3d/draw.c

   1 /*
   2 THE COMPUTER CODE CONTAINED HEREIN IS THE SOLE PROPERTY OF PARALLAX
   3 SOFTWARE CORPORATION ("PARALLAX").  PARALLAX, IN DISTRIBUTING THE CODE TO
   4 END-USERS, AND SUBJECT TO ALL OF THE TERMS AND CONDITIONS HEREIN, GRANTS A
   5 ROYALTY-FREE, PERPETUAL LICENSE TO SUCH END-USERS FOR USE BY SUCH END-USERS
   6 IN USING, DISPLAYING,  AND CREATING DERIVATIVE WORKS THEREOF, SO LONG AS
   7 SUCH USE, DISPLAY OR CREATION IS FOR NON-COMMERCIAL, ROYALTY OR REVENUE
   8 FREE PURPOSES.  IN NO EVENT SHALL THE END-USER USE THE COMPUTER CODE
   9 CONTAINED HEREIN FOR REVENUE-BEARING PURPOSES.  THE END-USER UNDERSTANDS
  10 AND AGREES TO THE TERMS HEREIN AND ACCEPTS THE SAME BY USE OF THIS FILE.
  11 COPYRIGHT 1993-1998 PARALLAX SOFTWARE CORPORATION.  ALL RIGHTS RESERVED.
  12 */
  13 /*
  14  *
  15  * Drawing routines
  16  *
  17  */
  18
  19 #ifdef RCS
  20 static char rcsid[] = "$Id: draw.c,v 1.1.1.1 2001-01-19 03:29:58 bradleyb Exp $";
  21 #endif
  22
  23 #include <conf.h>
  24 #include "error.h"
  25
  26 #include "fix.h"
  27 #include "vecmat.h"
  28 #include "gr.h"
  29 #include "3d.h"
  30 #include "globvars.h"
  31 #include "texmap.h"
  32 #include "clipper.h"
  33
  34 void (*tmap_drawer_ptr)(grs_bitmap *bm,int nv,g3s_point **vertlist) = draw_tmap;
  35 void (*flat_drawer_ptr)(int nv,int *vertlist) = gr_upoly_tmap;
  36 int (*line_drawer_ptr)(fix x0,fix y0,fix x1,fix y1) = gr_line;
  37
  38 //specifies 2d drawing routines to use instead of defaults.  Passing
  39 //NULL for either or both restores defaults
  40 void g3_set_special_render(void (*tmap_drawer)(),void (*flat_drawer)(),int (*line_drawer)(fix, fix, fix, fix))
  41 {
  42         tmap_drawer_ptr = (tmap_drawer)?tmap_drawer:draw_tmap;
  43         flat_drawer_ptr = (flat_drawer)?flat_drawer:gr_upoly_tmap;
  44         line_drawer_ptr = (line_drawer)?line_drawer:gr_line;
  45 }
  46 #ifndef OGL
  47 //deal with a clipped line
  48 bool must_clip_line(g3s_point *p0,g3s_point *p1,ubyte codes_or)
  49 {
  50         bool ret;
  51
  52         if ((p0->p3_flags&PF_TEMP_POINT) || (p1->p3_flags&PF_TEMP_POINT))
  53
  54                 ret = 0;                //line has already been clipped, so give up
  55
  56         else {
  57
  58                 clip_line(&p0,&p1,codes_or);
  59
  60                 ret = g3_draw_line(p0,p1);
  61         }
  62
  63         //free temp points
  64
  65         if (p0->p3_flags & PF_TEMP_POINT)
  66                 free_temp_point(p0);
  67
  68         if (p1->p3_flags & PF_TEMP_POINT)
  69                 free_temp_point(p1);
  70
  71         return ret;
  72 }
  73
  74 //draws a line. takes two points.  returns true if drew
  75 bool g3_draw_line(g3s_point *p0,g3s_point *p1)
  76 {
  77         ubyte codes_or;
  78
  79         if (p0->p3_codes & p1->p3_codes)
  80                 return 0;
  81
  82         codes_or = p0->p3_codes | p1->p3_codes;
  83
  84         if (codes_or & CC_BEHIND)
  85                 return must_clip_line(p0,p1,codes_or);
  86
  87         if (!(p0->p3_flags&PF_PROJECTED))
  88                 g3_project_point(p0);
  89
  90         if (p0->p3_flags&PF_OVERFLOW)
  91                 return must_clip_line(p0,p1,codes_or);
  92
  93
  94         if (!(p1->p3_flags&PF_PROJECTED))
  95                 g3_project_point(p1);
  96
  97         if (p1->p3_flags&PF_OVERFLOW)
  98                 return must_clip_line(p0,p1,codes_or);
  99
 100         return (bool) (*line_drawer_ptr)(p0->p3_sx,p0->p3_sy,p1->p3_sx,p1->p3_sy);
 101 }
 102 #endif
 103
 104 //returns true if a plane is facing the viewer. takes the unrotated surface
 105 //normal of the plane, and a point on it.  The normal need not be normalized
 106 bool g3_check_normal_facing(vms_vector *v,vms_vector *norm)
 107 {
 108         vms_vector tempv;
 109
 110         vm_vec_sub(&tempv,&View_position,v);
 111
 112         return (vm_vec_dot(&tempv,norm) > 0);
 113 }
 114
 115 bool do_facing_check(vms_vector *norm,g3s_point **vertlist,vms_vector *p)
 116 {
 117         if (norm) {             //have normal
 118
 119                 Assert(norm->x || norm->y || norm->z);
 120
 121                 return g3_check_normal_facing(p,norm);
 122         }
 123         else {  //normal not specified, so must compute
 124
 125                 vms_vector tempv;
 126
 127                 //get three points (rotated) and compute normal
 128
 129                 vm_vec_perp(&tempv,&vertlist[0]->p3_vec,&vertlist[1]->p3_vec,&vertlist[2]->p3_vec);
 130
 131                 return (vm_vec_dot(&tempv,&vertlist[1]->p3_vec) < 0);
 132         }
 133 }
 134
 135 //like g3_draw_poly(), but checks to see if facing.  If surface normal is
 136 //NULL, this routine must compute it, which will be slow.  It is better to
 137 //pre-compute the normal, and pass it to this function.  When the normal
 138 //is passed, this function works like g3_check_normal_facing() plus
 139 //g3_draw_poly().
 140 //returns -1 if not facing, 1 if off screen, 0 if drew
 141 bool g3_check_and_draw_poly(int nv,g3s_point **pointlist,vms_vector *norm,vms_vector *pnt)
 142 {
 143         if (do_facing_check(norm,pointlist,pnt))
 144                 return g3_draw_poly(nv,pointlist);
 145         else
 146                 return 255;
 147 }
 148
 149 bool g3_check_and_draw_tmap(int nv,g3s_point **pointlist,g3s_uvl *uvl_list,grs_bitmap *bm,vms_vector *norm,vms_vector *pnt)
 150 {
 151         if (do_facing_check(norm,pointlist,pnt))
 152                 return g3_draw_tmap(nv,pointlist,uvl_list,bm);
 153         else
 154                 return 255;
 155 }
 156
 157 //deal with face that must be clipped
 158 bool must_clip_flat_face(int nv,g3s_codes cc)
 159 {
 160         int i;
 161         bool ret=0;
 162         g3s_point **bufptr;
 163
 164         bufptr = clip_polygon(Vbuf0,Vbuf1,&nv,&cc);
 165
 166         if (nv>0 && !(cc.or&CC_BEHIND) && !cc.and) {
 167
 168                 for (i=0;i<nv;i++) {
 169                         g3s_point *p = bufptr[i];
 170
 171                         if (!(p->p3_flags&PF_PROJECTED))
 172                                 g3_project_point(p);
 173
 174                         if (p->p3_flags&PF_OVERFLOW) {
 175                                 ret = 1;
 176                                 goto free_points;
 177                         }
 178
 179                         Vertex_list[i*2]   = p->p3_sx;
 180                         Vertex_list[i*2+1] = p->p3_sy;
 181                 }
 182
 183                 (*flat_drawer_ptr)(nv,(int *)Vertex_list);
 184         }
 185         else
 186                 ret=1;
 187
 188         //free temp points
 189 free_points:
 190         ;
 191
 192         for (i=0;i<nv;i++)
 193                 if (Vbuf1[i]->p3_flags & PF_TEMP_POINT)
 194                         free_temp_point(Vbuf1[i]);
 195
 196 //      Assert(free_point_num==0);
 197
 198         return ret;
 199 }
 200
 201 #if (!(defined(D1XD3D) || defined(OGL)))
 202 //draw a flat-shaded face.
 203 //returns 1 if off screen, 0 if drew
 204 bool g3_draw_poly(int nv,g3s_point **pointlist)
 205 {
 206         int i;
 207         g3s_point **bufptr;
 208         g3s_codes cc;
 209
 210         cc.or = 0; cc.and = 0xff;
 211
 212         bufptr = Vbuf0;
 213
 214         for (i=0;i<nv;i++) {
 215
 216                 bufptr[i] = pointlist[i];
 217
 218                 cc.and &= bufptr[i]->p3_codes;
 219                 cc.or  |= bufptr[i]->p3_codes;
 220         }
 221
 222         if (cc.and)
 223                 return 1;       //all points off screen
 224
 225         if (cc.or)
 226                 return must_clip_flat_face(nv,cc);
 227
 228         //now make list of 2d coords (& check for overflow)
 229
 230         for (i=0;i<nv;i++) {
 231                 g3s_point *p = bufptr[i];
 232
 233                 if (!(p->p3_flags&PF_PROJECTED))
 234                         g3_project_point(p);
 235
 236                 if (p->p3_flags&PF_OVERFLOW)
 237                         return must_clip_flat_face(nv,cc);
 238
 239                 Vertex_list[i*2]   = p->p3_sx;
 240                 Vertex_list[i*2+1] = p->p3_sy;
 241         }
 242
 243         (*flat_drawer_ptr)(nv,(int *)Vertex_list);
 244
 245         return 0;       //say it drew
 246 }
 247
 248 bool must_clip_tmap_face(int nv,g3s_codes cc,grs_bitmap *bm);
 249
 250 //draw a texture-mapped face.
 251 //returns 1 if off screen, 0 if drew
 252 bool g3_draw_tmap(int nv,g3s_point **pointlist,g3s_uvl *uvl_list,grs_bitmap *bm)
 253 {
 254         int i;
 255         g3s_point **bufptr;
 256         g3s_codes cc;
 257
 258         cc.or = 0; cc.and = 0xff;
 259
 260         bufptr = Vbuf0;
 261
 262         for (i=0;i<nv;i++) {
 263                 g3s_point *p;
 264
 265                 p = bufptr[i] = pointlist[i];
 266
 267                 cc.and &= p->p3_codes;
 268                 cc.or  |= p->p3_codes;
 269
 270                 p->p3_u = uvl_list[i].u;
 271                 p->p3_v = uvl_list[i].v;
 272                 p->p3_l = uvl_list[i].l;
 273
 274                 p->p3_flags |= PF_UVS + PF_LS;
 275
 276         }
 277
 278         if (cc.and)
 279                 return 1;       //all points off screen
 280
 281         if (cc.or)
 282                 return must_clip_tmap_face(nv,cc,bm);
 283
 284         //now make list of 2d coords (& check for overflow)
 285
 286         for (i=0;i<nv;i++) {
 287                 g3s_point *p = bufptr[i];
 288
 289                 if (!(p->p3_flags&PF_PROJECTED))
 290                         g3_project_point(p);
 291
 292                 if (p->p3_flags&PF_OVERFLOW) {
 293                         Int3();         //should not overflow after clip
 294                         return 255;
 295                 }
 296         }
 297
 298         (*tmap_drawer_ptr)(bm,nv,bufptr);
 299
 300         return 0;       //say it drew
 301 }
 302 #endif
 303
 304 bool must_clip_tmap_face(int nv,g3s_codes cc,grs_bitmap *bm)
 305 {
 306         g3s_point **bufptr;
 307         int i;
 308
 309         bufptr = clip_polygon(Vbuf0,Vbuf1,&nv,&cc);
 310
 311         if (nv && !(cc.or&CC_BEHIND) && !cc.and) {
 312
 313                 for (i=0;i<nv;i++) {
 314                         g3s_point *p = bufptr[i];
 315
 316                         if (!(p->p3_flags&PF_PROJECTED))
 317                                 g3_project_point(p);
 318
 319                         if (p->p3_flags&PF_OVERFLOW) {
 320                                 Int3();         //should not overflow after clip
 321                                 goto free_points;
 322                         }
 323                 }
 324
 325                 (*tmap_drawer_ptr)(bm,nv,bufptr);
 326         }
 327
 328 free_points:
 329         ;
 330
 331         for (i=0;i<nv;i++)
 332                 if (bufptr[i]->p3_flags & PF_TEMP_POINT)
 333                         free_temp_point(bufptr[i]);
 334
 335 //      Assert(free_point_num==0);
 336
 337         return 0;
 338
 339 }
 340
 341 #ifndef __powerc
 342 int checkmuldiv(fix *r,fix a,fix b,fix c);
 343 #endif
 344
 345 #ifndef OGL
 346 //draw a sortof sphere - i.e., the 2d radius is proportional to the 3d
 347 //radius, but not to the distance from the eye
 348 int g3_draw_sphere(g3s_point *pnt,fix rad)
 349 {
 350         if (! (pnt->p3_codes & CC_BEHIND)) {
 351
 352                 if (! (pnt->p3_flags & PF_PROJECTED))
 353                         g3_project_point(pnt);
 354
 355                 if (! (pnt->p3_codes & PF_OVERFLOW)) {
 356                         fix r2,t;
 357
 358                         r2 = fixmul(rad,Matrix_scale.x);
 359 #ifndef __powerc
 360                         if (checkmuldiv(&t,r2,Canv_w2,pnt->p3_z))
 361                                 return gr_disk(pnt->p3_sx,pnt->p3_sy,t);
 362 #else
 363                         if (pnt->p3_z == 0)
 364                                 return 0;
 365                         return gr_disk(pnt->p3_sx, pnt->p3_sy, fl2f(((f2fl(r2) * fCanv_w2) / f2fl(pnt->p3_z))));
 366 #endif
 367                 }
 368         }
 369
 370         return 0;
 371 }
 372 #endif
 373