Avoid extra framebuffer copies

IsaacMarovitz · Apr 30, 2024 · 0c8afc7 · 0c8afc7
1 parent f218646
commit 0c8afc7
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Showing 4 changed files with 37 additions and 39 deletions.
diff --git a/src/components/cpu.rs b/src/components/cpu.rs
@@ -3,6 +3,7 @@ use std::io::Read;
 use std::process;
 use crate::config::Config;
 use crate::components::prelude::*;
+use crate::Framebuffer;
 
 pub struct CPU {
     pub reg: Registers,
@@ -16,7 +17,9 @@ pub struct CPU {
 unsafe impl Send for CPU {}
 
 impl CPU {
-    pub fn new(rom: Vec<u8>, config: Config) -> Self {
+    pub fn new(rom: Vec<u8>,
+               config: Config,
+               framebuffer: Framebuffer) -> Self {
         let mut boot_rom: [u8; 0x900] = [0; 0x900];
         let booting: bool = match config.boot_rom {
             Some(ref path) => {
@@ -45,7 +48,7 @@ impl CPU {
 
         Self {
             reg: Registers::new(config.clone().mode, booting),
-            mem: MMU::new(rom, config, booting, boot_rom),
+            mem: MMU::new(rom, config, booting, boot_rom, framebuffer),
             halted: false,
             ime: false,
             ime_ask: false

diff --git a/src/components/mmu.rs b/src/components/mmu.rs
@@ -2,6 +2,7 @@ use crate::components::prelude::*;
 use crate::config::Config;
 use crate::mbc::prelude::*;
 use crate::sound::apu::APU;
+use crate::Framebuffer;
 use bitflags::bitflags;
 use num_traits::FromPrimitive;
 
@@ -34,7 +35,11 @@ bitflags! {
 }
 
 impl MMU {
-    pub fn new(rom: Vec<u8>, config: Config, booting: bool, boot_rom: [u8; 0x900]) -> Self {
+    pub fn new(rom: Vec<u8>,
+               config: Config,
+               booting: bool,
+               boot_rom: [u8; 0x900],
+               framebuffer: Framebuffer) -> Self {
         let cart_type: CartTypes = FromPrimitive::from_u8(rom[0x0147]).expect("Failed to get Cart Type!");
         let mbc_mode = match cart_type.get_mbc() {
             MBCMode::Unsupported => panic!("Unsupported Cart Type! {:}", cart_type),
@@ -56,7 +61,7 @@ impl MMU {
         Self {
             mbc: mbc,
             apu: APU::new(),
-            ppu: PPU::new(config.clone()),
+            ppu: PPU::new(config.clone(), framebuffer),
             serial: Serial::new(config.print_serial),
             joypad: Joypad::new(),
             timer: Timer::new(),
@@ -71,24 +76,22 @@ impl MMU {
         }
     }
 
-    pub fn cycle(&mut self, cycles: u32) -> bool {
+    pub fn cycle(&mut self, cycles: u32) {
         self.timer.cycle(cycles);
         self.intf |= self.timer.interrupts;
         self.timer.interrupts = Interrupts::empty();
 
         self.intf |= self.joypad.interrupts;
         self.joypad.interrupts = Interrupts::empty();
 
-        let did_draw = self.ppu.cycle(cycles);
+        self.ppu.cycle(cycles);
         self.intf |= self.ppu.interrupts;
         self.ppu.interrupts = Interrupts::empty();
 
         self.apu.cycle(self.timer.div);
 
         self.intf |= self.serial.interrupts;
         self.serial.interrupts = Interrupts::empty();
-
-        did_draw
     }
 
     fn oamdma(&mut self, value: u8) {

diff --git a/src/components/ppu.rs b/src/components/ppu.rs
@@ -1,5 +1,6 @@
 use crate::components::prelude::*;
 use crate::config::{Color, Config, Palette};
+use crate::Framebuffer;
 use bitflags::bitflags;
 
 pub const SCREEN_W: usize = 160;
@@ -33,7 +34,7 @@ pub struct PPU {
     opri: bool,
     bgprio: [Priority; SCREEN_W],
     pub interrupts: Interrupts,
-    pub frame_buffer: Vec<u8>,
+    pub framebuffer: Framebuffer,
 }
 
 #[derive(PartialEq, Copy, Clone)]
@@ -130,7 +131,7 @@ impl BGPI {
 }
 
 impl PPU {
-    pub fn new(config: Config) -> Self {
+    pub fn new(config: Config, framebuffer: Framebuffer) -> Self {
         Self {
             mode: config.mode,
             palette: config.palette,
@@ -159,13 +160,13 @@ impl PPU {
             opri: true,
             bgprio: [Priority::Normal; SCREEN_W],
             interrupts: Interrupts::empty(),
-            frame_buffer: vec![0x00; 4 * SCREEN_W * SCREEN_H],
+            framebuffer,
         }
     }
 
-    pub fn cycle(&mut self, cycles: u32) -> bool {
+    pub fn cycle(&mut self, cycles: u32) {
         if !self.lcdc.contains(LCDC::LCD_ENABLE) {
-            return false;
+            return
         }
 
         self.cycle_count += cycles;
@@ -178,7 +179,6 @@ impl PPU {
                     self.ppu_mode = PPUMode::Draw;
                     // println!("[PPU] Switching to Draw!");
                 }
-                false
             }
             PPUMode::Draw => {
                 // TODO: Allow variable length Mode 3
@@ -194,9 +194,6 @@ impl PPU {
                         self.draw_sprites();
                     }
                     // println!("[PPU] Switching to HBlank!");
-                    false
-                } else {
-                    false
                 }
             }
             PPUMode::HBlank => {
@@ -211,18 +208,15 @@ impl PPU {
                         if self.lcds.contains(LCDS::MODE_1_SELECT) {
                             self.interrupts |= Interrupts::LCD;
                         }
-                        true
                         // println!("[PPU] Switching to VBlank!");
                     } else {
                         self.ppu_mode = PPUMode::OAMScan;
                         if self.lcds.contains(LCDS::MODE_2_SELECT) {
                             self.interrupts |= Interrupts::LCD;
                         }
-                        false
                         // println!("[PPU] Switching to OAMScan!");
                     };
                 }
-                false
             }
             PPUMode::VBlank => {
                 if self.cycle_count >= 456 {
@@ -243,7 +237,6 @@ impl PPU {
 
                     self.check_lyc();
                 }
-                false
             }
         };
     }
@@ -309,10 +302,11 @@ impl PPU {
         let horizontal_offset = x * bytes_per_pixel;
         let total_offset = vertical_offset + horizontal_offset;
 
-        self.frame_buffer[total_offset + 0] = r;
-        self.frame_buffer[total_offset + 1] = g;
-        self.frame_buffer[total_offset + 2] = b;
-        self.frame_buffer[total_offset + 3] = 0xFF;
+        let mut framebuffer = self.framebuffer.write().unwrap();
+        framebuffer[total_offset + 0] = r;
+        framebuffer[total_offset + 1] = g;
+        framebuffer[total_offset + 2] = b;
+        framebuffer[total_offset + 3] = 0xFF;
     }
 
     fn draw_bg(&mut self) {
@@ -615,7 +609,9 @@ impl Memory for PPU {
                 if !self.lcdc.contains(LCDC::LCD_ENABLE) {
                     self.reset_ly();
                     self.ppu_mode = PPUMode::HBlank;
-                    self.frame_buffer = vec![0x00; 4 * SCREEN_W * SCREEN_H];
+
+                    let mut framebuffer = self.framebuffer.write().unwrap();
+                    *framebuffer = vec![0x00; 4 * SCREEN_W * SCREEN_H];
                 }
             }
             0xFF41 => {

diff --git a/src/main.rs b/src/main.rs
@@ -22,6 +22,8 @@ use winit::event_loop::EventLoop;
 use winit::application::ApplicationHandler;
 use winit::window::{Window, WindowId};
 
+type Framebuffer = Arc<RwLock<Vec<u8>>>;
+
 mod config;
 mod context;
 mod components;
@@ -44,7 +46,7 @@ struct App {
     context: Option<Arc<Mutex<Context>>>,
     config: Config,
     input_tx: Sender<(JoypadButton, bool)>,
-    framebuffer: Arc<RwLock<Vec<u8>>>
+    framebuffer: Framebuffer
 }
 
 impl ApplicationHandler for App {
@@ -105,8 +107,8 @@ impl ApplicationHandler for App {
         let context_arc = Arc::clone(&self.context.as_ref().unwrap());
         let mut context = context_arc.lock().unwrap();
 
-        let framebuffer_arc = Arc::clone(&self.framebuffer);
-        context.update(&*framebuffer_arc.read().unwrap());
+        let framebuffer = Arc::clone(&self.framebuffer);
+        context.update(&*framebuffer.read().unwrap());
 
         let _ = context.render();
     }
@@ -160,19 +162,19 @@ fn main() {
     event_loop.set_control_flow(ControlFlow::Poll);
 
     let (input_tx, input_rx) = mpsc::channel::<(JoypadButton, bool)>();
-    let framebuffer_rw: Arc<RwLock<Vec<u8>>> = Arc::new(RwLock::new(vec![0; 4 * SCREEN_W * SCREEN_H]));
+    let framebuffer: Framebuffer = Arc::new(RwLock::new(vec![0; 4 * SCREEN_W * SCREEN_H]));
 
     let mut app = App {
         game_name: String::from(game_name),
         context: None,
         config: config.clone(),
         input_tx,
-        framebuffer: framebuffer_rw.clone()
+        framebuffer: framebuffer.clone()
     };
 
     // Start CPU
     thread::spawn(move || {
-        let mut cpu = CPU::new(buffer, config);
+        let mut cpu = CPU::new(buffer, config, framebuffer);
         let mut step_cycles = 0;
         let mut step_zero = Instant::now();
 
@@ -201,13 +203,7 @@ fn main() {
 
             let cycles = cpu.cycle();
             step_cycles += cycles;
-            let did_draw = cpu.mem.cycle(cycles);
-            if did_draw {
-                let framebuffer = cpu.mem.ppu.frame_buffer.clone();
-
-                let mut framebuffer_w = framebuffer_rw.write().unwrap();
-                *framebuffer_w = framebuffer;
-            }
+            cpu.mem.cycle(cycles);
         }
     });