14 static gfxpoly_t*current_polygon = 0;
15 void gfxpoly_fail(char*expr, char*file, int line, const char*function)
17 if(!current_polygon) {
18 fprintf(stderr, "assert(%s) failed in %s in line %d: %s\n", expr, file, line, function);
22 void*md5 = initialize_md5();
25 gfxpolystroke_t*stroke = current_polygon->strokes;
26 for(;stroke;stroke=stroke->next) {
27 for(t=0;t<stroke->num_points;t++) {
28 update_md5(md5, (unsigned char*)&stroke->points[t].x, sizeof(stroke->points[t].x));
29 update_md5(md5, (unsigned char*)&stroke->points[t].y, sizeof(stroke->points[t].y));
33 char filename[32+4+1];
35 sprintf(filename, "%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x.ps",
36 h[0],h[1],h[2],h[3],h[4],h[5],h[6],h[7],h[8],h[9],h[10],h[11],h[12],h[13],h[14],h[15]);
38 fprintf(stderr, "assert(%s) failed in %s in line %d: %s\n", expr, file, line, function);
39 fprintf(stderr, "I'm saving a debug file \"%s\" to the current directory.\n", filename);
41 gfxpoly_save(current_polygon, filename);
45 static char point_equals(const void*o1, const void*o2)
47 const point_t*p1 = o1;
48 const point_t*p2 = o2;
49 return p1->x == p2->x && p1->y == p2->y;
51 static unsigned int point_hash(const void*o)
56 static void* point_dup(const void*o)
59 point_t*n = malloc(sizeof(point_t));
64 static void point_free(void*o)
78 typedef struct _event {
85 /* compare_events_simple differs from compare_events in that it schedules
86 events from left to right regardless of type. It's only used in horizontal
87 processing, in order to get an x-wise sorting of the current scanline */
88 static inline int compare_events_simple(const void*_a,const void*_b)
90 event_t* a = (event_t*)_a;
91 event_t* b = (event_t*)_b;
92 int d = b->p.y - a->p.y;
99 static inline int compare_events(const void*_a,const void*_b)
101 event_t* a = (event_t*)_a;
102 event_t* b = (event_t*)_b;
103 int d = b->p.y - a->p.y;
105 /* we need to schedule end after intersect (so that a segment about
106 to end has a chance to tear up a few other segs first) and start
107 events after end (in order not to confuse the intersection check, which
108 assumes there's an actual y overlap between active segments, and
109 because ending segments in the active list make it difficult to insert
110 starting segments at the right position)).
111 Horizontal lines come last, because the only purpose
112 they have is to create snapping coordinates for the segments (still)
113 existing in this scanline.
115 d = b->type - a->type;
119 /* I don't see any reason why we would need to order by x- at least as long
120 as we do horizontal lines in a seperate pass */
121 //d = b->p.x - a->p.x;
125 #define COMPARE_EVENTS(x,y) (compare_events(x,y)>0)
126 #define COMPARE_EVENTS_SIMPLE(x,y) (compare_events_simple(x,y)>0)
127 HEAP_DEFINE(queue,event_t,COMPARE_EVENTS);
128 HEAP_DEFINE(hqueue,event_t,COMPARE_EVENTS_SIMPLE);
130 typedef struct _status {
136 windcontext_t*context;
137 segment_t*ending_segments;
139 gfxpolystroke_t*strokes;
141 dict_t*seen_crossings; //list of crossing we saw so far
142 dict_t*intersecting_segs; //list of segments intersecting in this scanline
143 dict_t*segs_with_point; //lists of segments that received a point in this scanline
148 int gfxpoly_num_segments(gfxpoly_t*poly)
150 gfxpolystroke_t*stroke = poly->strokes;
152 for(;stroke;stroke=stroke->next) {
157 int gfxpoly_size(gfxpoly_t*poly)
161 gfxpolystroke_t*stroke = poly->strokes;
162 for(;stroke;stroke=stroke->next) {
163 edges += stroke->num_points-1;
168 char gfxpoly_check(gfxpoly_t*poly)
170 current_polygon = poly;
171 dict_t*d = dict_new2(&point_type);
173 gfxpolystroke_t*stroke = poly->strokes;
174 for(;stroke;stroke=stroke->next) {
175 /* In order to not confuse the fill/wind logic, existing segments must have
176 a non-zero edge style */
179 /* put all the segments into dictionaries so that we can check
180 that the endpoint multiplicity is two */
181 for(s=0;s<stroke->num_points;s++) {
182 point_t p = stroke->points[s];
183 int num = (s>=1 && s<stroke->num_points-1)?2:1; // mid points are two points (start+end)
184 if(!dict_contains(d, &p)) {
185 dict_put(d, &p, (void*)(ptroff_t)num);
187 int count = (ptroff_t)dict_lookup(d, &p);
190 dict_put(d, &p, (void*)(ptroff_t)count);
194 DICT_ITERATE_ITEMS(d, point_t*, p, void*, c) {
195 int count = (ptroff_t)c;
197 fprintf(stderr, "Point (%d,%d) occurs %d times\n", p->x, p->y, count);
199 assert(count%2 == 0);
206 void gfxpoly_dump(gfxpoly_t*poly)
209 double g = poly->gridsize;
210 fprintf(stderr, "polyon %p (gridsize: %f)\n", poly, poly->gridsize);
211 gfxpolystroke_t*stroke = poly->strokes;
212 for(;stroke;stroke=stroke->next) {
213 fprintf(stderr, "%p", stroke);
214 for(s=0;s<stroke->num_points-1;s++) {
215 point_t a = stroke->points[s];
216 point_t b = stroke->points[s+1];
217 fprintf(stderr, "%s (%f,%f) -> (%f,%f)%s\n", s?" ":"", a.x*g, a.y*g, b.x*g, b.y*g,
218 s==stroke->num_points-2?"]":"");
223 void gfxpoly_save(gfxpoly_t*poly, const char*filename)
225 FILE*fi = fopen(filename, "wb");
226 fprintf(fi, "%% gridsize %f\n", poly->gridsize);
227 fprintf(fi, "%% begin\n");
229 gfxpolystroke_t*stroke = poly->strokes;
230 for(;stroke;stroke=stroke->next) {
231 fprintf(fi, "%g setgray\n", stroke->dir==DIR_UP ? 0.7 : 0);
232 point_t p = stroke->points[0];
233 fprintf(fi, "%d %d moveto\n", p.x, p.y);
234 for(s=1;s<stroke->num_points;s++) {
235 p = stroke->points[s];
236 fprintf(fi, "%d %d lineto\n", p.x, p.y);
238 fprintf(fi, "stroke\n");
240 fprintf(fi, "showpage\n");
244 inline static event_t* event_new()
246 event_t*e = rfx_calloc(sizeof(event_t));
249 inline static void event_free(event_t*e)
254 static void event_dump(event_t*e)
256 if(e->type == EVENT_HORIZONTAL) {
257 fprintf(stderr, "Horizontal [%d] (%d,%d) -> (%d,%d)\n", (int)e->s1->nr, e->s1->a.x, e->s1->a.y, e->s1->b.x, e->s1->b.y);
258 } else if(e->type == EVENT_START) {
259 fprintf(stderr, "event: segment [%d] starts at (%d,%d)\n", (int)e->s1->nr, e->p.x, e->p.y);
260 } else if(e->type == EVENT_END) {
261 fprintf(stderr, "event: segment [%d] ends at (%d,%d)\n", (int)e->s1->nr, e->p.x, e->p.y);
262 } else if(e->type == EVENT_CROSS) {
263 fprintf(stderr, "event: segment [%d] and [%d] intersect at (%d,%d)\n", (int)e->s1->nr, (int)e->s2->nr, e->p.x, e->p.y);
269 static inline int32_t max32(int32_t v1, int32_t v2) {return v1>v2?v1:v2;}
270 static inline int32_t min32(int32_t v1, int32_t v2) {return v1<v2?v1:v2;}
272 static void segment_dump(segment_t*s)
274 fprintf(stderr, "[%d] (%d,%d)->(%d,%d) ", (int)s->nr, s->a.x, s->a.y, s->b.x, s->b.y);
275 fprintf(stderr, " dx:%d dy:%d k:%f dx/dy=%f fs=%p\n", s->delta.x, s->delta.y, s->k,
276 (double)s->delta.x / s->delta.y, s->fs);
279 static void segment_init(segment_t*s, int32_t x1, int32_t y1, int32_t x2, int32_t y2, int polygon_nr, segment_dir_t dir)
285 /* We need to make sure horizontal segments always go from left to right.
286 "up/down" for horizontal segments is handled by "rotating"
287 them 90° anticlockwise in screen coordinates (tilt your head to
293 int32_t x = x1;x1=x2;x2=x;
294 int32_t y = y1;y1=y2;y2=y;
301 s->k = (double)x1*y2-(double)x2*y1;
302 s->left = s->right = 0;
305 s->minx = min32(x1,x2);
306 s->maxx = max32(x1,x2);
309 s->polygon_nr = polygon_nr;
310 static int segment_count=0;
311 s->nr = segment_count++;
314 /* notice: on some systems (with some compilers), for the line
315 (1073741823,-1073741824)->(1073741823,1073741823)
316 we get LINE_EQ(s->a, s) == 1.
317 That's why we now clamp to 26 bit.
319 assert(LINE_EQ(s->a, s) == 0);
320 assert(LINE_EQ(s->b, s) == 0);
322 /* check that all signs are in order:
330 p.x = min32(s->a.x, s->b.x);
331 assert(LINE_EQ(p, s) <= 0);
332 p.x = max32(s->a.x, s->b.x);
333 assert(LINE_EQ(p, s) >= 0);
336 #ifndef DONT_REMEMBER_CROSSINGS
337 dict_init2(&s->scheduled_crossings, &ptr_type, 0);
341 static segment_t* segment_new(point_t a, point_t b, int polygon_nr, segment_dir_t dir)
343 segment_t*s = (segment_t*)rfx_calloc(sizeof(segment_t));
344 segment_init(s, a.x, a.y, b.x, b.y, polygon_nr, dir);
348 static void segment_clear(segment_t*s)
350 #ifndef DONT_REMEMBER_CROSSINGS
351 dict_clear(&s->scheduled_crossings);
354 static void segment_destroy(segment_t*s)
360 static void advance_stroke(queue_t*queue, hqueue_t*hqueue, gfxpolystroke_t*stroke, int polygon_nr, int pos)
365 /* we need to queue multiple segments at once because we need to process start events
366 before horizontal events */
367 while(pos < stroke->num_points-1) {
368 assert(stroke->points[pos].y <= stroke->points[pos+1].y);
369 s = segment_new(stroke->points[pos], stroke->points[pos+1], polygon_nr, stroke->dir);
377 fprintf(stderr, "[%d] (%d,%d) -> (%d,%d) %s (stroke %p, %d more to come)\n",
378 s->nr, s->a.x, s->a.y, s->b.x, s->b.y,
379 s->dir==DIR_UP?"up":"down", stroke, stroke->num_points - 1 - pos);
381 event_t* e = event_new();
382 e->type = s->delta.y ? EVENT_START : EVENT_HORIZONTAL;
387 if(queue) queue_put(queue, e);
388 else hqueue_put(hqueue, e);
390 if(e->type != EVENT_HORIZONTAL) {
400 static void gfxpoly_enqueue(gfxpoly_t*p, queue_t*queue, hqueue_t*hqueue, int polygon_nr)
403 gfxpolystroke_t*stroke = p->strokes;
404 for(;stroke;stroke=stroke->next) {
405 assert(stroke->num_points > 1);
409 for(s=0;s<stroke->num_points-1;s++) {
410 assert(stroke->points[s].y <= stroke->points[s+1].y);
413 advance_stroke(queue, hqueue, stroke, polygon_nr, 0);
417 static void schedule_endpoint(status_t*status, segment_t*s)
419 // schedule end point of segment
420 assert(s->b.y > status->y);
421 event_t*e = event_new();
426 queue_put(&status->queue, e);
429 static void schedule_crossing(status_t*status, segment_t*s1, segment_t*s2)
431 /* the code that's required (and the checks you can perform) before
432 it can be said with 100% certainty that we indeed have a valid crossing
433 amazes me every time. -mk */
436 assert(s1->right == s2);
437 assert(s2->left == s1);
438 int32_t miny1 = min32(s1->a.y,s1->b.y);
439 int32_t maxy1 = max32(s1->a.y,s1->b.y);
440 int32_t miny2 = min32(s2->a.y,s2->b.y);
441 int32_t maxy2 = max32(s2->a.y,s2->b.y);
442 int32_t minx1 = min32(s1->a.x,s1->b.x);
443 int32_t minx2 = min32(s2->a.x,s2->b.x);
444 int32_t maxx1 = max32(s1->a.x,s1->b.x);
445 int32_t maxx2 = max32(s2->a.x,s2->b.x);
446 /* check that precomputation is sane */
447 assert(minx1 == s1->minx && minx2 == s2->minx);
448 assert(maxx1 == s1->maxx && maxx2 == s2->maxx);
449 /* both segments are active, so this can't happen */
450 assert(!(maxy1 <= miny2 || maxy2 <= miny1));
451 /* we know that right now, s2 is to the right of s1, so there's
452 no way the complete bounding box of s1 is to the right of s1 */
453 assert(!(s1->minx > s2->maxx));
454 assert(s1->minx != s2->maxx || (!s1->delta.x && !s2->delta.x));
457 if(s1->maxx <= s2->minx) {
459 fprintf(stderr, "[%d] doesn't intersect with [%d] because: bounding boxes don't intersect\n", s1->nr, s2->nr);
461 /* bounding boxes don't intersect */
465 #ifndef DONT_REMEMBER_CROSSINGS
466 if(dict_contains(&s1->scheduled_crossings, (void*)(ptroff_t)s2->nr)) {
467 /* FIXME: this whole segment hashing thing is really slow */
469 fprintf(stderr, "[%d] doesn't intersect with [%d] because: we already scheduled this intersection\n", s1->nr, s2->nr);
470 // DICT_ITERATE_KEY(&s1->scheduled_crossings, void*, x) {
471 // fprintf(stderr, "[%d]<->[%d]\n", s1->nr, (int)(ptroff_t)x);
474 return; // we already know about this one
478 double det = (double)s1->delta.x*s2->delta.y - (double)s1->delta.y*s2->delta.x;
481 // lines are exactly on top of each other (ignored)
483 fprintf(stderr, "Notice: segments [%d] and [%d] are exactly on top of each other\n", s1->nr, s2->nr);
488 fprintf(stderr, "[%d] doesn't intersect with [%d] because: they are parallel to each other\n", s1->nr, s2->nr);
490 /* lines are parallel */
495 double asign2 = LINE_EQ(s1->a, s2);
497 // segment1 touches segment2 in a single point (ignored)
499 fprintf(stderr, "Notice: segment [%d]'s start point touches segment [%d]\n", s1->nr, s2->nr);
503 double bsign2 = LINE_EQ(s1->b, s2);
505 // segment1 touches segment2 in a single point (ignored)
507 fprintf(stderr, "Notice: segment [%d]'s end point touches segment [%d]\n", s1->nr, s2->nr);
512 if(asign2<0 && bsign2<0) {
513 // segment1 is completely to the left of segment2
515 fprintf(stderr, "[%d] doesn't intersect with [%d] because: [%d] is completely to the left of [%d]\n", s1->nr, s2->nr, s1->nr, s2->nr);
519 if(asign2>0 && bsign2>0) {
520 // segment1 is completely to the right of segment2
521 #ifndef DONT_REMEMBER_CROSSINGS
525 fprintf(stderr, "[%d] doesn't intersect with [%d] because: [%d] is completely to the left of [%d]\n", s1->nr, s2->nr, s2->nr, s1->nr);
530 double asign1 = LINE_EQ(s2->a, s1);
532 // segment2 touches segment1 in a single point (ignored)
534 fprintf(stderr, "Notice: segment [%d]'s start point touches segment [%d]\n", s2->nr, s1->nr);
538 double bsign1 = LINE_EQ(s2->b, s1);
540 // segment2 touches segment1 in a single point (ignored)
542 fprintf(stderr, "Notice: segment [%d]'s end point touches segment [%d]\n", s2->nr, s1->nr);
547 if(asign1<0 && bsign1<0) {
548 // segment2 is completely to the left of segment1
549 #ifndef DONT_REMEMBER_CROSSINGS
553 fprintf(stderr, "[%d] doesn't intersect with [%d] because: [%d] is completely to the left of [%d]\n", s1->nr, s2->nr, s1->nr, s2->nr);
557 if(asign1>0 && bsign1>0) {
558 // segment2 is completely to the right of segment1
560 fprintf(stderr, "[%d] doesn't intersect with [%d] because: [%d] is completely to the left of [%d]\n", s1->nr, s2->nr, s2->nr, s1->nr);
565 #ifdef DONT_REMEMBER_CROSSINGS
566 /* s2 crosses s1 from *left* to *right*. This is a crossing we already processed-
567 there's not way s2 would be to the left of s1 otherwise */
568 if(asign1<0 && bsign1>0) return;
569 if(asign2>0 && bsign2<0) return;
572 assert(!(asign1<0 && bsign1>0));
573 assert(!(asign2>0 && bsign2<0));
575 /* TODO: should we precompute these? */
576 double la = (double)s1->a.x*(double)s1->b.y - (double)s1->a.y*(double)s1->b.x;
577 double lb = (double)s2->a.x*(double)s2->b.y - (double)s2->a.y*(double)s2->b.x;
580 p.x = (int32_t)ceil((-la*s2->delta.x + lb*s1->delta.x) / det);
581 p.y = (int32_t)ceil((+lb*s1->delta.y - la*s2->delta.y) / det);
583 assert(p.y >= status->y);
585 assert(p.x >= s1->minx && p.x <= s1->maxx);
586 assert(p.x >= s2->minx && p.x <= s2->maxx);
591 #ifndef DONT_REMEMBER_CROSSINGS
592 assert(!dict_contains(status->seen_crossings, &pair));
593 dict_put(status->seen_crossings, &pair, 0);
597 fprintf(stderr, "schedule crossing between [%d] and [%d] at (%d,%d)\n", s1->nr, s2->nr, p.x, p.y);
600 #ifndef DONT_REMEMBER_CROSSINGS
601 /* we insert into each other's intersection history because these segments might switch
602 places and we still want to look them up quickly after they did */
603 dict_put(&s1->scheduled_crossings, (void*)(ptroff_t)(s2->nr), 0);
604 dict_put(&s2->scheduled_crossings, (void*)(ptroff_t)(s1->nr), 0);
607 event_t* e = event_new();
608 e->type = EVENT_CROSS;
612 queue_put(&status->queue, e);
616 static void exchange_two(status_t*status, event_t*e)
618 //exchange two segments in list
619 segment_t*s1 = e->s1;
620 segment_t*s2 = e->s2;
622 if(!dict_contains(status->intersecting_segs, s1))
623 dict_put(status->intersecting_segs, s1, 0);
624 if(!dict_contains(status->intersecting_segs, s2))
625 dict_put(status->intersecting_segs, s2, 0);
627 assert(s2->left == s1);
628 assert(s1->right == s2);
629 actlist_swap(status->actlist, s1, s2);
630 assert(s2->right == s1);
631 assert(s1->left == s2);
632 segment_t*left = s2->left;
633 segment_t*right = s1->right;
635 schedule_crossing(status, left, s2);
637 schedule_crossing(status, s1, right);
640 typedef struct _box {
641 point_t left1, left2, right1, right2;
643 static inline box_t box_new(int32_t x, int32_t y)
646 box.right1.x = box.right2.x = x;
647 box.left1.x = box.left2.x = x-1;
648 box.left1.y = box.right1.y = y-1;
649 box.left2.y = box.right2.y = y;
653 static void insert_point_into_segment(status_t*status, segment_t*s, point_t p)
655 assert(s->pos.x != p.x || s->pos.y != p.y);
658 if(!dict_contains(status->segs_with_point, s))
659 dict_put(status->segs_with_point, s, 0);
660 assert(s->fs_out_ok);
665 fprintf(stderr, "[%d] receives next point (%d,%d)->(%d,%d) (drawing)\n", s->nr,
666 s->pos.x, s->pos.y, p.x, p.y);
668 edgestyle_t*fs = s->fs_out;
669 segment_dir_t dir = s->wind.is_filled?DIR_DOWN:DIR_UP;
671 // omit horizontal lines
672 if(s->pos.y != p.y) {
677 gfxpolystroke_t*stroke = status->strokes;
678 /* find a stoke to attach this segment to. It has to have an endpoint
679 matching our start point, and a matching edgestyle */
681 point_t p = stroke->points[stroke->num_points-1];
682 if(p.x == a.x && p.y == a.y && stroke->fs == fs && stroke->dir == dir)
684 stroke = stroke->next;
687 stroke = rfx_calloc(sizeof(gfxpolystroke_t));
690 stroke->next = status->strokes;
691 status->strokes = stroke;
692 stroke->points_size = 2;
693 stroke->points = rfx_calloc(sizeof(point_t)*stroke->points_size);
694 stroke->points[0] = a;
695 stroke->num_points = 1;
696 } else if(stroke->num_points == stroke->points_size) {
698 stroke->points_size *= 2;
699 stroke->points = rfx_realloc(stroke->points, sizeof(point_t)*stroke->points_size);
701 stroke->points[stroke->num_points++] = b;
705 fprintf(stderr, "[%d] receives next point (%d,%d) (omitting)\n", s->nr, p.x, p.y);
711 typedef struct _segrange {
718 static void segrange_adjust_endpoints(segrange_t*range, int32_t y)
720 #define XPOS_EQ(s1,s2,ypos) (XPOS((s1),(ypos))==XPOS((s2),(ypos)))
721 segment_t*min = range->segmin;
722 segment_t*max = range->segmax;
724 /* we need this because if two segments intersect exactly on
725 the scanline, segrange_test_segment_{min,max} can't tell which
726 one is smaller/larger */
727 if(min) while(min->left && XPOS_EQ(min, min->left, y)) {
730 if(max) while(max->right && XPOS_EQ(max, max->right, y)) {
736 static void segrange_test_segment_min(segrange_t*range, segment_t*seg, int32_t y)
739 /* we need to calculate the xpos anew (and can't use start coordinate or
740 intersection coordinate), because we need the xpos exactly at the end of
743 double x = XPOS(seg, y);
744 if(!range->segmin || x<range->xmin) {
749 static void segrange_test_segment_max(segrange_t*range, segment_t*seg, int32_t y)
752 double x = XPOS(seg, y);
753 if(!range->segmax || x>range->xmax) {
768 static void add_points_to_positively_sloped_segments(status_t*status, int32_t y, segrange_t*range)
770 segment_t*first=0, *last = 0;
772 for(t=0;t<status->xrow->num;t++) {
773 box_t box = box_new(status->xrow->x[t], y);
774 segment_t*seg = actlist_find(status->actlist, box.left2, box.left2);
776 seg = actlist_right(status->actlist, seg);
779 // this segment started in this scanline, ignore it
780 seg->changed = 1;last = seg;if(!first) {first=seg;}
781 } else if(seg->delta.x <= 0) {
782 // ignore segment w/ negative slope
784 last = seg;if(!first) {first=seg;}
785 double d1 = LINE_EQ(box.right1, seg);
786 double d2 = LINE_EQ(box.right2, seg);
789 insert_point_into_segment(status, seg, box.right2);
791 /* we unfortunately can't break here- the active list is sorted according
792 to the *bottom* of the scanline. hence pretty much everything that's still
793 coming might reach into our box */
800 segrange_test_segment_min(range, first, y);
801 segrange_test_segment_max(range, last, y);
811 static void add_points_to_negatively_sloped_segments(status_t*status, int32_t y, segrange_t*range)
813 segment_t*first=0, *last = 0;
815 for(t=status->xrow->num-1;t>=0;t--) {
816 box_t box = box_new(status->xrow->x[t], y);
817 segment_t*seg = actlist_find(status->actlist, box.right2, box.right2);
821 // this segment started in this scanline, ignore it
822 seg->changed = 1;last = seg;if(!first) {first=seg;}
823 } else if(seg->delta.x > 0) {
824 // ignore segment w/ positive slope
826 last = seg;if(!first) {first=seg;}
827 double d1 = LINE_EQ(box.left1, seg);
828 double d2 = LINE_EQ(box.left2, seg);
831 insert_point_into_segment(status, seg, box.right2);
839 segrange_test_segment_min(range, last, y);
840 segrange_test_segment_max(range, first, y);
843 /* segments ending in the current scanline need xrow treatment like everything else.
844 (consider an intersection taking place just above a nearly horizontal segment
845 ending on the current scanline- the intersection would snap down *below* the
846 ending segment if we don't add the intersection point to the latter right away)
847 we need to treat ending segments seperately, however. we have to delete them from
848 the active list right away to make room for intersect operations (which might
849 still be in the current scanline- consider two 45° polygons and a vertical polygon
850 intersecting on an integer coordinate). but once they're no longer in the active list,
851 we can't use the add_points_to_*_sloped_segments() functions anymore, and re-adding
852 them to the active list just for point snapping would be overkill.
853 (One other option to consider, however, would be to create a new active list only
856 static void add_points_to_ending_segments(status_t*status, int32_t y)
858 segment_t*seg = status->ending_segments;
860 segment_t*next = seg->right;seg->right=0;
862 assert(seg->b.y == status->y);
864 if(status->xrow->num == 1) {
866 assert(seg->b.x == status->xrow->x[0]);
867 point_t p = {status->xrow->x[0], y};
868 insert_point_into_segment(status, seg, p);
871 int start=0,end=status->xrow->num,dir=1;
872 if(seg->delta.x < 0) {
873 start = status->xrow->num-1;
876 for(t=start;t!=end;t+=dir) {
877 box_t box = box_new(status->xrow->x[t], y);
878 double d0 = LINE_EQ(box.left1, seg);
879 double d1 = LINE_EQ(box.left2, seg);
880 double d2 = LINE_EQ(box.right1, seg);
881 double d3 = LINE_EQ(box.right2, seg);
882 if(!(d0>=0 && d1>=0 && d2>=0 && d3>0 ||
883 d0<=0 && d1<=0 && d2<=0 && d3<0)) {
884 insert_point_into_segment(status, seg, box.right2);
890 /* we *need* to find a point to insert. the segment's own end point
891 is in that list, for Pete's sake. */
895 // now that this is done, too, we can also finally free this segment
896 segment_destroy(seg);
899 status->ending_segments = 0;
902 static void recalculate_windings(status_t*status, segrange_t*range)
905 fprintf(stderr, "range: [%d]..[%d]\n", SEGNR(range->segmin), SEGNR(range->segmax));
907 segrange_adjust_endpoints(range, status->y);
909 segment_t*s = range->segmin;
910 segment_t*end = range->segmax;
914 s = actlist_leftmost(status->actlist);
916 fprintf(stderr, "[%d]%d%s ", s->nr, s->changed,
917 s == range->segmin?"S":(
918 s == range->segmax?"E":""));
921 fprintf(stderr, "\n");
925 /* test sanity: verify that we don't have changed segments
926 outside of the given range */
927 s = actlist_leftmost(status->actlist);
928 while(s && s!=range->segmin) {
932 s = actlist_rightmost(status->actlist);
933 while(s && s!=range->segmax) {
937 /* in check mode, go through the whole interval so we can test
938 that all polygons where the edgestyle changed also have seg->changed=1 */
939 s = actlist_leftmost(status->actlist);
950 segment_t* left = actlist_left(status->actlist, s);
951 windstate_t wind = left?left->wind:status->windrule->start(status->context);
952 s->wind = status->windrule->add(status->context, wind, s->fs, s->dir, s->polygon_nr);
953 edgestyle_t*fs_old = s->fs_out;
954 s->fs_out = status->windrule->diff(&wind, &s->wind);
957 fprintf(stderr, "[%d] dir=%s wind=%d wind.filled=%s fs_old/new=%s/%s %s\n", s->nr, s->dir==DIR_UP?"up":"down", s->wind.wind_nr, s->wind.is_filled?"fill":"nofill",
958 fs_old?"draw":"omit", s->fs_out?"draw":"omit",
959 fs_old!=s->fs_out?"CHANGED":"");
961 assert(!(!s->changed && fs_old!=s->fs_out));
972 /* we need to handle horizontal lines in order to add points to segments
973 we otherwise would miss during the windrule re-evaluation */
974 static void intersect_with_horizontal(status_t*status, segment_t*h)
976 segment_t* left = actlist_find(status->actlist, h->a, h->a);
977 segment_t* right = actlist_find(status->actlist, h->b, h->b);
979 /* not strictly necessary, also done by the event */
980 xrow_add(status->xrow, h->a.x);
988 left = actlist_right(status->actlist, left); //first seg to the right of h->a
989 right = right->right; //first seg to the right of h->b
994 int32_t x = XPOS_INT(s, status->y);
996 fprintf(stderr, "...into [%d] (%d,%d) -> (%d,%d) at (%d,%d)\n", s->nr,
1002 assert(x >= h->a.x);
1003 assert(x <= h->b.x);
1004 assert(s->delta.x > 0 && x >= s->a.x || s->delta.x <= 0 && x <= s->a.x);
1005 assert(s->delta.x > 0 && x <= s->b.x || s->delta.x <= 0 && x >= s->b.x);
1006 xrow_add(status->xrow, x);
1012 static void event_apply(status_t*status, event_t*e)
1015 case EVENT_HORIZONTAL: {
1016 segment_t*s = e->s1;
1020 intersect_with_horizontal(status, s);
1021 advance_stroke(&status->queue, 0, s->stroke, s->polygon_nr, s->stroke_pos);
1022 segment_destroy(s);e->s1=0;
1026 //delete segment from list
1027 segment_t*s = e->s1;
1032 dict_del(status->intersecting_segs, s);
1033 dict_del(status->segs_with_point, s);
1034 assert(!dict_contains(status->intersecting_segs, s));
1035 assert(!dict_contains(status->segs_with_point, s));
1037 segment_t*left = s->left;
1038 segment_t*right = s->right;
1039 actlist_delete(status->actlist, s);
1041 schedule_crossing(status, left, right);
1043 /* schedule segment for xrow handling */
1044 s->left = 0; s->right = status->ending_segments;
1045 status->ending_segments = s;
1046 advance_stroke(&status->queue, 0, s->stroke, s->polygon_nr, s->stroke_pos);
1050 //insert segment into list
1054 segment_t*s = e->s1;
1055 assert(e->p.x == s->a.x && e->p.y == s->a.y);
1056 actlist_insert(status->actlist, s->a, s->b, s);
1057 segment_t*left = s->left;
1058 segment_t*right = s->right;
1060 schedule_crossing(status, left, s);
1062 schedule_crossing(status, s, right);
1063 schedule_endpoint(status, s);
1067 // exchange two segments
1071 if(e->s1->right == e->s2) {
1072 assert(e->s2->left == e->s1);
1073 exchange_two(status, e);
1075 assert(e->s2->left != e->s1);
1077 fprintf(stderr, "Ignore this crossing ([%d] not next to [%d])\n", e->s1->nr, e->s2->nr);
1079 #ifndef DONT_REMEMBER_CROSSINGS
1080 /* ignore this crossing for now (there are some line segments in between).
1081 it'll get rescheduled as soon as the "obstacles" are gone */
1082 char del1 = dict_del(&e->s1->scheduled_crossings, (void*)(ptroff_t)e->s2->nr);
1083 char del2 = dict_del(&e->s2->scheduled_crossings, (void*)(ptroff_t)e->s1->nr);
1084 assert(del1 && del2);
1090 #ifndef DONT_REMEMBER_CROSSINGS
1091 assert(dict_contains(status->seen_crossings, &pair));
1092 dict_del(status->seen_crossings, &pair);
1101 static void check_status(status_t*status)
1103 DICT_ITERATE_KEY(status->intersecting_segs, segment_t*, s) {
1104 if((s->pos.x != s->b.x ||
1105 s->pos.y != s->b.y) &&
1106 !dict_contains(status->segs_with_point, s)) {
1107 fprintf(stderr, "Error: segment [%d] (%sslope) intersects in scanline %d, but it didn't receive a point\n",
1109 s->delta.x<0?"-":"+",
1117 static void add_horizontals(gfxpoly_t*poly, windrule_t*windrule, windcontext_t*context)
1120 |..| |...........| | |
1121 |..| |...........| | |
1122 |..+ + +..| +--+ +--+
1123 |...........| |..| | |
1124 |...........| |..| | |
1128 fprintf(stderr, "========================================================================\n");
1131 hqueue_init(&hqueue);
1132 gfxpoly_enqueue(poly, 0, &hqueue, 0);
1134 actlist_t* actlist = actlist_new();
1136 event_t*e = hqueue_get(&hqueue);
1141 fprintf(stderr, "HORIZONTALS ----------------------------------- %d\n", y);
1142 actlist_dump(actlist, y-1);
1145 actlist_verify(actlist, y-1);
1147 edgestyle_t*fill = 0;
1153 if(fill && x != e->p.x) {
1154 assert(!dir_up || !dir_down);
1155 assert(dir_up || dir_down);
1157 fprintf(stderr, "%d) draw horizontal line from %d to %d\n", y, x, e->p.x);
1161 gfxpolystroke_t*stroke = rfx_calloc(sizeof(gfxpolystroke_t));
1162 stroke->next = poly->strokes;
1163 poly->strokes = stroke;
1165 stroke->num_points = 2;
1166 stroke->points = malloc(sizeof(point_t)*2);
1167 stroke->dir = dir_up?DIR_UP:DIR_DOWN;
1171 /* we draw from low x to high x so that left/right fillstyles add up
1172 (because the horizontal line's fill style controls the area *below* the line)
1176 stroke->points[0] = a;
1177 stroke->points[1] = b;
1179 /* the output should always be intersection free polygons, so check this horizontal
1180 line isn't puncturing any segments in the active list */
1181 segment_t* start = actlist_find(actlist, b, b);
1182 segment_t* s = actlist_find(actlist, a, a);
1184 assert(s->a.y == y || s->b.y == y);
1190 segment_t*s = e->s1;
1195 assert(e->p.x == s->a.x && e->p.y == s->a.y);
1196 actlist_insert(actlist, s->a, s->b, s);
1197 event_t* e = event_new();
1198 e->type = EVENT_END;
1202 hqueue_put(&hqueue, e);
1203 left = actlist_left(actlist, s);
1208 left = actlist_left(actlist, s);
1209 actlist_delete(actlist, s);
1210 advance_stroke(0, &hqueue, s->stroke, s->polygon_nr, s->stroke_pos);
1219 fill = fill?0:&edgestyle_default;
1221 if(windrule==&windrule_evenodd) {
1222 if(!!fill != !!fill2) {
1225 printf("at y=%d x=%d (hline:%p)\n", e->p.y, x, old_fill);
1226 if(e->type==EVENT_END) {
1227 printf(" %9p\n", s->fs);
1230 printf(" %3d %c%2d \n", before1.is_filled, e->type==EVENT_END?'|':' ', after1.is_filled);
1231 printf("%12p -----+----- %p\n", old_fill, fill2);
1232 printf(" %3d %c%2d \n", before2.is_filled, e->type==EVENT_START?'|':' ', after2.is_filled);
1233 if(e->type==EVENT_START) {
1235 printf(" %9p\n", s->fs);
1238 assert(!!fill == !!fill2);
1243 fprintf(stderr, "%d) event=%s[%d] left:[%d] x:%d\n",
1244 y, e->type==EVENT_START?"start":"end",
1250 if(e->type == EVENT_END)
1254 e = hqueue_get(&hqueue);
1255 } while(e && y == e->p.y);
1258 edgestyle_t*bleeding = fill;
1263 actlist_destroy(actlist);
1264 hqueue_destroy(&hqueue);
1267 gfxpoly_t* gfxpoly_process(gfxpoly_t*poly1, gfxpoly_t*poly2, windrule_t*windrule, windcontext_t*context)
1269 current_polygon = poly1;
1272 memset(&status, 0, sizeof(status_t));
1273 queue_init(&status.queue);
1274 gfxpoly_enqueue(poly1, &status.queue, 0, /*polygon nr*/0);
1276 assert(poly1->gridsize == poly2->gridsize);
1277 gfxpoly_enqueue(poly2, &status.queue, 0, /*polygon nr*/1);
1280 status.windrule = windrule;
1281 status.context = context;
1282 status.actlist = actlist_new();
1285 status.seen_crossings = dict_new2(&point_type);
1286 int32_t lasty=-0x80000000;
1289 status.xrow = xrow_new();
1291 event_t*e = queue_get(&status.queue);
1296 assert(status.y>=lasty);
1298 status.intersecting_segs = dict_new2(&ptr_type);
1299 status.segs_with_point = dict_new2(&ptr_type);
1303 fprintf(stderr, "----------------------------------- %d\n", status.y);
1304 actlist_dump(status.actlist, status.y-1);
1307 actlist_verify(status.actlist, status.y-1);
1309 xrow_reset(status.xrow);
1311 xrow_add(status.xrow, e->p.x);
1312 event_apply(&status, e);
1314 e = queue_get(&status.queue);
1315 } while(e && status.y == e->p.y);
1317 xrow_sort(status.xrow);
1319 memset(&range, 0, sizeof(range));
1321 actlist_dump(status.actlist, status.y);
1323 add_points_to_positively_sloped_segments(&status, status.y, &range);
1324 add_points_to_negatively_sloped_segments(&status, status.y, &range);
1325 add_points_to_ending_segments(&status, status.y);
1327 recalculate_windings(&status, &range);
1329 check_status(&status);
1330 dict_destroy(status.intersecting_segs);
1331 dict_destroy(status.segs_with_point);
1335 dict_destroy(status.seen_crossings);
1337 actlist_destroy(status.actlist);
1338 queue_destroy(&status.queue);
1339 xrow_destroy(status.xrow);
1341 gfxpoly_t*p = (gfxpoly_t*)malloc(sizeof(gfxpoly_t));
1342 p->gridsize = poly1->gridsize;
1343 p->strokes = status.strokes;
1346 /* we only add segments with non-empty edgestyles to strokes in
1347 recalculate_windings, but better safe than sorry */
1348 gfxpolystroke_t*stroke = p->strokes;
1351 stroke = stroke->next;
1355 add_horizontals(p, &windrule_evenodd, context); // output is always even/odd
1356 //add_horizontals(p, windrule, context);
1360 static windcontext_t twopolygons = {2};
1361 gfxpoly_t* gfxpoly_intersect(gfxpoly_t*p1, gfxpoly_t*p2)
1363 return gfxpoly_process(p1, p2, &windrule_intersect, &twopolygons);
1365 gfxpoly_t* gfxpoly_union(gfxpoly_t*p1, gfxpoly_t*p2)
1367 return gfxpoly_process(p1, p2, &windrule_union, &twopolygons);