add some basic pacing

1 files changed, 14 insertions, 2 deletions

diff --git a/src/main.rs b/src/main.rs
index bfcb63a..bb0ae71 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,4 +1,12 @@
-use std::{fs::File, io::BufReader};
+use std::{
+    fs::File,
+    io::BufReader,
+    time::{Duration, Instant},
+};
+
+const SECOND: u64 = 1_000_000_000;
+const REFRESH_RATE: u64 = 60;
+const FRAME_DURATION: Duration = Duration::from_nanos(SECOND / REFRESH_RATE);
 
 fn main() -> std::io::Result<()> {
     if let Some(arg) = std::env::args().nth(1) {
@@ -9,8 +17,12 @@ fn main() -> std::io::Result<()> {
             chip8.load_rom(buf_reader)?;
         }
         loop {
-            chip8.cycle();
+            let start = Instant::now();
+            for _ in 0..8 {
+                chip8.cycle();
+            }
             chip8.display()?;
+            std::thread::sleep(FRAME_DURATION - start.elapsed());
         }
     } else {
         println!("usage: chip8 rompath")