texmap/ntmap.c

   1 /* $Id: ntmap.c,v 1.8 2003-03-19 19:21:34 btb Exp $ */
   2 /*
   3 THE COMPUTER CODE CONTAINED HEREIN IS THE SOLE PROPERTY OF PARALLAX
   4 SOFTWARE CORPORATION ("PARALLAX").  PARALLAX, IN DISTRIBUTING THE CODE TO
   5 END-USERS, AND SUBJECT TO ALL OF THE TERMS AND CONDITIONS HEREIN, GRANTS A
   6 ROYALTY-FREE, PERPETUAL LICENSE TO SUCH END-USERS FOR USE BY SUCH END-USERS
   7 IN USING, DISPLAYING,  AND CREATING DERIVATIVE WORKS THEREOF, SO LONG AS
   8 SUCH USE, DISPLAY OR CREATION IS FOR NON-COMMERCIAL, ROYALTY OR REVENUE
   9 FREE PURPOSES.  IN NO EVENT SHALL THE END-USER USE THE COMPUTER CODE
  10 CONTAINED HEREIN FOR REVENUE-BEARING PURPOSES.  THE END-USER UNDERSTANDS
  11 AND AGREES TO THE TERMS HEREIN AND ACCEPTS THE SAME BY USE OF THIS FILE.
  12 COPYRIGHT 1993-1998 PARALLAX SOFTWARE CORPORATION.  ALL RIGHTS RESERVED.
  13 */
  14
  15 /*
  16  *
  17  * Start of conversion to new texture mapper.
  18  *
  19  * Old Log:
  20  * Revision 1.52  1995/03/14  15:13:06  john
  21  * Increased MAX_Y_Pointers to 480.
  22  *
  23  * Revision 1.51  1995/02/23  14:25:09  john
  24  * Added editor tmap.
  25  *
  26  * Revision 1.50  1995/02/20  18:22:58  john
  27  * Put all the externs in the assembly modules into tmap_inc.asm.
  28  * Also, moved all the C versions of the inner loops into a new module,
  29  * scanline.c.
  30  *
  31  * Revision 1.49  1995/02/20  17:09:11  john
  32  * Added code so that you can build the tmapper with no assembly!
  33  *
  34  * Revision 1.48  1995/01/06  11:11:30  mike
  35  * even when not in editor, have 400 lines in texture map scanline table.
  36  *
  37  * Revision 1.47  1994/12/15  16:43:25  matt
  38  * Took out code only needed by editor
  39  *
  40  * Revision 1.46  1994/12/09  22:35:37  mike
  41  * fix bug in before call to asm_tmap_scanline_per causing write of pixel onto past right border onto left.
  42  *
  43  * Revision 1.45  1994/12/06  16:31:06  mike
  44  * fix bug in asm_tmap_scanline_matt interface.
  45  *
  46  * Revision 1.44  1994/12/04  20:37:18  mike
  47  * *** empty log message ***
  48  *
  49  * Revision 1.43  1994/12/02  23:30:04  mike
  50  * optimizations.
  51  *
  52  * Revision 1.42  1994/11/30  00:57:43  mike
  53  * optimizations.
  54  *
  55  * Revision 1.41  1994/11/28  13:34:27  mike
  56  * optimizations.
  57  *
  58  * Revision 1.40  1994/11/28  01:30:01  mike
  59  * kill warning.
  60  *
  61  * Revision 1.39  1994/11/28  01:28:59  mike
  62  * optimizations.
  63  *
  64  * Revision 1.38  1994/11/21  14:08:07  john
  65  * Took out all multiple instead of divide code.
  66  *
  67  * Revision 1.37  1994/11/19  15:21:52  mike
  68  * rip out unused code.
  69  *
  70  * Revision 1.36  1994/11/14  11:42:51  mike
  71  * optimization.
  72  *
  73  * Revision 1.35  1994/11/12  16:41:36  mike
  74  * *** empty log message ***
  75  *
  76  * Revision 1.34  1994/11/10  21:28:41  mike
  77  * remove call to init_interface_vars_to_assembler.
  78  *
  79  * Revision 1.33  1994/11/10  11:08:59  mike
  80  * detail level stuff.
  81  *
  82  * Revision 1.32  1994/11/09  22:55:52  matt
  83  * Added variable Current_seg_depth for detail level optimization
  84  *
  85  * Revision 1.31  1994/11/09  19:57:31  john
  86  * Added texture rle caching.
  87  *
  88  * Revision 1.30  1994/11/09  19:54:48  mike
  89  * Call flat shader if Tmap_flat_flag set.
  90  *
  91  * Revision 1.29  1994/11/02  21:33:31  john
  92  * Added Burger Bill's optimization, ie.. 2 muls per 8 pixels.
  93  *
  94  * Revision 1.28  1994/11/02  11:32:16  john
  95  * Added code for c callable inner loop and code to
  96  * test dividing out z0.
  97  *
  98  * Revision 1.27  1994/10/28  20:54:32  matt
  99  * Added error checking
 100  *
 101  * Revision 1.26  1994/10/25  11:20:20  mike
 102  * fix bug in lighting overflow checking for one scanline tall linear texture maps.
 103  *
 104  * Revision 1.25  1994/08/03  15:40:33  mike
 105  * Prevent divide overflows, decrease occurrence of precision-caused glitches.
 106  *
 107  * Revision 1.24  1994/07/27  09:31:16  mike
 108  * Fix concave texture map problem, decrease occurrence of unimportant int 3.
 109  *
 110  * Revision 1.23  1994/06/17  12:23:31  mike
 111  * Support non-lighted texture maps.
 112  *
 113  * Revision 1.22  1994/06/11  08:10:24  mike
 114  * Fix mysterious hang bug, lighting value was out of range.
 115  *
 116  * Revision 1.21  1994/06/09  16:10:16  mike
 117  * Change SC2000 from constant to variable.
 118  *
 119  */
 120
 121 #ifdef HAVE_CONFIG_H
 122 #include <conf.h>
 123 #endif
 124
 125 #ifdef RCS
 126 static char rcsid[] = "$Id: ntmap.c,v 1.8 2003-03-19 19:21:34 btb Exp $";
 127 #endif
 128
 129 #define VESA 0
 130 #define NUM_TMAPS 16
 131
 132 #define HEADLIGHT_LIGHTING 0
 133
 134 #define WIREFRAME 0
 135 #define PERSPECTIVE 1
 136
 137 #include "pstypes.h"
 138 #include "fix.h"
 139 #include "vecmat.h"
 140 #include "gr.h"
 141 #include "3d.h"
 142 #include "error.h"
 143
 144 #include "texmap.h"
 145 #include "texmapl.h"
 146 #include "rle.h"
 147 #include "scanline.h"
 148
 149 #ifdef EDITOR
 150 #define EDITOR_TMAP 1       //if in, include extra stuff
 151 #endif
 152
 153 #define F15_5 (F1_0*15 + F0_5)
 154
 155 // Temporary texture map, interface from Matt's 3d system to Mike's texture mapper.
 156 g3ds_tmap Tmap1;
 157
 158 grs_bitmap Texmap_ptrs[NUM_TMAPS];
 159 grs_bitmap Texmap4_ptrs[NUM_TMAPS];
 160
 161 fix Range_max=0; // debug, kill me
 162
 163 int     Interpolation_method=0; // 0 = choose best method
 164 int     Lighting_on=1;                  // initialize to no lighting
 165 int     Tmap_flat_flag = 0;             //      1 = render texture maps as flat shaded polygons.
 166 int     Current_seg_depth;              // HACK INTERFACE: how far away the current segment (& thus texture) is
 167 int     Max_perspective_depth;
 168 int     Max_linear_depth;
 169 int     Max_flat_depth;
 170
 171 extern int Window_clip_left, Window_clip_bot, Window_clip_right, Window_clip_top;
 172
 173 // These variables are the interface to assembler.  They get set for each texture map, which is a real waste of time.
 174 //      They should be set only when they change, which is generally when the window bounds change.  And, even still, it's
 175 //      a pretty bad interface.
 176 int     bytes_per_row=-1;
 177 unsigned char *write_buffer;
 178 int     window_left;
 179 int     window_right;
 180 int     window_top;
 181 int     window_bottom;
 182 int     window_width;
 183 int     window_height;
 184
 185 #define MAX_Y_POINTERS  1024
 186
 187 int     y_pointers[MAX_Y_POINTERS];
 188
 189 fix fix_recip[FIX_RECIP_TABLE_SIZE];
 190
 191 int     Lighting_enabled;
 192 int     Fix_recip_table_computed=0;
 193
 194 fix fx_l, fx_u, fx_v, fx_z, fx_du_dx, fx_dv_dx, fx_dz_dx, fx_dl_dx;
 195 int fx_xleft, fx_xright, fx_y;
 196 unsigned char * pixptr;
 197 int per2_flag = 0;
 198 int Transparency_on = 0;
 199 int dither_intensity_lighting = 0;
 200
 201 ubyte * tmap_flat_cthru_table;
 202 ubyte tmap_flat_color;
 203 ubyte tmap_flat_shade_value;
 204
 205
 206
 207 // -------------------------------------------------------------------------------------
 208 void init_fix_recip_table(void)
 209 {
 210         int     i;
 211
 212         fix_recip[0] = F1_0;
 213
 214         for (i=1; i<FIX_RECIP_TABLE_SIZE; i++)
 215                 fix_recip[i] = F1_0/i;
 216
 217         Fix_recip_table_computed = 1;
 218 }
 219
 220 // -------------------------------------------------------------------------------------
 221 //      Initialize interface variables to assembler.
 222 //      These things used to be constants.  This routine is now (10/6/93) getting called for
 223 //      every texture map.  It should get called whenever the window changes, or, preferably,
 224 //      not at all.  I'm pretty sure these variables are only being used for range checking.
 225 void init_interface_vars_to_assembler(void)
 226 {
 227         grs_bitmap      *bp;
 228
 229         bp = &grd_curcanv->cv_bitmap;
 230
 231         Assert(bp!=NULL);
 232         Assert(bp->bm_data!=NULL);
 233         Assert(bp->bm_h <= MAX_Y_POINTERS);
 234
 235         //      If bytes_per_row has changed, create new table of pointers.
 236         if (bytes_per_row != (int) bp->bm_rowsize) {
 237                 int     y_val, i;
 238
 239                 bytes_per_row = (int) bp->bm_rowsize;
 240
 241                 y_val = 0;
 242                 for (i=0; i<MAX_Y_POINTERS; i++) {
 243                         y_pointers[i] = y_val;
 244                         y_val += bytes_per_row;
 245                 }
 246         }
 247
 248         write_buffer = (unsigned char *) bp->bm_data;
 249
 250         window_left = 0;
 251         window_right = (int) bp->bm_w-1;
 252         window_top = 0;
 253         window_bottom = (int) bp->bm_h-1;
 254
 255         Window_clip_left = window_left;
 256         Window_clip_right = window_right;
 257         Window_clip_top = window_top;
 258         Window_clip_bot = window_bottom;
 259
 260         window_width = bp->bm_w;
 261         window_height = bp->bm_h;
 262
 263         if (!Fix_recip_table_computed)
 264                 init_fix_recip_table();
 265 }
 266
 267 // -------------------------------------------------------------------------------------
 268 //                             VARIABLES
 269 extern g3ds_tmap Tmap1;
 270
 271 // -------------------------------------------------------------------------------------
 272 //      Returns number preceding val modulo modulus.
 273 //      prevmod(3,4) = 2
 274 //      prevmod(0,4) = 3
 275 int prevmod(int val,int modulus)
 276 {
 277         if (val > 0)
 278                 return val-1;
 279         else
 280                 return modulus-1;
 281 //      return (val + modulus - 1) % modulus;
 282 }
 283
 284
 285 //      Returns number succeeding val modulo modulus.
 286 //      succmod(3,4) = 0
 287 //      succmod(0,4) = 1
 288 int succmod(int val,int modulus)
 289 {
 290         if (val < modulus-1)
 291                 return val+1;
 292         else
 293                 return 0;
 294
 295 //      return (val + 1) % modulus;
 296 }
 297
 298 // -------------------------------------------------------------------------------------
 299 //      Select topmost vertex (minimum y coordinate) and bottommost (maximum y coordinate) in
 300 //      texture map.  If either is part of a horizontal edge, then select leftmost vertex for
 301 //      top, rightmost vertex for bottom.
 302 //      Important: Vertex is selected with integer precision.  So, if there are vertices at
 303 //      (0.0,0.7) and (0.5,0.3), the first vertex is selected, because they y coordinates are
 304 //      considered the same, so the smaller x is favored.
 305 //      Parameters:
 306 //              nv              number of vertices
 307 //              v3d     pointer to 3d vertices containing u,v,x2d,y2d coordinates
 308 //      Results in:
 309 //              *min_y_ind
 310 //              *max_y_ind
 311 // -------------------------------------------------------------------------------------
 312 void compute_y_bounds(g3ds_tmap *t, int *vlt, int *vlb, int *vrt, int *vrb,int *bottom_y_ind)
 313 {
 314         int     i;
 315         int     min_y,max_y;
 316         int     min_y_ind;
 317         int     original_vrt;
 318         fix     min_x;
 319
 320         // Scan all vertices, set min_y_ind to vertex with smallest y coordinate.
 321         min_y = f2i(t->verts[0].y2d);
 322         max_y = min_y;
 323         min_y_ind = 0;
 324         min_x = f2i(t->verts[0].x2d);
 325         *bottom_y_ind = 0;
 326
 327         for (i=1; i<t->nv; i++) {
 328                 if (f2i(t->verts[i].y2d) < min_y) {
 329                         min_y = f2i(t->verts[i].y2d);
 330                         min_y_ind = i;
 331                         min_x = f2i(t->verts[i].x2d);
 332                 } else if (f2i(t->verts[i].y2d) == min_y) {
 333                         if (f2i(t->verts[i].x2d) < min_x) {
 334                                 min_y_ind = i;
 335                                 min_x = f2i(t->verts[i].x2d);
 336                         }
 337                 }
 338                 if (f2i(t->verts[i].y2d) > max_y) {
 339                         max_y = f2i(t->verts[i].y2d);
 340                         *bottom_y_ind = i;
 341                 }
 342         }
 343
 344 //--removed mk, 11/27/94--      //      Check for a non-upright-hourglass polygon and fix, if necessary, by bashing a y coordinate.
 345 //--removed mk, 11/27/94--      //      min_y_ind = index of minimum y coordinate, *bottom_y_ind = index of maximum y coordinate
 346 //--removed mk, 11/27/94--{
 347 //--removed mk, 11/27/94--      int     max_temp, min_temp;
 348 //--removed mk, 11/27/94--
 349 //--removed mk, 11/27/94--      max_temp = *bottom_y_ind;
 350 //--removed mk, 11/27/94--      if (*bottom_y_ind < min_y_ind)
 351 //--removed mk, 11/27/94--              max_temp += t->nv;
 352 //--removed mk, 11/27/94--
 353 //--removed mk, 11/27/94--      for (i=min_y_ind; i<max_temp; i++) {
 354 //--removed mk, 11/27/94--              if (f2i(t->verts[i%t->nv].y2d) > f2i(t->verts[(i+1)%t->nv].y2d)) {
 355 //--removed mk, 11/27/94--                      Int3();
 356 //--removed mk, 11/27/94--                      t->verts[(i+1)%t->nv].y2d = t->verts[i%t->nv].y2d;
 357 //--removed mk, 11/27/94--              }
 358 //--removed mk, 11/27/94--      }
 359 //--removed mk, 11/27/94--
 360 //--removed mk, 11/27/94--      min_temp = min_y_ind;
 361 //--removed mk, 11/27/94--      if (min_y_ind < *bottom_y_ind)
 362 //--removed mk, 11/27/94--              min_temp += t->nv;
 363 //--removed mk, 11/27/94--
 364 //--removed mk, 11/27/94--      for (i=*bottom_y_ind; i<min_temp; i++) {
 365 //--removed mk, 11/27/94--              if (f2i(t->verts[i%t->nv].y2d) < f2i(t->verts[(i+1)%t->nv].y2d)) {
 366 //--removed mk, 11/27/94--                      Int3();
 367 //--removed mk, 11/27/94--                      t->verts[(i+1)%t->nv].y2d = t->verts[i%t->nv].y2d;
 368 //--removed mk, 11/27/94--              }
 369 //--removed mk, 11/27/94--      }
 370 //--removed mk, 11/27/94--}
 371
 372         // Set "vertex left top", etc. based on vertex with topmost y coordinate
 373         *vlt = min_y_ind;
 374         *vrt = *vlt;
 375         *vlb = prevmod(*vlt,t->nv);
 376         *vrb = succmod(*vrt,t->nv);
 377
 378         // If right edge is horizontal, then advance along polygon bound until it no longer is or until all
 379         // vertices have been examined.
 380         // (Left edge cannot be horizontal, because *vlt is set to leftmost point with highest y coordinate.)
 381
 382         original_vrt = *vrt;
 383
 384         while (f2i(t->verts[*vrt].y2d) == f2i(t->verts[*vrb].y2d)) {
 385                 if (succmod(*vrt,t->nv) == original_vrt) {
 386                         break;
 387                 }
 388                 *vrt = succmod(*vrt,t->nv);
 389                 *vrb = succmod(*vrt,t->nv);
 390         }
 391 }
 392
 393 // -------------------------------------------------------------------------------------
 394 //      Returns dx/dy given two vertices.
 395 //      If dy == 0, returns 0.0
 396 // -------------------------------------------------------------------------------------
 397 //--fix compute_dx_dy_lin(g3ds_tmap *t, int top_vertex,int bottom_vertex)
 398 //--{
 399 //--    int     dy;
 400 //--
 401 //--    // compute delta x with respect to y for any edge
 402 //--    dy = f2i(t->verts[bottom_vertex].y2d - t->verts[top_vertex].y2d) + 1;
 403 //--    if (dy)
 404 //--            return (t->verts[bottom_vertex].x2d - t->verts[top_vertex].x2d) / dy;
 405 //--    else
 406 //--            return 0;
 407 //--
 408 //--}
 409
 410 fix compute_du_dy_lin(g3ds_tmap *t, int top_vertex,int bottom_vertex, fix recip_dy)
 411 {
 412         return fixmul(t->verts[bottom_vertex].u - t->verts[top_vertex].u, recip_dy);
 413 }
 414
 415
 416 fix compute_dv_dy_lin(g3ds_tmap *t, int top_vertex,int bottom_vertex, fix recip_dy)
 417 {
 418         return fixmul(t->verts[bottom_vertex].v - t->verts[top_vertex].v, recip_dy);
 419 }
 420
 421 fix compute_dl_dy_lin(g3ds_tmap *t, int top_vertex,int bottom_vertex, fix recip_dy)
 422 {
 423         return fixmul(t->verts[bottom_vertex].l - t->verts[top_vertex].l, recip_dy);
 424
 425 }
 426
 427 fix compute_dx_dy(g3ds_tmap *t, int top_vertex,int bottom_vertex, fix recip_dy)
 428 {
 429         return fixmul(t->verts[bottom_vertex].x2d - t->verts[top_vertex].x2d, recip_dy);
 430 }
 431
 432 fix compute_du_dy(g3ds_tmap *t, int top_vertex,int bottom_vertex, fix recip_dy)
 433 {
 434         return fixmul(fixmul(t->verts[bottom_vertex].u,t->verts[bottom_vertex].z) - fixmul(t->verts[top_vertex].u,t->verts[top_vertex].z), recip_dy);
 435 }
 436
 437
 438 fix compute_dv_dy(g3ds_tmap *t, int top_vertex,int bottom_vertex, fix recip_dy)
 439 {
 440         return fixmul(fixmul(t->verts[bottom_vertex].v,t->verts[bottom_vertex].z) - fixmul(t->verts[top_vertex].v,t->verts[top_vertex].z), recip_dy);
 441
 442 }
 443
 444 fix compute_dz_dy(g3ds_tmap *t, int top_vertex,int bottom_vertex, fix recip_dy)
 445 {
 446         return fixmul(t->verts[bottom_vertex].z - t->verts[top_vertex].z, recip_dy);
 447
 448 }
 449 int Skip_short_flag=0;
 450
 451 // -------------------------------------------------------------------------------------
 452 //      Texture map current scanline in perspective.
 453 // -------------------------------------------------------------------------------------
 454 void ntmap_scanline_lighted(grs_bitmap *srcb, int y, fix xleft, fix xright, fix uleft, fix uright, fix vleft, fix vright, fix zleft, fix zright, fix lleft, fix lright)
 455 {
 456         fix     dx,recip_dx;
 457
 458         fx_xright = f2i(xright);
 459         //edited 06/27/99 Matt Mueller - moved these tests up from within the switch so as not to do a bunch of needless calculations when we are just gonna return anyway.  Slight fps boost?
 460         if (fx_xright < Window_clip_left)
 461                 return;
 462         fx_xleft = f2i(xleft);
 463         if (fx_xleft > Window_clip_right)
 464                 return;
 465         //end edit -MM
 466
 467         dx = fx_xright - fx_xleft;
 468         if ((dx < 0) || (xright < 0) || (xleft > xright))               // the (xleft > xright) term is not redundant with (dx < 0) because dx is computed using integers
 469                 return;
 470
 471         // setup to call assembler scanline renderer
 472         if (dx < FIX_RECIP_TABLE_SIZE)
 473                 recip_dx = fix_recip[dx];
 474         else
 475                 recip_dx = F1_0/dx;
 476
 477         fx_u = uleft;
 478         fx_v = vleft;
 479         fx_z = zleft;
 480
 481         fx_du_dx = fixmul(uright - uleft,recip_dx);
 482         fx_dv_dx = fixmul(vright - vleft,recip_dx);
 483         fx_dz_dx = fixmul(zright - zleft,recip_dx);
 484         fx_y = y;
 485         pixptr = srcb->bm_data;
 486
 487         switch (Lighting_enabled) {
 488                 case 0:
 489                         //added 05/17/99 Matt Mueller - prevent writing before the buffer
 490             if ((fx_y == 0) && (fx_xleft < 0))
 491                                 fx_xleft = 0;
 492                         //end addition -MM
 493                         if (fx_xright > Window_clip_right)
 494                                 fx_xright = Window_clip_right;
 495
 496                         cur_tmap_scanline_per();
 497                         break;
 498                 case 1: {
 499                         fix     mul_thing;
 500
 501                         if (lleft < 0) lleft = 0;
 502                         if (lright < 0) lright = 0;
 503                         if (lleft > (NUM_LIGHTING_LEVELS*F1_0-F1_0/2)) lleft = (NUM_LIGHTING_LEVELS*F1_0-F1_0/2);
 504                         if (lright > (NUM_LIGHTING_LEVELS*F1_0-F1_0/2)) lright = (NUM_LIGHTING_LEVELS*F1_0-F1_0/2);
 505
 506                         fx_l = lleft;
 507                         fx_dl_dx = fixmul(lright - lleft,recip_dx);
 508
 509                         //      This is a pretty ugly hack to prevent lighting overflows.
 510                         mul_thing = dx * fx_dl_dx;
 511                         if (lleft + mul_thing < 0)
 512                                 fx_dl_dx += 12;
 513                         else if (lleft + mul_thing > (NUM_LIGHTING_LEVELS*F1_0-F1_0/2))
 514                                 fx_dl_dx -= 12;
 515
 516                         //added 05/17/99 Matt Mueller - prevent writing before the buffer
 517             if ((fx_y == 0) && (fx_xleft < 0))
 518                                 fx_xleft = 0;
 519                         //end addition -MM
 520                         if (fx_xright > Window_clip_right)
 521                                 fx_xright = Window_clip_right;
 522
 523                         cur_tmap_scanline_per();
 524                         break;
 525                 }
 526                 case 2:
 527 #ifdef EDITOR_TMAP
 528                         fx_xright = f2i(xright);
 529                         fx_xleft = f2i(xleft);
 530
 531                         tmap_flat_color = 1;
 532                         cur_tmap_scanline_flat();
 533 #else
 534                         Int3(); //      Illegal, called an editor only routine!
 535 #endif
 536                         break;
 537         }
 538
 539 }
 540
 541 int Do_vertical_scan=0;
 542
 543 int     Break_on_flat=0;
 544
 545 // -------------------------------------------------------------------------------------
 546 //      Render a texture map with lighting using perspective interpolation in inner and outer loops.
 547 // -------------------------------------------------------------------------------------
 548 void ntexture_map_lighted(grs_bitmap *srcb, g3ds_tmap *t)
 549 {
 550         int     vlt,vrt,vlb,vrb;        // vertex left top, vertex right top, vertex left bottom, vertex right bottom
 551         int     topy,boty,y, dy;
 552         fix     dx_dy_left,dx_dy_right;
 553         fix     du_dy_left,du_dy_right;
 554         fix     dv_dy_left,dv_dy_right;
 555         fix     dz_dy_left,dz_dy_right;
 556         fix     dl_dy_left,dl_dy_right;
 557         fix     recip_dyl, recip_dyr;
 558         int     max_y_vertex;
 559         fix     xleft,xright,uleft,vleft,uright,vright,zleft,zright,lleft,lright;
 560         int     next_break_left, next_break_right;
 561
 562         g3ds_vertex *v3d;
 563
 564         //remove stupid warnings in compile
 565         dl_dy_left = F1_0;
 566         dl_dy_right = F1_0;
 567         lleft = F1_0;
 568         lright = F1_0;
 569
 570         v3d = t->verts;
 571
 572         // Determine top and bottom y coords.
 573         compute_y_bounds(t,&vlt,&vlb,&vrt,&vrb,&max_y_vertex);
 574
 575         // Set top and bottom (of entire texture map) y coordinates.
 576         topy = f2i(v3d[vlt].y2d);
 577         boty = f2i(v3d[max_y_vertex].y2d);
 578         if (topy > Window_clip_bot)
 579                 return;
 580         if (boty > Window_clip_bot)
 581                 boty = Window_clip_bot;
 582
 583         // Set amount to change x coordinate for each advance to next scanline.
 584         dy = f2i(t->verts[vlb].y2d) - f2i(t->verts[vlt].y2d);
 585         if (dy < FIX_RECIP_TABLE_SIZE)
 586                 recip_dyl = fix_recip[dy];
 587         else
 588                 recip_dyl = F1_0/dy;
 589
 590         dx_dy_left = compute_dx_dy(t,vlt,vlb, recip_dyl);
 591         du_dy_left = compute_du_dy(t,vlt,vlb, recip_dyl);
 592         dv_dy_left = compute_dv_dy(t,vlt,vlb, recip_dyl);
 593         dz_dy_left = compute_dz_dy(t,vlt,vlb, recip_dyl);
 594
 595         dy = f2i(t->verts[vrb].y2d) - f2i(t->verts[vrt].y2d);
 596         if (dy < FIX_RECIP_TABLE_SIZE)
 597                 recip_dyr = fix_recip[dy];
 598         else
 599                 recip_dyr = F1_0/dy;
 600
 601         du_dy_right = compute_du_dy(t,vrt,vrb, recip_dyr);
 602         dx_dy_right = compute_dx_dy(t,vrt,vrb, recip_dyr);
 603         dv_dy_right = compute_dv_dy(t,vrt,vrb, recip_dyr);
 604         dz_dy_right = compute_dz_dy(t,vrt,vrb, recip_dyr);
 605
 606         if (Lighting_enabled) {
 607                 dl_dy_left = compute_dl_dy_lin(t,vlt,vlb, recip_dyl);
 608                 dl_dy_right = compute_dl_dy_lin(t,vrt,vrb, recip_dyr);
 609
 610                 lleft = v3d[vlt].l;
 611                 lright = v3d[vrt].l;
 612         }
 613
 614         // Set initial values for x, u, v
 615         xleft = v3d[vlt].x2d;
 616         xright = v3d[vrt].x2d;
 617
 618         zleft = v3d[vlt].z;
 619         zright = v3d[vrt].z;
 620
 621         uleft = fixmul(v3d[vlt].u,zleft);
 622         uright = fixmul(v3d[vrt].u,zright);
 623         vleft = fixmul(v3d[vlt].v,zleft);
 624         vright = fixmul(v3d[vrt].v,zright);
 625
 626         // scan all rows in texture map from top through first break.
 627         next_break_left = f2i(v3d[vlb].y2d);
 628         next_break_right = f2i(v3d[vrb].y2d);
 629
 630         for (y = topy; y < boty; y++) {
 631
 632                 // See if we have reached the end of the current left edge, and if so, set
 633                 // new values for dx_dy and x,u,v
 634                 if (y == next_break_left) {
 635                         fix     recip_dy;
 636
 637                         // Handle problem of double points.  Search until y coord is different.  Cannot get
 638                         // hung in an infinite loop because we know there is a vertex with a lower y coordinate
 639                         // because in the for loop, we don't scan all spanlines.
 640                         while (y == f2i(v3d[vlb].y2d)) {
 641                                 vlt = vlb;
 642                                 vlb = prevmod(vlb,t->nv);
 643                         }
 644                         next_break_left = f2i(v3d[vlb].y2d);
 645
 646                         dy = f2i(t->verts[vlb].y2d) - f2i(t->verts[vlt].y2d);
 647                         if (dy < FIX_RECIP_TABLE_SIZE)
 648                                 recip_dy = fix_recip[dy];
 649                         else
 650                                 recip_dy = F1_0/dy;
 651
 652                         dx_dy_left = compute_dx_dy(t,vlt,vlb, recip_dy);
 653
 654                         xleft = v3d[vlt].x2d;
 655                         zleft = v3d[vlt].z;
 656                         uleft = fixmul(v3d[vlt].u,zleft);
 657                         vleft = fixmul(v3d[vlt].v,zleft);
 658                         lleft = v3d[vlt].l;
 659
 660                         du_dy_left = compute_du_dy(t,vlt,vlb, recip_dy);
 661                         dv_dy_left = compute_dv_dy(t,vlt,vlb, recip_dy);
 662                         dz_dy_left = compute_dz_dy(t,vlt,vlb, recip_dy);
 663
 664                         if (Lighting_enabled) {
 665                                 dl_dy_left = compute_dl_dy_lin(t,vlt,vlb, recip_dy);
 666                                 lleft = v3d[vlt].l;
 667                         }
 668                 }
 669
 670                 // See if we have reached the end of the current left edge, and if so, set
 671                 // new values for dx_dy and x.  Not necessary to set new values for u,v.
 672                 if (y == next_break_right) {
 673                         fix     recip_dy;
 674
 675                         while (y == f2i(v3d[vrb].y2d)) {
 676                                 vrt = vrb;
 677                                 vrb = succmod(vrb,t->nv);
 678                         }
 679
 680                         next_break_right = f2i(v3d[vrb].y2d);
 681
 682                         dy = f2i(t->verts[vrb].y2d) - f2i(t->verts[vrt].y2d);
 683                         if (dy < FIX_RECIP_TABLE_SIZE)
 684                                 recip_dy = fix_recip[dy];
 685                         else
 686                                 recip_dy = F1_0/dy;
 687
 688                         dx_dy_right = compute_dx_dy(t,vrt,vrb, recip_dy);
 689
 690                         xright = v3d[vrt].x2d;
 691                         zright = v3d[vrt].z;
 692                         uright = fixmul(v3d[vrt].u,zright);
 693                         vright = fixmul(v3d[vrt].v,zright);
 694
 695                         du_dy_right = compute_du_dy(t,vrt,vrb, recip_dy);
 696                         dv_dy_right = compute_dv_dy(t,vrt,vrb, recip_dy);
 697                         dz_dy_right = compute_dz_dy(t,vrt,vrb, recip_dy);
 698
 699                         if (Lighting_enabled) {
 700                                 dl_dy_right = compute_dl_dy_lin(t,vrt,vrb, recip_dy);
 701                                 lright = v3d[vrt].l;
 702                         }
 703                 }
 704
 705                 if (Lighting_enabled) {
 706                         if (y >= Window_clip_top)
 707                                 ntmap_scanline_lighted(srcb,y,xleft,xright,uleft,uright,vleft,vright,zleft,zright,lleft,lright);
 708                         lleft += dl_dy_left;
 709                         lright += dl_dy_right;
 710                 } else
 711                         if (y >= Window_clip_top)
 712                                 ntmap_scanline_lighted(srcb,y,xleft,xright,uleft,uright,vleft,vright,zleft,zright,lleft,lright);
 713
 714                 uleft += du_dy_left;
 715                 vleft += dv_dy_left;
 716
 717                 uright += du_dy_right;
 718                 vright += dv_dy_right;
 719
 720                 xleft += dx_dy_left;
 721                 xright += dx_dy_right;
 722
 723                 zleft += dz_dy_left;
 724                 zright += dz_dy_right;
 725
 726         }
 727
 728         // We can get lleft or lright out of bounds here because we compute dl_dy using fixed point values,
 729         //      but we plot an integer number of scanlines, therefore doing an integer number of additions of the delta.
 730
 731 //if (Break_on_flat)
 732 //      mprintf(0, "[%i %i %i] ", y, f2i(xleft), f2i(xright));
 733
 734         ntmap_scanline_lighted(srcb,y,xleft,xright,uleft,uright,vleft,vright,zleft,zright,lleft,lright);
 735 }
 736
 737
 738 // -------------------------------------------------------------------------------------
 739 //      Texture map current scanline using linear interpolation.
 740 // -------------------------------------------------------------------------------------
 741 void ntmap_scanline_lighted_linear(grs_bitmap *srcb, int y, fix xleft, fix xright, fix uleft, fix uright, fix vleft, fix vright, fix lleft, fix lright)
 742 {
 743         fix     u,v,l;
 744         fix     dx,recip_dx;
 745
 746         fix     du_dx,dv_dx,dl_dx;
 747
 748         u = uleft;
 749         v = vleft;
 750         l = lleft;
 751
 752         dx = f2i(xright) - f2i(xleft);
 753         if ((dx < 0) || (xright < 0) || (xleft > xright))               // the (xleft > xright) term is not redundant with (dx < 0) because dx is computed using integers
 754                 return;
 755
 756                 // setup to call assembler scanline renderer
 757                 if (dx < FIX_RECIP_TABLE_SIZE)
 758                         recip_dx = fix_recip[dx];
 759                 else
 760                         recip_dx = F1_0/dx;
 761
 762                 du_dx = fixmul(uright - uleft,recip_dx);
 763                 dv_dx = fixmul(vright - vleft,recip_dx);
 764
 765                 fx_u = uleft;
 766                 fx_v = vleft;
 767                 fx_du_dx = du_dx;
 768                 fx_dv_dx = dv_dx;
 769                 fx_y = y;
 770                 fx_xright = f2i(xright);
 771                 fx_xleft = f2i(xleft);
 772                 pixptr = srcb->bm_data;
 773
 774                 switch (Lighting_enabled) {
 775                         case 0:
 776                                 //added 07/11/99 adb - prevent writing before the buffer
 777                                 if (fx_xleft < 0)
 778                                         fx_xleft = 0;
 779                                 //end addition -adb
 780
 781                                 cur_tmap_scanline_lin_nolight();
 782                                 break;
 783                         case 1:
 784                                 if (lleft < F1_0/2)
 785                                         lleft = F1_0/2;
 786                                 if (lright < F1_0/2)
 787                                         lright = F1_0/2;
 788
 789                                 if (lleft > MAX_LIGHTING_VALUE*NUM_LIGHTING_LEVELS)
 790                                         lleft = MAX_LIGHTING_VALUE*NUM_LIGHTING_LEVELS;
 791                                 if (lright > MAX_LIGHTING_VALUE*NUM_LIGHTING_LEVELS)
 792                                         lright = MAX_LIGHTING_VALUE*NUM_LIGHTING_LEVELS;
 793
 794                                 //added 07/11/99 adb - prevent writing before the buffer
 795                                 if (fx_xleft < 0)
 796                                         fx_xleft = 0;
 797                                 //end addition -adb
 798
 799 {
 800                         fix mul_thing;
 801
 802                         fx_l = lleft;
 803                         fx_dl_dx = fixmul(lright - lleft,recip_dx);
 804
 805                         //      This is a pretty ugly hack to prevent lighting overflows.
 806                         mul_thing = dx * fx_dl_dx;
 807                         if (lleft + mul_thing < 0)
 808                                 fx_dl_dx += 12;
 809                         else if (lleft + mul_thing > (NUM_LIGHTING_LEVELS*F1_0-F1_0/2))
 810                                 fx_dl_dx -= 12;
 811 }
 812
 813                                 fx_l = lleft;
 814                                 dl_dx = fixmul(lright - lleft,recip_dx);
 815                                 fx_dl_dx = dl_dx;
 816                                 cur_tmap_scanline_lin();
 817                                 break;
 818                         case 2:
 819 #ifdef EDITOR_TMAP
 820                                 fx_xright = f2i(xright);
 821                                 fx_xleft = f2i(xleft);
 822                                 tmap_flat_color = 1;
 823                                 cur_tmap_scanline_flat();
 824 #else
 825                                 Int3(); //      Illegal, called an editor only routine!
 826 #endif
 827                                 break;
 828                 }
 829 }
 830
 831 // -------------------------------------------------------------------------------------
 832 //      Render a texture map with lighting using perspective interpolation in inner and outer loops.
 833 // -------------------------------------------------------------------------------------
 834 void ntexture_map_lighted_linear(grs_bitmap *srcb, g3ds_tmap *t)
 835 {
 836         int     vlt,vrt,vlb,vrb;        // vertex left top, vertex right top, vertex left bottom, vertex right bottom
 837         int     topy,boty,y, dy;
 838         fix     dx_dy_left,dx_dy_right;
 839         fix     du_dy_left,du_dy_right;
 840         fix     dv_dy_left,dv_dy_right;
 841         fix     dl_dy_left,dl_dy_right;
 842         int     max_y_vertex;
 843         fix     xleft,xright,uleft,vleft,uright,vright,lleft,lright;
 844         int     next_break_left, next_break_right;
 845         fix     recip_dyl, recip_dyr;
 846
 847         g3ds_vertex *v3d;
 848
 849         //remove stupid warnings in compile
 850         dl_dy_left = F1_0;
 851         dl_dy_right = F1_0;
 852         lleft = F1_0;
 853         lright = F1_0;
 854
 855         v3d = t->verts;
 856
 857         // Determine top and bottom y coords.
 858         compute_y_bounds(t,&vlt,&vlb,&vrt,&vrb,&max_y_vertex);
 859
 860         // Set top and bottom (of entire texture map) y coordinates.
 861         topy = f2i(v3d[vlt].y2d);
 862         boty = f2i(v3d[max_y_vertex].y2d);
 863
 864         if (topy > Window_clip_bot)
 865                 return;
 866         if (boty > Window_clip_bot)
 867                 boty = Window_clip_bot;
 868
 869         dy = f2i(t->verts[vlb].y2d) - f2i(t->verts[vlt].y2d);
 870         if (dy < FIX_RECIP_TABLE_SIZE)
 871                 recip_dyl = fix_recip[dy];
 872         else
 873                 recip_dyl = F1_0/dy;
 874
 875         dy = f2i(t->verts[vrb].y2d) - f2i(t->verts[vrt].y2d);
 876         if (dy < FIX_RECIP_TABLE_SIZE)
 877                 recip_dyr = fix_recip[dy];
 878         else
 879                 recip_dyr = F1_0/dy;
 880
 881         // Set amount to change x coordinate for each advance to next scanline.
 882         dx_dy_left = compute_dx_dy(t,vlt,vlb, recip_dyl);
 883         dx_dy_right = compute_dx_dy(t,vrt,vrb, recip_dyr);
 884
 885         du_dy_left = compute_du_dy_lin(t,vlt,vlb, recip_dyl);
 886         du_dy_right = compute_du_dy_lin(t,vrt,vrb, recip_dyr);
 887
 888         dv_dy_left = compute_dv_dy_lin(t,vlt,vlb, recip_dyl);
 889         dv_dy_right = compute_dv_dy_lin(t,vrt,vrb, recip_dyr);
 890
 891         if (Lighting_enabled) {
 892                 dl_dy_left = compute_dl_dy_lin(t,vlt,vlb, recip_dyl);
 893                 dl_dy_right = compute_dl_dy_lin(t,vrt,vrb, recip_dyr);
 894
 895                 lleft = v3d[vlt].l;
 896                 lright = v3d[vrt].l;
 897         }
 898
 899         // Set initial values for x, u, v
 900         xleft = v3d[vlt].x2d;
 901         xright = v3d[vrt].x2d;
 902
 903         uleft = v3d[vlt].u;
 904         uright = v3d[vrt].u;
 905         vleft = v3d[vlt].v;
 906         vright = v3d[vrt].v;
 907
 908         // scan all rows in texture map from top through first break.
 909         next_break_left = f2i(v3d[vlb].y2d);
 910         next_break_right = f2i(v3d[vrb].y2d);
 911
 912         for (y = topy; y < boty; y++) {
 913
 914                 // See if we have reached the end of the current left edge, and if so, set
 915                 // new values for dx_dy and x,u,v
 916                 if (y == next_break_left) {
 917                         fix     recip_dy;
 918
 919                         // Handle problem of double points.  Search until y coord is different.  Cannot get
 920                         // hung in an infinite loop because we know there is a vertex with a lower y coordinate
 921                         // because in the for loop, we don't scan all spanlines.
 922                         while (y == f2i(v3d[vlb].y2d)) {
 923                                 vlt = vlb;
 924                                 vlb = prevmod(vlb,t->nv);
 925                         }
 926                         next_break_left = f2i(v3d[vlb].y2d);
 927
 928                         dy = f2i(t->verts[vlb].y2d) - f2i(t->verts[vlt].y2d);
 929                         if (dy < FIX_RECIP_TABLE_SIZE)
 930                                 recip_dy = fix_recip[dy];
 931                         else
 932                                 recip_dy = F1_0/dy;
 933
 934                         dx_dy_left = compute_dx_dy(t,vlt,vlb, recip_dy);
 935
 936                         xleft = v3d[vlt].x2d;
 937                         uleft = v3d[vlt].u;
 938                         vleft = v3d[vlt].v;
 939                         lleft = v3d[vlt].l;
 940
 941                         du_dy_left = compute_du_dy_lin(t,vlt,vlb, recip_dy);
 942                         dv_dy_left = compute_dv_dy_lin(t,vlt,vlb, recip_dy);
 943
 944                         if (Lighting_enabled) {
 945                                 dl_dy_left = compute_dl_dy_lin(t,vlt,vlb, recip_dy);
 946                                 lleft = v3d[vlt].l;
 947                         }
 948                 }
 949
 950                 // See if we have reached the end of the current left edge, and if so, set
 951                 // new values for dx_dy and x.  Not necessary to set new values for u,v.
 952                 if (y == next_break_right) {
 953                         fix     recip_dy;
 954
 955                         while (y == f2i(v3d[vrb].y2d)) {
 956                                 vrt = vrb;
 957                                 vrb = succmod(vrb,t->nv);
 958                         }
 959
 960                         dy = f2i(t->verts[vrb].y2d) - f2i(t->verts[vrt].y2d);
 961                         if (dy < FIX_RECIP_TABLE_SIZE)
 962                                 recip_dy = fix_recip[dy];
 963                         else
 964                                 recip_dy = F1_0/dy;
 965
 966                         next_break_right = f2i(v3d[vrb].y2d);
 967                         dx_dy_right = compute_dx_dy(t,vrt,vrb, recip_dy);
 968
 969                         xright = v3d[vrt].x2d;
 970                         uright = v3d[vrt].u;
 971                         vright = v3d[vrt].v;
 972
 973                         du_dy_right = compute_du_dy_lin(t,vrt,vrb, recip_dy);
 974                         dv_dy_right = compute_dv_dy_lin(t,vrt,vrb, recip_dy);
 975
 976                         if (Lighting_enabled) {
 977                                 dl_dy_right = compute_dl_dy_lin(t,vrt,vrb, recip_dy);
 978                                 lright = v3d[vrt].l;
 979                         }
 980                 }
 981
 982                 if (Lighting_enabled) {
 983                         ntmap_scanline_lighted_linear(srcb,y,xleft,xright,uleft,uright,vleft,vright,lleft,lright);
 984                         lleft += dl_dy_left;
 985                         lright += dl_dy_right;
 986                 } else
 987                         ntmap_scanline_lighted_linear(srcb,y,xleft,xright,uleft,uright,vleft,vright,lleft,lright);
 988
 989                 uleft += du_dy_left;
 990                 vleft += dv_dy_left;
 991
 992                 uright += du_dy_right;
 993                 vright += dv_dy_right;
 994
 995                 xleft += dx_dy_left;
 996                 xright += dx_dy_right;
 997
 998         }
 999
1000         // We can get lleft or lright out of bounds here because we compute dl_dy using fixed point values,
1001         //      but we plot an integer number of scanlines, therefore doing an integer number of additions of the delta.
1002
1003         ntmap_scanline_lighted_linear(srcb,y,xleft,xright,uleft,uright,vleft,vright,lleft,lright);
1004 }
1005
1006 // fix  DivNum = F1_0*12;
1007
1008 extern void draw_tmap_flat(grs_bitmap *bp,int nverts,g3s_point **vertbuf);
1009
1010 // -------------------------------------------------------------------------------------
1011 // Interface from Matt's data structures to Mike's texture mapper.
1012 // -------------------------------------------------------------------------------------
1013 void draw_tmap(grs_bitmap *bp,int nverts,g3s_point **vertbuf)
1014 {
1015         int     i;
1016
1017         //      These variables are used in system which renders texture maps which lie on one scanline as a line.
1018         // fix  div_numerator;
1019         int     lighting_on_save = Lighting_on;
1020
1021         Assert(nverts <= MAX_TMAP_VERTS);
1022
1023
1024 #ifdef USE_MULT_CODE
1025         if ( !divide_table_filled ) fill_divide_table();
1026 #endif
1027
1028         // -- now called from g3_start_frame -- init_interface_vars_to_assembler();
1029
1030         //      If no transparency and seg depth is large, render as flat shaded.
1031         if ((Current_seg_depth > Max_linear_depth) && ((bp->bm_flags & 3) == 0)) {
1032                 draw_tmap_flat(bp, nverts, vertbuf);
1033                 return;
1034         }
1035
1036         if ( bp->bm_flags & BM_FLAG_RLE )
1037                 bp = rle_expand_texture( bp );          // Expand if rle'd
1038
1039         Transparency_on = bp->bm_flags & BM_FLAG_TRANSPARENT;
1040         if (bp->bm_flags & BM_FLAG_NO_LIGHTING)
1041                 Lighting_on = 0;
1042
1043
1044         // Setup texture map in Tmap1
1045         Tmap1.nv = nverts;                                              // Initialize number of vertices
1046
1047 //      div_numerator = DivNum; //f1_0*3;
1048
1049         for (i=0; i<nverts; i++) {
1050                 g3ds_vertex     *tvp = &Tmap1.verts[i];
1051                 g3s_point       *vp = vertbuf[i];
1052
1053                 tvp->x2d = vp->p3_sx;
1054                 tvp->y2d = vp->p3_sy;
1055
1056                 //      Check for overflow on fixdiv.  Will overflow on vp->z <= something small.  Allow only as low as 256.
1057                 if (vp->p3_z < 256) {
1058                         vp->p3_z = 256;
1059                         // Int3();              // we would overflow if we divided!
1060                 }
1061
1062                 tvp->z = fixdiv(F1_0*12, vp->p3_z);
1063                 tvp->u = vp->p3_u << 6; //* bp->bm_w;
1064                 tvp->v = vp->p3_v << 6; //* bp->bm_h;
1065
1066                 Assert(Lighting_on < 3);
1067
1068                 if (Lighting_on)
1069                         tvp->l = vp->p3_l * NUM_LIGHTING_LEVELS;
1070         }
1071
1072
1073         Lighting_enabled = Lighting_on;
1074
1075         // Now, call my texture mapper.
1076         if (Lighting_on) {
1077                 switch (Interpolation_method) { // 0 = choose, 1 = linear, 2 = /8 perspective, 3 = full perspective
1078                         case 0:                                                         // choose best interpolation
1079                                 per2_flag = 1;
1080                                 if (Current_seg_depth > Max_perspective_depth)
1081                                         ntexture_map_lighted_linear(bp, &Tmap1);
1082                                 else
1083                                         ntexture_map_lighted(bp, &Tmap1);
1084                                 break;
1085                         case 1:                                                         // linear interpolation
1086                                 per2_flag = 1;
1087                                 ntexture_map_lighted_linear(bp, &Tmap1);
1088                                 break;
1089                         case 2:                                                         // perspective every 8th pixel interpolation
1090                                 per2_flag = 1;
1091                                 ntexture_map_lighted(bp, &Tmap1);
1092                                 break;
1093                         case 3:                                                         // perspective every pixel interpolation
1094                                 per2_flag = 0;                                  // this hack means do divide every pixel
1095                                 ntexture_map_lighted(bp, &Tmap1);
1096                                 break;
1097                         default:
1098                                 Assert(0);                              // Illegal value for Interpolation_method, must be 0,1,2,3
1099                 }
1100         } else {
1101                 switch (Interpolation_method) { // 0 = choose, 1 = linear, 2 = /8 perspective, 3 = full perspective
1102                         case 0:                                                         // choose best interpolation
1103                                 per2_flag = 1;
1104                                 if (Current_seg_depth > Max_perspective_depth)
1105                                         ntexture_map_lighted_linear(bp, &Tmap1);
1106                                 else
1107                                         ntexture_map_lighted(bp, &Tmap1);
1108                                 break;
1109                         case 1:                                                         // linear interpolation
1110                                 per2_flag = 1;
1111                                 ntexture_map_lighted_linear(bp, &Tmap1);
1112                                 break;
1113                         case 2:                                                         // perspective every 8th pixel interpolation
1114                                 per2_flag = 1;
1115                                 ntexture_map_lighted(bp, &Tmap1);
1116                                 break;
1117                         case 3:                                                         // perspective every pixel interpolation
1118                                 per2_flag = 0;                                  // this hack means do divide every pixel
1119                                 ntexture_map_lighted(bp, &Tmap1);
1120                                 break;
1121                         default:
1122                                 Assert(0);                              // Illegal value for Interpolation_method, must be 0,1,2,3
1123                 }
1124         }
1125
1126         Lighting_on = lighting_on_save;
1127
1128 }