Function left 

pub unsafe extern "C" fn left(
    x1: *const c_double,
    y1: *const c_double,
    z1: *const c_double,
    x2: *const c_double,
    y2: *const c_double,
    z2: *const c_double,
    x0: *const c_double,
    y0: *const c_double,
    z0: *const c_double,
) -> bool

Determines whether a node is left of a plane through the origin.

This function determines whether node n0 is in the (closed) left hemisphere defined by the plane containing n1, n2, and the origin, where left is defined relative to an observer at n1 facing n2.

Arguments

• x1, y1, z1 - Input. The coordinates of n1.
• x2, y2, z2 - Input. The coordinates of n2.
• x0, y0, z0 - Input. The coordinates of n0.

Returns

True if and only if n0 is in the closed left hemisphere.