rust-flappy-dragon/src/main.rs

#![warn(clippy::all, clippy::pedantic)]
#![feature(stmt_expr_attributes)]

use bracket_lib::prelude::*;
use std::collections::VecDeque;

// const VERSION: &str = "0.3.0";
const SCREEN_WIDTH: u16 = 80;
const SCREEN_HEIGHT: u16 = 50;
const FRAME_DURATION: f32 = 35.0;

const X_OFFSET: i32 = 10;
const Y_START: i32 = 25;

#[derive(Debug)]
struct Obstacle {
    x: i32,
    gap_y: u16,
    gap_height: u16,
}

impl Obstacle {
    fn new(x: i32, score: u32) -> Self {
        let mut random = RandomNumberGenerator::new();
        Obstacle {
            x,
            gap_y: random.range(10, 40),
            gap_height: u16::max(5, 20 - (score as u16 / 3)),
        }
    }

    fn render(&mut self, ctx: &mut BTerm, current_x: i32) {
        let x = self.x - current_x + X_OFFSET;
        let (y_top_of_bottom, y_bottom_of_top) = self.y_bounds();
        let y_positions = [0..y_bottom_of_top, y_top_of_bottom..SCREEN_HEIGHT]
            .map(|r| r.collect::<Vec<u16>>())
            .concat();
        for y in y_positions {
            ctx.set(x, y as i32, RED, BLACK, to_cp437('|'));
        }
    }

    fn y_bounds(&mut self) -> (u16, u16) {
        let half_gap_height = self.gap_height / 2;
        let y_bottom_of_top = self.gap_y - half_gap_height;
        let y_top_of_bottom = self.gap_y + half_gap_height;
        (y_top_of_bottom, y_bottom_of_top)
    }
}

struct Player {
    x: i32,
    y: i32,
    velocity: f32,
}

impl Player {
    fn new(y: i32) -> Self {
        Player {
            x: 0,
            y,
            velocity: -2.0,
        }
    }

    fn render(&mut self, ctx: &mut BTerm) {
        ctx.set(X_OFFSET, self.y, YELLOW, BLACK, to_cp437('@'));
    }

    fn update(&mut self) {
        if self.velocity < 2.0 {
            self.velocity += 0.2;
            // self.velocity = self.velocity.clamp(-2.0
        }
        #[allow(clippy::cast_possible_truncation)]
        self.y += self.velocity.round() as i32;
        self.x += 1;
        if self.y < 0 {
            self.y = 0;
        }
    }

    fn flap(&mut self) {
        self.velocity = -2.0;
    }
}

struct State {
    player: Player,
    time: f32,
    mode: GameMode,
    obstacles: VecDeque<Obstacle>,
    obstacle_spawn_time: f32,
    score: u32,
}

enum GameMode {
    Menu,
    Playing,
    Dead,
}

impl State {
    fn new() -> Self {
        State {
            player: Player::new(Y_START),
            time: 0.0,
            mode: GameMode::Menu,
            obstacles: VecDeque::new(),
            obstacle_spawn_time: 0.0,
            score: 0u32,
        }
    }

    fn menu(&mut self, ctx: &mut BTerm) {
        ctx.cls();
        ctx.print_centered(5, "Welcome to Flappy Dragon");
        ctx.print_centered(8, "(P) Play");
        ctx.print_centered(9, "(Q) Quit");

        if let Some(key) = ctx.key {
            match key {
                VirtualKeyCode::P => self.restart(),
                VirtualKeyCode::Q => ctx.quitting = true,
                _ => {}
            }
        }
    }

    fn restart(&mut self) {
        self.player = Player::new(25);
        self.time = 0.0;
        self.mode = GameMode::Playing;
        self.obstacles = VecDeque::new();
        self.score = 0u32;
    }

    fn play(&mut self, ctx: &mut BTerm) {
        ctx.cls_bg(BLACK);
        self.time += ctx.frame_time_ms;
        self.obstacle_spawn_time -= ctx.frame_time_ms;

        ctx.print(1, 1, "Press Space to flap!");
        ctx.print(1, 2, &format!("Score: {}", self.score));
        // ctx.print(1, 3, &format!("Pos: {}, {}", self.player.x, self.player.y));
        // ctx.print(1, 4, &format!("Obstables: (Spawn: {}) #{} {:#?}", self.obstacle_spawn_time, self.obstacles.len(), self.obstacles));

        // update
        if self.time > FRAME_DURATION {
            self.player.update();
            self.time %= FRAME_DURATION;
        }

        if self.obstacle_spawn_time < 0.0 {
            let mut random = RandomNumberGenerator::new();
            self.obstacle_spawn_time += random.range(400.0, 1200.0) - self.score as f32;
            let o = Obstacle::new(self.player.x + SCREEN_WIDTH as i32, self.score);
            self.obstacles.push_back(o);
        }

        if let Some(o) = self.obstacles.front() {
            if o.x < self.player.x - X_OFFSET {
                self.obstacles.pop_front();
                self.score += 1;
            }
        }

        if let Some(VirtualKeyCode::Space) = ctx.key {
            self.player.flap();
        }

        self.player.render(ctx);
        let mut did_collide = false;
        self.obstacles.iter_mut().for_each(|o| {
            if o.x == self.player.x {
                let (y_top_of_bottom, y_bottom_of_top) = o.y_bounds();
                if (self.player.y as u16) >= y_top_of_bottom
                    || (self.player.y as u16) <= y_bottom_of_top
                {
                    did_collide = true;
                }
            }
            o.render(ctx, self.player.x);
        });

        if did_collide || self.player.y > (SCREEN_HEIGHT as i32) {
            self.die();
        }
        // self.mode = GameMode::Dead;
    }

    fn die(&mut self) {
        self.mode = GameMode::Dead;
    }

    fn dead(&mut self, ctx: &mut BTerm) {
        ctx.cls();
        ctx.print_centered(5, "You are dead. =(");
        ctx.print_centered(6, &format!("Final Score: {}", self.score));
        ctx.print_centered(8, "(P) Play Again");
        ctx.print_centered(9, "(Q) Quit");

        if let Some(key) = ctx.key {
            match key {
                VirtualKeyCode::P => self.restart(),
                VirtualKeyCode::Q => ctx.quitting = true,
                _ => {}
            }
        }
    }
}

impl GameState for State {
    fn tick(&mut self, ctx: &mut BTerm) {
        match self.mode {
            GameMode::Menu => self.menu(ctx),
            GameMode::Playing => self.play(ctx),
            GameMode::Dead => self.dead(ctx),
        }
    }
}

fn main() {
    let ctx = BTermBuilder::simple80x50()
        .with_title("Flappy Dragon")
        .build()
        .unwrap();

    main_loop(ctx, State::new()).unwrap();
}