more improvements to, and bugfixes in, the new polygon intersector

[swftools.git] / lib / gfxpoly / wind.c

diff --git a/lib/gfxpoly/wind.c b/lib/gfxpoly/wind.c
new file mode 100644 (file)
index 0000000..fa6d724
--- /dev/null
+++ b/lib/gfxpoly/wind.c
@@ -0,0 +1,144 @@
+#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;
+ }
+ */