Function ray_triangle_intersection

native/shared/src/picking.rs:227–255

(
    origin: &[f32; 3], dir: &[f32; 3],
    v0: &[f32; 3], v1: &[f32; 3], v2: &[f32; 3],
)

// ============================================================

fn ray_triangle_intersection(
    origin: &[f32; 3], dir: &[f32; 3],
    v0: &[f32; 3], v1: &[f32; 3], v2: &[f32; 3],
) -> Option<(f32, f32, f32)> {
    const EPSILON: f32 = 1e-7;

    let e1 = [v1[0]-v0[0], v1[1]-v0[1], v1[2]-v0[2]];
    let e2 = [v2[0]-v0[0], v2[1]-v0[1], v2[2]-v0[2]];

    let h = cross(dir, &e2);
    let a = dot(&e1, &h);
    if a.abs() < EPSILON { return None; }

    let f = 1.0 / a;
    let s = [origin[0]-v0[0], origin[1]-v0[1], origin[2]-v0[2]];
    let u = f * dot(&s, &h);
    if u < 0.0 || u > 1.0 { return None; }

    let q = cross(&s, &e1);
    let v = f * dot(dir, &q);
    if v < 0.0 || u + v > 1.0 { return None; }

    let t = f * dot(&e2, &q);
    if t > EPSILON {
        Some((t, u, v))
    } else {
        None
    }
}

fn cross(a: &[f32; 3], b: &[f32; 3]) -> [f32; 3] {
    [