         old_vel = obj->mtype.phys_info.velocity;
805
806                                         collide_two_objects( obj, &Objects[hit_info.hit_object], &pos_hit);
807
808                                 }
809
810                                 // Let object continue its movement
811                                 if ( !(obj->flags&OF_SHOULD_BE_DEAD)  ) {
812                                         //obj->pos = save_pos;
813
814                                         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)) {
815                                                 //if (Objects[hit_info.hit_object].type == OBJ_POWERUP)
816                                                         ignore_obj_list[n_ignore_objs++] = hit_info.hit_object;
817                                                 try_again = 1;
818                                         }
819                                 }
820
821                                 break;
822                         }       
823                         case HIT_NONE:          
824                         #ifdef TACTILE
825                                 if (TactileStick && obj==ConsoleObject && !(FrameCount & 15))
826                                  Tactile_Xvibrate_clear ();
827                         #endif
828                                 break;
829
830                         #ifndef NDEBUG
831                         case HIT_BAD_P0:
832                                 Int3();         // Unexpected collision type: start point not in specified segment.
833                                 mprintf((0,"Warning: Bad p0 in physics!!!\n"));
834                                 break;
835                         default:
836                                 // Unknown collision type returned from find_vector_intersection!!
837                                 Int3();
838                                 break;
839                         #endif
840                 }
841
842         } while ( try_again );
843
844         //      Pass retry count info to AI.
845         if (obj->control_type == CT_AI) {
846                 if (count > 0) {
847                         Ai_local_info[objnum].retry_count = count-1;
848                         #ifndef NDEBUG
849                         Total_retries += count-1;
850                         Total_sims++;
851                         #endif
852                 }
853         }
854
855         //I'm not sure why we do this.  I wish there were a comment that
856         //explained it.  I think maybe it only needs to be done if the object
857         //is sliding, but I don't know
858         if (!obj_stopped && !bounced)   {       //Set velocity from actual movement
859                 vms_vector moved_vec;
860
861                 vm_vec_sub(&moved_vec,&obj->pos,&start_pos);
862                 vm_vec_copy_scale(&obj->mtype.phys_info.velocity,&moved_vec,fixdiv(f1_0,FrameTime));
863
864                 #ifdef BUMP_HACK
865                 if (obj==ConsoleObject && (obj->mtype.phys_info.velocity.x==0 && obj->mtype.phys_info.velocity.y==0 && obj->mtype.phys_info.velocity.z==0) &&
866                           !(obj->mtype.phys_info.thrust.x==0 && obj->mtype.phys_info.thrust.y==0 && obj->mtype.phys_info.thrust.z==0)) {
867                         vms_vector center,bump_vec;
868
869                         //bump player a little towards center of segment to unstick
870
871                         compute_segment_center(&center,&Segments[obj->segnum]);
872                         vm_vec_normalized_dir_quick(&bump_vec,&center,&obj->pos);
873
874                         //don't bump player toward center of reactor segment
875                         if (Segment2s[obj->segnum].special == SEGMENT_IS_CONTROLCEN)
876                                 vm_vec_negate(&bump_vec);
877
878                         vm_vec_scale_add2(&obj->pos,&bump_vec,obj->size/5);
879
880                         //if moving away from seg, might move out of seg, so update
881                         if (Segment2s[obj->segnum].special == SEGMENT_IS_CONTROLCEN)
882                                 update_object_seg(obj);
883                 }
884                 #endif
885         }
886
887         //Assert(check_point_in_seg(&obj->pos,obj->segnum,0).centermask==0);
888
889         //if (obj->control_type == CT_FLYING)
890         if (obj->mtype.phys_info.flags & PF_LEVELLING)
891                 do_physics_align_object( obj );
892
893
894         //hack to keep player from going through closed doors
895         if (obj->type==OBJ_PLAYER && obj->segnum!=orig_segnum && (Physics_cheat_flag!=0xBADA55) ) {
896                 int sidenum;
897
898                 sidenum = find_connect_side(&Segments[obj->segnum],&Segments[orig_segnum]);
899
900                 if (sidenum != -1) {
901
902                         if (! (WALL_IS_DOORWAY(&Segments[orig_segnum],sidenum) & WID_FLY_FLAG)) {
903                                 side *s;
904                                 int vertnum,num_faces,i;
905                                 fix dist;
906                                 int vertex_list[6];
907
908                                 //bump object back
909
910                                 s = &Segments[orig_segnum].sides[sidenum];
911
912                                 if (orig_segnum==-1)
913                                         Error("orig_segnum == -1 in physics");
914
915                                 create_abs_vertex_lists( &num_faces, vertex_list, orig_segnum, sidenum);
916
917                                 //let's pretend this wall is not triangulated
918                                 vertnum = vertex_list[0];
919                                 for (i=1;i<4;i++)
920                                         if (vertex_list[i] < vertnum)
921                                                 vertnum = vertex_list[i];
922
923                                 #ifdef COMPACT_SEGS
924                                         {
925                                         vms_vector _vn;
926                                         get_side_normal(&Segments[orig_segnum], sidenum, 0, &_vn );
927                                         dist = vm_dist_to_plane(&start_pos, &_vn, &Vertices[vertnum]);
928                                         vm_vec_scale_add(&obj->pos,&start_pos,&_vn,obj->size-dist);
929                                         }
930                                 #else
931                                         dist = vm_dist_to_plane(&start_pos, &s->normals[0], &Vertices[vertnum]);
932                                         vm_vec_scale_add(&obj->pos,&start_pos,&s->normals[0],obj->size-dist);
933                                 #endif
934                                 update_object_seg(obj);
935
936                         }
937                 }
938         }
939
940 //--WE ALWYS WANT THIS IN, MATT AND MIKE DECISION ON 12/10/94, TWO MONTHS AFTER FINAL   #ifndef NDEBUG
941         //if end point not in segment, move object to last pos, or segment center
942         if (get_seg_masks(&obj->pos,obj->segnum,0).centermask!=0) {
943                 if (find_object_seg(obj)==-1) {
944                         int n;
945
946                         //Int3();
947                         if (obj->type==OBJ_PLAYER && (n=find_point_seg(&obj->last_pos,obj->segnum))!=-1) {
948                                 obj->pos = obj->last_pos;
949                                 obj_relink(objnum, n );
950                         }
951                         else {
952                                 compute_segment_center(&obj->pos,&Segments[obj->segnum]);
953                                 obj->pos.x += objnum;
954                         }
955                         if (obj->type == OBJ_WEAPON)
956                                 obj->flags |= OF_SHOULD_BE_DEAD;
957                 }
958         }
959 //--WE ALWYS WANT THIS IN, MATT AND MIKE DECISION ON 12/10/94, TWO MONTHS AFTER FINAL   #endif
960
961
962 }
963
964 //--unused-- //tell us what the given object will do (as far as hiting walls) in
965 //--unused-- //the given time (in seconds) t.  Igores acceleration (sorry) 
966 //--unused-- //if check_objects is set, check with objects, else just with walls
967 //--unused-- //returns fate, fills in hit time.  If fate==HIT_NONE, hit_time undefined
968 //--unused-- int physics_lookahead(object *obj,fix t,int fvi_flags,fix *hit_time, fvi_info *hit_info)
969 //--unused-- {
970 //--unused--    vms_vector new_pos;
971 //--unused--    int objnum,fate;
972 //--unused--    fvi_query fq;
973 //--unused-- 
974 //--unused--    Assert(obj->movement_type == MT_PHYSICS);
975 //--unused-- 
976 //--unused--    objnum = obj-Objects;
977 //--unused-- 
978 //--unused--    vm_vec_scale_add(&new_pos, &obj->pos, &obj->mtype.phys_info.velocity, t);
979 //--unused-- 
980 //--unused--    fq.p0                                           = &obj->pos;
981 //--unused--    fq.startseg                             = obj->segnum;
982 //--unused--    fq.p1                                           = &new_pos;
983 //--unused--    fq.rad                                  = obj->size;
984 //--unused--    fq.thisobjnum                   = objnum;
985 //--unused--    fq.ignore_obj_list      = NULL;
986 //--unused--    fq.flags                                        = fvi_flags;
987 //--unused-- 
988 //--unused--    fate = find_vector_intersection(&fq,hit_info);
989 //--unused-- 
990 //--unused--    if (fate != HIT_NONE) {
991 //--unused--            fix dist,speed;
992 //--unused-- 
993 //--unused--            dist = vm_vec_dist(&obj->pos, &hit_info->hit_pnt);
994 //--unused-- 
995 //--unused--            speed = vm_vec_mag(&obj->mtype.phys_info.velocity);
996 //--unused-- 
997 //--unused--            *hit_time = fixdiv(dist,speed);
998 //--unused-- 
999 //--unused--    }
1000 //--unused-- 
1001 //--unused--    return fate;
1002 //--unused-- 
1003 //--unused-- }
1004
1005 //Applies an instantaneous force on an object, resulting in an instantaneous
1006 //change in velocity.
1007 void phys_apply_force(object *obj,vms_vector *force_vec)
1008 {
1009
1010         //      Put in by MK on 2/13/96 for force getting applied to Omega blobs, which have 0 mass,
1011         //      in collision with crazy reactor robot thing on d2levf-s.
1012         if (obj->mtype.phys_info.mass == 0)
1013                 return;
1014
1015         if (obj->movement_type != MT_PHYSICS)
1016                 return;
1017
1018 #ifdef TACTILE
1019    if (TactileStick && obj==&Objects[Players[Player_num].objnum])
1020                 Tactile_apply_force (force_vec,&obj->orient);
1021 #endif
1022  
1023         //Add in acceleration due to force
1024         vm_vec_scale_add2(&obj->mtype.phys_info.velocity,force_vec,fixdiv(f1_0,obj->mtype.phys_info.mass));
1025
1026
1027 }
1028
1029 //      ----------------------------------------------------------------
1030 //      Do *dest = *delta unless:
1031 //                              *delta is pretty small
1032 //              and     they are of different signs.
1033 void physics_set_rotvel_and_saturate(fix *dest, fix delta)
1034 {
1035         if ((delta ^ *dest) < 0) {
1036                 if (abs(delta) < F1_0/8) {
1037                         // mprintf((0, "D"));
1038                         *dest = delta/4;
1039                 } else
1040                         // mprintf((0, "d"));
1041                         *dest = delta;
1042         } else {
1043                 // mprintf((0, "!"));
1044                 *dest = delta;
1045         }
1046 }
1047
1048 //      ------------------------------------------------------------------------------------------------------
1049 //      Note: This is the old ai_turn_towards_vector code.
1050 //      phys_apply_rot used to call ai_turn_towards_vector until I fixed it, which broke phys_apply_rot.
1051 void physics_turn_towards_vector(vms_vector *goal_vector, object *obj, fix rate)
1052 {
1053         vms_angvec      dest_angles, cur_angles;
1054         fix                     delta_p, delta_h;
1055         vms_vector      *rotvel_ptr = &obj->mtype.phys_info.rotvel;
1056
1057         // Make this object turn towards the goal_vector.  Changes orientation, doesn't change direction of movement.
1058         // If no one moves, will be facing goal_vector in 1 second.
1059
1060         //      Detect null vector.
1061         if ((goal_vector->x == 0) && (goal_vector->y == 0) && (goal_vector->z == 0))
1062                 return;
1063
1064         //      Make morph objects turn more slowly.
1065         if (obj->control_type == CT_MORPH)
1066                 rate *= 2;
1067
1068         vm_extract_angles_vector(&dest_angles, goal_vector);
1069         vm_extract_angles_vector(&cur_angles, &obj->orient.fvec);
1070
1071         delta_p = (dest_angles.p - cur_angles.p);
1072         delta_h = (dest_angles.h - cur_angles.h);
1073
1074         if (delta_p > F1_0/2) delta_p = dest_angles.p - cur_angles.p - F1_0;
1075         if (delta_p < -F1_0/2) delta_p = dest_angles.p - cur_angles.p + F1_0;
1076         if (delta_h > F1_0/2) delta_h = dest_angles.h - cur_angles.h - F1_0;
1077         if (delta_h < -F1_0/2) delta_h = dest_angles.h - cur_angles.h + F1_0;
1078
1079         delta_p = fixdiv(delta_p, rate);
1080         delta_h = fixdiv(delta_h, rate);
1081
1082         if (abs(delta_p) < F1_0/16) delta_p *= 4;
1083         if (abs(delta_h) < F1_0/16) delta_h *= 4;
1084
1085         physics_set_rotvel_and_saturate(&rotvel_ptr->x, delta_p);
1086         physics_set_rotvel_and_saturate(&rotvel_ptr->y, delta_h);
1087         rotvel_ptr->z = 0;
1088 }
1089
1090 //      -----------------------------------------------------------------------------
1091 //      Applies an instantaneous whack on an object, resulting in an instantaneous
1092 //      change in orientation.
1093 void phys_apply_rot(object *obj,vms_vector *force_vec)
1094 {
1095         fix     rate, vecmag;
1096
1097         if (obj->movement_type != MT_PHYSICS)
1098                 return;
1099
1100         vecmag = vm_vec_mag(force_vec)/8;
1101         if (vecmag < F1_0/256)
1102                 rate = 4*F1_0;
1103         else if (vecmag < obj->mtype.phys_info.mass >> 14)
1104                 rate = 4*F1_0;
1105         else {
1106                 rate = fixdiv(obj->mtype.phys_info.mass, vecmag);
1107                 if (obj->type == OBJ_ROBOT) {
1108                         if (rate < F1_0/4)
1109                                 rate = F1_0/4;
1110                         //      Changed by mk, 10/24/95, claw guys should not slow down when attacking!
1111                         if (!Robot_info[obj->id].thief && !Robot_info[obj->id].attack_type) {
1112                                 if (obj->ctype.ai_info.SKIP_AI_COUNT * FrameTime < 3*F1_0/4) {
1113                                         fix     tval = fixdiv(F1_0, 8*FrameTime);
1114                                         int     addval;
1115
1116                                         addval = f2i(tval);
1117
1118                                         if ( (d_rand() * 2) < (tval & 0xffff))
1119                                                 addval++;
1120                                         obj->ctype.ai_info.SKIP_AI_COUNT += addval;
1121                                         // -- mk: too much stuff making hard to see my debug messages...mprintf((0, "FrameTime = %7.3f, addval = %i\n", f2fl(FrameTime), addval));
1122                                 }
1123                         }
1124                 } else {
1125                         if (rate < F1_0/2)
1126                                 rate = F1_0/2;
1127                 }
1128         }
1129
1130         //      Turn amount inversely proportional to mass.  Third parameter is seconds to do 360 turn.
1131         physics_turn_towards_vector(force_vec, obj, rate);
1132
1133
1134 }
1135
1136
1137 //this routine will set the thrust for an object to a value that will
1138 //(hopefully) maintain the object's current velocity
1139 void set_thrust_from_velocity(object *obj)
1140 {
1141         fix k;
1142
1143         Assert(obj->movement_type == MT_PHYSICS);
1144
1145         k = fixmuldiv(obj->mtype.phys_info.mass,obj->mtype.phys_info.drag,(f1_0-obj->mtype.phys_info.drag));
1146
1147         vm_vec_copy_scale(&obj->mtype.phys_info.thrust,&obj->mtype.phys_info.velocity,k);
1148
1149 }
1150
1151