Function openexr::core::envmap::cube_map::direction_from_face_and_position_in_face

pub fn direction_from_face_and_position_in_face<B: Bound2<i32>, V2: Vec2<f32>, V3: Vec3<f32>>(
    face: CubeMapFace, 
    data_window: &B, 
    position_in_face: &V2
) -> V3

Given a cube face and a pixel position within that face, compute the corresponding 3D direction.