Function range_material 

pub fn range_material(
    world: &[Transform],
    set: Option<&[Option<String>]>,
    range: &DrawRange,
    resolve: &mut impl FnMut(&str) -> Option<MaterialInstance>,
) -> RangeMaterial

Describe a range: resolve its material instance (resolve reads a reference) and pick the shader kind and texture references the ported shaders sample.