+#include <assert.h>
+#include "wind.h"
+
+fillstyle_t fillstyle_default;
+
+windstate_t windstate_nonfilled = {
+ is_filled: 0,
+ wind_nr: 0,
+
+ /* TODO: move num_polygons into windstate_t.internal */
+ num_polygons: 1,
+};
+
+// -------------------- even/odd ----------------------
+
+windstate_t evenodd_start(int num_polygons)
+{
+ return windstate_nonfilled;
+}
+windstate_t evenodd_add(windstate_t left, fillstyle_t*edge, segment_dir_t dir, int master)
+{
+ left.is_filled ^= 1;
+ return left;
+}
+fillstyle_t* evenodd_diff(windstate_t*left, windstate_t*right)
+{
+ if(left->is_filled==right->is_filled)
+ return 0;
+ else
+ return &fillstyle_default;
+}
+
+windrule_t windrule_evenodd = {
+ start: evenodd_start,
+ add: evenodd_add,
+ diff: evenodd_diff,
+};
+
+// -------------------- circular ----------------------
+
+windstate_t circular_start(int num_polygons)
+{
+ return windstate_nonfilled;
+}
+
+windstate_t circular_add(windstate_t left, fillstyle_t*edge, segment_dir_t dir, int master)
+{
+ /* which one is + and which one - doesn't actually make any difference */
+ if(dir == DIR_DOWN)
+ left.wind_nr++;
+ else
+ left.wind_nr--;
+
+ left.is_filled = left.wind_nr != 0;
+ return left;
+}
+
+fillstyle_t* circular_diff(windstate_t*left, windstate_t*right)
+{
+ if(left->is_filled==right->is_filled)
+ return 0;
+ else
+ return &fillstyle_default;
+}
+
+windrule_t windrule_circular = {
+ start: circular_start,
+ add: circular_add,
+ diff: circular_diff,
+};
+
+// -------------------- intersect ----------------------
+
+windstate_t intersect_start(int num_polygons)
+{
+ windstate_t w;
+ w.num_polygons = num_polygons;
+ return w;
+}
+
+windstate_t intersect_add(windstate_t left, fillstyle_t*edge, segment_dir_t dir, int master)
+{
+ assert(master < left.num_polygons);
+
+ left.wind_nr ^= 1<<master;
+ if(left.wind_nr == (1<<left.num_polygons)-1)
+ left.is_filled = 1;
+ return left;
+}
+
+fillstyle_t* intersect_diff(windstate_t*left, windstate_t*right)
+{
+ if(left->is_filled==right->is_filled)
+ return 0;
+ else
+ return &fillstyle_default;
+}
+
+windrule_t windrule_intersect = {
+ start: intersect_start,
+ add: intersect_add,
+ diff: intersect_diff,
+};
+
+// -------------------- union ----------------------
+
+windstate_t union_start(int num_polygons)
+{
+ return windstate_nonfilled;
+}
+
+windstate_t union_add(windstate_t left, fillstyle_t*edge, segment_dir_t dir, int master)
+{
+ assert(master<sizeof(left.wind_nr)*8); //up to 32/64 polygons max
+ left.wind_nr ^= 1<<master;
+ if(left.wind_nr!=0)
+ left.is_filled = 1;
+ return left;
+}
+
+fillstyle_t* union_diff(windstate_t*left, windstate_t*right)
+{
+ if(left->is_filled==right->is_filled)
+ return 0;
+ else
+ return &fillstyle_default;
+}
+
+windrule_t windrule_union = {
+ start: union_start,
+ add: union_add,
+ diff: union_diff,
+};
+
+
+/*
+ } else if (rule == WIND_NONZERO) {
+ fill = wind!=0;
+ } else if (rule == WIND_ODDEVEN) {
+ fill = wind&1;
+ } else { // rule == WIND_POSITIVE
+ fill = wind>=1;
+ }
+ */