Function is_inside

nodedb-spatial/src/predicates/intersection.rs:165–171

Check if a point is on the "inside" (left side) of a directed edge.

(point: [f64; 2], edge_start: [f64; 2], edge_end: [f64; 2])

/// Check if a point is on the "inside" (left side) of a directed edge.
fn is_inside(point: [f64; 2], edge_start: [f64; 2], edge_end: [f64; 2]) -> bool {
    // Cross product: (edge_end - edge_start) × (point - edge_start)
    // Positive = left side = inside for CCW winding.
    let cross = (edge_end[0] - edge_start[0]) * (point[1] - edge_start[1])
        - (edge_end[1] - edge_start[1]) * (point[0] - edge_start[0]);
    cross >= 0.0
}

/// Compute the intersection point of two line segments (as infinite lines).
fn line_intersection(a1: [f64; 2], a2: [f64; 2], b1: [f64; 2], b2: [f64; 2]) -> Option<[f64; 2]> {