use rltk::{GameState, Rltk, VirtualKeyCode, RGB}; use specs::prelude::*; use specs_derive::Component; use std::cmp::{max, min}; #[derive(Component)] struct Position { x: i32, y: i32, } #[derive(Component)] struct Renderable { glyph: rltk::FontCharType, fg: RGB, bg: RGB, } #[derive(Component)] struct LeftMover {} #[derive(Component, Debug)] struct Player {} struct State { ecs: World, } fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) { let mut positions = ecs.write_storage::(); let mut players = ecs.write_storage::(); for (_player, pos) in (&mut players, &mut positions).join() { pos.x = min(79, max(0, pos.x + delta_x)); pos.y = min(49, max(0, pos.y + delta_y)); } } fn player_input(gs: &mut State, ctx: &mut Rltk) { // Player movement match ctx.key { None => {} // Nothing happened Some(key) => match key { VirtualKeyCode::Left => try_move_player(-1, 0, &mut gs.ecs), VirtualKeyCode::Right => try_move_player(1, 0, &mut gs.ecs), VirtualKeyCode::Up => try_move_player(0, -1, &mut gs.ecs), VirtualKeyCode::Down => try_move_player(0, 1, &mut gs.ecs), _ => {}, }, } } impl GameState for State { fn tick(&mut self, ctx: &mut Rltk) { ctx.cls(); player_input(self, ctx); self.run_systems(); let positions = self.ecs.read_storage::(); let renderables = self.ecs.read_storage::(); for (pos, render) in (&positions, &renderables).join() { ctx.set(pos.x, pos.y, render.fg, render.bg, render.glyph); } } } struct LeftWalker {} impl<'a> System<'a> for LeftWalker { type SystemData = (ReadStorage<'a, LeftMover>, 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; } } } } impl State { fn run_systems(&mut self) { let mut lw = LeftWalker{}; lw.run_now(&self.ecs); self.ecs.maintain(); } } fn main() -> rltk::BError { use rltk::RltkBuilder; let context = RltkBuilder::simple80x50() .with_title("Roguelike Tutorial") .build()?; let mut gs = State { ecs: World::new() }; gs.ecs.register::(); gs.ecs.register::(); gs.ecs.register::(); gs.ecs.register::(); gs.ecs .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(); for i in 0..10 { gs.ecs .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(LeftMover {}) .build(); } rltk::main_loop(context, gs) }