0236-RLTK-渲染动态字符

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

在前一节的基础上，将静止的字符进行移动。

Component

#[derive(Component)]
struct Position {
    x: i32,
    y: i32,
}

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

#[derive(Component)]
struct LeftWalker {}

System

impl<'a> System<'a> for LeftWalker {
    type SystemData = (ReadStorage<'a, LeftWalker>, WriteStorage<'a, Position>);

    fn run(&mut self, (lefty, mut pos): Self::SystemData) {
        for (_lefty, pos) in (&lefty, &mut pos).join() {
            pos.x -= 1;
            if pos.x < 0 {
                pos.x = 79;
            }
        }
    }
}

GameState

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

        self.run_systems();
        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);
        }
    }
}

impl State {
    fn run_systems(&mut self) {
        let mut lw = LeftWalker {};
        lw.run_now(&self.world);
        self.world.maintain();
    }
}

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

    for i in 0..10 {
        state
            .world
            .create_entity()
            .with(Position { x: i * 7, y: 20 })
            .with(Renderable {
                glyph: rltk::to_cp437('☺'),
                fg: RGB::named(rltk::RED),
                bg: RGB::named(rltk::BLACK),
            })
            .with(LeftWalker {})
            .build();
    }

    rltk::main_loop(context, state)
}

效果

总结

将前一节渲染的字符进行了向左移动。

附录

源码

use rltk::prelude::*;
use specs::prelude::*;
use specs_derive::Component;

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

        self.run_systems();
        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);
        }
    }
}

impl State {
    fn run_systems(&mut self) {
        let mut lw = LeftWalker {};
        lw.run_now(&self.world);
        self.world.maintain();
    }
}

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

    for i in 0..10 {
        state
            .world
            .create_entity()
            .with(Position { x: i * 7, y: 20 })
            .with(Renderable {
                glyph: rltk::to_cp437('☺'),
                fg: RGB::named(rltk::RED),
                bg: RGB::named(rltk::BLACK),
            })
            .with(LeftWalker {})
            .build();
    }

    rltk::main_loop(context, state)
}

#[derive(Component)]
struct Position {
    x: i32,
    y: i32,
}

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

#[derive(Component)]
struct LeftWalker {}

impl<'a> System<'a> for LeftWalker {
    type SystemData = (ReadStorage<'a, LeftWalker>, WriteStorage<'a, Position>);

    fn run(&mut self, (lefty, mut pos): Self::SystemData) {
        for (_lefty, pos) in (&lefty, &mut pos).join() {
            pos.x -= 1;
            if pos.x < 0 {
                pos.x = 79;
            }
        }
    }
}