early rollback code (#1054)

* some rollback test

* more

src/device/vi.rs

@@ -103,7 +103,9 @@ pub fn write_regs(device: &mut device::Device, address: u64, value: u32, mask: u
                 if device.netplay.is_none() {
                     savestates::process_savestates(device);
                 }
-                let _ = device.ui.video.fps_tx.as_ref().unwrap().try_send(true);
+                if !netplay::in_rollback(device.netplay.as_ref()) {
+                    let _ = device.ui.video.fps_tx.as_ref().unwrap().try_send(true);
+                }
             }
         }
         _ => {
@@ -114,7 +116,9 @@ pub fn write_regs(device: &mut device::Device, address: u64, value: u32, mask: u
 }
 
 pub fn update_screen(device: &mut device::Device) {
-    ui::video::render_frame();
+    if !netplay::in_rollback(device.netplay.as_ref()) {
+        ui::video::render_frame();
+    }
 
     let (speed_limiter_toggled, paused) = ui::video::check_callback(device);
 
@@ -122,18 +126,22 @@ pub fn update_screen(device: &mut device::Device) {
         reset_pace_deadline(device);
     }
 
-    if device
-        .speed_limiter
-        .frame_counter
-        .is_multiple_of(device.speed_limiter.limit_freq)
+    if !netplay::in_rollback(device.netplay.as_ref())
+        && device
+            .speed_limiter
+            .frame_counter
+            .is_multiple_of(device.speed_limiter.limit_freq)
         && device.speed_limiter.enabled
     {
         speed_limiter(device);
     }
 
-    unsafe { sdl3_sys::events::SDL_PumpEvents() };
-    ui::video::update_screen();
-    device.speed_limiter.frame_counter += 1;
+    if !netplay::in_rollback(device.netplay.as_ref()) {
+        unsafe { sdl3_sys::events::SDL_PumpEvents() };
+        ui::video::update_screen();
+        device.speed_limiter.frame_counter += 1;
+        let _ = device.ui.video.vis_tx.as_ref().unwrap().try_send(true);
+    }
 
     if device.netplay.is_some() {
         device.netplay.as_mut().unwrap().inputs = netplay::process_requests(device);
@@ -156,8 +164,6 @@ pub fn vertical_interrupt_event(device: &mut device::Device) {
         cheats::execute_cheats(device, device.cheats.cheats.clone());
     }
 
-    let _ = device.ui.video.vis_tx.as_ref().unwrap().try_send(true);
-
     retroachievements::do_frame();
 
     /* toggle vi field if in interlaced mode */

src/netplay.rs

@@ -210,6 +210,22 @@ fn check_input_delay(netplay: &mut Netplay) {
     }
 }
 
+fn pending_frames(netplay: &Netplay) -> usize {
+    netplay
+        .requests
+        .iter()
+        .filter(|r| matches!(r, ggrs::GgrsRequest::AdvanceFrame { .. }))
+        .count()
+}
+
+pub fn in_rollback(netplay: Option<&Netplay>) -> bool {
+    if let Some(netplay) = netplay {
+        pending_frames(netplay) != 0
+    } else {
+        false
+    }
+}
+
 pub fn process_requests(
     device: &mut device::Device,
 ) -> Vec<(ui::input::InputData, ggrs::InputStatus)> {

src/savestates.rs

@@ -266,7 +266,9 @@ pub fn load_savestate(device: &mut device::Device, rewind: bool, rewind_frame: O
     if let Some(mut state) = state_data
         && device.rdram.size == state.device.rdram.size
     {
-        ui::video::idle();
+        if device.netplay.is_none() {
+            ui::video::idle();
+        }
 
         device.savestate.last_rewind_saved = state.device.vi.elapsed_time;
 

src/ui/audio.rs

@@ -1,4 +1,5 @@
 use crate::device;
+use crate::netplay;
 use crate::ui;
 
 static ADJUST_LOCKED: std::sync::atomic::AtomicBool = std::sync::atomic::AtomicBool::new(false);
@@ -174,6 +175,10 @@ pub fn play_audio(device: &device::Device, dram_addr: usize, length: u64) {
         return;
     }
 
+    if netplay::in_rollback(device.netplay.as_ref()) {
+        return;
+    }
+
     let mut primary_buffer: Vec<i16> = vec![0; length as usize / 2];
     let mut i = 0;
     while i < length as usize / 2 {