refactor frame loop

snes-core/src/emulator.rs

@@ -25,12 +25,17 @@ impl Emulator {
         self.cpu.cycles = 0;
     }
 
-    pub fn is_frame_ending(&self) -> bool {
-        self.bus.ppu.registers.v_count == 0
-    }
-
-    pub fn is_frame_starting(&self) -> bool {
-        self.bus.ppu.registers.v_count == 1
+    pub fn loop_frame(&mut self) {
+        let mut frame_started = true;
+        loop {
+            self.tick();
+            if !frame_started && self.bus.ppu.registers.v_count == 260 {
+                break;
+            }
+            if self.bus.ppu.registers.v_count >= 261 {
+                frame_started = false;
+            }
+        }
     }
 
     pub fn reset(&mut self) {

snes-frontend/src/main.rs

@@ -450,15 +450,7 @@ fn main() {
 
                     // Actually run the emulation
                     if !state.emulation.is_paused {
-                        // We want to keep the emulator running
-                        // as long as we are not at the end of the frame
-                        while !emulator.is_frame_ending() {
-                            emulator.tick()
-                        }
-                        // It takes some amount of cycles to get out of 0 v-count
-                        while !emulator.is_frame_starting() {
-                            emulator.tick()
-                        }
+                        emulator.loop_frame();
                     }
 
                     // Render emulator framebuffer