Make cross_prod used in SkPath::cheapComputeDirection fallback to double computation when result is 0. Verbal LGTM from reed.
git-svn-id: http://skia.googlecode.com/svn/trunk@3216 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/core/SkPath.cpp b/src/core/SkPath.cpp
index b37342f..4b3505a 100644
--- a/src/core/SkPath.cpp
+++ b/src/core/SkPath.cpp
@@ -1909,8 +1909,26 @@
SkDEBUGCODE(++fContourCounter;)
}
+// returns cross product of (p1 - p0) and (p2 - p0)
static SkScalar cross_prod(const SkPoint& p0, const SkPoint& p1, const SkPoint& p2) {
- return SkPoint::CrossProduct(p1 - p0, p2 - p0);
+ SkScalar cross = SkPoint::CrossProduct(p1 - p0, p2 - p0);
+ // We may get 0 when the above subtracts underflow. We expect this to be
+ // very rare and lazily promote to double.
+ if (0 == cross) {
+ double p0x = SkScalarToDouble(p0.fX);
+ double p0y = SkScalarToDouble(p0.fY);
+
+ double p1x = SkScalarToDouble(p1.fX);
+ double p1y = SkScalarToDouble(p1.fY);
+
+ double p2x = SkScalarToDouble(p2.fX);
+ double p2y = SkScalarToDouble(p2.fY);
+
+ cross = SkDoubleToScalar((p1x - p0x) * (p2y - p0y) -
+ (p1y - p0y) * (p2x - p0x));
+
+ }
+ return cross;
}
// Returns the first pt with the maximum Y coordinate