使用 Rust 开发一个微型游戏
使用 Rust 构建微型游戏 -- 用于理解游戏开发
一、 创建游戏
Agenda
- 建立项目
- 实现 Game loop
- 不同的游戏模式
- 添加玩家
- 添加障碍和计分
- 汇总
理解 Game loop
为了让游戏流畅、顺滑的运行，需要使用 Game loop
Game loop：
- 初始化窗口、图形和其它资源
- 每当屏幕刷新（通常是每秒 30、60或更多次），它都会运行
- 每次通过循环，它都会调用游戏的 tick() 函数
Game loop
开始 -> 配置 App、Window 和图形 -> Poll （轮询 OS 监听输入状态 -> 调用 tick() 函数 -> 更新屏幕 -> 停止？ -> 退出
游戏引擎
- 游戏引擎用来处理平台特定的部分
- 以便开发者专心开发游戏
Bracket-Lib （Amethyst Foundation）
Bracket-Lib 是一个 Rust 游戏编程库：
- 作为简单的教学工具
- 抽象了游戏开发很多复杂的东西
- 但保留了相关的概念
Bracket-Lib 包括很多库：
- 随机数生成、几何、路径寻找、颜色处理、常用算法等
Bracket-terminal
bracket-terminal 是 Bracket-Lib 中负责显示部分
- 它提供了模拟控制台
- 可与多种渲染平台配合：
- 从文本控制台到 Web Assembly
- 例如：OpenGL、Vulkan、Metal
- 支持 sprites 和原生 OpenGL 开发
Codepage 437：IBM 扩展 ASCII 字符集
Codepage 437：
- 来自 Dos PC 上的字符，用于终端输出，除了字母和数字，还提供了一些符号
- Bracket-lib 会把字符翻译成图形 sprites 并提供一个有限的字符集，字符所展示的是相应的图片
~ via 🅒 base
➜ cd rust
~/rust via 🅒 base
➜ cargo new flappy
Created binary (application) `flappy` package
~/rust via 🅒 base
➜ cd flappy
flappy on master [?] via 🦀 1.67.1 via 🅒 base
➜ c
flappy on master [?] via 🦀 1.67.1 via 🅒 base
➜
main.rs
use bracket_lib::prelude::*;
struct State {}
impl GameState for State {
fn tick(&mut self, ctx: &mut BTerm) {
ctx.cls();
ctx.print(1, 1, "Hello, Bracket Terminal!");
}
}
fn main() -> BError {
let context = BTermBuilder::simple80x50()
.with_title("Flappy Dragon")
.build()?;
main_loop(context, State {})
}
游戏的模式
- 游戏通常在不同的模式中运行
- 每种模式会明确游戏在当前的 tick() 中应该做什么
我们这个游戏需要 3 种模式：
- 菜单
- 游戏中
- 结束
use bracket_lib::prelude::*;
enum GameMode {
Menu,
Playing,
End,
}
struct State {
mode: GameMode,
}
impl State {
fn new() -> Self {
State {
mode: GameMode::Menu,
}
}
fn play(&mut self, ctx: &mut BTerm) {
// TODO
self.mode = GameMode::End;
}
fn restart(&mut self) {
self.mode = GameMode::Playing;
}
fn main_menu(&mut self, ctx: &mut BTerm) {
ctx.cls();
ctx.print_centered(5, "Welcome to Flappy Dragon");
ctx.print_centered(8, "(P) Play Game");
ctx.print_centered(9, "(Q) Quit Game");
if let Some(key) = ctx.key {
match key {
VirtualKeyCode::P => self.restart(),
VirtualKeyCode::Q => ctx.quitting = true,
_ => {}
}
}
}
fn dead(&mut self, ctx: &mut BTerm) {
ctx.cls();
ctx.print_centered(5, "You are dead!");
ctx.print_centered(8, "(P) Play Game");
ctx.print_centered(9, "(Q) Quit Game");
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.main_menu(ctx),
GameMode::End => self.dead(ctx),
GameMode::Playing => self.play(ctx),
}
}
}
fn main() -> BError {
let context = BTermBuilder::simple80x50()
.with_title("Flappy Dragon")
.build()?;
main_loop(context, State::new())
}
二、添加 Player
main.rs
use bracket_lib::prelude::*;
enum GameMode {
Menu,
Playing,
End,
}
const SCREEN_WIDTH: i32 = 80;
const SCREEN_HEIGHT: i32 = 50;
const FRAME_DURATION: f32 = 75.0;
struct Player {
x: i32,
y: i32,
velocity: f32,
}
impl Player {
fn new(x: i32, y: i32) -> Self {
Player {
x: 0,
y: 0,
velocity: 0.0,
}
}
fn render(&mut self, ctx: &mut BTerm) {
ctx.set(0, self.y, YELLOW, BLACK, to_cp437('@'))
}
fn gravity_and_move(&mut self) {
if self.velocity < 2.0 {
self.velocity += 0.2;
}
self.y += self.velocity as i32;
self.x += 1;
if self.y < 0 {
self.y = 0;
}
}
fn flap(&mut self) {
self.velocity = -2.0; // 往上飞是负的
}
}
struct State {
player: Player,
frame_time: f32,
mode: GameMode,
}
impl State {
fn new() -> Self {
State {
player: Player::new(5, 25),
frame_time: 0.0,
mode: GameMode::Menu,
}
}
fn play(&mut self, ctx: &mut BTerm) {
ctx.cls_bg(NAVY);
self.frame_time += ctx.frame_time_ms;
if self.frame_time > FRAME_DURATION {
self.frame_time = 0.0;
self.player.gravity_and_move();
}
if let Some(VirtualKeyCode::Space) = ctx.key {
self.player.flap();
}
self.player.render(ctx);
ctx.print(0, 0, "Press Space to Flap");
if self.player.y > SCREEN_HEIGHT {
self.mode = GameMode::End;
}
}
fn restart(&mut self) {
self.player = Player::new(5, 25);
self.frame_time = 0.0;
self.mode = GameMode::Playing;
}
fn main_menu(&mut self, ctx: &mut BTerm) {
ctx.cls();
ctx.print_centered(5, "Welcome to Flappy Dragon");
ctx.print_centered(8, "(P) Play Game");
ctx.print_centered(9, "(Q) Quit Game");
if let Some(key) = ctx.key {
match key {
VirtualKeyCode::P => self.restart(),
VirtualKeyCode::Q => ctx.quitting = true,
_ => {}
}
}
}
fn dead(&mut self, ctx: &mut BTerm) {
ctx.cls();
ctx.print_centered(5, "You are dead!");
ctx.print_centered(8, "(P) Play Game");
ctx.print_centered(9, "(Q) Quit Game");
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.main_menu(ctx),
GameMode::End => self.dead(ctx),
GameMode::Playing => self.play(ctx),
}
}
}
fn main() -> BError {
let context = BTermBuilder::simple80x50()
.with_title("Flappy Dragon")
.build()?;
main_loop(context, State::new())
}
三、添加障碍
use bracket_lib::prelude::*;
enum GameMode {
Menu,
Playing,
End,
}
const SCREEN_WIDTH: i32 = 80;
const SCREEN_HEIGHT: i32 = 50;
const FRAME_DURATION: f32 = 75.0;
struct Player {
x: i32, // 世界空间
y: i32,
velocity: f32,
}
impl Player {
fn new(x: i32, y: i32) -> Self {
Player {
x: 0,
y: 0,
velocity: 0.0,
}
}
fn render(&mut self, ctx: &mut BTerm) {
ctx.set(0, self.y, YELLOW, BLACK, to_cp437('@'))
}
fn gravity_and_move(&mut self) {
if self.velocity < 2.0 {
self.velocity += 0.2;
}
self.y += self.velocity as i32;
self.x += 1;
if self.y < 0 {
self.y = 0;
}
}
fn flap(&mut self) {
self.velocity = -2.0; // 往上飞是负的
}
}
struct State {
player: Player,
frame_time: f32,
mode: GameMode,
obstacle: Obstacle,
score: i32,
}
impl State {
fn new() -> Self {
State {
player: Player::new(5, 25),
frame_time: 0.0,
mode: GameMode::Menu,
obstacle: Obstacle::new(SCREEN_WIDTH, 0),
score: 0,
}
}
fn play(&mut self, ctx: &mut BTerm) {
ctx.cls_bg(NAVY);
self.frame_time += ctx.frame_time_ms;
if self.frame_time > FRAME_DURATION {
self.frame_time = 0.0;
self.player.gravity_and_move();
}
if let Some(VirtualKeyCode::Space) = ctx.key {
self.player.flap();
}
self.player.render(ctx);
ctx.print(0, 0, "Press Space to Flap");
ctx.print(0, 1, &format!("Score: {}", self.score));
self.obstacle.render(ctx, self.player.x);
if self.player.x > self.obstacle.x {
self.score += 1;
self.obstacle = Obstacle::new(self.player.x + SCREEN_WIDTH, self.score);
}
if self.player.y > SCREEN_HEIGHT || self.obstacle.hit_obstacle(&self.player) {
self.mode = GameMode::End;
}
}
fn restart(&mut self) {
self.player = Player::new(5, 25);
self.frame_time = 0.0;
self.mode = GameMode::Playing;
self.obstacle = Obstacle::new(SCREEN_WIDTH, 0);
self.score = 0;
}
fn main_menu(&mut self, ctx: &mut BTerm) {
ctx.cls();
ctx.print_centered(5, "Welcome to Flappy Dragon");
ctx.print_centered(8, "(P) Play Game");
ctx.print_centered(9, "(Q) Quit Game");
if let Some(key) = ctx.key {
match key {
VirtualKeyCode::P => self.restart(),
VirtualKeyCode::Q => ctx.quitting = true,
_ => {}
}
}
}
fn dead(&mut self, ctx: &mut BTerm) {
ctx.cls();
ctx.print_centered(5, "You are dead!");
ctx.print_centered(6, &format!("You earned {} points", self.score));
ctx.print_centered(8, "(P) Play Game");
ctx.print_centered(9, "(Q) Quit Game");
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.main_menu(ctx),
GameMode::End => self.dead(ctx),
GameMode::Playing => self.play(ctx),
}
}
}
struct Obstacle {
x: i32, // 世界空间
gap_y: i32,
size: i32,
}
impl Obstacle {
fn new(x: i32, score: i32) -> Self {
let mut random = RandomNumberGenerator::new();
Obstacle {
x,
gap_y: random.range(10, 40),
size: i32::max(2, 20 - score),
}
}
fn render(&mut self, ctx: &mut BTerm, player_x: i32) {
let screen_x = self.x - player_x; // 屏幕空间
let half_size = self.size / 2;
for y in 0..self.gap_y - half_size {
ctx.set(screen_x, y, RED, BLACK, to_cp437('|'));
}
for y in self.gap_y + half_size..SCREEN_HEIGHT {
ctx.set(screen_x, y, RED, BLACK, to_cp437('|'))
}
}
fn hit_obstacle(&self, player: &Player) -> bool {
let half_size = self.size / 2;
let does_x_match = player.x == self.x;
let player_above_gap = player.y < self.gap_y - half_size;
let player_below_gap = player.y > self.gap_y + half_size;
does_x_match && (player_above_gap || player_below_gap)
}
}
fn main() -> BError {
let context = BTermBuilder::simple80x50()
.with_title("Flappy Dragon")
.build()?;
main_loop(context, State::new())
}
本文来自博客园，作者：寻月隐君，转载请注明原文链接：https://www.cnblogs.com/QiaoPengjun/p/17435616.html
