0242-RLTK-只渲染可視區

波尔發表於2024-08-19

環境

  • Time 2022-11-30
  • WSL-Ubuntu 22.04
  • RLTK 0.8.7

前言

說明

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

目標

基於前一節的內容,不渲染整個大地圖,而只渲染角色周圍的可視區。

重構地圖結構


#[derive(Default)]
pub struct Map {
    pub tiles: Vec<TileType>,
    pub rooms: Vec<Rect>,
    pub width: i32,
    pub height: i32,
}

impl Map {
    pub fn index(&self, x: i32, y: i32) -> usize {
        (y as usize * self.width as usize) + x as usize
    }

    pub fn new_map() -> Map {
        let mut map = Map {
            tiles: vec![TileType::Wall; 80 * 50],
            rooms: Vec::new(),
            width: 80,
            height: 50,
        };
        let mut rng = RandomNumberGenerator::new();

        const MAX_ROOMS: i32 = 30;
        const MIN_SIZE: i32 = 6;
        const MAX_SIZE: i32 = 10;

        for _ in 0..MAX_ROOMS {
            let w = rng.range(MIN_SIZE, MAX_SIZE);
            let h = rng.range(MIN_SIZE, MAX_SIZE);
            let x = rng.roll_dice(1, 80 - w - 1) - 1;
            let y = rng.roll_dice(1, 50 - h - 1) - 1;
            let new_room = Rect::with_size(x, y, w, h);
            let mut ok = true;
            for other_room in map.rooms.iter() {
                if new_room.intersect(other_room) {
                    ok = false
                }
            }
            if ok {
                map.apply_room(&new_room);

                if !map.rooms.is_empty() {
                    let cur = new_room.center();
                    let pre = map.rooms[map.rooms.len() - 1].center();
                    if rng.range(0, 2) == 1 {
                        map.horizontal_tunnel(pre.x, cur.x, pre.y);
                        map.vertical_tunnel(pre.y, cur.y, cur.x);
                    } else {
                        map.vertical_tunnel(pre.y, cur.y, pre.x);
                        map.horizontal_tunnel(pre.x, cur.x, cur.y);
                    }
                }

                map.rooms.push(new_room);
            }
        }

        map
    }

    fn apply_room(&mut self, room: &Rect) {
        for y in room.y1 + 1..=room.y2 {
            for x in room.x1 + 1..=room.x2 {
                let index = self.index(x, y);
                self.tiles[index] = TileType::Floor;
            }
        }
    }

    fn horizontal_tunnel(&mut self, x1: i32, x2: i32, y: i32) {
        for x in min(x1, x2)..=max(x1, x2) {
            let idx = self.index(x, y);
            if idx > 0 && idx < self.width as usize * self.height as usize {
                self.tiles[idx as usize] = TileType::Floor;
            }
        }
    }

    fn vertical_tunnel(&mut self, y1: i32, y2: i32, x: i32) {
        for y in min(y1, y2)..=max(y1, y2) {
            let idx = self.index(x, y);
            if idx > 0 && idx < 80 * 50 {
                self.tiles[idx as usize] = TileType::Floor;
            }
        }
    }
}

impl BaseMap for Map {
    fn is_opaque(&self, idx: usize) -> bool {
        self.tiles[idx as usize] == TileType::Wall
    }
}

impl Algorithm2D for Map {
    fn dimensions(&self) -> Point {
        Point::new(self.width, self.height)
    }
}

Component

use rltk::{field_of_view, Point, RGB};
use specs::prelude::*;
use specs_derive::Component;

use crate::map::Map;

#[derive(Component)]
pub struct Renderable {
    pub glyph: rltk::FontCharType,
    pub fg: RGB,
    pub bg: RGB,
}

#[derive(Component, Debug)]
pub struct Player {}

#[derive(Component)]
pub struct Viewshed {
    pub visible_tiles: Vec<rltk::Point>,
    pub range: i32,
}

pub struct VisibilitySystem {}

impl<'a> System<'a> for VisibilitySystem {
    type SystemData = (
        ReadExpect<'a, Map>,
        WriteStorage<'a, Viewshed>,
        WriteStorage<'a, Point>,
    );

    fn run(&mut self, data: Self::SystemData) {
        let (map, mut views, pos) = data;

        for (views, pos) in (&mut views, &pos).join() {
            views.visible_tiles.clear();
            views.visible_tiles = field_of_view(Point::new(pos.x, pos.y), views.range, &*map);
            views
                .visible_tiles
                .retain(|p| p.x >= 0 && p.x < map.width && p.y >= 0 && p.y < map.height);
        }
    }
}

渲染可視區地圖

pub fn draw_map(world: &World, ctx: &mut Rltk) {
    let mut viewsheds = world.write_storage::<Viewshed>();
    let mut players = world.write_storage::<Player>();
    let map = world.fetch::<Map>();

    for (_player, viewshed) in (&mut players, &mut viewsheds).join() {
        let mut y = 0;
        let mut x = 0;
        for tile in map.tiles.iter() {
            let pt = Point::new(x, y);
            if viewshed.visible_tiles.contains(&pt) {
                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;
            }
        }
    }
}

main

use comp::{Player, Renderable, Viewshed, VisibilitySystem};
use map::Map;
use rltk::prelude::*;
use specs::prelude::*;

mod comp;
mod map;
mod player;

pub struct State {
    world: World,
}
impl GameState for State {
    fn tick(&mut self, context: &mut Rltk) {
        context.cls();

        player::player_input(self, context);
        self.run_systems();

        map::draw_map(&self.world, context);

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

impl State {
    fn run_systems(&mut self) {
        let mut vis = VisibilitySystem {};
        vis.run_now(&self.world);

        self.world.maintain();
    }
}

fn main() -> rltk::BError {
    let context = rltk::RltkBuilder::simple80x50()
        .with_title("冒險遊戲")
        .build()?;

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

    let map = Map::new_map();
    let point = map.rooms[0].center();
    state.world.insert(map);

    state
        .world
        .create_entity()
        .with(point)
        .with(Renderable {
            glyph: rltk::to_cp437('@'),
            fg: RGB::named(rltk::YELLOW),
            bg: RGB::named(rltk::BLACK),
        })
        .with(Player {})
        .with(Viewshed {
            visible_tiles: Vec::new(),
            range: 8,
        })
        .build();

    rltk::main_loop(context, state)
}

效果

渲染可視區

總結

只渲染角色周圍一部分的視野。

附錄

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