From 6f04925ea5e56f8d6bc8b0ea0c53086b25753129 Mon Sep 17 00:00:00 2001
From: alban <git@albancrommer.com>
Date: Mon, 24 Jul 2023 17:34:06 +0200
Subject: [PATCH] feat: add framerate with fixed value for now (20Hz)

---
 src/framerate.rs | 39 +++++++++++++++++++++++++++++++++++++++
 src/lib.rs       |  1 +
 src/main.rs      |  6 ++++++
 3 files changed, 46 insertions(+)
 create mode 100644 src/framerate.rs

diff --git a/src/framerate.rs b/src/framerate.rs
new file mode 100644
index 0000000..dbab25b
--- /dev/null
+++ b/src/framerate.rs
@@ -0,0 +1,39 @@
+use log::{debug, warn};
+use std::time::{Duration, Instant};
+use crate::errors::LJResult;
+use std::{thread};
+
+/// Converts helios Geometry to Helios
+#[derive(Debug, Clone, Copy)]
+pub struct Framerate {
+	prev_trace_time: Instant,
+	fps: u8,
+}
+
+impl Framerate {
+	pub fn new() -> LJResult<Self> {
+		Ok(Framerate {
+			prev_trace_time: Instant::now(),
+			fps: 20,
+		})
+	}
+	pub fn handle_time(&mut self) -> LJResult<()> {
+		let frame_time = 1000000000 / self.fps as u128;
+		let now = Instant::now();
+		// How long since last loop ?
+		let nanotime_spent = self.prev_trace_time.elapsed().as_nanos();
+		// Diw it go too fast? If so : sleep a bit
+		if frame_time > nanotime_spent {
+			let nanotime_towait = frame_time - nanotime_spent;
+			let dur = Duration::new(0, (nanotime_towait as f32 * 0.9) as u32);
+			// debug!("{:?} - {:?} : {:?}", nanotime_towait, self.prev_trace_time, now );
+			thread::sleep(dur);
+			debug!("Framerate OK");
+		} else {
+			warn!("Frame longer than expected {:?} > {:?}", nanotime_spent, frame_time, );
+		}
+
+		self.prev_trace_time = now;
+		Ok(())
+	}
+}
diff --git a/src/lib.rs b/src/lib.rs
index 9048f40..ac3d833 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -5,3 +5,4 @@ pub mod device;
 pub mod point;
 pub mod transformer;
 pub mod worldstate;
+pub mod framerate;
diff --git a/src/main.rs b/src/main.rs
index 62067a8..c1ba308 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -9,6 +9,7 @@ mod point;
 mod transformer;
 mod device;
 mod worldstate;
+mod framerate;
 
 use device::device_factory;
 use std::sync::atomic::{AtomicBool, Ordering};
@@ -21,6 +22,7 @@ use transformer::Transformers;
 use log::{LevelFilter, info, /* warn, */ error};
 use env_logger::Builder;
 use worldstate::WorldState;
+use framerate::Framerate;
 
 const DEFAULT_CONF_FILE: &str = "settings.toml";
 
@@ -68,9 +70,13 @@ fn run_all() -> LJResult<()> {
 	// Setup geometry transformers on points lists
 	let transformers = config.get_transformers();
 
+	// Setup framerate limiter
+	let mut framerate_handler = Framerate::new()?;
+
 	// Dispatch based on redis requests
 	while running.load(Ordering::SeqCst) {
 		rs.set_status(tracer.status())?;
+		let _ = framerate_handler.handle_time()?;
 		let order = rs.get_order(config.laser_id)?;
 		match order {
 			Order::Draw | Order::Black | Order::Grid => {