portals.c

   1
   2 #include "quakedef.h"
   3
   4 #define MAXRECURSIVEPORTALPLANES 1024
   5 #define MAXRECURSIVEPORTALS 256
   6
   7 static tinyplane_t portalplanes[MAXRECURSIVEPORTALPLANES];
   8 static int portalplanecount;
   9 static int ranoutofportalplanes;
  10 static int ranoutofportals;
  11 static float portaltemppoints[2][256][3];
  12 static float portaltemppoints2[256][3];
  13 static int portal_markid = 0;
  14 static float boxpoints[4*3];
  15
  16 int Portal_ClipPolygonToPlane(float *in, float *out, int inpoints, int maxoutpoints, tinyplane_t *p)
  17 {
  18         int i, outpoints, prevside, side;
  19         float *prevpoint, prevdist, dist, dot;
  20
  21         if (inpoints < 3)
  22                 return inpoints;
  23         // begin with the last point, then enter the loop with the first point as current
  24         prevpoint = in + 3 * (inpoints - 1);
  25         prevdist = DotProduct(prevpoint, p->normal) - p->dist;
  26         prevside = prevdist >= 0 ? SIDE_FRONT : SIDE_BACK;
  27         i = 0;
  28         outpoints = 0;
  29         goto begin;
  30         for (;i < inpoints;i++)
  31         {
  32                 prevpoint = in;
  33                 prevdist = dist;
  34                 prevside = side;
  35                 in += 3;
  36
  37 begin:
  38                 dist = DotProduct(in, p->normal) - p->dist;
  39                 side = dist >= 0 ? SIDE_FRONT : SIDE_BACK;
  40
  41                 if (prevside == SIDE_FRONT)
  42                 {
  43                         if (outpoints >= maxoutpoints)
  44                                 return -1;
  45                         VectorCopy(prevpoint, out);
  46                         out += 3;
  47                         outpoints++;
  48                         if (side == SIDE_FRONT)
  49                                 continue;
  50                 }
  51                 else if (side == SIDE_BACK)
  52                         continue;
  53
  54                 // generate a split point
  55                 if (outpoints >= maxoutpoints)
  56                         return -1;
  57                 dot = prevdist / (prevdist - dist);
  58                 out[0] = prevpoint[0] + dot * (in[0] - prevpoint[0]);
  59                 out[1] = prevpoint[1] + dot * (in[1] - prevpoint[1]);
  60                 out[2] = prevpoint[2] + dot * (in[2] - prevpoint[2]);
  61                 out += 3;
  62                 outpoints++;
  63         }
  64
  65         return outpoints;
  66 }
  67
  68
  69 int Portal_PortalThroughPortalPlanes(tinyplane_t *clipplanes, int clipnumplanes, float *targpoints, int targnumpoints, float *out, int maxpoints)
  70 {
  71         int numpoints, i;
  72         if (targnumpoints < 3)
  73                 return targnumpoints;
  74         if (maxpoints < 3)
  75                 return -1;
  76         numpoints = targnumpoints;
  77         memcpy(&portaltemppoints[0][0][0], targpoints, numpoints * 3 * sizeof(float));
  78         for (i = 0;i < clipnumplanes;i++)
  79         {
  80                 numpoints = Portal_ClipPolygonToPlane(&portaltemppoints[0][0][0], &portaltemppoints[1][0][0], numpoints, 256, clipplanes + i);
  81                 if (numpoints < 3)
  82                         return numpoints;
  83                 memcpy(&portaltemppoints[0][0][0], &portaltemppoints[1][0][0], numpoints * 3 * sizeof(float));
  84         }
  85         if (numpoints > maxpoints)
  86                 return -1;
  87         memcpy(out, &portaltemppoints[1][0][0], numpoints * 3 * sizeof(float));
  88         return numpoints;
  89 }
  90
  91 int Portal_RecursiveFlowSearch (mleaf_t *leaf, vec3_t eye, int firstclipplane, int numclipplanes)
  92 {
  93         mportal_t *p;
  94         int newpoints, i, prev;
  95         vec3_t center, v1, v2;
  96         tinyplane_t *newplanes;
  97
  98         if (leaf->portalmarkid == portal_markid)
  99                 return true;
 100
 101         // follow portals into other leafs
 102         for (p = leaf->portals;p;p = p->next)
 103         {
 104                 // only flow through portals facing away from the viewer
 105                 if (PlaneDiff(eye, (&p->plane)) < 0)
 106                 {
 107                         newpoints = Portal_PortalThroughPortalPlanes(&portalplanes[firstclipplane], numclipplanes, (float *) p->points, p->numpoints, &portaltemppoints2[0][0], 256);
 108                         if (newpoints < 3)
 109                                 continue;
 110                         else if (firstclipplane + numclipplanes + newpoints > MAXRECURSIVEPORTALPLANES)
 111                                 ranoutofportalplanes = true;
 112                         else
 113                         {
 114                                 // find the center by averaging
 115                                 VectorClear(center);
 116                                 for (i = 0;i < newpoints;i++)
 117                                         VectorAdd(center, portaltemppoints2[i], center);
 118                                 // ixtable is a 1.0f / N table
 119                                 VectorScale(center, ixtable[newpoints], center);
 120                                 // calculate the planes, and make sure the polygon can see it's own center
 121                                 newplanes = &portalplanes[firstclipplane + numclipplanes];
 122                                 for (prev = newpoints - 1, i = 0;i < newpoints;prev = i, i++)
 123                                 {
 124                                         VectorSubtract(eye, portaltemppoints2[i], v1);
 125                                         VectorSubtract(portaltemppoints2[prev], portaltemppoints2[i], v2);
 126                                         CrossProduct(v1, v2, newplanes[i].normal);
 127                                         VectorNormalizeFast(newplanes[i].normal);
 128                                         newplanes[i].dist = DotProduct(eye, newplanes[i].normal);
 129                                         if (DotProduct(newplanes[i].normal, center) <= newplanes[i].dist)
 130                                         {
 131                                                 // polygon can't see it's own center, discard and use parent portal
 132                                                 break;
 133                                         }
 134                                 }
 135                                 if (i == newpoints)
 136                                 {
 137                                         if (Portal_RecursiveFlowSearch(p->past, eye, firstclipplane + numclipplanes, newpoints))
 138                                                 return true;
 139                         }
 140                                 else
 141                                 {
 142                                         if (Portal_RecursiveFlowSearch(p->past, eye, firstclipplane, numclipplanes))
 143                                                 return true;
 144                         }
 145                         }
 146                 }
 147         }
 148
 149         return false;
 150 }
 151
 152 void Portal_PolygonRecursiveMarkLeafs(mnode_t *node, float *polypoints, int numpoints)
 153 {
 154         int i, front;
 155         float *p;
 156
 157 loc0:
 158         if (node->contents < 0)
 159         {
 160                 ((mleaf_t *)node)->portalmarkid = portal_markid;
 161                 return;
 162         }
 163
 164         front = 0;
 165         for (i = 0, p = polypoints;i < numpoints;i++, p += 3)
 166         {
 167                 if (DotProduct(p, node->plane->normal) > node->plane->dist)
 168                         front++;
 169         }
 170         if (front > 0)
 171         {
 172                 if (front == numpoints)
 173                 {
 174                         node = node->children[0];
 175                         goto loc0;
 176                 }
 177                 else
 178                         Portal_PolygonRecursiveMarkLeafs(node->children[0], polypoints, numpoints);
 179         }
 180         node = node->children[1];
 181         goto loc0;
 182 }
 183
 184 int Portal_CheckPolygon(model_t *model, vec3_t eye, float *polypoints, int numpoints)
 185 {
 186         int i, prev, returnvalue;
 187         mleaf_t *eyeleaf;
 188         vec3_t center, v1, v2;
 189
 190         // if there is no model, it can not block visibility
 191         if (model == NULL)
 192                 return true;
 193
 194         portal_markid++;
 195
 196         Mod_CheckLoaded(model);
 197         Portal_PolygonRecursiveMarkLeafs(model->nodes, polypoints, numpoints);
 198
 199         eyeleaf = Mod_PointInLeaf(eye, model);
 200
 201         // find the center by averaging
 202         VectorClear(center);
 203         for (i = 0;i < numpoints;i++)
 204                 VectorAdd(center, (&polypoints[i * 3]), center);
 205         // ixtable is a 1.0f / N table
 206         VectorScale(center, ixtable[numpoints], center);
 207
 208         // calculate the planes, and make sure the polygon can see it's own center
 209         for (prev = numpoints - 1, i = 0;i < numpoints;prev = i, i++)
 210         {
 211                 VectorSubtract(eye, (&polypoints[i * 3]), v1);
 212                 VectorSubtract((&polypoints[prev * 3]), (&polypoints[i * 3]), v2);
 213                 CrossProduct(v1, v2, portalplanes[i].normal);
 214                 VectorNormalizeFast(portalplanes[i].normal);
 215                 portalplanes[i].dist = DotProduct(eye, portalplanes[i].normal);
 216                 if (DotProduct(portalplanes[i].normal, center) <= portalplanes[i].dist)
 217                 {
 218                         // polygon can't see it's own center, discard
 219                         return false;
 220                 }
 221         }
 222
 223         portalplanecount = 0;
 224         ranoutofportalplanes = false;
 225         ranoutofportals = false;
 226
 227         returnvalue = Portal_RecursiveFlowSearch(eyeleaf, eye, 0, numpoints);
 228
 229         if (ranoutofportalplanes)
 230                 Con_Printf("Portal_RecursiveFlowSearch: ran out of %d plane stack when recursing through portals\n", MAXRECURSIVEPORTALPLANES);
 231         if (ranoutofportals)
 232                 Con_Printf("Portal_RecursiveFlowSearch: ran out of %d portal stack when recursing through portals\n", MAXRECURSIVEPORTALS);
 233
 234         return returnvalue;
 235 }
 236
 237 #define Portal_MinsBoxPolygon(axis, axisvalue, x1, y1, z1, x2, y2, z2, x3, y3, z3, x4, y4, z4) \
 238 {\
 239         if (eye[(axis)] < ((axisvalue) - 0.5f))\
 240         {\
 241                 boxpoints[ 0] = x1;boxpoints[ 1] = y1;boxpoints[ 2] = z1;\
 242                 boxpoints[ 3] = x2;boxpoints[ 4] = y2;boxpoints[ 5] = z2;\
 243                 boxpoints[ 6] = x3;boxpoints[ 7] = y3;boxpoints[ 8] = z3;\
 244                 boxpoints[ 9] = x4;boxpoints[10] = y4;boxpoints[11] = z4;\
 245                 if (Portal_CheckPolygon(model, eye, boxpoints, 4))\
 246                         return true;\
 247         }\
 248 }
 249
 250 #define Portal_MaxsBoxPolygon(axis, axisvalue, x1, y1, z1, x2, y2, z2, x3, y3, z3, x4, y4, z4) \
 251 {\
 252         if (eye[(axis)] > ((axisvalue) + 0.5f))\
 253         {\
 254                 boxpoints[ 0] = x1;boxpoints[ 1] = y1;boxpoints[ 2] = z1;\
 255                 boxpoints[ 3] = x2;boxpoints[ 4] = y2;boxpoints[ 5] = z2;\
 256                 boxpoints[ 6] = x3;boxpoints[ 7] = y3;boxpoints[ 8] = z3;\
 257                 boxpoints[ 9] = x4;boxpoints[10] = y4;boxpoints[11] = z4;\
 258                 if (Portal_CheckPolygon(model, eye, boxpoints, 4))\
 259                         return true;\
 260         }\
 261 }
 262
 263 int Portal_CheckBox(model_t *model, vec3_t eye, vec3_t a, vec3_t b)
 264 {
 265         if (eye[0] >= (a[0] - 1.0f) && eye[0] < (b[0] + 1.0f)
 266          && eye[1] >= (a[1] - 1.0f) && eye[1] < (b[1] + 1.0f)
 267          && eye[2] >= (a[2] - 1.0f) && eye[2] < (b[2] + 1.0f))
 268                 return true;
 269
 270         Portal_MinsBoxPolygon
 271         (
 272                 0, a[0],
 273                 a[0], a[1], a[2],
 274                 a[0], b[1], a[2],
 275                 a[0], b[1], b[2],
 276                 a[0], a[1], b[2]
 277         );
 278         Portal_MaxsBoxPolygon
 279         (
 280                 0, b[0],
 281                 b[0], b[1], a[2],
 282                 b[0], a[1], a[2],
 283                 b[0], a[1], b[2],
 284                 b[0], b[1], b[2]
 285         );
 286         Portal_MinsBoxPolygon
 287         (
 288                 1, a[1],
 289                 b[0], a[1], a[2],
 290                 a[0], a[1], a[2],
 291                 a[0], a[1], b[2],
 292                 b[0], a[1], b[2]
 293         );
 294         Portal_MaxsBoxPolygon
 295         (
 296                 1, b[1],
 297                 a[0], b[1], a[2],
 298                 b[0], b[1], a[2],
 299                 b[0], b[1], b[2],
 300                 a[0], b[1], b[2]
 301         );
 302         Portal_MinsBoxPolygon
 303         (
 304                 2, a[2],
 305                 a[0], a[1], a[2],
 306                 b[0], a[1], a[2],
 307                 b[0], b[1], a[2],
 308                 a[0], b[1], a[2]
 309         );
 310         Portal_MaxsBoxPolygon
 311         (
 312                 2, b[2],
 313                 b[0], a[1], b[2],
 314                 a[0], a[1], b[2],
 315                 a[0], b[1], b[2],
 316                 b[0], b[1], b[2]
 317         );
 318
 319         return false;
 320 }
 321