work in progress

git-svn-id: http://skia.googlecode.com/svn/trunk@3702 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/experimental/Intersection/QuadraticUtilities.cpp b/experimental/Intersection/QuadraticUtilities.cpp
index 51a7569..ea4cd85 100644
--- a/experimental/Intersection/QuadraticUtilities.cpp
+++ b/experimental/Intersection/QuadraticUtilities.cpp
@@ -9,12 +9,19 @@
     }
     double squareRt = sqrt(square);
     double Q = (B + (B < 0 ? -squareRt : squareRt)) / -2;
+    double ratio;
     int foundRoots = 0;
     if ((Q <= A) ^ (Q < 0)) {
-        t[foundRoots++] = Q / A;
+        ratio = Q / A;
+        if (!isnan(ratio)) {
+            t[foundRoots++] = ratio;
+        }
     }
     if ((C <= Q) ^ (C < 0)) {
-        t[foundRoots++] = C / Q;
+        ratio = C / Q;
+        if (!isnan(ratio)) {
+            t[foundRoots++] = ratio;
+        }
     }
     return foundRoots;
 }