rust-rl/src/map_builders/dla.rs

use super::{ paint, BuilderMap, InitialMapBuilder, MetaMapBuilder, Position, Symmetry, TileType };
use rltk::RandomNumberGenerator;

#[derive(PartialEq, Copy, Clone)]
#[allow(dead_code)]
pub enum DLAAlgorithm {
    WalkInwards,
    WalkOutwards,
    CentralAttractor,
}

pub struct DLABuilder {
    algorithm: DLAAlgorithm,
    brush_size: i32,
    symmetry: Symmetry,
    floor_percent: f32,
}

impl InitialMapBuilder for DLABuilder {
    #[allow(dead_code)]
    fn build_map(&mut self, rng: &mut rltk::RandomNumberGenerator, build_data: &mut BuilderMap) {
        self.build(rng, build_data);
    }
}

impl MetaMapBuilder for DLABuilder {
    #[allow(dead_code)]
    fn build_map(&mut self, rng: &mut rltk::RandomNumberGenerator, build_data: &mut BuilderMap) {
        self.build(rng, build_data);
    }
}

impl DLABuilder {
    #[allow(dead_code)]
    pub fn new() -> Box<DLABuilder> {
        Box::new(DLABuilder {
            algorithm: DLAAlgorithm::WalkInwards,
            brush_size: 2,
            symmetry: Symmetry::None,
            floor_percent: 0.25,
        })
    }

    #[allow(dead_code)]
    pub fn walk_inwards() -> Box<DLABuilder> {
        Box::new(DLABuilder {
            algorithm: DLAAlgorithm::WalkInwards,
            brush_size: 1,
            symmetry: Symmetry::None,
            floor_percent: 0.25,
        })
    }

    #[allow(dead_code)]
    pub fn walk_outwards() -> Box<DLABuilder> {
        Box::new(DLABuilder {
            algorithm: DLAAlgorithm::WalkOutwards,
            brush_size: 2,
            symmetry: Symmetry::None,
            floor_percent: 0.25,
        })
    }

    #[allow(dead_code)]
    pub fn central_attractor() -> Box<DLABuilder> {
        Box::new(DLABuilder {
            algorithm: DLAAlgorithm::CentralAttractor,
            brush_size: 2,
            symmetry: Symmetry::None,
            floor_percent: 0.25,
        })
    }

    #[allow(dead_code)]
    pub fn insectoid() -> Box<DLABuilder> {
        Box::new(DLABuilder {
            algorithm: DLAAlgorithm::CentralAttractor,
            brush_size: 2,
            symmetry: Symmetry::Horizontal,
            floor_percent: 0.25,
        })
    }

    #[allow(dead_code)]
    pub fn heavy_erosion() -> Box<DLABuilder> {
        Box::new(DLABuilder {
            algorithm: DLAAlgorithm::WalkInwards,
            brush_size: 2,
            symmetry: Symmetry::None,
            floor_percent: 0.35,
        })
    }

    #[allow(clippy::map_entry)]
    fn build(&mut self, rng: &mut RandomNumberGenerator, build_data: &mut BuilderMap) {
        // Carve a starting seed
        let starting_position = Position { x: build_data.map.width / 2, y: build_data.map.height / 2 };
        let start_idx = build_data.map.xy_idx(starting_position.x, starting_position.y);
        build_data.take_snapshot();
        build_data.map.tiles[start_idx] = TileType::Floor;
        build_data.map.tiles[start_idx - 1] = TileType::Floor;
        build_data.map.tiles[start_idx + 1] = TileType::Floor;
        build_data.map.tiles[start_idx - (build_data.map.width as usize)] = TileType::Floor;
        build_data.map.tiles[start_idx + (build_data.map.width as usize)] = TileType::Floor;

        // Random walker
        let total_tiles = build_data.map.width * build_data.map.height;
        let desired_floor_tiles = (self.floor_percent * (total_tiles as f32)) as usize;
        let mut floor_tile_count = build_data.map.tiles
            .iter()
            .filter(|a| **a == TileType::Floor)
            .count();
        while floor_tile_count < desired_floor_tiles {
            match self.algorithm {
                DLAAlgorithm::WalkInwards => {
                    let mut digger_x = rng.roll_dice(1, build_data.map.width - 3) + 1;
                    let mut digger_y = rng.roll_dice(1, build_data.map.height - 3) + 1;
                    let mut prev_x = digger_x;
                    let mut prev_y = digger_y;
                    let mut digger_idx = build_data.map.xy_idx(digger_x, digger_y);
                    while build_data.map.tiles[digger_idx] == TileType::Wall {
                        prev_x = digger_x;
                        prev_y = digger_y;
                        let stagger_direction = rng.roll_dice(1, 4);
                        match stagger_direction {
                            1 => {
                                if digger_x > 2 {
                                    digger_x -= 1;
                                }
                            }
                            2 => {
                                if digger_x < build_data.map.width - 2 {
                                    digger_x += 1;
                                }
                            }
                            3 => {
                                if digger_y > 2 {
                                    digger_y -= 1;
                                }
                            }
                            _ => {
                                if digger_y < build_data.map.height - 2 {
                                    digger_y += 1;
                                }
                            }
                        }
                        digger_idx = build_data.map.xy_idx(digger_x, digger_y);
                    }
                    paint(&mut build_data.map, self.symmetry, self.brush_size, prev_x, prev_y);
                }

                DLAAlgorithm::WalkOutwards => {
                    let mut digger_x = starting_position.x;
                    let mut digger_y = starting_position.y;
                    let mut digger_idx = build_data.map.xy_idx(digger_x, digger_y);
                    while build_data.map.tiles[digger_idx] == TileType::Floor {
                        let stagger_direction = rng.roll_dice(1, 4);
                        match stagger_direction {
                            1 => {
                                if digger_x > 2 {
                                    digger_x -= 1;
                                }
                            }
                            2 => {
                                if digger_x < build_data.map.width - 2 {
                                    digger_x += 1;
                                }
                            }
                            3 => {
                                if digger_y > 2 {
                                    digger_y -= 1;
                                }
                            }
                            _ => {
                                if digger_y < build_data.map.height - 2 {
                                    digger_y += 1;
                                }
                            }
                        }
                        digger_idx = build_data.map.xy_idx(digger_x, digger_y);
                    }
                    paint(&mut build_data.map, self.symmetry, self.brush_size, digger_x, digger_y);
                }

                DLAAlgorithm::CentralAttractor => {
                    let mut digger_x = rng.roll_dice(1, build_data.map.width - 3) + 1;
                    let mut digger_y = rng.roll_dice(1, build_data.map.height - 3) + 1;
                    let mut prev_x = digger_x;
                    let mut prev_y = digger_y;
                    let mut digger_idx = build_data.map.xy_idx(digger_x, digger_y);

                    let mut path = rltk::line2d(
                        rltk::LineAlg::Bresenham,
                        rltk::Point::new(digger_x, digger_y),
                        rltk::Point::new(starting_position.x, starting_position.y)
                    );

                    while build_data.map.tiles[digger_idx] == TileType::Wall && !path.is_empty() {
                        prev_x = digger_x;
                        prev_y = digger_y;
                        digger_x = path[0].x;
                        digger_y = path[0].y;
                        path.remove(0);
                        digger_idx = build_data.map.xy_idx(digger_x, digger_y);
                    }
                    paint(&mut build_data.map, self.symmetry, self.brush_size, prev_x, prev_y);
                }
            }

            build_data.take_snapshot();

            floor_tile_count = build_data.map.tiles
                .iter()
                .filter(|a| **a == TileType::Floor)
                .count();
        }
    }
}