collision.c

   1
   2 #include "quakedef.h"
   3 #include "winding.h"
   4
   5 typedef struct
   6 {
   7         // the hull we're tracing through
   8         const hull_t *hull;
   9
  10         // the trace structure to fill in
  11         trace_t *trace;
  12
  13         // start and end of the trace (in model space)
  14         double start[3];
  15         double end[3];
  16
  17         // end - start
  18         double dist[3];
  19
  20         // overrides the CONTENTS_SOLID in the box bsp tree
  21         int boxsupercontents;
  22 }
  23 RecursiveHullCheckTraceInfo_t;
  24
  25 // 1/32 epsilon to keep floating point happy
  26 #define DIST_EPSILON (0.03125)
  27
  28 #define HULLCHECKSTATE_EMPTY 0
  29 #define HULLCHECKSTATE_SOLID 1
  30 #define HULLCHECKSTATE_DONE 2
  31
  32 static int RecursiveHullCheck(RecursiveHullCheckTraceInfo_t *t, int num, double p1f, double p2f, double p1[3], double p2[3])
  33 {
  34         // status variables, these don't need to be saved on the stack when
  35         // recursing...  but are because this should be thread-safe
  36         // (note: tracing against a bbox is not thread-safe, yet)
  37         int ret;
  38         mplane_t *plane;
  39         double t1, t2;
  40
  41         // variables that need to be stored on the stack when recursing
  42         dclipnode_t *node;
  43         int side;
  44         double midf, mid[3];
  45
  46         // LordHavoc: a goto!  everyone flee in terror... :)
  47 loc0:
  48         // check for empty
  49         if (num < 0)
  50         {
  51                 // translate the fake CONTENTS values in the box bsp tree
  52                 if (num == CONTENTS_SOLID)
  53                         num = t->boxsupercontents;
  54                 else
  55                         num = 0;
  56                 if (!t->trace->startfound)
  57                 {
  58                         t->trace->startfound = true;
  59                         t->trace->startsupercontents |= num;
  60                 }
  61                 if (num & t->trace->hitsupercontentsmask)
  62                 {
  63                         // if the first leaf is solid, set startsolid
  64                         if (t->trace->allsolid)
  65                                 t->trace->startsolid = true;
  66                         return HULLCHECKSTATE_SOLID;
  67                 }
  68                 else
  69                 {
  70                         t->trace->allsolid = false;
  71                         return HULLCHECKSTATE_EMPTY;
  72                 }
  73         }
  74
  75         // find the point distances
  76         node = t->hull->clipnodes + num;
  77
  78         plane = t->hull->planes + node->planenum;
  79         if (plane->type < 3)
  80         {
  81                 t1 = p1[plane->type] - plane->dist;
  82                 t2 = p2[plane->type] - plane->dist;
  83         }
  84         else
  85         {
  86                 t1 = DotProduct (plane->normal, p1) - plane->dist;
  87                 t2 = DotProduct (plane->normal, p2) - plane->dist;
  88         }
  89
  90         if (t1 < 0)
  91         {
  92                 if (t2 < 0)
  93                 {
  94                         num = node->children[1];
  95                         goto loc0;
  96                 }
  97                 side = 1;
  98         }
  99         else
 100         {
 101                 if (t2 >= 0)
 102                 {
 103                         num = node->children[0];
 104                         goto loc0;
 105                 }
 106                 side = 0;
 107         }
 108
 109         // the line intersects, find intersection point
 110         // LordHavoc: this uses the original trace for maximum accuracy
 111         if (plane->type < 3)
 112         {
 113                 t1 = t->start[plane->type] - plane->dist;
 114                 t2 = t->end[plane->type] - plane->dist;
 115         }
 116         else
 117         {
 118                 t1 = DotProduct (plane->normal, t->start) - plane->dist;
 119                 t2 = DotProduct (plane->normal, t->end) - plane->dist;
 120         }
 121
 122         midf = t1 / (t1 - t2);
 123         midf = bound(p1f, midf, p2f);
 124         VectorMA(t->start, midf, t->dist, mid);
 125
 126         // recurse both sides, front side first
 127         ret = RecursiveHullCheck (t, node->children[side], p1f, midf, p1, mid);
 128         // if this side is not empty, return what it is (solid or done)
 129         if (ret != HULLCHECKSTATE_EMPTY)
 130                 return ret;
 131
 132         ret = RecursiveHullCheck (t, node->children[side ^ 1], midf, p2f, mid, p2);
 133         // if other side is not solid, return what it is (empty or done)
 134         if (ret != HULLCHECKSTATE_SOLID)
 135                 return ret;
 136
 137         // front is air and back is solid, this is the impact point...
 138         if (side)
 139         {
 140                 t->trace->plane.dist = -plane->dist;
 141                 VectorNegate (plane->normal, t->trace->plane.normal);
 142         }
 143         else
 144         {
 145                 t->trace->plane.dist = plane->dist;
 146                 VectorCopy (plane->normal, t->trace->plane.normal);
 147         }
 148
 149         // bias away from surface a bit
 150         t1 = DotProduct(t->trace->plane.normal, t->start) - (t->trace->plane.dist + DIST_EPSILON);
 151         t2 = DotProduct(t->trace->plane.normal, t->end) - (t->trace->plane.dist + DIST_EPSILON);
 152
 153         midf = t1 / (t1 - t2);
 154         t->trace->fraction = bound(0.0f, midf, 1.0);
 155
 156         VectorMA(t->start, t->trace->fraction, t->dist, t->trace->endpos);
 157
 158         return HULLCHECKSTATE_DONE;
 159 }
 160
 161 #if 0
 162 // used if start and end are the same
 163 static void RecursiveHullCheckPoint (RecursiveHullCheckTraceInfo_t *t, int num)
 164 {
 165         // If you can read this, you understand BSP trees
 166         while (num >= 0)
 167                 num = t->hull->clipnodes[num].children[((t->hull->planes[t->hull->clipnodes[num].planenum].type < 3) ? (t->start[t->hull->planes[t->hull->clipnodes[num].planenum].type]) : (DotProduct(t->hull->planes[t->hull->clipnodes[num].planenum].normal, t->start))) < t->hull->planes[t->hull->clipnodes[num].planenum].dist];
 168
 169         // check for empty
 170         t->trace->endcontents = num;
 171         if (t->trace->thiscontents)
 172         {
 173                 if (num == t->trace->thiscontents)
 174                         t->trace->allsolid = false;
 175                 else
 176                 {
 177                         // if the first leaf is solid, set startsolid
 178                         if (t->trace->allsolid)
 179                                 t->trace->startsolid = true;
 180                 }
 181         }
 182         else
 183         {
 184                 if (num != CONTENTS_SOLID)
 185                 {
 186                         t->trace->allsolid = false;
 187                         if (num == CONTENTS_EMPTY)
 188                                 t->trace->inopen = true;
 189                         else
 190                                 t->trace->inwater = true;
 191                 }
 192                 else
 193                 {
 194                         // if the first leaf is solid, set startsolid
 195                         if (t->trace->allsolid)
 196                                 t->trace->startsolid = true;
 197                 }
 198         }
 199 }
 200 #endif
 201
 202 static hull_t box_hull;
 203 static dclipnode_t box_clipnodes[6];
 204 static mplane_t box_planes[6];
 205
 206 void Collision_Init (void)
 207 {
 208         int             i;
 209         int             side;
 210
 211         //Set up the planes and clipnodes so that the six floats of a bounding box
 212         //can just be stored out and get a proper hull_t structure.
 213
 214         box_hull.clipnodes = box_clipnodes;
 215         box_hull.planes = box_planes;
 216         box_hull.firstclipnode = 0;
 217         box_hull.lastclipnode = 5;
 218
 219         for (i = 0;i < 6;i++)
 220         {
 221                 box_clipnodes[i].planenum = i;
 222
 223                 side = i&1;
 224
 225                 box_clipnodes[i].children[side] = CONTENTS_EMPTY;
 226                 if (i != 5)
 227                         box_clipnodes[i].children[side^1] = i + 1;
 228                 else
 229                         box_clipnodes[i].children[side^1] = CONTENTS_SOLID;
 230
 231                 box_planes[i].type = i>>1;
 232                 box_planes[i].normal[i>>1] = 1;
 233         }
 234 }
 235
 236 void Collision_ClipTrace_Box(trace_t *trace, const vec3_t cmins, const vec3_t cmaxs, const vec3_t start, const vec3_t mins, const vec3_t maxs, const vec3_t end, int hitsupercontentsmask, int boxsupercontents)
 237 {
 238         RecursiveHullCheckTraceInfo_t rhc;
 239         // fill in a default trace
 240         memset(&rhc, 0, sizeof(rhc));
 241         memset(trace, 0, sizeof(trace_t));
 242         //To keep everything totally uniform, bounding boxes are turned into small
 243         //BSP trees instead of being compared directly.
 244         // create a temp hull from bounding box sizes
 245         box_planes[0].dist = cmaxs[0] - mins[0];
 246         box_planes[1].dist = cmins[0] - maxs[0];
 247         box_planes[2].dist = cmaxs[1] - mins[1];
 248         box_planes[3].dist = cmins[1] - maxs[1];
 249         box_planes[4].dist = cmaxs[2] - mins[2];
 250         box_planes[5].dist = cmins[2] - maxs[2];
 251         // trace a line through the generated clipping hull
 252         rhc.boxsupercontents = boxsupercontents;
 253         rhc.hull = &box_hull;
 254         rhc.trace = trace;
 255         rhc.trace->hitsupercontentsmask = hitsupercontentsmask;
 256         rhc.trace->fraction = 1;
 257         rhc.trace->allsolid = true;
 258         VectorCopy(start, rhc.start);
 259         VectorCopy(end, rhc.end);
 260         VectorSubtract(rhc.end, rhc.start, rhc.dist);
 261         RecursiveHullCheck(&rhc, rhc.hull->firstclipnode, 0, 1, rhc.start, rhc.end);
 262 }
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278 void Collision_PrintBrushAsQHull(colbrushf_t *brush, const char *name)
 279 {
 280         int i;
 281         Con_Printf("3 %s\n%i\n", name, brush->numpoints);
 282         for (i = 0;i < brush->numpoints;i++)
 283                 Con_Printf("%g %g %g\n", brush->points[i].v[0], brush->points[i].v[1], brush->points[i].v[2]);
 284         // FIXME: optimize!
 285         Con_Printf("4\n%i\n", brush->numplanes);
 286         for (i = 0;i < brush->numplanes;i++)
 287                 Con_Printf("%g %g %g %g\n", brush->planes[i].normal[0], brush->planes[i].normal[1], brush->planes[i].normal[2], brush->planes[i].dist);
 288 }
 289
 290 void Collision_ValidateBrush(colbrushf_t *brush)
 291 {
 292         int j, k;
 293         if (!brush->numpoints)
 294         {
 295                 Con_Printf("Collision_ValidateBrush: brush with no points!\n");
 296                 Collision_PrintBrushAsQHull(brush, "unnamed");
 297                 return;
 298         }
 299         // it's ok for a brush to have one point and no planes...
 300         if (brush->numplanes == 0 && brush->numpoints != 1)
 301         {
 302                 Con_Printf("Collision_ValidateBrush: brush with no planes and more than one point!\n");
 303                 Collision_PrintBrushAsQHull(brush, "unnamed");
 304                 return;
 305         }
 306         for (k = 0;k < brush->numplanes;k++)
 307         {
 308                 for (j = 0;j < brush->numpoints;j++)
 309                 {
 310                         if (DotProduct(brush->points[j].v, brush->planes[k].normal) - brush->planes[k].dist > (1.0f / 8.0f))
 311                         {
 312                                 Con_Printf("Collision_NewBrushFromPlanes: point #%i (%f %f %f) infront of plane #%i (%f %f %f %f)\n", j, brush->points[j].v[0], brush->points[j].v[1], brush->points[j].v[2], k, brush->planes[k].normal[0], brush->planes[k].normal[1], brush->planes[k].normal[2], brush->planes[k].dist);
 313                                 Collision_PrintBrushAsQHull(brush, "unnamed");
 314                                 return;
 315                         }
 316                 }
 317         }
 318 }
 319
 320
 321 colbrushf_t *Collision_NewBrushFromPlanes(mempool_t *mempool, int numoriginalplanes, const mplane_t *originalplanes, int supercontents)
 322 {
 323         int j, k, m;
 324         int numpoints, maxpoints, numplanes, maxplanes, numelements, maxelements, numtriangles, numpolypoints, maxpolypoints;
 325         winding_t *w;
 326         colbrushf_t *brush;
 327         colpointf_t pointsbuf[256];
 328         colplanef_t planesbuf[256];
 329         int elementsbuf[1024];
 330         int polypointbuf[256];
 331         // construct a collision brush (points, planes, and renderable mesh) from
 332         // a set of planes, this also optimizes out any unnecessary planes (ones
 333         // whose polygon is clipped away by the other planes)
 334         numpoints = 0;maxpoints = 256;
 335         numplanes = 0;maxplanes = 256;
 336         numelements = 0;maxelements = 1024;
 337         numtriangles = 0;
 338         maxpolypoints = 256;
 339         for (j = 0;j < numoriginalplanes;j++)
 340         {
 341                 // add the plane uniquely (no duplicates)
 342                 for (k = 0;k < numplanes;k++)
 343                         if (VectorCompare(planesbuf[k].normal, originalplanes[j].normal) && planesbuf[k].dist == originalplanes[j].dist)
 344                                 break;
 345                 // if the plane is a duplicate, skip it
 346                 if (k < numplanes)
 347                         continue;
 348                 // check if there are too many and skip the brush
 349                 if (numplanes >= 256)
 350                 {
 351                         Con_Printf("Mod_Q3BSP_LoadBrushes: failed to build collision brush: too many planes for buffer\n");
 352                         Winding_Free(w);
 353                         return NULL;
 354                 }
 355
 356                 // create a large polygon from the plane
 357                 w = Winding_NewFromPlane(originalplanes[j].normal[0], originalplanes[j].normal[1], originalplanes[j].normal[2], originalplanes[j].dist);
 358                 // clip it by all other planes
 359                 for (k = 0;k < numoriginalplanes && w;k++)
 360                 {
 361                         if (k != j)
 362                         {
 363                                 // we want to keep the inside of the brush plane so we flip
 364                                 // the cutting plane
 365                                 w = Winding_Clip(w, -originalplanes[k].normal[0], -originalplanes[k].normal[1], -originalplanes[k].normal[2], -originalplanes[k].dist, true);
 366                         }
 367                 }
 368                 // if nothing is left, skip it
 369                 if (!w)
 370                         continue;
 371
 372                 // copy off the number of points for later when the winding is freed
 373                 numpolypoints = w->numpoints;
 374
 375                 // check if there are too many polygon vertices for buffer
 376                 if (numpolypoints > maxpolypoints)
 377                 {
 378                         Con_Printf("Collision_NewBrushFromPlanes: failed to build collision brush: too many points for buffer\n");
 379                         return NULL;
 380                 }
 381
 382                 // check if there are too many triangle elements for buffer
 383                 if (numelements + (w->numpoints - 2) * 3 > maxelements)
 384                 {
 385                         Con_Printf("Collision_NewBrushFromPlanes: failed to build collision brush: too many triangle elements for buffer\n");
 386                         return NULL;
 387                 }
 388
 389                 for (k = 0;k < w->numpoints;k++)
 390                 {
 391                         // check if there is already a matching point (no duplicates)
 392                         for (m = 0;m < numpoints;m++)
 393                                 if (VectorDistance2(w->points[k], pointsbuf[m].v) < DIST_EPSILON)
 394                                         break;
 395
 396                         // if there is no match, add a new one
 397                         if (m == numpoints)
 398                         {
 399                                 // check if there are too many and skip the brush
 400                                 if (numpoints >= 256)
 401                                 {
 402                                         Con_Printf("Collision_NewBrushFromPlanes: failed to build collision brush: too many points for buffer\n");
 403                                         Winding_Free(w);
 404                                         return NULL;
 405                                 }
 406                                 // add the new one
 407                                 VectorCopy(w->points[k], pointsbuf[numpoints].v);
 408                                 numpoints++;
 409                         }
 410
 411                         // store the index into a buffer
 412                         polypointbuf[k] = m;
 413                 }
 414                 Winding_Free(w);
 415                 w = NULL;
 416
 417                 // add the triangles for the polygon
 418                 // (this particular code makes a triangle fan)
 419                 for (k = 0;k < numpolypoints - 2;k++)
 420                 {
 421                         numtriangles++;
 422                         elementsbuf[numelements++] = polypointbuf[0];
 423                         elementsbuf[numelements++] = polypointbuf[k + 1];
 424                         elementsbuf[numelements++] = polypointbuf[k + 2];
 425                 }
 426
 427                 // add the new plane
 428                 VectorCopy(originalplanes[j].normal, planesbuf[numplanes].normal);
 429                 planesbuf[numplanes].dist = originalplanes[j].dist;
 430                 numplanes++;
 431         }
 432
 433         // if nothing is left, there's nothing to allocate
 434         if (numtriangles < 4 || numplanes < 4 || numpoints < 4)
 435                 return NULL;
 436
 437         // allocate the brush and copy to it
 438         brush = Collision_AllocBrushFloat(mempool, numpoints, numplanes, numtriangles, supercontents);
 439         memcpy(brush->points, pointsbuf, numpoints * sizeof(colpointf_t));
 440         memcpy(brush->planes, planesbuf, numplanes * sizeof(colplanef_t));
 441         memcpy(brush->elements, elementsbuf, numtriangles * sizeof(int[3]));
 442         Collision_ValidateBrush(brush);
 443         return brush;
 444 }
 445
 446
 447
 448 colbrushf_t *Collision_AllocBrushFloat(mempool_t *mempool, int numpoints, int numplanes, int numtriangles, int supercontents)
 449 {
 450         colbrushf_t *brush;
 451         brush = Mem_Alloc(mempool, sizeof(colbrushf_t) + sizeof(colpointf_t) * numpoints + sizeof(colplanef_t) * numplanes + sizeof(int[3]) * numtriangles);
 452         brush->supercontents = supercontents;
 453         brush->numplanes = numplanes;
 454         brush->numpoints = numpoints;
 455         brush->numtriangles = numtriangles;
 456         brush->planes = (void *)(brush + 1);
 457         brush->points = (void *)(brush->planes + brush->numplanes);
 458         brush->elements = (void *)(brush->points + brush->numpoints);
 459         return brush;
 460 }
 461
 462 void Collision_CalcPlanesForPolygonBrushFloat(colbrushf_t *brush)
 463 {
 464         int i;
 465         float edge0[3], edge1[3], normal[3], dist, bestdist;
 466         colpointf_t *p, *p2;
 467
 468         // choose best surface normal for polygon's plane
 469         bestdist = 0;
 470         for (i = 0, p = brush->points + 1;i < brush->numpoints - 2;i++, p++)
 471         {
 472                 VectorSubtract(p[-1].v, p[0].v, edge0);
 473                 VectorSubtract(p[1].v, p[0].v, edge1);
 474                 CrossProduct(edge0, edge1, normal);
 475                 dist = DotProduct(normal, normal);
 476                 if (i == 0 || bestdist < dist)
 477                 {
 478                         bestdist = dist;
 479                         VectorCopy(normal, brush->planes->normal);
 480                 }
 481         }
 482
 483         VectorNormalize(brush->planes->normal);
 484         brush->planes->dist = DotProduct(brush->points->v, brush->planes->normal);
 485
 486         // negate plane to create other side
 487         VectorNegate(brush->planes[0].normal, brush->planes[1].normal);
 488         brush->planes[1].dist = -brush->planes[0].dist;
 489         for (i = 0, p = brush->points + (brush->numpoints - 1), p2 = brush->points;i < brush->numpoints;i++, p = p2, p2++)
 490         {
 491                 VectorSubtract(p->v, p2->v, edge0);
 492                 CrossProduct(edge0, brush->planes->normal, brush->planes[i + 2].normal);
 493                 VectorNormalize(brush->planes[i + 2].normal);
 494                 brush->planes[i + 2].dist = DotProduct(p->v, brush->planes[i + 2].normal);
 495         }
 496
 497 #if 1
 498         // validity check - will be disabled later
 499         for (i = 0;i < brush->numplanes;i++)
 500         {
 501                 int j;
 502                 for (j = 0, p = brush->points;j < brush->numpoints;j++, p++)
 503                         if (DotProduct(p->v, brush->planes[i].normal) > brush->planes[i].dist + (1.0 / 32.0))
 504                                 Con_Printf("Error in brush plane generation, plane %i\n", i);
 505         }
 506 #endif
 507 }
 508
 509 colbrushf_t *Collision_AllocBrushFromPermanentPolygonFloat(mempool_t *mempool, int numpoints, float *points, int supercontents)
 510 {
 511         colbrushf_t *brush;
 512         brush = Mem_Alloc(mempool, sizeof(colbrushf_t) + sizeof(colplanef_t) * (numpoints + 2));
 513         brush->supercontents = supercontents;
 514         brush->numpoints = numpoints;
 515         brush->numplanes = numpoints + 2;
 516         brush->planes = (void *)(brush + 1);
 517         brush->points = (colpointf_t *)points;
 518         Host_Error("Collision_AllocBrushFromPermanentPolygonFloat: FIXME: this code needs to be updated to generate a mesh...\n");
 519         return brush;
 520 }
 521
 522 float nearestplanedist_float(const float *normal, const colpointf_t *points, int numpoints)
 523 {
 524         float dist, bestdist;
 525         bestdist = DotProduct(points->v, normal);
 526         points++;
 527         while(--numpoints)
 528         {
 529                 dist = DotProduct(points->v, normal);
 530                 bestdist = min(bestdist, dist);
 531                 points++;
 532         }
 533         return bestdist;
 534 }
 535
 536 float furthestplanedist_float(const float *normal, const colpointf_t *points, int numpoints)
 537 {
 538         float dist, bestdist;
 539         bestdist = DotProduct(points->v, normal);
 540         points++;
 541         while(--numpoints)
 542         {
 543                 dist = DotProduct(points->v, normal);
 544                 bestdist = max(bestdist, dist);
 545                 points++;
 546         }
 547         return bestdist;
 548 }
 549
 550 #define COLLISIONEPSILON (1.0f / 32.0f)
 551 #define COLLISIONEPSILON2 0//(1.0f / 32.0f)
 552
 553 // NOTE: start and end of each brush pair must have same numplanes/numpoints
 554 void Collision_TraceBrushBrushFloat(trace_t *trace, const colbrushf_t *thisbrush_start, const colbrushf_t *thisbrush_end, const colbrushf_t *thatbrush_start, const colbrushf_t *thatbrush_end)
 555 {
 556         int nplane, nplane2, fstartsolid, fendsolid, brushsolid;
 557         float enterfrac, leavefrac, d1, d2, f, newimpactnormal[3];
 558         const colplanef_t *startplane, *endplane;
 559
 560         enterfrac = -1;
 561         leavefrac = 1;
 562         fstartsolid = true;
 563         fendsolid = true;
 564
 565         for (nplane = 0;nplane < thatbrush_start->numplanes + thisbrush_start->numplanes;nplane++)
 566         {
 567                 nplane2 = nplane;
 568                 if (nplane2 >= thatbrush_start->numplanes)
 569                 {
 570                         nplane2 -= thatbrush_start->numplanes;
 571                         startplane = thisbrush_start->planes + nplane2;
 572                         endplane = thisbrush_end->planes + nplane2;
 573                 }
 574                 else
 575                 {
 576                         startplane = thatbrush_start->planes + nplane2;
 577                         endplane = thatbrush_end->planes + nplane2;
 578                 }
 579                 d1 = nearestplanedist_float(startplane->normal, thisbrush_start->points, thisbrush_start->numpoints) - furthestplanedist_float(startplane->normal, thatbrush_start->points, thatbrush_start->numpoints);
 580                 d2 = nearestplanedist_float(endplane->normal, thisbrush_end->points, thisbrush_end->numpoints) - furthestplanedist_float(endplane->normal, thatbrush_end->points, thatbrush_end->numpoints) - COLLISIONEPSILON2;
 581                 //Con_Printf("%c%i: d1 = %f, d2 = %f, d1 / (d1 - d2) = %f\n", nplane2 != nplane ? 'b' : 'a', nplane2, d1, d2, d1 / (d1 - d2));
 582
 583                 f = d1 - d2;
 584                 if (f >= 0)
 585                 {
 586                         // moving into brush
 587                         if (d2 > 0)
 588                                 return;
 589                         if (d1 < 0)
 590                                 continue;
 591                         // enter
 592                         fstartsolid = false;
 593                         f = (d1 - COLLISIONEPSILON) / f;
 594                         f = bound(0, f, 1);
 595                         if (enterfrac < f)
 596                         {
 597                                 enterfrac = f;
 598                                 VectorBlend(startplane->normal, endplane->normal, enterfrac, newimpactnormal);
 599                         }
 600                 }
 601                 else if (f < 0)
 602                 {
 603                         // moving out of brush
 604                         if (d1 > 0)
 605                                 return;
 606                         if (d2 < 0)
 607                                 continue;
 608                         // leave
 609                         fendsolid = false;
 610                         f = (d1 + COLLISIONEPSILON) / f;
 611                         f = bound(0, f, 1);
 612                         if (leavefrac > f)
 613                                 leavefrac = f;
 614                 }
 615         }
 616
 617         brushsolid = trace->hitsupercontentsmask & thatbrush_start->supercontents;
 618         if (fstartsolid)
 619         {
 620                 trace->startsupercontents |= thatbrush_start->supercontents;
 621                 if (brushsolid)
 622                 {
 623                         trace->startsolid = true;
 624                         if (fendsolid)
 625                                 trace->allsolid = true;
 626                 }
 627         }
 628
 629         // LordHavoc: we need an epsilon nudge here because for a point trace the
 630         // penetrating line segment is normally zero length if this brush was
 631         // generated from a polygon (infinitely thin), and could even be slightly
 632         // positive or negative due to rounding errors in that case.
 633         if (brushsolid && enterfrac > -1 && enterfrac < trace->fraction && enterfrac - (1.0f / 1024.0f) <= leavefrac)
 634         {
 635                 trace->fraction = bound(0, enterfrac, 1);
 636                 VectorCopy(newimpactnormal, trace->plane.normal);
 637         }
 638 }
 639
 640 static colplanef_t polyf_planes[256 + 2];
 641 static colbrushf_t polyf_brush;
 642
 643 void Collision_TraceBrushPolygonFloat(trace_t *trace, const colbrushf_t *thisbrush_start, const colbrushf_t *thisbrush_end, int numpoints, const float *points)
 644 {
 645         if (numpoints > 256)
 646         {
 647                 Con_Printf("Polygon with more than 256 points not supported yet (fixme!)\n");
 648                 return;
 649         }
 650         polyf_brush.numpoints = numpoints;
 651         polyf_brush.numplanes = numpoints + 2;
 652         polyf_brush.points = (colpointf_t *)points;
 653         polyf_brush.planes = polyf_planes;
 654         Collision_CalcPlanesForPolygonBrushFloat(&polyf_brush);
 655         //Collision_PrintBrushAsQHull(&polyf_brush, "polyf_brush");
 656         Collision_TraceBrushBrushFloat(trace, thisbrush_start, thisbrush_end, &polyf_brush, &polyf_brush);
 657 }
 658
 659 static colpointf_t polyf_pointsstart[256], polyf_pointsend[256];
 660 static colplanef_t polyf_planesstart[256 + 2], polyf_planesend[256 + 2];
 661 static colbrushf_t polyf_brushstart, polyf_brushend;
 662
 663 void Collision_TraceBrushPolygonTransformFloat(trace_t *trace, const colbrushf_t *thisbrush_start, const colbrushf_t *thisbrush_end, int numpoints, const float *points, const matrix4x4_t *polygonmatrixstart, const matrix4x4_t *polygonmatrixend)
 664 {
 665         int i;
 666         if (numpoints > 256)
 667         {
 668                 Con_Printf("Polygon with more than 256 points not supported yet (fixme!)\n");
 669                 return;
 670         }
 671         polyf_brushstart.numpoints = numpoints;
 672         polyf_brushstart.numplanes = numpoints + 2;
 673         polyf_brushstart.points = polyf_pointsstart;//(colpointf_t *)points;
 674         polyf_brushstart.planes = polyf_planesstart;
 675         for (i = 0;i < numpoints;i++)
 676                 Matrix4x4_Transform(polygonmatrixstart, points + i * 3, polyf_brushstart.points[i].v);
 677         polyf_brushend.numpoints = numpoints;
 678         polyf_brushend.numplanes = numpoints + 2;
 679         polyf_brushend.points = polyf_pointsend;//(colpointf_t *)points;
 680         polyf_brushend.planes = polyf_planesend;
 681         for (i = 0;i < numpoints;i++)
 682                 Matrix4x4_Transform(polygonmatrixend, points + i * 3, polyf_brushend.points[i].v);
 683         Collision_CalcPlanesForPolygonBrushFloat(&polyf_brushstart);
 684         Collision_CalcPlanesForPolygonBrushFloat(&polyf_brushend);
 685
 686         //Collision_PrintBrushAsQHull(&polyf_brushstart, "polyf_brushstart");
 687         //Collision_PrintBrushAsQHull(&polyf_brushend, "polyf_brushend");
 688
 689         Collision_TraceBrushBrushFloat(trace, thisbrush_start, thisbrush_end, &polyf_brushstart, &polyf_brushend);
 690 }
 691
 692
 693
 694 #define MAX_BRUSHFORBOX 16
 695 static int brushforbox_index = 0;
 696 static colpointf_t brushforbox_point[MAX_BRUSHFORBOX*8];
 697 static colplanef_t brushforbox_plane[MAX_BRUSHFORBOX*6];
 698 static colbrushf_t brushforbox_brush[MAX_BRUSHFORBOX];
 699
 700 void Collision_InitBrushForBox(void)
 701 {
 702         int i;
 703         for (i = 0;i < MAX_BRUSHFORBOX;i++)
 704         {
 705                 brushforbox_brush[i].supercontents = SUPERCONTENTS_SOLID;
 706                 brushforbox_brush[i].numpoints = 8;
 707                 brushforbox_brush[i].numplanes = 6;
 708                 brushforbox_brush[i].points = brushforbox_point + i * 8;
 709                 brushforbox_brush[i].planes = brushforbox_plane + i * 6;
 710         }
 711 }
 712
 713 colbrushf_t *Collision_BrushForBox(const matrix4x4_t *matrix, const vec3_t mins, const vec3_t maxs)
 714 {
 715         int i;
 716         vec3_t v;
 717         colbrushf_t *brush;
 718         if (brushforbox_brush[0].numpoints == 0)
 719                 Collision_InitBrushForBox();
 720         brush = brushforbox_brush + ((brushforbox_index++) % MAX_BRUSHFORBOX);
 721         // FIXME: optimize
 722         for (i = 0;i < 8;i++)
 723         {
 724                 v[0] = i & 1 ? maxs[0] : mins[0];
 725                 v[1] = i & 2 ? maxs[1] : mins[1];
 726                 v[2] = i & 4 ? maxs[2] : mins[2];
 727                 Matrix4x4_Transform(matrix, v, brush->points[i].v);
 728         }
 729         // FIXME: optimize!
 730         for (i = 0;i < 6;i++)
 731         {
 732                 VectorClear(v);
 733                 v[i >> 1] = i & 1 ? 1 : -1;
 734                 Matrix4x4_Transform3x3(matrix, v, brush->planes[i].normal);
 735                 VectorNormalize(brush->planes[i].normal);
 736                 brush->planes[i].dist = furthestplanedist_float(brush->planes[i].normal, brush->points, brush->numpoints);
 737         }
 738         Collision_ValidateBrush(brush);
 739         return brush;
 740 }
 741
 742 void Collision_ClipTrace_BrushBox(trace_t *trace, const vec3_t cmins, const vec3_t cmaxs, const vec3_t start, const vec3_t mins, const vec3_t maxs, const vec3_t end, int hitsupercontentsmask)
 743 {
 744         colbrushf_t *boxbrush, *thisbrush_start, *thisbrush_end;
 745         matrix4x4_t identitymatrix;
 746         vec3_t startmins, startmaxs, endmins, endmaxs;
 747
 748         // create brushes for the collision
 749         VectorAdd(start, mins, startmins);
 750         VectorAdd(start, maxs, startmaxs);
 751         VectorAdd(end, mins, endmins);
 752         VectorAdd(end, maxs, endmaxs);
 753         Matrix4x4_CreateIdentity(&identitymatrix);
 754         boxbrush = Collision_BrushForBox(&identitymatrix, cmins, cmaxs);
 755         thisbrush_start = Collision_BrushForBox(&identitymatrix, startmins, startmaxs);
 756         thisbrush_end = Collision_BrushForBox(&identitymatrix, endmins, endmaxs);
 757
 758         memset(trace, 0, sizeof(trace_t));
 759         trace->hitsupercontentsmask = hitsupercontentsmask;
 760         trace->fraction = 1;
 761         trace->allsolid = true;
 762         Collision_TraceBrushBrushFloat(trace, thisbrush_start, thisbrush_end, boxbrush, boxbrush);
 763 }
 764
 765 // LordHavoc: currently unused and not yet tested
 766 // note: this can be used for tracing a moving sphere vs a stationary sphere,
 767 // by simply adding the moving sphere's radius to the sphereradius parameter,
 768 // all the results are correct (impactpoint, impactnormal, and fraction)
 769 float Collision_ClipTrace_Line_Sphere(double *linestart, double *lineend, double *sphereorigin, double sphereradius, double *impactpoint, double *impactnormal)
 770 {
 771         double dir[3], scale, v[3], deviationdist, impactdist, linelength;
 772         // make sure the impactpoint and impactnormal are valid even if there is
 773         // no collision
 774         impactpoint[0] = lineend[0];
 775         impactpoint[1] = lineend[1];
 776         impactpoint[2] = lineend[2];
 777         impactnormal[0] = 0;
 778         impactnormal[1] = 0;
 779         impactnormal[2] = 0;
 780         // calculate line direction
 781         dir[0] = lineend[0] - linestart[0];
 782         dir[1] = lineend[1] - linestart[1];
 783         dir[2] = lineend[2] - linestart[2];
 784         // normalize direction
 785         linelength = sqrt(dir[0] * dir[0] + dir[1] * dir[1] + dir[2] * dir[2]);
 786         if (linelength)
 787         {
 788                 scale = 1.0 / linelength;
 789                 dir[0] *= scale;
 790                 dir[1] *= scale;
 791                 dir[2] *= scale;
 792         }
 793         // this dotproduct calculates the distance along the line at which the
 794         // sphere origin is (nearest point to the sphere origin on the line)
 795         impactdist = dir[0] * (sphereorigin[0] - linestart[0]) + dir[1] * (sphereorigin[1] - linestart[1]) + dir[2] * (sphereorigin[2] - linestart[2]);
 796         // calculate point on line at that distance, and subtract the
 797         // sphereorigin from it, so we have a vector to measure for the distance
 798         // of the line from the sphereorigin (deviation, how off-center it is)
 799         v[0] = linestart[0] + impactdist * dir[0] - sphereorigin[0];
 800         v[1] = linestart[1] + impactdist * dir[1] - sphereorigin[1];
 801         v[2] = linestart[2] + impactdist * dir[2] - sphereorigin[2];
 802         deviationdist = v[0] * v[0] + v[1] * v[1] + v[2] * v[2];
 803         // if outside the radius, it's a miss for sure
 804         // (we do this comparison using squared radius to avoid a sqrt)
 805         if (deviationdist > sphereradius*sphereradius)
 806                 return 1; // miss (off to the side)
 807         // nudge back to find the correct impact distance
 808         impactdist += (sqrt(deviationdist) - sphereradius);
 809         if (impactdist >= linelength)
 810                 return 1; // miss (not close enough)
 811         if (impactdist < 0)
 812                 return 1; // miss (linestart is past or inside sphere)
 813         // calculate new impactpoint
 814         impactpoint[0] = linestart[0] + impactdist * dir[0];
 815         impactpoint[1] = linestart[1] + impactdist * dir[1];
 816         impactpoint[2] = linestart[2] + impactdist * dir[2];
 817         // calculate impactnormal (surface normal at point of impact)
 818         impactnormal[0] = impactpoint[0] - sphereorigin[0];
 819         impactnormal[1] = impactpoint[1] - sphereorigin[1];
 820         impactnormal[2] = impactpoint[2] - sphereorigin[2];
 821         // normalize impactnormal
 822         scale = impactnormal[0] * impactnormal[0] + impactnormal[1] * impactnormal[1] + impactnormal[2] * impactnormal[2];
 823         if (scale)
 824         {
 825                 scale = 1.0 / sqrt(scale);
 826                 impactnormal[0] *= scale;
 827                 impactnormal[1] *= scale;
 828                 impactnormal[2] *= scale;
 829         }
 830         // return fraction of movement distance
 831         return impactdist / linelength;
 832 }
 833