#include <memory.h>
#include <math.h>
#include "../mem.h"
+#include "../types.h"
#include "../q.h"
#include "poly.h"
#include "active.h"
#include "xrow.h"
+#include "wind.h"
//#define DEBUG
//#undef assert
-//#define assert(x)
+//#define assert(x)
-char point_equals(const void*o1, const void*o2)
+char point_equals(const void*o1, const void*o2)
{
const point_t*p1 = o1;
const point_t*p2 = o2;
return p1->x == p2->x && p1->y == p2->y;
}
-unsigned int point_hash(const void*o)
+unsigned int point_hash(const void*o)
{
const point_t*p = o;
return p->x^p->y;
}
-void* point_dup(const void*o)
+void* point_dup(const void*o)
{
const point_t*p = o;
point_t*n = malloc(sizeof(point_t));
n->y = p->y;
return n;
}
-void point_free(void*o)
+void point_free(void*o)
{
point_t*p = o;
p->x = 0;
typedef struct _status {
int y;
+ int num_polygons;
actlist_t*actlist;
heap_t*queue;
edge_t*output;
xrow_t*xrow;
+ windrule_t*windrule;
#ifdef DEBUG
dict_t*seen_crossings; //list of crossing we saw so far
dict_t*intersecting_segs; //list of segments intersecting in this scanline
#endif
} status_t;
-int compare_events(const void*_a,const void*_b)
+int compare_events_simple(const void*_a,const void*_b)
{
event_t* a = (event_t*)_a;
- event_t* b = (event_t*)_b;
+ event_t* b = (event_t*)_b;
if(a->p.y < b->p.y) {
return 1;
} else if(a->p.y > b->p.y) {
return -1;
- /* we should schedule start events after end/intersect.
- The order of end/intersect doesn't actually matter, however,
- so this might be doing too much */
- } else if(a->type < b->type) {
- return 1;
- } else if(a->type > b->type) {
- return -1;
} else if(a->p.x < b->p.x) {
return 1;
} else if(a->p.x > b->p.x) {
return 0;
}
-gfxpoly_t* gfxpoly_new()
+int compare_events(const void*_a,const void*_b)
+{
+ event_t* a = (event_t*)_a;
+ event_t* b = (event_t*)_b;
+ int d = b->p.y - a->p.y;
+ if(d) return d;
+ /* we should schedule start events after end/intersect.
+ The order of end/intersect doesn't actually matter, however,
+ so this might be doing too much */
+ d = b->type - a->type;
+ if(d) return d;
+ d = b->p.x - a->p.x;
+ return d;
+}
+
+gfxpoly_t* gfxpoly_new(double gridsize)
{
- return 0;
+ gfxpoly_t*p = (gfxpoly_t*)rfx_calloc(sizeof(gfxpoly_t));
+ p->gridsize = gridsize;
+ return p;
}
void gfxpoly_destroy(gfxpoly_t*poly)
{
- edge_t* s = poly;
+ edge_t* s = poly->edges;
while(s) {
edge_t*next = s->next;
free(s);
s = next;
}
+ free(poly);
+}
+char gfxpoly_check(gfxpoly_t*poly)
+{
+ edge_t* s = poly->edges;
+ dict_t*d = dict_new2(&point_type);
+ while(s) {
+ if(!dict_contains(d, &s->a)) {
+ dict_put(d, &s->a, (void*)(ptroff_t)1);
+ } else {
+ int count = (ptroff_t)dict_lookup(d, &s->a);
+ dict_del(d, &s->a);
+ count++;
+ dict_put(d, &s->a, (void*)(ptroff_t)count);
+ }
+ if(!dict_contains(d, &s->b)) {
+ dict_put(d, &s->b, (void*)(ptroff_t)1);
+ } else {
+ int count = (ptroff_t)dict_lookup(d, &s->b);
+ dict_del(d, &s->b);
+ count++;
+ dict_put(d, &s->b, (void*)(ptroff_t)count);
+ }
+ s = s->next;
+ }
+ DICT_ITERATE_ITEMS(d, point_t*, p, void*, c) {
+ int count = (ptroff_t)c;
+ if(count&1) {
+ fprintf(stderr, "Point (%f,%f) occurs %d times\n", p->x*poly->gridsize, p->y*poly->gridsize, count);
+ return 0;
+ }
+ }
+ return 1;
}
void gfxpoly_dump(gfxpoly_t*poly)
{
- edge_t* s = (edge_t*)poly;
+ edge_t* s = poly->edges;
+ double g = poly->gridsize;
while(s) {
- fprintf(stderr, "(%d,%d) -> (%d,%d)\n", s->a.x, s->a.y, s->b.x, s->b.y);
+ fprintf(stderr, "(%f,%f) -> (%f,%f)\n", s->a.x*g, s->a.y*g, s->b.x*g, s->b.y*g);
s = s->next;
}
}
static inline max32(int32_t v1, int32_t v2) {return v1>v2?v1:v2;}
static inline min32(int32_t v1, int32_t v2) {return v1<v2?v1:v2;}
-void segment_init(segment_t*s, int x1, int y1, int x2, int y2)
+void segment_init(segment_t*s, int x1, int y1, int x2, int y2, windstate_t windstate, int polygon_nr)
{
if(y1<y2) {
s->dir = DIR_DOWN;
int y = y1;y1=y2;y2=y;
s->dir = DIR_UP;
} else {
- s->dir = DIR_HORIZONTAL;
+ /* up/down for horizontal segments is handled by "rotating"
+ them 90° anticlockwise in screen coordinates (tilt your head to
+ the right) */
+ s->dir = DIR_UP;
if(x1>x2) {
+ s->dir = DIR_DOWN;
int x = x1;x1=x2;x2=x;
int y = y1;y1=y2;y2=y;
}
s->delta.x = x2-x1;
s->delta.y = y2-y1;
s->pos = s->a;
- s->tmp = -1;
- s->new_point.y = y1-1;
+ s->polygon_nr = polygon_nr;
#define XDEBUG
#ifdef XDEBUG
static int segment_count=0;
assert(LINE_EQ(s->a, s) == 0);
assert(LINE_EQ(s->b, s) == 0);
-
+
/* check that all signs are in order:
a a
|\ /|
dict_init2(&s->scheduled_crossings, &ptr_type, 0);
}
-segment_t* segment_new(int32_t x1, int32_t y1, int32_t x2, int32_t y2)
+segment_t* segment_new(int32_t x1, int32_t y1, int32_t x2, int32_t y2, windstate_t initial, int polygon_nr)
{
segment_t*s = (segment_t*)rfx_calloc(sizeof(segment_t));
- segment_init(s, x1, y1, x2, y2);
+ segment_init(s, x1, y1, x2, y2, initial, polygon_nr);
return s;
}
void segment_destroy(segment_t*s)
free(s);
}
-void gfxpoly_enqueue(edge_t*list, heap_t*queue)
+void gfxpoly_enqueue(edge_t*list, heap_t*queue, windstate_t initial, int polygon_nr)
{
edge_t*l;
for(l=list;l;l=l->next) {
- if(l->a.x == l->b.x &&
+ if(l->a.x == l->b.x &&
l->a.y == l->b.y) {
fprintf(stderr, "Warning: intersector input contains zero-length segments\n");
continue;
}
- segment_t*s = segment_new(l->a.x, l->a.y, l->b.x, l->b.y);
+ segment_t*s = segment_new(l->a.x, l->a.y, l->b.x, l->b.y, initial, polygon_nr);
#ifdef DEBUG
fprintf(stderr, "[%d] (%d,%d) -> (%d,%d) %s\n",
s->nr, s->a.x, s->a.y, s->b.x, s->b.y,
s->dir==DIR_UP?"up":"down");
#endif
event_t e = event_new();
- e.type = s->dir==DIR_HORIZONTAL?EVENT_HORIZONTAL:EVENT_START;
+ e.type = s->delta.y ? EVENT_START : EVENT_HORIZONTAL;
e.p = s->a;
e.s1 = s;
e.s2 = 0;
int32_t miny2 = min32(s2->a.y,s2->b.y);
int32_t maxx2 = max32(s2->a.x,s2->b.x);
int32_t maxy2 = max32(s2->a.y,s2->b.y);
-
+
/* both segments are active, so this can't happen */
assert(!(maxy1 <= miny2 || maxy2 <= miny1));
/* bounding boxes don't intersect */
return;
}
-
+
if(dict_contains(&s1->scheduled_crossings, s2)) {
/* FIXME: this whole segment hashing thing is really slow */
//fprintf(stderr, "Encountered crossing between [%d] and [%d] twice\n", s1->nr, s2->nr);
return box;
}
-void insert_point_into_segment(status_t*status, segment_t*s, point_t p)
-{
- edge_t*e = malloc(sizeof(edge_t));
- e->a = s->pos;
- e->b = p;
- assert(e->a.y != e->b.y);
- e->next = status->output;
- status->output = e;
-}
-void mark_point_in_segment(status_t*status, segment_t*s, point_t p)
+static void insert_point_into_segment(status_t*status, segment_t*s, point_t p)
{
-#ifdef DEBUG
- if(s->pos.x == p.x && s->pos.y == p.y) {
- fprintf(stderr, "Error: tried to add (%d,%d) to segment [%d] twice\n", p.x, p.y, s->nr);
- }
-#endif
assert(s->pos.x != p.x || s->pos.y != p.y);
+
#ifdef DEBUG
- fprintf(stderr, "[%d] gets extra point (%d,%d)\n", s->nr, p.x, p.y);
if(!dict_contains(status->segs_with_point, s))
dict_put(status->segs_with_point, s, 0);
#endif
- if(s->new_point.y != p.y) {
- s->new_point = p;
+
+ assert(s->fs_out_ok);
+ if(s->fs_out) {
+#ifdef DEBUG
+ fprintf(stderr, "[%d] receives next point (%d,%d) (drawing)\n", s->nr, p.x, p.y);
+#endif
+ // omit horizontal lines
+ if(s->pos.y != p.y) {
+ edge_t*e = malloc(sizeof(edge_t));
+ e->a = s->pos;
+ e->b = p;
+ assert(e->a.y != e->b.y);
+ e->next = status->output;
+ status->output = e;
+ }
+ } else {
+#ifdef DEBUG
+ fprintf(stderr, "[%d] receives next point (%d,%d) (omitting)\n", s->nr, p.x, p.y);
+#endif
}
- s->new_pos = p;
+ s->pos = p;
}
/* possible optimizations:
*/
/*
SLOPE_POSITIVE:
- \+ \ +
------- I \I
- -I\---- I
+ \+ \ +
+------ I \I
+ -I\---- I
I \ --I\---
I \ I \ -------
+ \ + \
*/
-static void mark_points_in_positively_sloped_segments(status_t*status, int32_t y)
+static void add_points_to_positively_sloped_segments(status_t*status, int32_t y)
{
int t;
for(t=0;t<status->xrow->num;t++) {
double d1 = LINE_EQ(box.right1, seg);
double d2 = LINE_EQ(box.right2, seg);
if(d1>=0 || d2>=0) {
- mark_point_in_segment(status, seg, box.right2);
+ insert_point_into_segment(status, seg, box.right2);
} else {
break;
}
| I | /I /
| /+ |/ + /
*/
-static void mark_points_in_negatively_sloped_segments(status_t*status, int32_t y)
+static void add_points_to_negatively_sloped_segments(status_t*status, int32_t y)
{
int t;
for(t=status->xrow->num-1;t>=0;t--) {
double d1 = LINE_EQ(box.left1, seg);
double d2 = LINE_EQ(box.left2, seg);
if(d1<0 || d2<0) {
- mark_point_in_segment(status, seg, box.right2);
+ insert_point_into_segment(status, seg, box.right2);
} else {
break;
}
}
}
-static void add_points(status_t*status)
+static void recalculate_windings(status_t*status)
{
/* TODO: we could use some clever second linked list structure so that we
- only need to process points which we know we marked */
- int t;
+ only need to process points we know we marked */
+
segment_t*s = actlist_leftmost(status->actlist);
+ segment_t*last = 0;
while(s) {
- if(s->new_point.y == status->y) {
- insert_point_into_segment(status, s, s->new_point);
- s->pos = s->new_pos;
- }
+ windstate_t wind = last?last->wind:status->windrule->start(status->num_polygons);
+ s->wind = status->windrule->add(wind, s->fs, s->dir, s->polygon_nr);
+ s->fs_out = status->windrule->diff(&wind, &s->wind);
+ s->fs_out_ok = 1;
+#ifdef DEBUG
+ fprintf(stderr, "[%d] %s/%d/%s/%s ", s->nr, s->dir==DIR_UP?"up":"down", s->wind.wind_nr, s->wind.is_filled?"fill":"nofill", s->fs_out?"draw":"omit");
+#endif
+ last = s;
s = actlist_right(status->actlist, s);
}
+#ifdef DEBUG
+ fprintf(stderr, "\n");
+#endif
+
}
+/* we need to handle horizontal lines in order to add points to segments
+ we otherwise would miss during the windrule re-evaluation */
void intersect_with_horizontal(status_t*status, segment_t*h)
{
segment_t* left = actlist_find(status->actlist, h->a, h->a);
segment_t* right = actlist_find(status->actlist, h->b, h->b);
- segment_t* s = right;
+ /* not strictly necessary, also done by the event */
+ xrow_add(status->xrow, h->a.x);
+ point_t o = h->a;
+
+ left = actlist_right(status->actlist, left);
+ right = actlist_right(status->actlist, right);
+ segment_t* s = left;
- while(s!=left) {
+ while(s!=right) {
assert(s);
/*
- x1 + ((x2-x1)*(y-y1)) / dy =
+ x1 + ((x2-x1)*(y-y1)) / dy =
(x1*(y2-y) + x2*(y-y1)) / dy
*/
point_t p;
p.y = status->y;
p.x = XPOS(s, p.y);
#ifdef DEBUG
- fprintf(stderr, "...into [%d] (%d,%d) -> (%d,%d) at (%d,%d)\n", s->nr,
+ fprintf(stderr, "...into [%d] (%d,%d) -> (%d,%d) at (%d,%d)\n", s->nr,
s->a.x, s->a.y,
s->b.x, s->b.y,
p.x, p.y
assert(s->delta.x > 0 && p.x <= s->b.x || s->delta.x <= 0 && p.x >= s->b.x);
xrow_add(status->xrow, p.x);
- s = actlist_left(status->actlist, s);
+ s = actlist_right(status->actlist, s);
}
- xrow_add(status->xrow, h->a.x);
}
void event_apply(status_t*status, event_t*e)
schedule_crossing(status, left, s);
if(right)
schedule_crossing(status, s, right);
-
schedule_endpoint(status, e->s1);
break;
}
case EVENT_CROSS: {
- // exchange two (or more) segments
+ // exchange two segments
+#ifdef DEBUG
+ event_dump(e);
+#endif
if(actlist_right(status->actlist, e->s1) == e->s2 &&
actlist_left(status->actlist, e->s2) == e->s1) {
exchange_two(status, e);
{
DICT_ITERATE_KEY(status->intersecting_segs, segment_t*, s) {
if((s->pos.x != s->b.x ||
- s->pos.y != s->b.y) &&
+ s->pos.y != s->b.y) &&
!dict_contains(status->segs_with_point, s)) {
- fprintf(stderr, "Error: segment [%d] (%sslope) intersects in scanline %d, but it didn't receive a point\n",
- s->nr,
+ fprintf(stderr, "Error: segment [%d] (%sslope) intersects in scanline %d, but it didn't receive a point\n",
+ s->nr,
s->delta.x<0?"-":"+",
status->y);
assert(0);
}
#endif
-edge_t* gfxpoly_process(edge_t*poly)
+static void add_horizontals(gfxpoly_t*poly, windrule_t*windrule)
+{
+ /*
+ |..| |...........| | |
+ |..| |...........| | |
+ |..+ + +..| +--+ +--+
+ |...........| |..| | |
+ |...........| |..| | |
+ */
+
+#ifdef DEBUG
+ fprintf(stderr, "========================================================================\n");
+#endif
+ heap_t* queue = heap_new(sizeof(event_t), compare_events_simple);
+ gfxpoly_enqueue(poly->edges, queue, windrule->start(1), 0);
+
+ actlist_t* actlist = actlist_new();
+
+ event_t*e = heap_chopmax(queue);
+ while(e) {
+ int y = e->p.y;
+ int x = 0;
+ char fill = 0;
+#ifdef DEBUG
+ actlist_verify_and_dump(actlist, y-1);
+#endif
+ do {
+ if(fill && x != e->p.x) {
+#ifdef DEBUG
+ fprintf(stderr, "%d) draw horizontal line from %d to %d\n", y, x, e->p.x);
+#endif
+ edge_t*l= malloc(sizeof(edge_t));
+ l->a.y = l->b.y = y;
+ l->a.x = x;
+ l->b.x = e->p.x;
+ l->next = poly->edges;
+ poly->edges = l;
+ }
+ segment_t*left = 0;
+ segment_t*s = e->s1;
+
+ windstate_t before,after;
+ switch(e->type) {
+ case EVENT_START: {
+ actlist_insert(actlist, e->p, s);
+ event_t e;
+ e.type = EVENT_END;
+ e.p = s->b;
+ e.s1 = s;
+ e.s2 = 0;
+ heap_put(queue, &e);
+ left = actlist_left(actlist, s);
+
+ before = left?left->wind:windrule->start(1);
+ after = s->wind = windrule->add(before, s->fs, s->dir, s->polygon_nr);
+ break;
+ }
+ case EVENT_END: {
+ left = actlist_left(actlist, s);
+ actlist_delete(actlist, s);
+
+ before = s->wind;
+ after = left?left->wind:windrule->start(1);
+ break;
+ }
+ default: assert(0);
+ }
+
+ x = e->p.x;
+ fill ^= 1;//(before.is_filled != after.is_filled);
+#ifdef DEBUG
+ fprintf(stderr, "%d) event=%s[%d] left:[%d] x:%d before:%d after:%d\n",
+ y, e->type==EVENT_START?"start":"end",
+ s->nr,
+ left?left->nr:-1,
+ x,
+ before.is_filled, after.is_filled);
+#endif
+
+ if(e->type == EVENT_END)
+ segment_destroy(s);
+
+ e = heap_chopmax(queue);
+ } while(e && y == e->p.y);
+
+ if(fill) {
+ fprintf(stderr, "Error: polygon is bleeding\n");
+ exit(0);
+ }
+ }
+}
+
+gfxpoly_t* gfxpoly_process(gfxpoly_t*poly, windrule_t*windrule)
{
heap_t* queue = heap_new(sizeof(event_t), compare_events);
- gfxpoly_enqueue(poly, queue);
+
+ gfxpoly_enqueue(poly->edges, queue, windrule->start(1), /*polygon nr*/0);
+
status_t status;
memset(&status, 0, sizeof(status_t));
+ status.num_polygons = 1;
status.queue = queue;
+ status.windrule = windrule;
status.actlist = actlist_new();
#ifdef DEBUG
status.seen_crossings = dict_new2(&point_type);
- gfxpoly_dump(poly);
#endif
-
+
status.xrow = xrow_new();
event_t*e = heap_chopmax(queue);
#endif
xrow_reset(status.xrow);
do {
- if(e->type != EVENT_HORIZONTAL) {
- xrow_add(status.xrow, e->p.x);
- }
+ xrow_add(status.xrow, e->p.x);
event_apply(&status, e);
free(e);
e = heap_chopmax(queue);
} while(e && status.y == e->p.y);
xrow_sort(status.xrow);
- mark_points_in_positively_sloped_segments(&status, status.y);
- mark_points_in_negatively_sloped_segments(&status, status.y);
- add_points(&status);
+ add_points_to_positively_sloped_segments(&status, status.y);
+ add_points_to_negatively_sloped_segments(&status, status.y);
+ recalculate_windings(&status);
#ifdef DEBUG
check_status(&status);
dict_destroy(status.intersecting_segs);
heap_destroy(queue);
xrow_destroy(status.xrow);
- return status.output;
+ gfxpoly_t*p = gfxpoly_new(poly->gridsize);
+ p->edges = status.output;
+
+ add_horizontals(p, &windrule_evenodd); // output is always even/odd
+ return p;
}