r_clip.c

   1
   2 #include "quakedef.h"
   3
   4 typedef struct clipsurf_s
   5 {
   6         struct clipsurf_s *next, *prev;
   7         int state;
   8         int visible;
   9         int solid;
  10         int removed;
  11         void (*callback)(void *nativedata, void *nativedata2);
  12         void *nativedata;
  13         void *nativedata2;
  14         float wstepx, wstepy, w00;
  15         // wcurrent is a cached copy of w00 + wstepy * y,
  16         // updated each time the surface is added to the stack,
  17         // for quicker comparisons.
  18         float wcurrent;
  19         // this is a linked list of all edges belonging to this surface,
  20         // used to remove them if this is a non-solid surface that is
  21         // marked visible (it can not hide anything, so it is useless)
  22 //      struct clipedge_s *edgechain;
  23 }
  24 clipsurf_t;
  25
  26 typedef struct clipedge_s
  27 {
  28         float x, realx, realxstep;
  29         struct clipedge_s *next, *prev, *nextremove;
  30         clipsurf_t *psurf;
  31         int leading;
  32         int pad;
  33 }
  34 clipedge_t;
  35
  36 clipsurf_t *pavailsurf, *clipsurfs, *clipsurfsend;
  37 clipedge_t *pavailedge, *clipedges, *clipedgesend, *newedges, **removeedges;
  38
  39 clipsurf_t surfstack;
  40 clipedge_t edgehead, edgetail;
  41 clipedge_t maxedge = {2000000000.0f};
  42
  43 cvar_t r_clipwidth = {0, "r_clipwidth", "800"};
  44 cvar_t r_clipheight = {0, "r_clipheight", "600"};
  45 cvar_t r_clipedges = {CVAR_SAVE, "r_clipedges", "32768"};
  46 cvar_t r_clipsurfaces = {CVAR_SAVE, "r_clipsurfaces", "8192"};
  47
  48 int clipwidth = 0, clipheight = 0;
  49 int maxclipsurfs = 0, maxclipedges = 0;
  50 int needededges, neededsurfs;
  51
  52 #if CLIPTEST
  53 typedef struct
  54 {
  55         float w; // inverse depth (1/z)
  56 }
  57 clippixel_t;
  58
  59 clippixel_t *clipbuffer;
  60 #endif
  61
  62 float r_clip_viewmatrix[3][3], r_clip_viewmulx, r_clip_viewmuly, r_clip_viewcenterx, r_clip_viewcentery;
  63 // REMOVELATER
  64 //float xscale, yscale, xscaleinv, yscaleinv;
  65 //float r_clip_nearclipdist, r_clip_nearclipdist2;
  66 tinyplane_t r_clip_viewplane[5];
  67
  68 void R_Clip_MakeViewMatrix(void)
  69 {
  70         float pixelaspect, screenaspect, horizontalfieldofview, verticalfieldofview;
  71         pixelaspect = (float) clipheight / (float) clipwidth * 320 / 240.0;
  72         horizontalfieldofview = 2.0 * tan (r_refdef.fov_x/360*M_PI);
  73         screenaspect = clipwidth * pixelaspect / clipheight;
  74         verticalfieldofview = horizontalfieldofview / screenaspect;
  75         r_clip_viewcenterx = clipwidth * 0.5 - 0.5;
  76         r_clip_viewcentery = clipheight * 0.5 - 0.5;
  77         r_clip_viewmulx = clipwidth / horizontalfieldofview;
  78         r_clip_viewmuly = r_clip_viewmulx * pixelaspect;
  79         // this constructs a transposed rotation matrix for the view (transposed matrices do the opposite of their normal behavior)
  80         VectorCopy (vright, r_clip_viewmatrix[0]);
  81         VectorNegate (vup, r_clip_viewmatrix[1]);
  82         VectorCopy (vpn, r_clip_viewmatrix[2]);
  83 //      r_clip_nearclipdist = DotProduct(r_origin, vpn) + 4.0f;
  84 //      r_clip_nearclipdist2 = r_clip_nearclipdist - 8.0f;
  85         VectorCopy (vpn, r_clip_viewplane[0].normal);
  86         r_clip_viewplane[0].dist = DotProduct(r_origin, vpn);
  87         memcpy(&r_clip_viewplane[1], &frustum[0], sizeof(tinyplane_t));
  88         memcpy(&r_clip_viewplane[2], &frustum[1], sizeof(tinyplane_t));
  89         memcpy(&r_clip_viewplane[3], &frustum[2], sizeof(tinyplane_t));
  90         memcpy(&r_clip_viewplane[4], &frustum[3], sizeof(tinyplane_t));
  91 // REMOVELATER
  92 //      maxscreenscaleinv = (1.0f / max(clipwidth, clipheight)) * horizontalfieldofview * 0.5f;
  93 //      xscale = clipwidth / horizontalfieldofview;
  94 //      xscaleinv = 1.0 / xscale;
  95 //      yscale = xscale * pixelaspect;
  96 //      yscaleinv = 1.0 / yscale;
  97 }
  98
  99 void R_Clip_StartFrame(void)
 100 {
 101         int i;
 102         int newwidth, newheight, newmaxedges, newmaxsurfs;
 103         newwidth = bound(80, (int) r_clipwidth.value, vid.width * 2);
 104         newheight = bound(60, (int) r_clipheight.value, vid.height * 2);
 105         newmaxedges = bound(128, (int) r_clipedges.value, 262144);
 106         newmaxsurfs = bound(32, (int) r_clipsurfaces.value, 65536);
 107         if (newwidth != clipwidth || newheight != clipheight || maxclipedges != newmaxedges || maxclipsurfs != newmaxsurfs)
 108         {
 109 #if CLIPTEST
 110                 if (clipbuffer)
 111                         qfree(clipbuffer);
 112 #endif
 113                 if (clipedges)
 114                         qfree(clipedges);
 115                 if (clipsurfs)
 116                         qfree(clipsurfs);
 117                 if (newedges)
 118                         qfree(newedges);
 119                 if (removeedges)
 120                         qfree(removeedges);
 121                 clipwidth = newwidth;
 122                 clipheight = newheight;
 123                 maxclipedges = newmaxedges;
 124                 maxclipsurfs = newmaxsurfs;
 125 #if CLIPTEST
 126                 clipbuffer = qmalloc(clipwidth * clipheight * sizeof(clippixel_t));
 127 #endif
 128                 clipedges = qmalloc(maxclipedges * sizeof(clipedge_t));
 129                 clipsurfs = qmalloc(maxclipsurfs * sizeof(clipsurf_t));
 130                 newedges = qmalloc(clipheight * sizeof(clipedge_t));
 131                 removeedges = qmalloc(clipheight * sizeof(clipedge_t *));
 132                 clipedgesend = clipedges + maxclipedges;
 133                 clipsurfsend = clipsurfs + maxclipsurfs;
 134         }
 135 #if CLIPTEST
 136         memset(clipbuffer, 0, clipwidth * clipheight * sizeof(clippixel_t));
 137 #endif
 138         pavailedge = clipedges;
 139         pavailsurf = clipsurfs;
 140         // Clear the lists of edges to add and remove on each scan line.
 141
 142         needededges = 0;
 143         neededsurfs = 0;
 144         for (i = 0;i < clipheight;i++)
 145         {
 146                 newedges[i].next = &maxedge;
 147                 removeedges[i] = NULL;
 148         }
 149
 150         R_Clip_MakeViewMatrix();
 151 }
 152
 153 void ScanEdges (void);
 154
 155 void R_Clip_EndFrame(void)
 156 {
 157         ScanEdges();
 158         if (maxclipedges < needededges)
 159         {
 160                 Con_Printf("R_Clip: ran out of edges, increasing limit from %d to %d\n", maxclipedges, needededges);
 161                 Cvar_SetValue("r_clipedges", needededges);
 162         }
 163         if (maxclipsurfs < neededsurfs)
 164         {
 165                 Con_Printf("R_Clip: ran out of surfaces, increasing limit from %d to %d\n", maxclipsurfs, neededsurfs);
 166                 Cvar_SetValue("r_clipsurfaces", neededsurfs);
 167         }
 168 }
 169
 170 void r_clip_start(void)
 171 {
 172 }
 173
 174 void r_clip_shutdown(void)
 175 {
 176 #if CLIPTEST
 177         if (clipbuffer)
 178                 qfree(clipbuffer);
 179         clipbuffer = NULL;
 180 #endif
 181         if (clipsurfs)
 182                 qfree(clipsurfs);
 183         clipsurfs = NULL;
 184         if (clipedges)
 185                 qfree(clipedges);
 186         clipedges = NULL;
 187         if (newedges)
 188                 qfree(newedges);
 189         newedges = NULL;
 190         if (removeedges)
 191                 qfree(removeedges);
 192         removeedges = NULL;
 193         clipwidth = -1;
 194         clipheight = -1;
 195 }
 196
 197 void r_clip_newmap(void)
 198 {
 199 }
 200
 201 void R_Clip_Init(void)
 202 {
 203         Cvar_RegisterVariable(&r_clipwidth);
 204         Cvar_RegisterVariable(&r_clipheight);
 205         Cvar_RegisterVariable(&r_clipedges);
 206         Cvar_RegisterVariable(&r_clipsurfaces);
 207         R_RegisterModule("R_Clip", r_clip_start, r_clip_shutdown, r_clip_newmap);
 208 }
 209
 210 int R_Clip_TriangleToPlane(vec3_t point1, vec3_t point2, vec3_t point3, tinyplane_t *p)
 211 {
 212         float y, number;
 213         vec3_t v1, v2;
 214         VectorSubtract(point1, point2, v1);
 215         VectorSubtract(point3, point2, v2);
 216         CrossProduct(v1, v2, p->normal);
 217         number = DotProduct(p->normal, p->normal);
 218         if (number >= 0.1f)
 219         {
 220                 *((long *)&y) = 0x5f3759df - ((* (long *) &number) >> 1);
 221                 y = y * (1.5f - (number * 0.5f * y * y));
 222                 VectorScale(p->normal, y, p->normal);
 223                 p->dist = DotProduct(point1, p->normal);
 224                 return true;
 225         }
 226         else
 227                 return false;
 228 }
 229
 230 /*
 231 int R_Clip_TriangleToDoublePlane(double *point1, double *point2, double *point3, tinydoubleplane_t *p)
 232 {
 233         double y, number;
 234         double v1[3], v2[3];
 235         VectorSubtract(point1, point2, v1);
 236         VectorSubtract(point3, point2, v2);
 237         CrossProduct(v1, v2, p->normal);
 238         number = DotProduct(p->normal, p->normal);
 239         if (number >= 0.1)
 240         {
 241                 y = 1.0 / sqrt(number);
 242                 VectorScale(p->normal, y, p->normal);
 243                 p->dist = DotProduct(point1, p->normal);
 244                 return true;
 245         }
 246         else
 247                 return false;
 248 }
 249 */
 250
 251 int R_Clip_ClipPolygonToPlane(float *in, float *out, int inpoints, int stride, tinyplane_t *plane)
 252 {
 253         int i, outpoints, prevside, side;
 254         float *prevpoint, prevdist, dist, dot;
 255
 256         // begin with the last point, then enter the loop with the first point as current
 257         prevpoint = (float *) ((byte *)in + stride * (inpoints - 1));
 258         prevdist = DotProduct(prevpoint, plane->normal) - plane->dist;
 259         prevside = prevdist >= 0 ? SIDE_FRONT : SIDE_BACK;
 260         i = 0;
 261         outpoints = 0;
 262         goto begin;
 263         for (;i < inpoints;i++)
 264         {
 265                 prevpoint = in;
 266                 prevdist = dist;
 267                 prevside = side;
 268                 (byte *)in += stride;
 269
 270 begin:
 271                 dist = DotProduct(in, plane->normal) - plane->dist;
 272                 side = dist >= 0 ? SIDE_FRONT : SIDE_BACK;
 273
 274                 if (prevside == SIDE_FRONT)
 275                 {
 276                         VectorCopy(prevpoint, out);
 277                         out += 3;
 278                         outpoints++;
 279                         if (side == SIDE_FRONT)
 280                                 continue;
 281                 }
 282                 else if (side == SIDE_BACK)
 283                         continue;
 284
 285                 // generate a split point
 286                 dot = prevdist / (prevdist - dist);
 287                 out[0] = prevpoint[0] + dot * (in[0] - prevpoint[0]);
 288                 out[1] = prevpoint[1] + dot * (in[1] - prevpoint[1]);
 289                 out[2] = prevpoint[2] + dot * (in[2] - prevpoint[2]);
 290                 out += 3;
 291                 outpoints++;
 292         }
 293
 294         return outpoints;
 295 }
 296
 297 float tempverts[256][3];
 298 float tempverts2[256][3];
 299 float screenverts[256][3];
 300
 301 // LordHavoc: this code is based primarily on the ddjzsort code
 302
 303 // Clips polygon to view frustum and nearclip, transforms polygon to viewspace, perspective projects polygon to screenspace,
 304 // and adds polygon's edges to the global edge table.
 305 void R_Clip_AddPolygon (vec_t *points, int numverts, int stride, int solid, void (*callback)(void *nativedata, void *nativedata2), void *nativedata, void *nativedata2, tinyplane_t *polyplane)
 306 {
 307         float deltax, deltay, vx, vy, vz, fx;
 308         int i, j, k, nextvert, temp, topy, bottomy, height, addededges;
 309         clipedge_t *pedge;
 310 //      tinydoubleplane_t plane;
 311         tinyplane_t localplane;
 312 //      tinyplane_t testplane;
 313         float distinv;
 314
 315 //      if (!solid)
 316 //              return;
 317
 318         if (polyplane == NULL)
 319         {
 320                 polyplane = &localplane;
 321                 // calculate the plane for the polygon
 322                 if (!R_Clip_TriangleToPlane((float *) points, (float *) ((byte *)points + stride), (float *) ((byte *)points + 2 * stride), polyplane))
 323                 {
 324                         for (i = 0;i < numverts;i++)
 325                                 for (j = i + 1;j < numverts;j++)
 326                                         for (k = j + 1;k < numverts;k++)
 327                                                 if (R_Clip_TriangleToPlane((float *) ((byte *)points + i * stride), (float *) ((byte *)points + j * stride), (float *) ((byte *)points + k * stride), polyplane))
 328                                                         goto valid1;
 329                         return; // gave up
 330                         valid1:;
 331                 }
 332
 333                 // caller hasn't checked if this polygon faces the view, so we have to check
 334                 if (DotProduct(r_origin, polyplane->normal) < (polyplane->dist + 0.5f))
 335                         return;
 336         }
 337 #if 0 // debugging (validates planes passed in)
 338         else
 339         {
 340                 // calculate the plane for the polygon
 341                 if (!R_Clip_TriangleToPlane((float *) points, (float *) ((byte *)points + stride), (float *) ((byte *)points + 2 * stride), &localplane))
 342                 {
 343                         for (i = 0;i < numverts;i++)
 344                                 for (j = i + 1;j < numverts;j++)
 345                                         for (k = j + 1;k < numverts;k++)
 346                                                 if (R_Clip_TriangleToPlane((float *) ((byte *)points + i * stride), (float *) ((byte *)points + j * stride), (float *) ((byte *)points + k * stride), &localplane))
 347                                                         goto valid4;
 348                         return; // gave up
 349                         valid4:;
 350                 }
 351
 352 //              if ((DotProduct(r_origin, polyplane->normal) < (polyplane->dist + 0.5f)) != (DotProduct(r_origin, localplane.normal) < (localplane.dist + 0.5f)))
 353                 if (DotProduct(polyplane->normal, localplane.normal) < 0.9f)
 354                 {
 355                         Con_Printf("*\n");
 356                         return;
 357                 }
 358         }
 359 #endif
 360
 361         // for adaptive limits
 362         needededges += numverts;
 363         neededsurfs++;
 364
 365         if (pavailsurf >= clipsurfsend)
 366                 return;
 367
 368         // clip to view frustum and nearclip
 369         if (numverts < 3) return;numverts = R_Clip_ClipPolygonToPlane(points      , tempverts2[0], numverts, stride, &r_clip_viewplane[0]);
 370         if (numverts < 3) return;numverts = R_Clip_ClipPolygonToPlane(tempverts2[0], tempverts[0], numverts, sizeof(float) * 3, &r_clip_viewplane[1]);
 371         if (numverts < 3) return;numverts = R_Clip_ClipPolygonToPlane(tempverts[0], tempverts2[0], numverts, sizeof(float) * 3, &r_clip_viewplane[2]);
 372         if (numverts < 3) return;numverts = R_Clip_ClipPolygonToPlane(tempverts2[0], tempverts[0], numverts, sizeof(float) * 3, &r_clip_viewplane[3]);
 373         if (numverts < 3) return;numverts = R_Clip_ClipPolygonToPlane(tempverts[0], tempverts2[0], numverts, sizeof(float) * 3, &r_clip_viewplane[4]);
 374         if (numverts < 3)
 375                 return;
 376         if (numverts > 256)
 377                 Sys_Error("R_Clip_AddPolygon: polygon exceeded 256 vertex buffer\n");
 378
 379         // it survived the clipping, transform to viewspace and project to screenspace
 380
 381         if (pavailedge + numverts > clipedgesend)
 382                 return;
 383
 384 #if 1
 385         for (i = 0;i < numverts;i++)
 386         {
 387                 vx = tempverts2[i][0] - r_origin[0];
 388                 vy = tempverts2[i][1] - r_origin[1];
 389                 vz = tempverts2[i][2] - r_origin[2];
 390                 screenverts[i][2] = 1.0f / (r_clip_viewmatrix[2][0] * vx + r_clip_viewmatrix[2][1] * vy + r_clip_viewmatrix[2][2] * vz);
 391                 screenverts[i][0] = (r_clip_viewmatrix[0][0] * vx + r_clip_viewmatrix[0][1] * vy + r_clip_viewmatrix[0][2] * vz) * r_clip_viewmulx * screenverts[i][2] + r_clip_viewcenterx;
 392                 screenverts[i][1] = (r_clip_viewmatrix[1][0] * vx + r_clip_viewmatrix[1][1] * vy + r_clip_viewmatrix[1][2] * vz) * r_clip_viewmuly * screenverts[i][2] + r_clip_viewcentery;
 393         }
 394
 395         /*
 396         if (polyplane != NULL)
 397         {
 398         */
 399         /*
 400                 distinv = 1.0f / (polyplane->dist - DotProduct(r_origin, polyplane->normal));
 401                 pavailsurf->wstepx = DotProduct(r_clip_viewmatrix[0], polyplane->normal) * xscaleinv * distinv;
 402                 pavailsurf->wstepy = DotProduct(r_clip_viewmatrix[1], polyplane->normal) * yscaleinv * distinv;
 403                 pavailsurf->w00 = DotProduct(r_clip_viewmatrix[2], polyplane->normal) * distinv - r_clip_viewcenterx * pavailsurf->wstepx - r_clip_viewcentery * pavailsurf->wstepy;
 404         */
 405         /*
 406         }
 407         else
 408         {
 409         */
 410                 // calculate the plane for the polygon
 411                 if (!R_Clip_TriangleToPlane(screenverts[0], screenverts[1], screenverts[2], &localplane))
 412                 {
 413                         for (i = 0;i < numverts;i++)
 414                                 for (j = i + 1;j < numverts;j++)
 415                                         for (k = j + 1;k < numverts;k++)
 416                                                 if (R_Clip_TriangleToPlane(screenverts[i], screenverts[j], screenverts[k], &localplane))
 417                                                         goto valid;
 418                         return; // gave up
 419                         valid:;
 420                 }
 421
 422                 // Set up the 1/z gradients from the polygon, calculating the
 423                 // base value at screen coordinate 0,0 so we can use screen
 424                 // coordinates directly when calculating 1/z from the gradients
 425                 distinv = 1.0f / localplane.normal[2];
 426                 pavailsurf->wstepx = -(localplane.normal[0] * distinv);
 427                 pavailsurf->wstepy = -(localplane.normal[1] * distinv);
 428                 pavailsurf->w00 = localplane.dist * distinv;
 429         /*
 430         }
 431         */
 432         // REMOVELATER
 433         /*
 434         prevdist = z1 * plane.normal[2] - plane.dist;
 435         dist = z2 * plane.normal[2] - plane.dist;
 436         d = prevdist / (prevdist - dist);
 437         zc = z1 + d * (z2 - z1);
 438
 439         prevdist = plane.normal[0] + z1 * plane.normal[2] - plane.dist;
 440         dist = plane.normal[0] + z2 * plane.normal[2] - plane.dist;
 441         d = prevdist / (prevdist - dist);
 442         zx = (z1 + d * (z2 - z1)) - zc;
 443
 444         prevdist = plane.normal[1] + z1 * plane.normal[2] - plane.dist;
 445         dist = plane.normal[1] + z2 * plane.normal[2] - plane.dist;
 446         d = prevdist / (prevdist - dist);
 447         zy = (z1 + d * (z2 - z1)) - zc;
 448         */
 449
 450         /*
 451         zc = (-plane.dist) / ((-plane.dist) - (plane.normal[2] - plane.dist));
 452         zx = ((plane.normal[0] - plane.dist) / ((plane.normal[0] - plane.dist) - (plane.normal[0] + plane.normal[2] - plane.dist))) - zc;
 453         zy = ((plane.normal[1] - plane.dist) / ((plane.normal[1] - plane.dist) - (plane.normal[1] + plane.normal[2] - plane.dist))) - zc;
 454         */
 455
 456 //      zc = (plane.dist / plane.normal[2]);
 457 //      zx = -(plane.normal[0] / plane.normal[2]);
 458 //      zy = -(plane.normal[1] / plane.normal[2]);
 459 //      zy = ((plane.normal[1] - plane.dist) / (-plane.normal[2])) + ((plane.dist) / (-plane.normal[2]));
 460 #else // REMOVELATER
 461         for (i = 0;i < numverts;i++)
 462         {
 463                 vx = tempverts2[i][0] - r_origin[0];
 464                 vy = tempverts2[i][1] - r_origin[1];
 465                 vz = tempverts2[i][2] - r_origin[2];
 466                 screenverts[i][0] = r_clip_viewmatrix[0][0] * vx + r_clip_viewmatrix[0][1] * vy + r_clip_viewmatrix[0][2] * vz;
 467                 screenverts[i][1] = r_clip_viewmatrix[1][0] * vx + r_clip_viewmatrix[1][1] * vy + r_clip_viewmatrix[1][2] * vz;
 468                 screenverts[i][2] = r_clip_viewmatrix[2][0] * vx + r_clip_viewmatrix[2][1] * vy + r_clip_viewmatrix[2][2] * vz;
 469         }
 470
 471         // REMOVELATER
 472         // calculate the plane for the polygon
 473         for (i = 0;i < numverts;i++)
 474                 for (j = i + 1;j < numverts;j++)
 475                         for (k = j + 1;k < numverts;k++)
 476                                 if (R_Clip_TriangleToDoublePlane(screenverts[i], screenverts[j], screenverts[k], &plane))
 477                                         goto valid2;
 478         return; // gave up
 479 valid2:;
 480
 481         distinv = 1.0f / plane.dist;
 482         pavailsurf->d_zistepx = plane.normal[0] * xscaleinv * distinv;
 483         pavailsurf->d_zistepy = -plane.normal[1] * yscaleinv * distinv;
 484         pavailsurf->d_ziorigin = plane.normal[2] * distinv - r_clip_viewcenterx * pavailsurf->wstepx - r_clip_viewcentery * pavailsurf->wstepy;
 485
 486         for (i = 0;i < numverts;i++)
 487         {
 488                 screenverts[i][2] = 1.0f / (screenverts[i][2]);
 489                 screenverts[i][0] = screenverts[i][0] * r_clip_viewmulx * screenverts[i][2] + r_clip_viewcenterx;
 490                 screenverts[i][1] = screenverts[i][1] * r_clip_viewmuly * screenverts[i][2] + r_clip_viewcentery;
 491                 // REMOVELATER
 492 //              if (screenverts[i][0] < -0.5)
 493 //                      screenverts[i][0] = -0.5;
 494 //              if (screenverts[i][0] > (clipwidth - 0.5))
 495 //                      screenverts[i][0] = clipwidth - 0.5;
 496 //              if (screenverts[i][1] < -0.5)
 497 //                      screenverts[i][1] = -0.5;
 498 //              if (screenverts[i][1] > (clipheight - 0.5))
 499 //                      screenverts[i][1] = clipheight - 0.5;
 500 //              if (screenverts[i][2] <= 0.0)
 501 //                      Con_Printf("R_Clip_AddPolygon: vertex z <= 0!\n");
 502         }
 503 #endif
 504
 505         addededges = false;
 506
 507         // Add each edge in turn
 508         for (i = 0;i < numverts;i++)
 509         {
 510                 nextvert = i + 1;
 511                 if (nextvert >= numverts)
 512                         nextvert = 0;
 513
 514                 topy = (int)ceil(screenverts[i][1]);
 515                 bottomy = (int)ceil(screenverts[nextvert][1]);
 516                 height = bottomy - topy;
 517                 if (height == 0)
 518                         continue;       // doesn't cross any scan lines
 519                 if (height < 0)
 520                 {
 521                         // Leading edge
 522                         temp = topy;
 523                         topy = bottomy;
 524                         bottomy = temp;
 525                         if (topy < 0)
 526                                 topy = 0;
 527                         if (bottomy > clipheight)
 528                                 bottomy = clipheight;
 529                         if (topy >= bottomy)
 530                                 continue;
 531
 532                         pavailedge->leading = 1;
 533
 534                         deltax = screenverts[i][0] - screenverts[nextvert][0];
 535                         deltay = screenverts[i][1] - screenverts[nextvert][1];
 536
 537                         pavailedge->realxstep = deltax / deltay;
 538                         pavailedge->realx = screenverts[nextvert][0] + ((float)topy - screenverts[nextvert][1]) * pavailedge->realxstep;
 539                 }
 540                 else
 541                 {
 542                         // Trailing edge
 543                         if (topy < 0)
 544                                 topy = 0;
 545                         if (bottomy > clipheight)
 546                                 bottomy = clipheight;
 547                         if (topy >= bottomy)
 548                                 continue;
 549
 550                         pavailedge->leading = 0;
 551
 552                         deltax = screenverts[nextvert][0] - screenverts[i][0];
 553                         deltay = screenverts[nextvert][1] - screenverts[i][1];
 554
 555                         pavailedge->realxstep = deltax / deltay;
 556                         pavailedge->realx = screenverts[i][0] + ((float)topy - screenverts[i][1]) * pavailedge->realxstep;
 557                 }
 558
 559                 // Put the edge on the list to be added on top scan
 560                 fx = pavailedge->x = bound(0.0f, pavailedge->realx, clipwidth - 0.5f);
 561                 pedge = &newedges[topy];
 562                 while (fx > pedge->next->x)
 563                         pedge = pedge->next;
 564                 pavailedge->next = pedge->next;
 565                 pedge->next = pavailedge;
 566
 567                 // Put the edge on the list to be removed after final scan
 568                 pavailedge->nextremove = removeedges[bottomy - 1];
 569                 removeedges[bottomy - 1] = pavailedge;
 570
 571                 // Associate the edge with the surface
 572                 pavailedge->psurf = pavailsurf;
 573
 574                 pavailedge++;
 575
 576                 addededges = true;
 577         }
 578
 579         if (!addededges)
 580                 return;
 581
 582         // Create the surface, so we'll know how to sort and draw from the edges
 583         pavailsurf->next = NULL;
 584         pavailsurf->prev = NULL;
 585         pavailsurf->state = 0;
 586         pavailsurf->visible = false;
 587         pavailsurf->callback = callback;
 588         pavailsurf->nativedata = nativedata;
 589         pavailsurf->nativedata2 = nativedata2;
 590         pavailsurf->solid = solid;
 591         pavailsurf->removed = false;
 592         pavailsurf++;
 593 }
 594
 595 /////////////////////////////////////////////////////////////////////
 596 // Scan all the edges in the global edge table into spans.
 597 /////////////////////////////////////////////////////////////////////
 598 void ScanEdges (void)
 599 {
 600         int y, rescan;
 601         float fx, fy, w, w2, clipwidthf = clipwidth - 0.5f;
 602         clipedge_t *pedge, *pedge2, *ptemp;
 603         clipsurf_t *psurf, *psurf2;
 604 #if CLIPTEST
 605         int x, x2;
 606         float zi;
 607         clippixel_t *cb;
 608 #endif
 609         float cx;
 610
 611         // Set up the active edge list as initially empty, containing
 612         // only the sentinels (which are also the background fill). Most
 613         // of these fields could be set up just once at start-up
 614         edgehead.next = &edgetail;
 615         edgehead.prev = NULL;
 616         edgehead.x = edgehead.realx = -0.9999f; // left edge of screen
 617         edgehead.realxstep = 0;
 618         edgehead.leading = 1;
 619         edgehead.psurf = &surfstack;
 620
 621         edgetail.next = NULL; // mark end of list
 622         edgetail.prev = &edgehead;
 623         edgetail.x = edgetail.realx = clipwidth + 0.5f; // right edge of screen
 624         edgetail.realxstep = 0;
 625         edgetail.leading = 0;
 626         edgetail.psurf = &surfstack;
 627
 628         // The background surface is the entire stack initially, and
 629         // is infinitely far away, so everything sorts in front of it.
 630         // This could be set just once at start-up
 631         surfstack.solid = true;
 632         surfstack.visible = true; // no callback
 633         surfstack.next = surfstack.prev = &surfstack;
 634         surfstack.wcurrent = surfstack.w00 = -999999.0;
 635         surfstack.wstepx = surfstack.wstepy = 0.0;
 636         surfstack.removed = false;
 637
 638         // rescan causes the edges to be compared at the span level
 639         // it is false if the scanline will be identical to the previous
 640         rescan = true;
 641         for (y = 0;y < clipheight;y++)
 642         {
 643                 fy = y;
 644 #if CLIPTEST
 645                 cb = clipbuffer + y * clipwidth;
 646 #endif
 647
 648                 // Sort in any edges that start on this scan
 649                 if (newedges[y].next != &maxedge)
 650                 {
 651                         rescan = true;
 652                         pedge = newedges[y].next;
 653                         pedge2 = &edgehead;
 654                         while (pedge != &maxedge)
 655                         {
 656                                 if (pedge->psurf->removed)
 657                                 {
 658                                         pedge = pedge->next;
 659                                         continue;
 660                                 }
 661
 662                                 while (pedge->x > pedge2->next->x)
 663                                         pedge2 = pedge2->next;
 664
 665                                 ptemp = pedge->next;
 666                                 pedge->next = pedge2->next;
 667                                 pedge->prev = pedge2;
 668                                 pedge2->next->prev = pedge;
 669                                 pedge2->next = pedge;
 670
 671                                 pedge2 = pedge;
 672                                 pedge = ptemp;
 673                         }
 674                 }
 675
 676                 // Scan out the active edges into spans
 677
 678                 // Start out with the left background edge already inserted, and the surface stack containing only the background
 679                 surfstack.state = 1;
 680                 cx = 0;
 681
 682                 // must always rescan if rendering to wbuffer
 683 #ifndef CLIPTEST
 684 //              if (rescan)
 685 #endif
 686                 {
 687                         for (pedge = edgehead.next;pedge;pedge = pedge->next)
 688                         {
 689                                 edgeremoved:
 690                                 psurf = pedge->psurf;
 691                                 if (psurf->removed)
 692                                 {
 693                                         pedge2 = pedge->next;
 694                                         pedge->prev->next = pedge->next;
 695                                         pedge->next->prev = pedge->prev;
 696                                         pedge->next = pedge->prev = pedge;
 697                                         pedge = pedge2;
 698                                         if (pedge)
 699                                                 goto edgeremoved;
 700                                         else
 701                                                 break;
 702                                 }
 703
 704                                 if (pedge->leading)
 705                                 {
 706                                         // It's a leading edge. Figure out where it is
 707                                         // relative to the current surfaces and insert in
 708                                         // the surface stack; if it's on top, emit the span
 709                                         // for the current top.
 710                                         // First, make sure the edges don't cross
 711                                         if (++psurf->state == 1)
 712                                         {
 713                                                 fx = pedge->x;
 714                                                 // Calculate the surface's 1/z value at this pixel, and cache the y depth for quick compares later
 715                                                 w = (psurf->wcurrent = psurf->w00 + psurf->wstepy * fy) + psurf->wstepx * fx;
 716 //                                              if (w < 0)
 717 //                                                      w = 0;
 718
 719                                                 // See if that makes it a new top surface
 720                                                 psurf2 = surfstack.next;
 721                                                 w2 = psurf2->wcurrent + psurf2->wstepx * fx;
 722 //                                              if (w2 < 0 && psurf2 != &surfstack)
 723 //                                                      w2 = 0;
 724
 725                                                 if (w >= w2)
 726                                                 {
 727                                                         // It's a new top surface
 728                                                         // emit the span for the current top
 729                                                         if (fx > cx && !psurf2->visible)
 730                                                         {
 731                                                                 psurf2->visible = true;
 732                                                                 psurf2->callback(psurf2->nativedata, psurf2->nativedata2);
 733                                                         }
 734
 735 #if CLIPTEST
 736                                                         for (x = ceil(cx), x2 = ceil(fx) >= clipwidth ? clipwidth : ceil(fx), zi = psurf2->wcurrent + psurf2->wstepx * x;x < x2;x++, zi += psurf2->wstepx)
 737                                                                 cb[x].w = zi;
 738 #endif
 739
 740                                                         cx = fx;
 741
 742                                                         // Add the edge to the stack
 743                                                         psurf->next = psurf2;
 744                                                         psurf2->prev = psurf;
 745                                                         surfstack.next = psurf;
 746                                                         psurf->prev = &surfstack;
 747                                                 }
 748                                                 else
 749                                                 {
 750                                                         // Not a new top; sort into the surface stack.
 751                                                         // Guaranteed to terminate due to sentinel background surface
 752                                                         do
 753                                                         {
 754                                                                 psurf2 = psurf2->next;
 755                                                                 w2 = psurf2->wcurrent + psurf2->wstepx * fx;
 756 //                                                              if (w2 < 0 && psurf2 != &surfstack)
 757 //                                                                      w2 = 0;
 758                                                         }
 759                                                         while (w < w2);
 760
 761                                                         // Insert the surface into the stack
 762                                                         psurf->next = psurf2;
 763                                                         psurf->prev = psurf2->prev;
 764                                                         psurf2->prev->next = psurf;
 765                                                         psurf2->prev = psurf;
 766                                                 }
 767                                         }
 768                                 }
 769                                 else
 770                                 {
 771                                         // It's a trailing edge; if this was the top surface,
 772                                         // emit the span and remove it.
 773                                         // First, make sure the edges didn't cross
 774                                         if (--psurf->state == 0)
 775                                         {
 776                                                 if (surfstack.next == psurf)
 777                                                 {
 778                                                         fx = pedge->x;
 779
 780                                                         // It's on top, emit the span
 781                                                         if (fx > cx && !psurf->visible)
 782                                                         {
 783                                                                 psurf->visible = true;
 784                                                                 psurf->callback(psurf->nativedata, psurf->nativedata2);
 785                                                         }
 786
 787 #if CLIPTEST
 788                                                         fx = pedge->x;
 789                                                         for (x = ceil(cx), x2 = ceil(fx) >= clipwidth ? clipwidth : ceil(fx), zi = psurf->w00 + psurf->wstepx * x + psurf->wstepy * fy;x < x2;x++, zi += psurf->wstepx)
 790                                                                 cb[x].w = zi;
 791 #endif
 792
 793                                                         cx = fx;
 794                                                 }
 795
 796                                                 // Remove the surface from the stack
 797                                                 psurf->next->prev = psurf->prev;
 798                                                 psurf->prev->next = psurf->next;
 799                                         }
 800                                 }
 801
 802                                 // mark and remove all non-solid surfaces that are ontop
 803                                 while (!surfstack.next->solid)
 804                                 {
 805                                         psurf = surfstack.next;
 806                                         if (!psurf->visible)
 807                                         {
 808                                                 psurf->visible = true;
 809                                                 psurf->callback(psurf->nativedata, psurf->nativedata2);
 810                                         }
 811                                         psurf->removed = true;
 812                                         psurf->next->prev = psurf->prev;
 813                                         psurf->prev->next = psurf->next;
 814                                         // isolate the surface
 815                                         psurf->next = psurf->prev = psurf;
 816                                 }
 817                         }
 818                         rescan = false;
 819                 }
 820
 821                 // Remove edges that are done
 822                 pedge = removeedges[y];
 823                 if (pedge)
 824                 {
 825                         while (pedge)
 826                         {
 827                                 if (!pedge->psurf->removed)
 828                                 {
 829                                         pedge->prev->next = pedge->next;
 830                                         pedge->next->prev = pedge->prev;
 831                                         if (pedge->psurf->visible)
 832                                                 rescan = true;
 833                                 }
 834                                 pedge = pedge->nextremove;
 835                         }
 836                 }
 837
 838                 // Step the remaining edges one scan line, and re-sort
 839                 for (pedge = edgehead.next;pedge != &edgetail;)
 840                 {
 841                         ptemp = pedge->next;
 842                         if (pedge->psurf->removed)
 843                         {
 844                                 pedge->next->prev = pedge->prev;
 845                                 pedge->prev->next = pedge->next;
 846                                 pedge->next = pedge->prev = pedge;
 847                                 pedge = ptemp;
 848                                 continue;
 849                         }
 850
 851                         // Step the edge
 852                         if (pedge->realxstep)
 853                         {
 854                                 pedge->realx += pedge->realxstep;
 855                                 pedge->x = bound(0.0f, pedge->realx, clipwidthf);
 856                         }
 857                         fx = pedge->x;
 858
 859                         // Move the edge back to the proper sorted location, if necessary
 860                         while (fx < pedge->prev->x)
 861                         {
 862                                 if (!rescan && (pedge->psurf->solid || pedge->prev->psurf->solid))
 863                                         rescan = true;
 864                                 pedge2 = pedge->prev;
 865                                 pedge2->next = pedge->next;
 866                                 pedge->next->prev = pedge2;
 867                                 pedge2->prev->next = pedge;
 868                                 pedge->prev = pedge2->prev;
 869                                 pedge->next = pedge2;
 870                                 pedge2->prev = pedge;
 871                         }
 872
 873                         pedge = ptemp;
 874                 }
 875         }
 876 }
 877
 878 void R_Clip_DisplayBuffer(void)
 879 {
 880 #if CLIPTEST
 881         int i;
 882         static int firstupload = true;
 883         byte clipbuffertex[256*256], *b;
 884         if (!r_render.value)
 885                 return;
 886         if (clipwidth > 256 || clipheight > 256)
 887                 return;
 888         glBlendFunc(GL_ONE, GL_ONE);
 889         glBindTexture(GL_TEXTURE_2D, 8000);
 890         if (firstupload)
 891         {
 892                 memset(clipbuffertex, 0, sizeof(clipbuffertex));
 893                 glTexImage2D(GL_TEXTURE_2D, 0, 1, 256, 256, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, clipbuffertex);
 894         }
 895         glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
 896         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 897         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 898         if (lighthalf)
 899                 glColor3f(0.5, 0.5, 0.5);
 900         else
 901                 glColor3f(1, 1, 1);
 902         firstupload = false;
 903         b = clipbuffertex;
 904         for (i = 0;i < clipwidth*clipheight;i++)
 905         {
 906                 if (clipbuffer[i].w > 0)
 907                         *b++ = bound(0, (int) (clipbuffer[i].w * 4096.0f), 255);
 908                 else
 909                         *b++ = 0;
 910         }
 911         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, clipwidth, clipheight, GL_LUMINANCE, GL_UNSIGNED_BYTE, clipbuffertex);
 912         glBegin (GL_QUADS);
 913         glTexCoord2f (0                 , 0                  );glVertex2f (0        , 0         );
 914         glTexCoord2f (clipwidth / 256.0f, 0                  );glVertex2f (vid.width, 0         );
 915         glTexCoord2f (clipwidth / 256.0f, clipheight / 256.0f);glVertex2f (vid.width, vid.height);
 916         glTexCoord2f (0                 , clipheight / 256.0f);glVertex2f (0        , vid.height);
 917         glEnd ();
 918         glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 919 //      glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 920 //      glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 921 #endif
 922 }
 923
 924 float boxpoints[4*3];
 925
 926 #define R_Clip_MinsBoxPolygon(axis, axisvalue, x1, y1, z1, x2, y2, z2, x3, y3, z3, x4, y4, z4, callback, nativedata, nativedata2, plane) \
 927 {\
 928         if (r_origin[(axis)] < ((axisvalue) - 0.5f))\
 929         {\
 930                 (plane)->dist = -axisvalue;\
 931                 boxpoints[ 0] = x1;boxpoints[ 1] = y1;boxpoints[ 2] = z1;\
 932                 boxpoints[ 3] = x2;boxpoints[ 4] = y2;boxpoints[ 5] = z2;\
 933                 boxpoints[ 6] = x3;boxpoints[ 7] = y3;boxpoints[ 8] = z3;\
 934                 boxpoints[ 9] = x4;boxpoints[10] = y4;boxpoints[11] = z4;\
 935                 R_Clip_AddPolygon (boxpoints, 4, sizeof(float[3]), false, callback, nativedata, nativedata2, plane);\
 936         }\
 937 }
 938
 939 #define R_Clip_MaxsBoxPolygon(axis, axisvalue, x1, y1, z1, x2, y2, z2, x3, y3, z3, x4, y4, z4, callback, nativedata, nativedata2, plane) \
 940 {\
 941         if (r_origin[(axis)] > ((axisvalue) + 0.5f))\
 942         {\
 943                 (plane)->dist = axisvalue;\
 944                 boxpoints[ 0] = x1;boxpoints[ 1] = y1;boxpoints[ 2] = z1;\
 945                 boxpoints[ 3] = x2;boxpoints[ 4] = y2;boxpoints[ 5] = z2;\
 946                 boxpoints[ 6] = x3;boxpoints[ 7] = y3;boxpoints[ 8] = z3;\
 947                 boxpoints[ 9] = x4;boxpoints[10] = y4;boxpoints[11] = z4;\
 948                 R_Clip_AddPolygon (boxpoints, 4, sizeof(float[3]), false, callback, nativedata, nativedata2, plane);\
 949         }\
 950 }
 951
 952 tinyplane_t clipboxplane[6] =
 953 {
 954         {{-1,  0,  0}, 0},
 955         {{ 1,  0,  0}, 0},
 956         {{ 0, -1,  0}, 0},
 957         {{ 0,  1,  0}, 0},
 958         {{ 0,  0, -1}, 0},
 959         {{ 0,  0,  1}, 0},
 960 };
 961
 962 void R_Clip_AddBox(float *a, float *b, void (*callback)(void *nativedata, void *nativedata2), void *nativedata, void *nativedata2)
 963 {
 964         if (r_origin[0] >= (a[0] - 5.0f) && r_origin[0] < (b[0] + 5.0f)
 965          && r_origin[1] >= (a[1] - 5.0f) && r_origin[1] < (b[1] + 5.0f)
 966          && r_origin[2] >= (a[2] - 5.0f) && r_origin[2] < (b[2] + 5.0f))
 967         {
 968                 callback(nativedata, nativedata2);
 969                 return;
 970         }
 971
 972         if (R_CullBox(a, b))
 973                 return;
 974
 975         R_Clip_MinsBoxPolygon
 976         (
 977                 0, a[0],
 978                 a[0], a[1], a[2],
 979                 a[0], b[1], a[2],
 980                 a[0], b[1], b[2],
 981                 a[0], a[1], b[2],
 982                 callback, nativedata, nativedata2, &clipboxplane[0]
 983         );
 984         R_Clip_MaxsBoxPolygon
 985         (
 986                 0, b[0],
 987                 b[0], b[1], a[2],
 988                 b[0], a[1], a[2],
 989                 b[0], a[1], b[2],
 990                 b[0], b[1], b[2],
 991                 callback, nativedata, nativedata2, &clipboxplane[1]
 992         );
 993         R_Clip_MinsBoxPolygon
 994         (
 995                 1, a[1],
 996                 b[0], a[1], a[2],
 997                 a[0], a[1], a[2],
 998                 a[0], a[1], b[2],
 999                 b[0], a[1], b[2],
1000                 callback, nativedata, nativedata2, &clipboxplane[2]
1001         );
1002         R_Clip_MaxsBoxPolygon
1003         (
1004                 1, b[1],
1005                 a[0], b[1], a[2],
1006                 b[0], b[1], a[2],
1007                 b[0], b[1], b[2],
1008                 a[0], b[1], b[2],
1009                 callback, nativedata, nativedata2, &clipboxplane[3]
1010         );
1011         R_Clip_MinsBoxPolygon
1012         (
1013                 2, a[2],
1014                 a[0], a[1], a[2],
1015                 b[0], a[1], a[2],
1016                 b[0], b[1], a[2],
1017                 a[0], b[1], a[2],
1018                 callback, nativedata, nativedata2, &clipboxplane[4]
1019         );
1020         R_Clip_MaxsBoxPolygon
1021         (
1022                 2, b[2],
1023                 b[0], a[1], b[2],
1024                 a[0], a[1], b[2],
1025                 a[0], b[1], b[2],
1026                 b[0], b[1], b[2],
1027                 callback, nativedata, nativedata2, &clipboxplane[5]
1028         );
1029 }