From f6b9fcd3d2436348e11b8de6f5aba94343eaf7b2 Mon Sep 17 00:00:00 2001
From: Logan McNaughton <848146+loganmc10@users.noreply.github.com>
Date: Wed, 11 Nov 2026 18:50:58 +0000
Subject: [PATCH] allow input delay of 0 (#1379)

---
 src/netplay.rs                |  4 ++--
 src/ui/gui/appwindow.slint    |  1 +
 src/ui/gui/netplay_wait.slint |  5 +++--
 src/ui/netplay.rs             | 13 ++++++++-----
 4 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/src/netplay.rs b/src/netplay.rs
index a6bd2141..1da77372 100644
--- a/src/netplay.rs
+++ b/src/netplay.rs
@@ -3,7 +3,7 @@ use crate::savestates;
 use crate::ui;
 use sha2::digest::Digest;
 
-const MAX_PREDICTION_WINDOW: usize = 16;
+pub const MAX_PREDICTION_WINDOW: usize = 16;
 
 #[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 pub struct RtcIceServerConfig {
@@ -203,7 +203,7 @@ pub fn receive_save(netplay: &mut Netplay, save_type: &str, save_data: &mut Vec<
 }
 
 pub fn change_input_delay(netplay: &mut Netplay, input_delay: usize) {
-    if !(1..=MAX_PREDICTION_WINDOW).contains(&input_delay) {
+    if input_delay > MAX_PREDICTION_WINDOW {
         return;
     }
 
diff --git a/src/ui/gui/appwindow.slint b/src/ui/gui/appwindow.slint
index 3820bcc5..9896cfe6 100644
--- a/src/ui/gui/appwindow.slint
+++ b/src/ui/gui/appwindow.slint
@@ -132,6 +132,7 @@ export component AppWindow inherits Window {
     in-out property netplay_chat_text <=> NetplayWaitData.chat_text;
     in-out property netplay_input_delay <=> NetplayWaitData.input_delay;
     in-out property netplay_recommended_delay <=> NetplayWaitData.recommended_delay;
+    in-out property netplay_max_input_delay <=> NetplayWaitData.max_input_delay;
     in-out property netplay_game_pal <=> NetplayWaitData.game_pal;
     in-out property netplay_connected_peers_count <=> NetplayWaitData.connected_peers_count;
 
diff --git a/src/ui/gui/netplay_wait.slint b/src/ui/gui/netplay_wait.slint
index 9cb17370..99f469de 100644
--- a/src/ui/gui/netplay_wait.slint
+++ b/src/ui/gui/netplay_wait.slint
@@ -19,6 +19,7 @@ export global NetplayWaitData {
     in-out property <string> chat_text;
     in-out property <int> input_delay;
     in-out property <int> recommended_delay;
+    in-out property <int> max_input_delay;
     in-out property <bool> game_pal;
     in-out property <int> connected_peers_count;
 }
@@ -116,8 +117,8 @@ export component NetplayWait inherits Page {
 
                     SpinBox {
                         height: self.min-height;
-                        minimum: 1;
-                        maximum: 16;
+                        minimum: 0;
+                        maximum: NetplayWaitData.max_input_delay;
                         value: NetplayWaitData.input_delay;
                         enabled: NetplayWaitData.recommended_delay != 0;
                         edited => {
diff --git a/src/ui/netplay.rs b/src/ui/netplay.rs
index 5e459003..916b1e68 100644
--- a/src/ui/netplay.rs
+++ b/src/ui/netplay.rs
@@ -1,4 +1,5 @@
 use crate::device;
+use crate::netplay;
 use crate::netplay::RtcIceServerConfig;
 use crate::ui;
 use crate::ui::gui::{AppWindow, open_uri, run_rom, save_settings, show_touch_overlay};
@@ -688,8 +689,8 @@ fn update_ping(
                                                 60.0
                                             };
                                             let latency_frames = (ping_avg / (1000.0 / refresh_rate)).ceil() as i32;
-                                            let recommendation =
-                                                (latency_frames + 1).min(16);
+                                            let recommendation = (latency_frames + 1)
+                                                .min(netplay::MAX_PREDICTION_WINDOW as i32);
 
                                             if handle.get_netplay_recommended_delay() == 0 {
                                                 handle.set_netplay_input_delay(recommendation);
@@ -801,9 +802,9 @@ fn setup_wait_window(
                                     let players = handle.get_netplay_players();
                                     // Input delay is per-player: use our own choice, falling back
                                     // to the host's if our recommendation hasn't been calculated yet.
-                                    let local_input_delay = handle.get_netplay_input_delay();
-                                    let input_delay = if local_input_delay > 0 {
-                                        local_input_delay as usize
+                                    let input_delay = if handle.get_netplay_recommended_delay() > 0
+                                    {
+                                        handle.get_netplay_input_delay() as usize
                                     } else {
                                         response
                                             .sessions
@@ -1027,6 +1028,8 @@ pub fn netplay_window(
     app: &AppWindow,
     no_intro_map: std::sync::Arc<tokio::sync::Mutex<rustc_hash::FxHashMap<String, String>>>,
 ) {
+    app.set_netplay_max_input_delay(netplay::MAX_PREDICTION_WINDOW as i32);
+
     let (netplay_read_sender, netplay_read_receiver): (
         tokio::sync::broadcast::Sender<Option<NetplayLobbyMessage>>,
         tokio::sync::broadcast::Receiver<Option<NetplayLobbyMessage>>,