Merge pull request #28 from mindbrix/reversedFlag
Add a reversed flag to tessAddContour()
diff --git a/Include/tesselator.h b/Include/tesselator.h
index 38e05f1..3d43155 100755
--- a/Include/tesselator.h
+++ b/Include/tesselator.h
@@ -118,10 +118,15 @@
// TESS_CONSTRAINED_DELAUNAY_TRIANGULATION
// If enabled, the initial triagulation is improved with non-robust Constrained Delayney triangulation.
// Disable by default.
+//
+// TESS_REVERSE_CONTOURS
+// If enabled, tessAddContour() will treat CW contours as CCW and vice versa
+// Disabled by default.
enum TessOption
{
TESS_CONSTRAINED_DELAUNAY_TRIANGULATION,
+ TESS_REVERSE_CONTOURS
};
typedef float TESSreal;
diff --git a/Source/tess.c b/Source/tess.c
index 8059bf4..a2f5e14 100755
--- a/Source/tess.c
+++ b/Source/tess.c
@@ -629,6 +629,8 @@
tess->bmax[0] = 0;
tess->bmax[1] = 0;
+ tess->reverseContours = 0;
+
tess->windingRule = TESS_WINDING_ODD;
if (tess->alloc.regionBucketSize < 16)
@@ -973,8 +975,8 @@
* vertices in such an order that a CCW contour will add +1 to
* the winding number of the region inside the contour.
*/
- e->winding = 1;
- e->Sym->winding = -1;
+ e->winding = tess->reverseContours ? -1 : 1;
+ e->Sym->winding = tess->reverseContours ? 1 : -1;
}
}
@@ -985,6 +987,9 @@
case TESS_CONSTRAINED_DELAUNAY_TRIANGULATION:
tess->processCDT = value > 0 ? 1 : 0;
break;
+ case TESS_REVERSE_CONTOURS:
+ tess->reverseContours = value > 0 ? 1 : 0;
+ break;
}
}
diff --git a/Source/tess.h b/Source/tess.h
index c1f981f..30fda27 100755
--- a/Source/tess.h
+++ b/Source/tess.h
@@ -62,7 +62,8 @@
TESSreal bmax[2];
int processCDT; /* option to run Constrained Delayney pass. */
-
+ int reverseContours; /* tessAddContour() will treat CCW contours as CW and vice versa */
+
/*** state needed for the line sweep ***/
int windingRule; /* rule for determining polygon interior */
