From 7bfe760a57fca33e5084da04edbf0dcf6fe76d41 Mon Sep 17 00:00:00 2001
From: Franco Colmenarez <info@francoacg.com>
Date: Sun, 9 Jul 2023 12:09:09 -0500
Subject: [PATCH] Fix tearing

---
 src/emulator.rs | 36 +++++++++++++++++++++++++-----------
 src/ppu.rs      |  4 ++++
 src/render.rs   |  3 +--
 3 files changed, 30 insertions(+), 13 deletions(-)

diff --git a/src/emulator.rs b/src/emulator.rs
index e21d4b7..a1934c6 100644
--- a/src/emulator.rs
+++ b/src/emulator.rs
@@ -109,21 +109,35 @@ impl Emulator {
         }
     }
 
+    fn tick(&mut self, frame_buffer: &mut [u8]) {
+        self.cpu.run(&mut self.bus);
+        let cycles = self.cpu.get_last_op_cycles().to_t();
+        self.bus.ppu.do_cycles(&mut self.bus.interrupts, cycles, frame_buffer);
+        self.bus.sound.do_cycles(cycles);
+        self.bus.timer.do_cycles(&mut self.bus.interrupts, cycles);
+        if self.bus.double_speed_mode() {
+            self.bus.timer.do_cycles(&mut self.bus.interrupts, Cycles(cycles.0 * 3.0));
+        }
+
+        // 1 CPU cycle = 238.42ns
+        // thread::sleep(time::Duration::from_nanos((self.cpu.get_last_op_cycles().0 * 238).try_into().unwrap()));
+    }
+
     pub fn run(&mut self, cpu_cycles: Cycles, frame_buffer: &mut [u8]) {
         self.cpu.reset_cycles();
         while self.cpu.get_cycles().to_t().0 <= cpu_cycles.0 {
-            self.cpu.run(&mut self.bus);
-            let cycles = self.cpu.get_last_op_cycles().to_t();
-            self.bus.ppu.do_cycles(&mut self.bus.interrupts, cycles, frame_buffer);
-            self.bus.sound.do_cycles(cycles);
-            self.bus.timer.do_cycles(&mut self.bus.interrupts, cycles);
-            if self.bus.double_speed_mode() {
-                self.bus.timer.do_cycles(&mut self.bus.interrupts, Cycles(cycles.0 * 3.0));
+            self.tick(frame_buffer);
+        }
+    }
+
+    pub fn run_frame(&mut self, frame_buffer: &mut [u8]) {
+        self.cpu.reset_cycles();
+        let mut frame_started = true;
+        while self.bus.ppu.lcd_y() < 144 || frame_started {
+            self.tick(frame_buffer);
+            if self.bus.ppu.lcd_y() == 0 {
+                frame_started = false;
             }
-
-            // 1 CPU cycle = 238.42ns
-            // thread::sleep(time::Duration::from_nanos((self.cpu.get_last_op_cycles().0 * 238).try_into().unwrap()));
-
         }
     }
 
diff --git a/src/ppu.rs b/src/ppu.rs
index 7bc433b..a939372 100644
--- a/src/ppu.rs
+++ b/src/ppu.rs
@@ -345,6 +345,10 @@ impl PPU {
         }
     }
 
+    pub fn lcd_y(&self) -> u8 {
+        self.lcd_y
+    }
+
     pub fn set_vram_bank(&mut self, bank: u8) {
         if self.cgb_mode {
             self.vram_bank = bank & 1;
diff --git a/src/render.rs b/src/render.rs
index f2e640c..ba9cba4 100644
--- a/src/render.rs
+++ b/src/render.rs
@@ -1,6 +1,5 @@
 use crate::emulator::Emulator;
 use crate::frames::Frames;
-use crate::cpu::Cycles;
 use crate::ppu::{WIDTH, HEIGHT};
 
 use log::error;
@@ -81,7 +80,7 @@ pub fn start_eventloop() {
                 *control_flow = ControlFlow::Exit
             },
             Event::MainEventsCleared => {
-                emulator.run(Cycles(70224.0), pixels.get_frame());
+                emulator.run_frame(pixels.get_frame());
                 frame_counter.increment();
                 if frame_counter.elapsed_ms() >= 1000 {
                     window.set_title(&format!("rmg-001 (FPS: {})", frame_counter.count()));