shape ops work in progress

git-svn-id: http://skia.googlecode.com/svn/trunk@7758 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/experimental/Intersection/QuadraticUtilities.cpp b/experimental/Intersection/QuadraticUtilities.cpp
index d33fda8..fa8acea 100644
--- a/experimental/Intersection/QuadraticUtilities.cpp
+++ b/experimental/Intersection/QuadraticUtilities.cpp
@@ -232,3 +232,13 @@
         y = a * quad[0].y + b * quad[1].y + c * quad[2].y;
     }
 }
+
+_Point xy_at_t(const Quadratic& quad, double t) {
+    double one_t = 1 - t;
+    double a = one_t * one_t;
+    double b = 2 * one_t * t;
+    double c = t * t;
+    _Point result = { a * quad[0].x + b * quad[1].x + c * quad[2].x,
+            a * quad[0].y + b * quad[1].y + c * quad[2].y };
+    return result;
+}