0238-RLTK-生成大地图

环境

• Time 2022-11-29
• WSL-Ubuntu 22.04
• RLTK 0.8.7

前言

说明

参考：https://bfnightly.bracketproductions.com/rustbook

目标

基于前一节的内容，生成一张可以让角色移动的大地图。

地板和墙

#[derive(PartialEq, Copy, Clone)]
enum TileType {
    Wall, Floor
}

计算坐标

pub fn index(x: i32, y: i32) -> usize {
    (y as usize * 80) + x as usize
}

生成地图

fn new_map() -> Vec<TileType> {
    let mut map = vec![TileType::Floor; 80 * 50];

    for x in 0..80 {
        map[index(x, 0)] = TileType::Wall;
        map[index(x, 49)] = TileType::Wall;
    }
    for y in 0..50 {
        map[index(0, y)] = TileType::Wall;
        map[index(79, y)] = TileType::Wall;
    }

    let mut rng = rltk::RandomNumberGenerator::new();

    for _i in 0..400 {
        let x = rng.roll_dice(1, 79);
        let y = rng.roll_dice(1, 49);
        let idx = index(x, y);
        if idx != index(40, 25) {
            map[idx] = TileType::Wall;
        }
    }

    map
}

绘制地图

fn draw_map(map: &[TileType], ctx: &mut Rltk) {
    let mut y = 0;
    let mut x = 0;
    for tile in map.iter() {
        match tile {
            TileType::Floor => {
                ctx.set(
                    x,
                    y,
                    RGB::from_f32(0.5, 0.5, 0.5),
                    RGB::from_f32(0., 0., 0.),
                    rltk::to_cp437('.'),
                );
            }
            TileType::Wall => {
                ctx.set(
                    x,
                    y,
                    RGB::from_f32(0.0, 1.0, 0.0),
                    RGB::from_f32(0., 0., 0.),
                    rltk::to_cp437('#'),
                );
            }
        }

        x += 1;
        if x > 79 {
            x = 0;
            y += 1;
        }
    }
}

墙壁碰撞

fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
    let mut positions = ecs.write_storage::<Position>();
    let mut players = ecs.write_storage::<Player>();
    let map = ecs.fetch::<Vec<TileType>>();

    for (_player, pos) in (&mut players, &mut positions).join() {
        let destination_idx = xy_idx(pos.x + delta_x, pos.y + delta_y);
        if map[destination_idx] != TileType::Wall {
            pos.x = min(79 , max(0, pos.x + delta_x));
            pos.y = min(49, max(0, pos.y + delta_y));
        }
    }
}

GameState

impl GameState for State {
    fn tick(&mut self, ctx: &mut Rltk) {
        ctx.cls();

        player_input(self, ctx);
        self.run_systems();

        let map = self.world.fetch::<Vec<TileType>>();
        draw_map(&map, ctx);

        let positions = self.world.read_storage::<Position>();
        let renderables = self.world.read_storage::<Renderable>();
        for (pos, render) in (&positions, &renderables).join() {
            ctx.set(pos.x, pos.y, render.fg, render.bg, render.glyph);
        }
    }
}

main

fn main() -> rltk::BError {
    let context = rltk::RltkBuilder::simple80x50()
        .with_title("冒险游戏")
        .build()?;

    let mut state = State {
        world: World::new(),
    };
    state.world.register::<Position>();
    state.world.register::<Renderable>();
    state.world.register::<LeftWalker>();
    state.world.register::<Player>();

    state.world.insert(new_map());

    state
        .world
        .create_entity()
        .with(Position { x: 40, y: 25 })
        .with(Renderable {
            glyph: rltk::to_cp437('@'),
            fg: RGB::named(rltk::YELLOW),
            bg: RGB::named(rltk::BLACK),
        })
        .with(Player {})
        .build();

    rltk::main_loop(context, state)
}

效果

总结

生成一张大地图，角色可以在除了墙的地方行走。

附录