From 6954a60864428e2933bdc417e4fcc3e17dab9fbb Mon Sep 17 00:00:00 2001
From: Rekai Musuka <musukarekai@gmail.com>
Date: Wed, 15 Jul 2020 16:50:57 -0500
Subject: [PATCH] Run Sound + Delay Timers in another thread in Safe Rust

There is yet to be communication between the Parallel timers and the
actual CHIP-8 Emulator
---
 Cargo.lock    |  1 +
 Cargo.toml    |  1 +
 src/emu.rs    |  1 -
 src/main.rs   |  7 +++----
 src/periph.rs | 27 +++++++++++++++++++++++++++
 5 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 89d6383..ccb954a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -152,6 +152,7 @@ checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
 name = "chip8"
 version = "0.1.0"
 dependencies = [
+ "lazy_static",
  "pixels",
  "rand",
  "rodio",
diff --git a/Cargo.toml b/Cargo.toml
index 96206e8..7c3ce74 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -12,3 +12,4 @@ rand = "0.7.3"
 winit = "0.22.2"
 winit_input_helper = "0.7.0"
 rodio = "0.11.0"
+lazy_static = "1.4.0"
diff --git a/src/emu.rs b/src/emu.rs
index a809850..f47311e 100644
--- a/src/emu.rs
+++ b/src/emu.rs
@@ -62,7 +62,6 @@ impl Chip8 {
     pub fn execute_cycle(&mut self) {
         // Reset Request Redraw
         self.request_redraw = false;
-
         let opcode = self.get_opcode();
         self.pc += 2; // Immediately increment the Program Counter
 
diff --git a/src/main.rs b/src/main.rs
index d38fdf5..982cafe 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,7 +1,4 @@
-// I used: http://devernay.free.fr/hacks/chip8/C8TECH10.HTM#00E0
-// and https://en.wikipedia.org/wiki/CHIP-8#Opcode_table
-// for information about how to implement a CHIP-8 Emulator
-use chip8::emu::Chip8;
+use chip8::{emu::Chip8, periph::TimerManager};
 use pixels::{wgpu::Surface, Pixels, SurfaceTexture};
 use std::path::Path;
 use std::time::{Duration, Instant};
@@ -25,6 +22,8 @@ fn main() {
     let rom_path = Path::new("./games/c8games/INVADERS");
     chip8.load_rom(rom_path).expect("Unable to load ROM");
 
+    TimerManager::start();
+
     let mut start = Instant::now();
     let frametime = Duration::from_nanos(1e+9 as u64 / OPCODES_PER_SECOND);
 
diff --git a/src/periph.rs b/src/periph.rs
index ed93f57..3966abb 100644
--- a/src/periph.rs
+++ b/src/periph.rs
@@ -1,6 +1,14 @@
+use lazy_static::lazy_static;
 use rodio::{source::SineWave, Sink};
+use std::sync::Mutex;
+use std::thread;
 use std::time::{Duration, Instant};
 
+lazy_static! {
+    static ref SOUND_TIMER: Mutex<Timer> = Mutex::new(Timer::default().with_beep());
+    static ref DELAY_TIMER: Mutex<Timer> = Mutex::new(Timer::default());
+}
+
 #[derive(Copy, Clone)]
 pub struct Display {
     pub buf: [u8; Self::WIDTH as usize * Self::HEIGHT as usize],
@@ -57,6 +65,25 @@ impl Default for Display {
     }
 }
 
+pub struct TimerManager;
+
+impl TimerManager {
+    pub fn start() {
+        thread::spawn(|| {
+            let duration = Duration::from_nanos(1e+9 as u64 / 60);
+            let mut start = Instant::now();
+
+            loop {
+                if Instant::now().duration_since(start) > duration {
+                    SOUND_TIMER.lock().unwrap().tick();
+                    DELAY_TIMER.lock().unwrap().tick();
+                    start = Instant::now();
+                }
+            }
+        });
+    }
+}
+
 #[derive(Debug, Copy, Clone)]
 pub struct Timer {
     remaining: u8,