Intersection work in progress

Review URL: https://codereview.appspot.com/5576043

git-svn-id: http://skia.googlecode.com/svn/trunk@3087 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 15 insertions, 0 deletions

diff --git a/experimental/Intersection/QuadraticParameterization_TestUtility.cpp b/experimental/Intersection/QuadraticParameterization_TestUtility.cpp
new file mode 100644
index 0000000000..326b28e4df
--- /dev/null
+++ b/experimental/Intersection/QuadraticParameterization_TestUtility.cpp
@@ -0,0 +1,15 @@
+// included by QuadraticParameterization.cpp
+// accesses internal functions to validate parameterized coefficients
+
+bool point_on_parameterized_curve(const Quadratic& quad, const _Point& point) {
+    double coeffs[coeff_count];
+    implicit_coefficients(quad, coeffs);
+    double  xx = coeffs[ xx_coeff] * point.x * point.x;
+    double  xy = coeffs[ xy_coeff] * point.x * point.y;
+    double  yy = coeffs[ yy_coeff] * point.y * point.y;
+    double   x = coeffs[  x_coeff] * point.x;
+    double   y = coeffs[  y_coeff] * point.y;
+    double   c = coeffs[  c_coeff];
+    double sum = xx + xy + yy + x + y + c;
+    return approximately_zero(sum);
+}