skia2/experimental/Intersection/QuadraticParameterization_TestUtility.cpp
caryclark@google.com 27accef223 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
2012-01-25 18:57:23 +00:00

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646 B
C++

// 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);
}