3 files changed, 139 insertions, 1 deletions
diff --git a/src/buffer.rs b/src/buffer.rs
new file mode 100644
index 0000000..fa0feaa
--- /dev/null
+++ b/src/buffer.rs
@@ -0,0 +1,92 @@
+use std::io::Write;
+
+use crossterm::{
+	cursor::{Hide, MoveTo, Show},
+	event::{self, Event},
+	execute,
+	style::{ContentStyle, PrintStyledContent, StyledContent},
+	terminal::{
+		BeginSynchronizedUpdate, Clear, ClearType, EndSynchronizedUpdate, EnterAlternateScreen,
+		LeaveAlternateScreen, WindowSize, disable_raw_mode, enable_raw_mode, window_size,
+	},
+};
+
+#[derive(Debug, Clone, Copy, Default, Eq, PartialEq)]
+pub struct Cell {
+	pub character: char,
+	pub style: ContentStyle,
+	pub x: u16,
+	pub y: u16,
+	pub z: u8,
+}
+
+#[derive(Debug)]
+pub struct Buffer<'a, W: Write> {
+	stdout: &'a mut W,
+	pub cells: Vec<Cell>,
+	pub window_size: WindowSize,
+}
+
+impl<'a, W: Write> Buffer<'a, W> {
+	pub fn new(stdout: &'a mut W) -> std::io::Result<Self> {
+		Ok(Self {
+			stdout,
+			cells: Vec::new(),
+			window_size: window_size()?,
+		})
+	}
+
+	fn initialize(writer: &mut impl Write) -> std::io::Result<()> {
+		enable_raw_mode()?;
+		execute!(writer, Hide, EnterAlternateScreen)?;
+		Ok(())
+	}
+
+	fn render(&mut self) -> std::io::Result<()> {
+		self.cells.sort_unstable_by_key(|cell| cell.z);
+		execute!(self.stdout, BeginSynchronizedUpdate, Clear(ClearType::All))?;
+		for cell in &self.cells {
+			execute!(
+				self.stdout,
+				MoveTo(cell.x, cell.y),
+				PrintStyledContent(StyledContent::new(cell.style, cell.character))
+			)?;
+		}
+		execute!(self.stdout, EndSynchronizedUpdate)?;
+		Ok(())
+	}
+
+	pub fn finish(&mut self) -> std::io::Result<()> {
+		execute!(self.stdout, Show, LeaveAlternateScreen)?;
+		disable_raw_mode()?;
+		Ok(())
+	}
+
+	pub fn render_loop(
+		&mut self,
+		mut event_handler: impl FnMut(&mut Self, Event),
+		mut update: impl FnMut(&mut Self),
+	) -> std::io::Result<()> {
+		Self::initialize(self.stdout)?;
+		let (sender, receiver) = std::sync::mpsc::channel();
+		std::thread::scope(|scope| -> std::io::Result<()> {
+			scope.spawn(|| {
+				loop {
+					let Ok(event) = event::read() else {
+						continue;
+					};
+					let _ = sender.send(event);
+				}
+			});
+			loop {
+				while let Ok(event) = receiver.try_recv() {
+					event_handler(self, event);
+				}
+				update(self);
+				self.render()?;
+			}
+		})?;
+		self.finish()?;
+		Ok(())
+	}
+}
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..86b6256
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1 @@
+pub mod buffer;
diff --git a/src/main.rs b/src/main.rs
index e7a11a9..e8c9f23 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,3 +1,48 @@
+use std::time::Instant;
+
+use crossterm::{
+	event::{Event, KeyCode},
+	style::ContentStyle,
+};
+use tortuise::buffer::{Buffer, Cell};
+
 fn main() {
-    println!("Hello, world!");
+	let mut stdout = std::io::stdout().lock();
+	let mut buffer = Buffer::new(&mut stdout).unwrap();
+	let mut last_frame_start = Instant::now();
+	buffer
+		.render_loop(
+			|renderer, event| {
+				if let Event::Key(event) = event
+					&& event.code == KeyCode::Esc
+				{
+					let _ = renderer.finish();
+					std::process::exit(0);
+				}
+			},
+			|renderer| {
+				renderer.cells.clear();
+				let end = Instant::now();
+				let frame_time = (end - last_frame_start).as_micros();
+				let digits = [
+					frame_time % 1_000_000 / 100_000,
+					frame_time % 100_000 / 10_000,
+					frame_time % 10_000 / 1_000,
+					frame_time % 1_000 / 100,
+					frame_time % 100 / 10,
+					frame_time % 10,
+				];
+				for (x, digit) in digits.into_iter().enumerate() {
+					renderer.cells.push(Cell {
+						character: char::from_digit(digit as u32, 10).unwrap(),
+						x: x as u16,
+						y: 0,
+						z: 0,
+						style: ContentStyle::new(),
+					});
+				}
+				last_frame_start = Instant::now();
+			},
+		)
+		.unwrap();
 }