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pub mod error;
pub mod graphics;
use std::collections::VecDeque;
use std::time::{Duration, Instant};
use sfml::graphics::{RenderTarget, RenderWindow};
use sfml::window::{Event, Style};
use crate::graphics::Color;
use self::error::Result;
pub fn duration_to_f64(duration: Duration) -> f64 {
let seconds = duration.as_secs() as f64;
let nanos = f64::from(duration.subsec_nanos()) * 1e-9;
seconds + nanos
}
pub fn f64_to_duration(duration: f64) -> Duration {
debug_assert!(duration >= 0.0);
let seconds = duration.trunc() as u64;
let nanos = (duration.fract() * 1e9) as u32;
Duration::new(seconds, nanos)
}
pub fn get_fps(ctx: &Context) -> f64 {
1.0 / (ctx.fps_tracker.iter().sum::<f64>() / ctx.fps_tracker.len() as f64)
}
pub trait State {
fn update(&mut self, ctx: &mut Context) -> Result<()>;
fn draw(&mut self, ctx: &mut Context, dt: f64) -> Result<()>;
}
pub struct Context {
pub window: RenderWindow,
is_running: bool,
tick_rate: Duration,
fps_tracker: VecDeque<f64>,
}
impl Context {
pub fn run<S>(&mut self, state: &mut S) -> Result<()>
where
S: State,
{
self.window.set_active(true);
let mut last_time = Instant::now();
let mut lag = Duration::from_secs(0);
self.is_running = true;
while self.is_running {
let current_time = Instant::now();
let elapsed_time = current_time - last_time;
last_time = current_time;
lag += elapsed_time;
self.fps_tracker.pop_front();
self.fps_tracker.push_back(duration_to_f64(elapsed_time));
while let Some(event) = self.window.poll_event() {
if let Err(err) = self.handle_event(event) {
self.is_running = false;
return Err(err);
}
}
while lag >= self.tick_rate {
if let Err(err) = state.update(self) {
self.is_running = false;
return Err(err);
}
lag -= self.tick_rate;
}
let dt = duration_to_f64(lag) / duration_to_f64(self.tick_rate);
self.window.clear(&Color::MAGENTA);
if let Err(err) = state.draw(self, dt) {
self.is_running = false;
return Err(err);
}
self.window.display();
std::thread::yield_now();
}
self.window.close();
Ok(())
}
fn handle_event(&mut self, event: Event) -> Result<Event> {
match event {
Event::Closed => self.is_running = false,
_ => {}
}
Ok(event)
}
}
#[derive(Debug, Clone)]
pub struct ContextBuilder<'a> {
title: &'a str,
width: i32,
height: i32,
vsync: bool,
tick_rate: f64,
quit_on_escape: bool,
}
impl<'a> ContextBuilder<'a> {
pub fn new(title: &'a str, width: i32, height: i32) -> Self {
Self {
title,
width,
height,
..ContextBuilder::default()
}
}
pub fn vsync(&mut self, vsync: bool) -> &mut Self {
self.vsync = vsync;
self
}
pub fn tick_rate(&mut self, tick_rate: f64) -> &mut Self {
self.tick_rate = tick_rate;
self
}
pub fn build(&self) -> Result<Context> {
let mut window = RenderWindow::new(
(self.width as u32, self.height as u32),
self.title,
Style::CLOSE,
&Default::default(),
);
window.set_vertical_sync_enabled(self.vsync);
let mut fps_tracker = VecDeque::with_capacity(200);
fps_tracker.resize(200, 1.0 / 60.0);
Ok(Context {
window,
is_running: false,
tick_rate: f64_to_duration(self.tick_rate),
fps_tracker,
})
}
}
impl<'a> Default for ContextBuilder<'a> {
fn default() -> Self {
Self {
title: "Game",
width: 800,
height: 600,
vsync: true,
tick_rate: 1.0 / 60.0,
quit_on_escape: true,
}
}
}