Frame counter

src/bus.rs

@@ -59,11 +59,15 @@ impl Bus {
     pub fn new() -> Self {
         let args: Vec<String> = std::env::args().collect();
         if args.len() < 2 {
-            panic!("Please, specify a ROM");
+            println!("Please, specify a ROM file");
+            std::process::exit(1);
         }
         let game_rom = match ROM::load_file(&args[1]) {
             Ok(rom) => rom,
-            Err(_) => panic!("Could not read ROM"),
+            Err(err) => {
+                println!("Could not read ROM: {}", err);
+                std::process::exit(1);
+            },
         };
         let mut data = [0x00; 0x10000];
         // Hardware registers after the bootrom

src/frames.rs

@@ -0,0 +1,37 @@
+use std::time::Instant;
+
+pub struct Frames {
+    count: usize,
+    timer: Instant,
+    time_start: u128,
+}
+
+impl Frames {
+    pub fn new() -> Self {
+        Self {
+            count: 0,
+            timer: Instant::now(),
+            time_start: 0,
+        }
+    }
+
+    pub fn reset_count(&mut self) {
+        self.count = 0;
+    }
+
+    pub fn reset_timer(&mut self) {
+        self.time_start = self.timer.elapsed().as_millis();
+    }
+
+    pub fn increment(&mut self) {
+        self.count = self.count.saturating_add(1);
+    }
+
+    pub fn elapsed_ms(&self) -> u128 {
+        self.timer.elapsed().as_millis().saturating_sub(self.time_start)
+    }
+
+    pub fn count(&self) -> usize {
+        self.count
+    }
+}

src/lib.rs

@@ -7,3 +7,4 @@ pub mod bus;
 pub mod joypad;
 pub mod emulator;
 pub mod render;
+pub mod frames;

src/render.rs

@@ -1,4 +1,5 @@
 use crate::emulator::Emulator;
+use crate::frames::Frames;
 use crate::cpu::{Cycles};
 use crate::ppu::{WIDTH, HEIGHT};
 
@@ -42,6 +43,9 @@ pub fn create_window<T>(width: u32, height: u32, title: String, event_loop: &Eve
 }
 
 pub fn start_eventloop() {
+    let mut emulator = Emulator::new();
+    let mut frames = Frames::new();
+
     env_logger::init();
     let event_loop = EventLoop::new();
     let mut input = WinitInputHelper::new();
@@ -49,8 +53,6 @@ pub fn start_eventloop() {
     let window = create_window(WIDTH, HEIGHT, "rmg-001".to_string(), &event_loop);
     let mut pixels = create_pixels(WIDTH, HEIGHT, &window);
 
-    let mut emulator = Emulator::new();
-
     event_loop.run(move |event, _, control_flow| {
         *control_flow = ControlFlow::Wait;
 
@@ -80,6 +82,12 @@ pub fn start_eventloop() {
             },
             Event::MainEventsCleared => {
                 emulator.run(Cycles(70224), pixels.get_frame());
+                frames.increment();
+                if frames.elapsed_ms() >= 1000 {
+                    window.set_title(&format!("rmg-001 (FPS: {})", frames.count()));
+                    frames.reset_count();
+                    frames.reset_timer();
+                }
 
                 // thread::sleep(time::Duration::from_millis(1));
                 window.request_redraw();