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8 FREE PURPOSES. IN NO EVENT SHALL THE END-USER USE THE COMPUTER CODE
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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.
24 static char rcsid[] = "$Id: draw.c,v 1.2 2001-01-31 15:17:48 bradleyb Exp $";
37 void (*tmap_drawer_ptr)(grs_bitmap *bm,int nv,g3s_point **vertlist) = draw_tmap;
38 void (*flat_drawer_ptr)(int nv,int *vertlist) = gr_upoly_tmap;
39 int (*line_drawer_ptr)(fix x0,fix y0,fix x1,fix y1) = gr_line;
41 //specifies 2d drawing routines to use instead of defaults. Passing
42 //NULL for either or both restores defaults
43 void g3_set_special_render(void (*tmap_drawer)(),void (*flat_drawer)(),int (*line_drawer)(fix, fix, fix, fix))
45 tmap_drawer_ptr = (tmap_drawer)?tmap_drawer:draw_tmap;
46 flat_drawer_ptr = (flat_drawer)?flat_drawer:gr_upoly_tmap;
47 line_drawer_ptr = (line_drawer)?line_drawer:gr_line;
50 //deal with a clipped line
51 bool must_clip_line(g3s_point *p0,g3s_point *p1,ubyte codes_or)
55 if ((p0->p3_flags&PF_TEMP_POINT) || (p1->p3_flags&PF_TEMP_POINT))
57 ret = 0; //line has already been clipped, so give up
61 clip_line(&p0,&p1,codes_or);
63 ret = g3_draw_line(p0,p1);
68 if (p0->p3_flags & PF_TEMP_POINT)
71 if (p1->p3_flags & PF_TEMP_POINT)
77 //draws a line. takes two points. returns true if drew
78 bool g3_draw_line(g3s_point *p0,g3s_point *p1)
82 if (p0->p3_codes & p1->p3_codes)
85 codes_or = p0->p3_codes | p1->p3_codes;
87 if (codes_or & CC_BEHIND)
88 return must_clip_line(p0,p1,codes_or);
90 if (!(p0->p3_flags&PF_PROJECTED))
93 if (p0->p3_flags&PF_OVERFLOW)
94 return must_clip_line(p0,p1,codes_or);
97 if (!(p1->p3_flags&PF_PROJECTED))
100 if (p1->p3_flags&PF_OVERFLOW)
101 return must_clip_line(p0,p1,codes_or);
103 return (bool) (*line_drawer_ptr)(p0->p3_sx,p0->p3_sy,p1->p3_sx,p1->p3_sy);
107 //returns true if a plane is facing the viewer. takes the unrotated surface
108 //normal of the plane, and a point on it. The normal need not be normalized
109 bool g3_check_normal_facing(vms_vector *v,vms_vector *norm)
113 vm_vec_sub(&tempv,&View_position,v);
115 return (vm_vec_dot(&tempv,norm) > 0);
118 bool do_facing_check(vms_vector *norm,g3s_point **vertlist,vms_vector *p)
120 if (norm) { //have normal
122 Assert(norm->x || norm->y || norm->z);
124 return g3_check_normal_facing(p,norm);
126 else { //normal not specified, so must compute
130 //get three points (rotated) and compute normal
132 vm_vec_perp(&tempv,&vertlist[0]->p3_vec,&vertlist[1]->p3_vec,&vertlist[2]->p3_vec);
134 return (vm_vec_dot(&tempv,&vertlist[1]->p3_vec) < 0);
138 //like g3_draw_poly(), but checks to see if facing. If surface normal is
139 //NULL, this routine must compute it, which will be slow. It is better to
140 //pre-compute the normal, and pass it to this function. When the normal
141 //is passed, this function works like g3_check_normal_facing() plus
143 //returns -1 if not facing, 1 if off screen, 0 if drew
144 bool g3_check_and_draw_poly(int nv,g3s_point **pointlist,vms_vector *norm,vms_vector *pnt)
146 if (do_facing_check(norm,pointlist,pnt))
147 return g3_draw_poly(nv,pointlist);
152 bool g3_check_and_draw_tmap(int nv,g3s_point **pointlist,g3s_uvl *uvl_list,grs_bitmap *bm,vms_vector *norm,vms_vector *pnt)
154 if (do_facing_check(norm,pointlist,pnt))
155 return g3_draw_tmap(nv,pointlist,uvl_list,bm);
160 //deal with face that must be clipped
161 bool must_clip_flat_face(int nv,g3s_codes cc)
167 bufptr = clip_polygon(Vbuf0,Vbuf1,&nv,&cc);
169 if (nv>0 && !(cc.or&CC_BEHIND) && !cc.and) {
172 g3s_point *p = bufptr[i];
174 if (!(p->p3_flags&PF_PROJECTED))
177 if (p->p3_flags&PF_OVERFLOW) {
182 Vertex_list[i*2] = p->p3_sx;
183 Vertex_list[i*2+1] = p->p3_sy;
186 (*flat_drawer_ptr)(nv,(int *)Vertex_list);
196 if (Vbuf1[i]->p3_flags & PF_TEMP_POINT)
197 free_temp_point(Vbuf1[i]);
199 // Assert(free_point_num==0);
204 #if (!(defined(D1XD3D) || defined(OGL)))
205 //draw a flat-shaded face.
206 //returns 1 if off screen, 0 if drew
207 bool g3_draw_poly(int nv,g3s_point **pointlist)
213 cc.or = 0; cc.and = 0xff;
219 bufptr[i] = pointlist[i];
221 cc.and &= bufptr[i]->p3_codes;
222 cc.or |= bufptr[i]->p3_codes;
226 return 1; //all points off screen
229 return must_clip_flat_face(nv,cc);
231 //now make list of 2d coords (& check for overflow)
234 g3s_point *p = bufptr[i];
236 if (!(p->p3_flags&PF_PROJECTED))
239 if (p->p3_flags&PF_OVERFLOW)
240 return must_clip_flat_face(nv,cc);
242 Vertex_list[i*2] = p->p3_sx;
243 Vertex_list[i*2+1] = p->p3_sy;
246 (*flat_drawer_ptr)(nv,(int *)Vertex_list);
248 return 0; //say it drew
251 bool must_clip_tmap_face(int nv,g3s_codes cc,grs_bitmap *bm);
253 //draw a texture-mapped face.
254 //returns 1 if off screen, 0 if drew
255 bool g3_draw_tmap(int nv,g3s_point **pointlist,g3s_uvl *uvl_list,grs_bitmap *bm)
261 cc.or = 0; cc.and = 0xff;
268 p = bufptr[i] = pointlist[i];
270 cc.and &= p->p3_codes;
271 cc.or |= p->p3_codes;
273 p->p3_u = uvl_list[i].u;
274 p->p3_v = uvl_list[i].v;
275 p->p3_l = uvl_list[i].l;
277 p->p3_flags |= PF_UVS + PF_LS;
282 return 1; //all points off screen
285 return must_clip_tmap_face(nv,cc,bm);
287 //now make list of 2d coords (& check for overflow)
290 g3s_point *p = bufptr[i];
292 if (!(p->p3_flags&PF_PROJECTED))
295 if (p->p3_flags&PF_OVERFLOW) {
296 Int3(); //should not overflow after clip
301 (*tmap_drawer_ptr)(bm,nv,bufptr);
303 return 0; //say it drew
307 bool must_clip_tmap_face(int nv,g3s_codes cc,grs_bitmap *bm)
312 bufptr = clip_polygon(Vbuf0,Vbuf1,&nv,&cc);
314 if (nv && !(cc.or&CC_BEHIND) && !cc.and) {
317 g3s_point *p = bufptr[i];
319 if (!(p->p3_flags&PF_PROJECTED))
322 if (p->p3_flags&PF_OVERFLOW) {
323 Int3(); //should not overflow after clip
328 (*tmap_drawer_ptr)(bm,nv,bufptr);
335 if (bufptr[i]->p3_flags & PF_TEMP_POINT)
336 free_temp_point(bufptr[i]);
338 // Assert(free_point_num==0);
345 int checkmuldiv(fix *r,fix a,fix b,fix c);
349 //draw a sortof sphere - i.e., the 2d radius is proportional to the 3d
350 //radius, but not to the distance from the eye
351 int g3_draw_sphere(g3s_point *pnt,fix rad)
353 if (! (pnt->p3_codes & CC_BEHIND)) {
355 if (! (pnt->p3_flags & PF_PROJECTED))
356 g3_project_point(pnt);
358 if (! (pnt->p3_codes & PF_OVERFLOW)) {
361 r2 = fixmul(rad,Matrix_scale.x);
363 if (checkmuldiv(&t,r2,Canv_w2,pnt->p3_z))
364 return gr_disk(pnt->p3_sx,pnt->p3_sy,t);
368 return gr_disk(pnt->p3_sx, pnt->p3_sy, fl2f(((f2fl(r2) * fCanv_w2) / f2fl(pnt->p3_z))));