Function transvoxel::extraction::extract_from_fn

pub fn extract_from_fn<D, F>(
    f: F, 
    block: &Block, 
    threshold: D, 
    transition_sides: TransitionSides
) -> Mesh where
    D: Density,
    F: FnMut(f32, f32, f32) -> D, 

Extracts an iso-surface Mesh for a ScalarField-compatible closure

Arguments:

• f: the closure providing world densities
• block: the world zone for which to extract, and its subdivisions count
• threshold: density value defining the iso-surface
• transition_sides: the set of sides of the block which need to be adapted to neighbour double-resolution blocks (twice the subdivisions)