Function cavalier_contours::core::math::line_circle_intr

pub fn line_circle_intr<T>(
    p0: Vector2<T>,
    p1: Vector2<T>,
    radius: T,
    circle_center: Vector2<T>,
    epsilon: T
) -> LineCircleIntr<T>
where
    T: Real,

Finds the intersects between a line segment and a circle.

This function returns the parametric solution(s) for the line segment equation P(t) = p0 + t * (p1 - p0) for t = 0 to t = 1. If t < 0 or t > 1 then intersect occurs only when extending the segment out past the points p0 and p1 given. If t < 0 then the intersect is nearest to p0, if t > 1.0 then the intersect is nearest to p1. Intersects are “sticky” and “snap” to tangent points using fuzzy comparisons, e.g. a segment very close to being tangent line will return a single intersect point.

epsilon is used for fuzzy float comparisons.

Examples

// A line segment tangent-intersecting a circle with one of the line segments end points.
let p0 = Vector2::new(0.0, 0.0);
let p1 = Vector2::new(1.0, 0.0);
let r = 1.0;
let c = Vector2::new(0.0, 1.0);

if let LineCircleIntr::TangentIntersect{ t0: t } = line_circle_intr(p0, p1, r, c, 1e-5) {
    assert_eq!(t, 0.0);
} else {
    unreachable!("expected tangent intersect");
}