stevenarella/src/world/block/mod.rs

use std::fmt::{Display, Formatter, Error};

pub use self::Block::*;

macro_rules! consume_token { ($i:tt) => (0) }

macro_rules! offsets {
    ($first:ident, $($other:ident),*) => (
        #[allow(non_upper_case_globals)]
        pub const $first: usize = 0;
        offsets!(prev($first), $($other),*);
    );
    (prev($prev:ident), $first:ident, $($other:ident),*) => (
        #[allow(non_upper_case_globals)]
        pub const $first: usize = $prev + internal_sizes::$prev;
        offsets!(prev($first), $($other),*);
    );
    (prev($prev:ident), $first:ident) => (
        #[allow(non_upper_case_globals)]
        pub const $first: usize = $prev + internal_sizes::$prev;
    )
}

macro_rules! define_blocks {
    (
        $(
            $name:ident {
                props {
                    $(
                        $fname:ident : $ftype:ty = [$($val:expr),+],
                    )*
                },
                data $datafunc:expr,
                material $mat:expr,
            }
        )+
    ) => (
        #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
        pub enum Block {
            $(
                $name {
                    $(
                        $fname : $ftype,
                    )*
                },
            )+
        }
        mod internal_ids {
            create_ids!(usize, $($name),+);
        }
        mod internal_sizes {
            $(
                #[allow(non_upper_case_globals)]
                pub const $name : usize = $(($(1 + consume_token!($val) + )+ 0) *  )* 1;
            )+
        }
        mod internal_offsets {
            use super::internal_sizes;
            offsets!($($name),+);
        }
        mod internal_offset_max {
            use super::internal_sizes;
            use super::internal_offsets;
            $(
                #[allow(non_upper_case_globals)]
                pub const $name: usize = internal_offsets::$name + internal_sizes::$name - 1;
            )+
        }

        impl Block {
            #[allow(unused_variables, unused_mut, unused_assignments)]
            pub fn get_steven_id(&self) -> usize {
                match *self {
                    $(
                        Block::$name {
                            $($fname,)*
                        } => {
                            let mut offset = internal_offsets::$name;
                            let mut mul = 1;
                            $(
                                offset += [$($val),+].into_iter().position(|v| *v == $fname).unwrap() * mul;
                                mul *= $(1 + consume_token!($val) + )+ 0;
                            )*
                            offset
                        },
                    )+
                }
            }

            #[allow(unused_variables, unused_assignments)]
            pub fn by_steven_id(id: usize) -> Block {
                match id {
                    $(
                        mut data @ internal_offsets::$name ... internal_offset_max::$name=> {
                            data -= internal_offsets::$name;
                            $(
                                let vals = [$($val),+];
                                let $fname = vals[data % vals.len()];
                                data /= vals.len();
                            )*
                            Block::$name {
                                $(
                                    $fname: $fname,
                                )*
                            }
                        },
                    )*
                    _ => Block::Missing {}
                }
            }

            pub fn get_vanilla_id(&self) -> Option<usize> {
                match *self {
                    $(
                        Block::$name {
                            $($fname,)*
                        } => {
                            ($datafunc).map(|v| v + (internal_ids::$name << 4))
                        }
                    )+
                }
            }

            pub fn by_vanilla_id(id: usize) -> Block {
                VANILLA_ID_MAP.get(id).and_then(|v| *v).unwrap_or(Block::Missing{})
            }

            pub fn get_material(&self) -> Material {
                match *self {
                    $(
                        Block::$name {
                            $($fname,)*
                        } => {
                            $mat
                        }
                    )+
                }
            }
        }

        lazy_static! {
            static ref VANILLA_ID_MAP: Vec<Option<Block>> = {
                let mut blocks = vec![];
                for i in 0 .. internal_offsets::Missing {
                    let block = Block::by_steven_id(i);
                    if let Some(id) = block.get_vanilla_id() {
                        if blocks.len() <= id {
                            blocks.resize(id + 1, None);
                        }
                        blocks[id] = Some(block);
                    }
                }
                blocks
            };
        }
    );
}

pub struct Material {
    pub renderable: bool,
    // TEMP
    pub texture: &'static str,
}

define_blocks! {
    Air {
        props {},
        data { Some(0) },
        material Material {
            renderable: false,
            texture: "none",
        },
    }
    Stone {
        props {
            variant: StoneVariant = [
                StoneVariant::Normal,
                StoneVariant::Granite, StoneVariant::SmoothGranite,
                StoneVariant::Diorite, StoneVariant::SmoothDiorite,
                StoneVariant::Andesite, StoneVariant::SmoothAndesite
            ],
        },
        data { Some(variant.data()) },
        material Material {
            renderable: true,
            texture: match variant {
                StoneVariant::Normal => "stone",
                StoneVariant::Granite => "stone_granite",
                StoneVariant::SmoothGranite => "stone_granite_smooth",
                StoneVariant::Diorite => "stone_diorite",
                StoneVariant::SmoothDiorite => "stone_diorite_smooth",
                StoneVariant::Andesite => "stone_andesite",
                StoneVariant::SmoothAndesite => "stone_andesite_smooth",
            },
        },
    }
    Grass {
        props {
        },
        data { Some(0) },
        material Material {
            renderable: true,
            texture: "grass_path_top",
        },
    }
    Dirt {
        props {
        },
        data { Some(0) },
        material Material {
            renderable: true,
            texture: "dirt",
        },
    }
    Missing {
        props {},
        data { None::<usize> },
        material Material {
            renderable: true,
            texture: "missing_texture",
        },
    }
}


#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
pub enum StoneVariant {
    Normal,
    Granite,
    SmoothGranite,
    Diorite,
    SmoothDiorite,
    Andesite,
    SmoothAndesite,
}

impl Display for StoneVariant {
    fn fmt(&self, f: &mut Formatter) -> Result<(), Error> {
        write!(f, "{}", match *self {
            StoneVariant::Normal => "stone",
            StoneVariant::Granite => "granite",
            StoneVariant::SmoothGranite => "smooth_granite",
            StoneVariant::Diorite => "diorite",
            StoneVariant::SmoothDiorite => "smooth_diorite",
            StoneVariant::Andesite => "andesite",
            StoneVariant::SmoothAndesite => "smooth_andesite",
        })
    }
}

impl StoneVariant {
    fn data(&self) -> usize {
        match *self {
            StoneVariant::Normal => 0,
            StoneVariant::Granite => 1,
            StoneVariant::SmoothGranite => 2,
            StoneVariant::Diorite => 3,
            StoneVariant::SmoothDiorite => 4,
            StoneVariant::Andesite => 5,
            StoneVariant::SmoothAndesite => 6,
        }
    }
}