cargo.toml

[package]
name = "snake_game"
version = "0.1.0"
authors = ["youcodethings <[email protected]>"]

[dependencies]
piston = "0.36.0"
piston2d-graphics = "0.26.0"
pistoncore-glutin_window = "0.45.0"
piston2d-opengl_graphics = "0.52.0"
rand = "0.4"

main.rs

//! Snake game
//!
//! Example of 2d graphics in Rust.
//!
//! Completed code for https://youtu.be/HCwMb0KslX8
//! Author: @youcodethings
//!
//! All additional changes are in logic only.
//! No new rendering or library stuff.

extern crate glutin_window;
extern crate graphics;
extern crate opengl_graphics;
extern crate piston;

extern crate rand;

use piston::window::WindowSettings;
use piston::event_loop::*;
use piston::input::*;
use glutin_window::GlutinWindow;
use opengl_graphics::{GlGraphics, OpenGL};

use std::collections::LinkedList;
use std::iter::FromIterator;

pub struct Game {
    gl: GlGraphics,
    rows: u32,
    cols: u32,
    snake: Snake,
    just_eaten: bool,
    square_width: u32,
    food: Food,
    score: u32,
}

impl Game {
    fn render(&mut self, args: &RenderArgs) {
        use graphics;

        const GREEN: [f32; 4] = [0.0, 1.0, 0.0, 1.0];

        self.gl.draw(args.viewport(), |c, gl| {
            graphics::clear(GREEN, gl);
        });

        self.snake.render(args);
        self.food.render(&mut self.gl, args, self.square_width);
    }

    fn update(&mut self, args: &UpdateArgs) -> bool {
        if !self.snake.update(self.just_eaten, self.cols, self.rows) {
            return false;
        }

        if self.just_eaten {
            self.score += 1;
            self.just_eaten = false;
        }

        self.just_eaten = self.food.update(&self.snake);
        if self.just_eaten {
            use rand::Rng;
            use rand::thread_rng;
            // try my luck
            let mut r = thread_rng();
            loop {
                let new_x = r.gen_range(0, self.cols);
                let new_y = r.gen_range(0, self.rows);
                if !self.snake.is_collide(new_x, new_y) {
                    self.food = Food { x: new_x, y: new_y };
                    break;
                }
            }
        }

        true
    }

    fn pressed(&mut self, btn: &Button) {
        let last_direction = self.snake.d.clone();
        self.snake.d = match btn {
            &Button::Keyboard(Key::Up) if last_direction != Direction::DOWN => Direction::UP,
            &Button::Keyboard(Key::Down) if last_direction != Direction::UP => Direction::DOWN,
            &Button::Keyboard(Key::Left) if last_direction != Direction::RIGHT => Direction::LEFT,
            &Button::Keyboard(Key::Right) if last_direction != Direction::LEFT => Direction::RIGHT,
            _ => last_direction,
        };
    }
}

/// The direction the snake moves in.
#[derive(Clone, PartialEq)]
enum Direction {
    UP,
    DOWN,
    LEFT,
    RIGHT,
}

pub struct Snake {
    gl: GlGraphics,
    snake_parts: LinkedList<Snake_Piece>,
    width: u32,
    d: Direction,
}

#[derive(Clone)]
pub struct Snake_Piece(u32, u32);

impl Snake {
    pub fn render(&mut self, args: &RenderArgs) {
        use graphics;

        const RED: [f32; 4] = [1.0, 0.0, 0.0, 1.0];

        let squares: Vec<graphics::types::Rectangle> = self.snake_parts
            .iter()
            .map(|p| Snake_Piece(p.0 * self.width, p.1 * self.width))
            .map(|p| graphics::rectangle::square(p.0 as f64, p.1 as f64, self.width as f64))
            .collect();

        self.gl.draw(args.viewport(), |c, gl| {
            let transform = c.transform;

            squares
                .into_iter()
                .for_each(|square| graphics::rectangle(RED, square, transform, gl));
        })
    }

    /// Move the snake if valid, otherwise returns false.
    pub fn update(&mut self, just_eaten: bool, cols: u32, rows: u32) -> bool {
        let mut new_front: Snake_Piece =
            (*self.snake_parts.front().expect("No front of snake found.")).clone();

        if (self.d == Direction::UP && new_front.1 == 0)
            || (self.d == Direction::LEFT && new_front.0 == 0)
            || (self.d == Direction::DOWN && new_front.1 == rows - 1)
            || (self.d == Direction::RIGHT && new_front.0 == cols - 1)
        {
            return false;
        }

        match self.d {
            Direction::UP => new_front.1 -= 1,
            Direction::DOWN => new_front.1 += 1,
            Direction::LEFT => new_front.0 -= 1,
            Direction::RIGHT => new_front.0 += 1,
        }

        if !just_eaten {
            self.snake_parts.pop_back();
        }

        // Checks self collision.
        if self.is_collide(new_front.0, new_front.1) {
            return false;
        }

        self.snake_parts.push_front(new_front);
        true
    }

    fn is_collide(&self, x: u32, y: u32) -> bool {
        self.snake_parts.iter().any(|p| x == p.0 && y == p.1)
    }
}

pub struct Food {
    x: u32,
    y: u32,
}

impl Food {
    // Return true if snake ate food this update
    fn update(&mut self, s: &Snake) -> bool {
        let front = s.snake_parts.front().unwrap();
        if front.0 == self.x && front.1 == self.y {
            true
        } else {
            false
        }
    }

    fn render(&mut self, gl: &mut GlGraphics, args: &RenderArgs, width: u32) {
        use graphics;

        const BLACK: [f32; 4] = [1.0, 1.0, 1.0, 1.0];

        let x = self.x * width;
        let y = self.y * width;

        let square = graphics::rectangle::square(x as f64, y as f64, width as f64);

        gl.draw(args.viewport(), |c, gl| {
            let transform = c.transform;

            graphics::rectangle(BLACK, square, transform, gl)
        });
    }
}

fn main() {
    // Change this to OpenGL::V2_1 if this fails.
    let opengl = OpenGL::V3_2;

    const COLS: u32 = 30;
    const ROWS: u32 = 20;
    const SQUARE_WIDTH: u32 = 20;

    let WIDTH = COLS * SQUARE_WIDTH;
    let HEIGHT = ROWS * SQUARE_WIDTH;

    let mut window: GlutinWindow = WindowSettings::new("Snake Game", [WIDTH, HEIGHT])
        .opengl(opengl)
        .exit_on_esc(true)
        .build()
        .unwrap();

    let mut game = Game {
        gl: GlGraphics::new(opengl),
        rows: ROWS,
        cols: COLS,
        square_width: SQUARE_WIDTH,
        just_eaten: false,
        food: Food { x: 1, y: 1 },
        score: 0,
        snake: Snake {
            gl: GlGraphics::new(opengl),
            snake_parts: LinkedList::from_iter((vec![Snake_Piece(COLS / 2, ROWS / 2)]).into_iter()),
            width: SQUARE_WIDTH,
            d: Direction::DOWN,
        },
    };

    let mut events = Events::new(EventSettings::new()).ups(10);
    while let Some(e) = events.next(&mut window) {
        if let Some(r) = e.render_args() {
            game.render(&r);
        }

        if let Some(u) = e.update_args() {
            if !game.update(&u) {
                break;
            }
        }

        if let Some(k) = e.button_args() {
            if k.state == ButtonState::Press {
                game.pressed(&k.button);
            }
        }
    }
    println!("Congratulations, your score was: {}", game.score);
}

Hi @SpyR1014 is there a specific reason this doesn't run on a mac.
Here is the error I've been getting.

Screenshot

Thanks for pointing this out @JeanAbayo. I didn't test on mac so don't know why that error is occurring.
Are you using the most up to date Rust, and/or nightly Rust?

Are you able to get the basic code working? I fear there is an error in the winit library.

maybe just in windows ？

tried it on Windows but it just shows the screen for a few seconds then dies with "Congratulations" message

it just flashes and terminates by popping out the congratulations message on ubuntu.

Unsure what is going on. But I now recommend checking out GGEZ and their snake example: https://github.com/ggez/ggez/blob/master/examples/04_snake.rs

There is also amethyst: https://github.com/amethyst/amethyst

I don't know how to push commit to GitHub Gist, so I just put link for tweaked version here: https://gist.github.com/640f17e2e92b5d7db5002b84b662deed.git

Although there is a LOT of room for improvement, I decided to fix the very minimum so that the code does not differ much from the one shown in the video. What I did:

• updated dependencies;
• removed redundant imports;
• removed extern(s) (not needed after 2015 edition, I believe);
• a couple of naming and formatting fixes;
• fixes in a couple of places with changed API.

If @AndrewJakubowicz "merge" it here, I'll delete my gist.

please tell me the dependencies. It doesn't work for me

Hi @SpyR1014 is there a specific reason this doesn't run on a mac. Here is the error I've been getting.

Screenshot

Hi, (I'm only a beginner in Rust programming, but i got intermediate knowledge in Rust). You said that the code isn't running, and you've gotten that error, As i can see in your terminal the code panicked at window.rs at line number 13 in main.rs "extern crate opengl_graphics;" which i think is the cause, so maybe opengl. I don't know the exact cause of the problem but that's worth to find out.

Suprisingly enough, it runs on mine, and i'm running this Rust compiler version(rustc version) rustc 1.70.0 (90c541806 2023-05-31). Not important, but I run Endeavour OS cassini nova, Based on Arch